Merge branch '1.10.2' into 1.11

325d041 Merge branch '1.9.4' into 1.10.2
d9d57e2 Merge branch '1.8.9' into 1.9.4
24c58cb Merge branch '1.8' into 1.8.9
1ffeb01 Update jGui
c122d30 Merge branch '1.8-path-segments' into 1.8
27fd25a Fix crash when server responds with garbage to language query (fixes #51)
db6b0ff Fix / by 0 when two spectator keyframes are closer than 50ms (fixes #60)
d61d0ac Fix hand of invisible spectated player being visible (fixes #59)
f7460f9 Re-enable time path after path playback (fixes #55)
bdbffd5 Add Catmull-Rom spline interpolator to simplepathing
5cbfd28 Generate interpolator settings from InterpolatorType enum
6095aef Fix loading and storing of default interpolator with settings
3f52336 Revert "Fix AbstractMethodError caused by FG2.0 not supporting lambdas (fixes #58)"
c6293bc Update to FG2.2
c8126ed Merge '1.8' into 1.8.9
64898ce Fix NPE when saving recorded resource pack
70e3e54 Fix AbstractMethodError caused by FG2.0 not supporting lambdas (fixes #58)
3f2b3d6 Fix replacing source file in Replay Editor (fixes #57)
d2def94 Fix duration of replays corrupted because of JVM/OS crash
2c64030 Refactor simple pathing timeline logic into dedicated class with unit tests Fix logic for user-set interpolators
4deb374 Enable validation on focus change for all number input fields
5302bca Fix id and text of Replay Editor button in docs
057edcc Manually inject root cert for cross-signed LetsEncrypt cert in requests
cd16211 Register new Property to imply that the path segment following a keyframe has a user-set interpolator instead of the default Modified Keyframe GUI to allow for custom Path interpolator

build.gradle

@@ -36,9 +36,9 @@ archivesBaseName = "replaymod"
 
 minecraft {
     coreMod = 'com.replaymod.core.LoadingPlugin'
-    version = '1.9.4-12.17.0.1976'
+    version = '1.11-13.19.1.2188'
     runDir = "eclipse"
-    mappings = "snapshot_20160518"
+    mappings = "snapshot_20161111"
     replace '@MOD_VERSION@', project.version
     replace '@MC_VERSION@', project.minecraft.version
 }

docs/content.md

@@ -56,7 +56,7 @@ Please use [Optifine](https://optifine.net/) instead.
 
 ### Custom Main Menu [custom-main-menu]
 The [Custom Main Menu](https://mods.curse.com/mc-mods/minecraft/226406-custom-main-menu) mod is often used in mod packs to customize their Main Menu with a button layout fitting the background image, links to their website / bug tracker and similar.
-If you are familiar with it, the button ids for the Replay Mod are: **17890234** (text: `replaymod.gui.replayviewer`), **17890235** (text: `replaymod.gui.replayviewer`) and **17890236** (text: `replaymod.gui.replaycenter`)
+If you are familiar with it, the button ids for the Replay Mod are: **17890234** (text: `replaymod.gui.replayviewer`), **17890237** (text: `replaymod.gui.replayeditor`) and **17890236** (text: `replaymod.gui.replaycenter`)
 
 Due to the nature of this Custom Main Menu mod, buttons added to the Main Menu by 3rd party mods like the **Replay Mod** will not show up by default.  
 Thus, to access the Replay Viewer/Editor/Center, you need to manually configure the position for those buttons.  

src/main/java/com/replaymod/core/gui/RestoreReplayGui.java

@@ -3,6 +3,7 @@ package com.replaymod.core.gui;
 import com.google.common.io.Files;
 import com.replaymod.replaystudio.PacketData;
 import com.replaymod.replaystudio.io.ReplayInputStream;
+import com.replaymod.replaystudio.io.ReplayOutputStream;
 import com.replaymod.replaystudio.replay.ReplayFile;
 import com.replaymod.replaystudio.replay.ReplayMetaData;
 import com.replaymod.replaystudio.replay.ZipReplayFile;
@@ -45,15 +46,19 @@ public class RestoreReplayGui extends AbstractGuiScreen<RestoreReplayGui> {
                 ReplayMetaData metaData = replayFile.getMetaData();
                 if (metaData != null && metaData.getDuration() == 0) {
                     // Try to restore replay duration
-                    try (ReplayInputStream in = replayFile.getPacketData()) {
+                    // We need to re-write the packet data in case there are any incomplete packets dangling at the end
+                    try (ReplayInputStream in = replayFile.getPacketData();
+                         ReplayOutputStream out = replayFile.writePacketData()) {
                         PacketData last = null;
                         while ((last = in.readPacket()) != null) {
                             metaData.setDuration((int) last.getTime());
+                            out.write(last);
                         }
-                        replayFile.writeMetaData(metaData);
                     } catch (Throwable t) {
                         t.printStackTrace();
                     }
+                    // Write back the actual duration
+                    replayFile.writeMetaData(metaData);
                 }
                 replayFile.save();
                 replayFile.close();

src/main/java/com/replaymod/core/utils/Utils.java

@@ -27,8 +27,20 @@ import org.lwjgl.util.ReadableDimension;
 
 import javax.annotation.Nullable;
 import javax.imageio.ImageIO;
+import javax.net.ssl.SSLContext;
+import javax.net.ssl.SSLSocketFactory;
+import javax.net.ssl.TrustManagerFactory;
 import java.awt.image.BufferedImage;
 import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.KeyManagementException;
+import java.security.KeyStore;
+import java.security.KeyStoreException;
+import java.security.NoSuchAlgorithmException;
+import java.security.cert.Certificate;
+import java.security.cert.CertificateException;
+import java.security.cert.CertificateFactory;
 import java.text.SimpleDateFormat;
 import java.util.Arrays;
 import java.util.Date;
@@ -51,6 +63,42 @@ public class Utils {
         DEFAULT_THUMBNAIL = thumbnail;
     }
 
+
+    /**
+     * Neither the root certificate of LetsEncrypt nor the root that cross-signed it is included in the default
+     * Java keystore prior to 8u101.
+     * Therefore whenever a connection to the replaymod.com site is made, this SSLContext has to be used instead.
+     * It has been constructed to include the necessary root certificates.
+     * @see #SSL_SOCKET_FACTORY
+     */
+    public static final SSLContext SSL_CONTEXT;
+
+    /**
+     * @see #SSL_CONTEXT
+     */
+    public static final SSLSocketFactory SSL_SOCKET_FACTORY;
+
+    static {
+        // Largely from https://community.letsencrypt.org/t/134/37
+        try (InputStream in = Utils.class.getResourceAsStream("/dst_root_ca_x3.pem")){
+            Certificate certificate = CertificateFactory.getInstance("X.509").generateCertificate(in);
+
+            KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
+            keyStore.load(null, null);
+            keyStore.setCertificateEntry("1", certificate);
+
+            TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
+            trustManagerFactory.init(keyStore);
+
+            SSLContext ctx = SSLContext.getInstance("TLS");
+            ctx.init(null, trustManagerFactory.getTrustManagers(), null);
+            SSL_CONTEXT = ctx;
+            SSL_SOCKET_FACTORY = ctx.getSocketFactory();
+        } catch (IOException | CertificateException | KeyStoreException | NoSuchAlgorithmException | KeyManagementException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     public static String convertSecondsToShortString(int seconds) {
         int hours = seconds/(60*60);
         int min = seconds/60 - hours*60;

src/main/java/com/replaymod/editor/gui/GuiReplayEditor.java

@@ -1,5 +1,6 @@
 package com.replaymod.editor.gui;
 
+import com.google.common.io.Files;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.gson.JsonObject;
@@ -34,6 +35,7 @@ import de.johni0702.minecraft.gui.popup.GuiInfoPopup;
 import de.johni0702.minecraft.gui.popup.GuiYesNoPopup;
 import de.johni0702.minecraft.gui.utils.Colors;
 import net.minecraft.crash.CrashReport;
+import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.FilenameUtils;
 import org.lwjgl.util.ReadableDimension;
 
@@ -119,10 +121,21 @@ public class GuiReplayEditor extends GuiScreen {
     public void save(File inputFile, PacketStream.FilterInfo...filters) {
         save(FilenameUtils.getBaseName(inputFile.getName()), (outputFile) -> {
             Studio studio = new ReplayStudio();
-            try (ReplayFile outputReplay = new ZipReplayFile(studio, inputFile, outputFile);
-                 ReplayOutputStream out = outputReplay.writePacketData()) {
-                // The input replay file MUST be closed before saving the output file
-                try (ReplayFile inputReplay = new ZipReplayFile(studio, inputFile);
+            File tmpDir = null;
+            try {
+                File actualOutputFile  = outputFile;
+                if (outputFile.getCanonicalPath().equals(inputFile.getCanonicalPath())) {
+                    // Input and output files are identical. Due to the way the ZipReplayFile stores its temporary
+                    // data, the same replay file must not be opened twice for writing (tmp files will be deleted once
+                    // either one is closed or, on Windows, will throw an exception when deleted).
+                    tmpDir = Files.createTempDir();
+                    outputFile = new File(tmpDir, "replay.mcpr");
+                    LOGGER.debug("Output file is identical to input file, using temporary output file {} instead",
+                            outputFile);
+                }
+                try (ReplayFile outputReplay = new ZipReplayFile(studio, inputFile, outputFile);
+                     ReplayOutputStream out = outputReplay.writePacketData();
+                     ReplayFile inputReplay = new ZipReplayFile(studio, inputFile);
                      ReplayInputStream in = inputReplay.getPacketData()) {
                     ReplayMetaData metaData = inputReplay.getMetaData();
                     PacketStream stream = studio.createReplayStream(in, true);
@@ -154,11 +167,21 @@ public class GuiReplayEditor extends GuiScreen {
                     // Update duration of new replay
                     metaData.setDuration((int) lastTimestamp);
                     outputReplay.writeMetaData(metaData);
+
+                    out.close();
+                    outputReplay.save();
+                }
+                if (outputFile != actualOutputFile) {
+                    LOGGER.debug("Moving temporary output file {} to {}");
+                    FileUtils.forceDelete(actualOutputFile);
+                    FileUtils.moveFile(outputFile, actualOutputFile);
                 }
-                out.close();
-                outputReplay.save();
             } catch (IOException e) {
                 throw new RuntimeException(e);
+            } finally {
+                if (tmpDir != null && !FileUtils.deleteQuietly(tmpDir)) {
+                    LOGGER.warn("Failed to delete temporary directory {}", tmpDir);
+                }
             }
         });
     }

src/main/java/com/replaymod/editor/gui/GuiTrimPanel.java

@@ -39,6 +39,10 @@ import static com.replaymod.editor.ReplayModEditor.LOGGER;
 import static java.util.Optional.ofNullable;
 
 public class GuiTrimPanel extends GuiPanel {
+    private static GuiNumberField newGuiNumberField() {
+        return new GuiNumberField().setMaxLength(2).setSize(20, 20).setValidateOnFocusChange(true);
+    }
+
     // Special value indicating no replay files were found
     private static final File NO_REPLAY = new File(".");
     // Special value for the initial "Select Marker Keyframe" entry
@@ -50,16 +54,16 @@ public class GuiTrimPanel extends GuiPanel {
             .setMinSize(new Dimension(200, 20)).onSelection(i -> updateSelectedReplay())
             .setToString(f -> f == NO_REPLAY ? "" : FilenameUtils.getBaseName(f.getName()));
 
-    public final GuiNumberField startHour = new GuiNumberField().setSize(20, 20).setMaxLength(2);
-    public final GuiNumberField startMin = new GuiNumberField().setSize(20, 20).setMaxLength(2);
-    public final GuiNumberField startSec = new GuiNumberField().setSize(20, 20).setMaxLength(2);
-    public final GuiNumberField startMilli = new GuiNumberField().setSize(40, 20).setMaxLength(4);
+    public final GuiNumberField startHour = newGuiNumberField();
+    public final GuiNumberField startMin = newGuiNumberField();
+    public final GuiNumberField startSec = newGuiNumberField();
+    public final GuiNumberField startMilli = newGuiNumberField().setSize(40, 20).setMaxLength(4);
     public final GuiDropdownMenu<Marker> startMarker = new GuiDropdownMenu<>();
 
-    public final GuiNumberField endHour = new GuiNumberField().setSize(20, 20).setMaxLength(2);
-    public final GuiNumberField endMin = new GuiNumberField().setSize(20, 20).setMaxLength(2);
-    public final GuiNumberField endSec = new GuiNumberField().setSize(20, 20).setMaxLength(2);
-    public final GuiNumberField endMilli = new GuiNumberField().setSize(40, 20).setMaxLength(4);
+    public final GuiNumberField endHour = newGuiNumberField();
+    public final GuiNumberField endMin = newGuiNumberField();
+    public final GuiNumberField endSec = newGuiNumberField();
+    public final GuiNumberField endMilli = newGuiNumberField().setSize(40, 20).setMaxLength(4);
     public final GuiDropdownMenu<Marker> endMarker = new GuiDropdownMenu<>();
 
     public final GuiPanel timePanel = new GuiPanel(this)

src/main/java/com/replaymod/extras/LocalizationExtra.java

@@ -82,7 +82,7 @@ public class LocalizationExtra implements Extra {
                 availableLanguages.put(langcode, prop);
                 return true;
             } catch (ApiException e) {
-                if (e.getError().getId() != 16) { // This language has not been translated
+                if (e.getError() == null || e.getError().getId() != 16) { // This language has not been translated
                     e.printStackTrace();
                 }
             } catch(ConnectException ce) {

src/main/java/com/replaymod/extras/OpenEyeExtra.java

@@ -17,6 +17,7 @@ import de.johni0702.minecraft.gui.utils.Colors;
 import net.minecraftforge.fml.common.Loader;
 import org.apache.commons.io.FileUtils;
 
+import javax.net.ssl.HttpsURLConnection;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.net.URL;
@@ -24,8 +25,10 @@ import java.nio.channels.Channels;
 import java.nio.channels.FileChannel;
 import java.nio.channels.ReadableByteChannel;
 
+import static com.replaymod.core.utils.Utils.SSL_SOCKET_FACTORY;
+
 public class OpenEyeExtra implements Extra {
-    private static final String DOWNLOAD_URL = "http://www.replaymod.com/dl/openeye/" + Loader.MC_VERSION;
+    private static final String DOWNLOAD_URL = "https://www.replaymod.com/dl/openeye/" + Loader.MC_VERSION;
     private static final Setting<Boolean> ASK_FOR_OPEN_EYE = new Setting<>("advanced", "askForOpenEye", null, true);
 
     private ReplayMod mod;
@@ -69,7 +72,9 @@ public class OpenEyeExtra implements Extra {
                         File targetFile = new File("mods/" + Loader.MC_VERSION, "OpenEye.jar");
                         FileUtils.forceMkdir(targetFile.getParentFile());
 
-                        ReadableByteChannel in = Channels.newChannel(new URL(DOWNLOAD_URL).openStream());
+                        HttpsURLConnection connection = (HttpsURLConnection) new URL(DOWNLOAD_URL).openConnection();
+                        connection.setSSLSocketFactory(SSL_SOCKET_FACTORY);
+                        ReadableByteChannel in = Channels.newChannel(connection.getInputStream());
                         FileChannel out = new FileOutputStream(targetFile).getChannel();
                         out.transferFrom(in, 0, Long.MAX_VALUE);
                     } catch (Throwable e) {

src/main/java/com/replaymod/extras/playeroverview/PlayerOverview.java

@@ -11,7 +11,9 @@ import com.replaymod.replay.events.ReplayCloseEvent;
 import com.replaymod.replay.events.ReplayOpenEvent;
 import net.minecraft.client.renderer.entity.RenderManager;
 import net.minecraft.client.renderer.entity.RenderPlayer;
+import net.minecraft.entity.Entity;
 import net.minecraft.entity.player.EntityPlayer;
+import net.minecraftforge.client.event.RenderHandEvent;
 import net.minecraftforge.common.MinecraftForge;
 import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
 import org.lwjgl.input.Keyboard;
@@ -92,6 +94,14 @@ public class PlayerOverview implements Extra {
         hiddenPlayers.clear();
     }
 
+    @SubscribeEvent
+    public void oRenderHand(RenderHandEvent event) {
+        Entity view = module.getCore().getMinecraft().getRenderViewEntity();
+        if (view != null && isHidden(view.getUniqueID())) {
+            event.setCanceled(true);
+        }
+    }
+
     public boolean isSavingEnabled() {
         return savingEnabled;
     }

src/main/java/com/replaymod/online/api/ApiClient.java

@@ -15,13 +15,19 @@ import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
 
 import javax.imageio.ImageIO;
+import javax.net.ssl.HttpsURLConnection;
 import java.awt.image.BufferedImage;
-import java.io.*;
-import java.net.HttpURLConnection;
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
 import java.net.URL;
 import java.util.List;
 import java.util.function.Consumer;
 
+import static com.replaymod.core.utils.Utils.SSL_SOCKET_FACTORY;
+
 public class ApiClient {
 
     private static final Minecraft mc = Minecraft.getMinecraft();
@@ -130,7 +136,11 @@ public class ApiClient {
         QueryBuilder builder = new QueryBuilder(ReplayModApiMethods.get_thumbnail);
         builder.put("id", file);
         URL url = new URL(builder.toString());
-        return ImageIO.read(url);
+        HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
+        connection.setSSLSocketFactory(SSL_SOCKET_FACTORY);
+        try (InputStream in = connection.getInputStream()) {
+            return ImageIO.read(in);
+        }
     }
 
     private boolean cancelDownload = false;
@@ -143,7 +153,8 @@ public class ApiClient {
         builder.put("id", file);
         String url = builder.toString();
         URL website = new URL(url);
-        HttpURLConnection con = (HttpURLConnection) website.openConnection();
+        HttpsURLConnection con = (HttpsURLConnection) website.openConnection();
+        con.setSSLSocketFactory(SSL_SOCKET_FACTORY);
 
         int fileSize = con.getContentLength();
 

src/main/java/com/replaymod/online/api/SimpleApiClient.java

@@ -7,12 +7,14 @@ import com.google.gson.JsonParser;
 import com.replaymod.online.api.replay.holders.ApiError;
 import org.apache.commons.io.IOUtils;
 
+import javax.net.ssl.HttpsURLConnection;
 import java.io.IOException;
 import java.io.InputStream;
-import java.net.HttpURLConnection;
 import java.net.URL;
 import java.util.Map;
 
+import static com.replaymod.core.utils.Utils.SSL_SOCKET_FACTORY;
+
 public class SimpleApiClient {
 
     private static final JsonParser jsonParser = new JsonParser();
@@ -72,10 +74,11 @@ public class SimpleApiClient {
         // read response
         String responseContent = null;
         InputStream is = null;
-        HttpURLConnection httpUrlConnection = null;
+        HttpsURLConnection httpUrlConnection = null;
         try {
             URL url = new URL(urlString);
-            httpUrlConnection = (HttpURLConnection) url.openConnection();
+            httpUrlConnection = (HttpsURLConnection) url.openConnection();
+            httpUrlConnection.setSSLSocketFactory(SSL_SOCKET_FACTORY);
 
             httpUrlConnection.setRequestMethod("GET");
 

src/main/java/com/replaymod/online/api/replay/FileUploader.java

@@ -9,16 +9,18 @@ import lombok.RequiredArgsConstructor;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.StringUtils;
 
+import javax.net.ssl.HttpsURLConnection;
 import java.io.DataOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.InputStream;
-import java.net.HttpURLConnection;
 import java.net.URL;
 import java.net.URLEncoder;
 import java.util.Set;
 import java.util.function.Consumer;
 
+import static com.replaymod.core.utils.Utils.SSL_SOCKET_FACTORY;
+
 @RequiredArgsConstructor
 public class FileUploader {
     private static final Gson gson = new Gson();
@@ -48,7 +50,8 @@ public class FileUploader {
             postData += "&name=" + URLEncoder.encode(filename, "UTF-8");
 
             String url = ReplayModApiMethods.upload_file + postData;
-            HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection();
+            HttpsURLConnection con = (HttpsURLConnection) new URL(url).openConnection();
+            con.setSSLSocketFactory(SSL_SOCKET_FACTORY);
             con.setUseCaches(false);
             con.setDoOutput(true);
             con.setRequestMethod("POST");

src/main/java/com/replaymod/online/api/replay/ReplayModApiMethods.java

@@ -2,7 +2,7 @@ package com.replaymod.online.api.replay;
 
 public class ReplayModApiMethods {
 
-    public static final String REPLAYMOD_BASE_URL = "http://ReplayMod.com/api/";
+    public static final String REPLAYMOD_BASE_URL = "https://ReplayMod.com/api/";
 
     public static final String register = REPLAYMOD_BASE_URL+"register";
     public static final String check_authkey = REPLAYMOD_BASE_URL+"check_authkey";

src/main/java/com/replaymod/online/api/replay/holders/MinecraftVersion.java

@@ -3,7 +3,9 @@ package com.replaymod.online.api.replay.holders;
 public enum MinecraftVersion {
 
     MC_1_8("Minecraft 1.8", "1.8"),
-    MC_1_9_4("Minecraft 1.9.4", "1.9.4");
+    MC_1_9_4("Minecraft 1.9.4", "1.9.4"),
+    MC_1_10_2("Minecraft 1.10.2", "1.10.2"),
+    MC_1_11("Minecraft 1.11", "1.11");
 
     private String niceName, apiName;
 

src/main/java/com/replaymod/recording/handler/ConnectionEventHandler.java

@@ -66,6 +66,9 @@ public class ConnectionEventHandler {
                 worldName = mc.getIntegratedServer().getWorldName();
             } else if (Minecraft.getMinecraft().getCurrentServerData() != null) {
                 worldName = Minecraft.getMinecraft().getCurrentServerData().serverIP;
+            } else if (Minecraft.getMinecraft().isConnectedToRealms()) {
+                // we can't access the server name without tapping too deep in the Realms Library
+                worldName = "A Realms Server";
             } else {
                 logger.info("Recording not started as the world is neither local nor remote (probably a replay).");
                 return;

src/main/java/com/replaymod/recording/handler/RecordingEventHandler.java

@@ -178,23 +178,23 @@ public class RecordingEventHandler {
                 packetListener.save(new SPacketEntityEquipment(e.player.getEntityId(), EntityEquipmentSlot.OFFHAND, playerItems[1]));
             }
 
-            if (playerItems[2] != mc.thePlayer.inventory.armorInventory[0]) {
-                playerItems[2] = mc.thePlayer.inventory.armorInventory[0];
+            if (playerItems[2] != mc.thePlayer.getItemStackFromSlot(EntityEquipmentSlot.FEET)) {
+                playerItems[2] = mc.thePlayer.getItemStackFromSlot(EntityEquipmentSlot.FEET);
                 packetListener.save(new SPacketEntityEquipment(e.player.getEntityId(), EntityEquipmentSlot.FEET, playerItems[2]));
             }
 
-            if (playerItems[3] != mc.thePlayer.inventory.armorInventory[1]) {
-                playerItems[3] = mc.thePlayer.inventory.armorInventory[1];
+            if (playerItems[3] != mc.thePlayer.getItemStackFromSlot(EntityEquipmentSlot.LEGS)) {
+                playerItems[3] = mc.thePlayer.getItemStackFromSlot(EntityEquipmentSlot.LEGS);
                 packetListener.save(new SPacketEntityEquipment(e.player.getEntityId(), EntityEquipmentSlot.LEGS, playerItems[3]));
             }
 
-            if (playerItems[4] != mc.thePlayer.inventory.armorInventory[2]) {
-                playerItems[4] = mc.thePlayer.inventory.armorInventory[2];
+            if (playerItems[4] != mc.thePlayer.getItemStackFromSlot(EntityEquipmentSlot.CHEST)) {
+                playerItems[4] = mc.thePlayer.getItemStackFromSlot(EntityEquipmentSlot.CHEST);
                 packetListener.save(new SPacketEntityEquipment(e.player.getEntityId(), EntityEquipmentSlot.CHEST, playerItems[4]));
             }
 
-            if (playerItems[5] != mc.thePlayer.inventory.armorInventory[3]) {
-                playerItems[5] = mc.thePlayer.inventory.armorInventory[3];
+            if (playerItems[5] != mc.thePlayer.getItemStackFromSlot(EntityEquipmentSlot.HEAD)) {
+                playerItems[5] = mc.thePlayer.getItemStackFromSlot(EntityEquipmentSlot.HEAD);
                 packetListener.save(new SPacketEntityEquipment(e.player.getEntityId(), EntityEquipmentSlot.HEAD, playerItems[5]));
             }
 
@@ -234,7 +234,8 @@ public class RecordingEventHandler {
     @SubscribeEvent
     public void onPickupItem(ItemPickupEvent event) {
         try {
-            packetListener.save(new SPacketCollectItem(event.pickedUp.getEntityId(), event.player.getEntityId()));
+            packetListener.save(new SPacketCollectItem(event.pickedUp.getEntityId(), event.player.getEntityId(),
+                    event.pickedUp.getEntityItem().getMaxStackSize()));
         } catch(Exception e) {
             e.printStackTrace();
         }

src/main/java/com/replaymod/recording/packet/ResourcePackRecorder.java

@@ -26,6 +26,7 @@ import javax.annotation.Nonnull;
 import java.io.File;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.util.HashMap;
 import java.util.Map;
 
 /**
@@ -52,6 +53,9 @@ public class ResourcePackRecorder {
             boolean doWrite = false; // Whether we are the first and have to write it
             synchronized (replayFile) { // Need to read, modify and write the resource pack index atomically
                 Map<Integer, String> index = replayFile.getResourcePackIndex();
+                if (index == null) {
+                    index = new HashMap<>();
+                }
                 if (!index.containsValue(hash)) {
                     // Hash is unknown, we have to write the resource pack ourselves
                     doWrite = true;
@@ -83,39 +87,39 @@ public class ResourcePackRecorder {
             final File levelDir = new File(savesDir, levelName);
 
             if (levelDir.isFile()) {
-                netManager.sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.ACCEPTED));
+                netManager.sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.ACCEPTED));
                 Futures.addCallback(mc.getResourcePackRepository().setResourcePackInstance(levelDir), new FutureCallback<Object>() {
                     @Override
                     public void onSuccess(Object result) {
                         recordResourcePack(levelDir, requestId);
-                        netManager.sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.SUCCESSFULLY_LOADED));
+                        netManager.sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.SUCCESSFULLY_LOADED));
                     }
 
                     @Override
                     public void onFailure(@Nonnull Throwable throwable) {
-                        netManager.sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.FAILED_DOWNLOAD));
+                        netManager.sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.FAILED_DOWNLOAD));
                     }
                 });
             } else {
-                netManager.sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.FAILED_DOWNLOAD));
+                netManager.sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.FAILED_DOWNLOAD));
             }
         } else {
             final ServerData serverData = mc.getCurrentServerData();
             if (serverData != null && serverData.getResourceMode() == ServerData.ServerResourceMode.ENABLED) {
-                netManager.sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.ACCEPTED));
+                netManager.sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.ACCEPTED));
                 downloadResourcePackFuture(requestId, url, hash);
             } else if (serverData != null && serverData.getResourceMode() != ServerData.ServerResourceMode.PROMPT) {
-                netManager.sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.DECLINED));
+                netManager.sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.DECLINED));
             } else {
                 mc.addScheduledTask(() -> mc.displayGuiScreen(new GuiYesNo((result, id) -> {
                     if (serverData != null) {
                         serverData.setResourceMode(result ? ServerData.ServerResourceMode.ENABLED : ServerData.ServerResourceMode.DISABLED);
                     }
                     if (result) {
-                        netManager.sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.ACCEPTED));
+                        netManager.sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.ACCEPTED));
                         downloadResourcePackFuture(requestId, url, hash);
                     } else {
-                        netManager.sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.DECLINED));
+                        netManager.sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.DECLINED));
                     }
 
                     ServerList.saveSingleServer(serverData);
@@ -131,12 +135,12 @@ public class ResourcePackRecorder {
         Futures.addCallback(downloadResourcePack(requestId, url, hash), new FutureCallback() {
             @Override
             public void onSuccess(Object result) {
-                mc.getConnection().sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.SUCCESSFULLY_LOADED));
+                mc.getConnection().sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.SUCCESSFULLY_LOADED));
             }
 
             @Override
             public void onFailure(@Nonnull Throwable throwable) {
-                mc.getConnection().sendPacket(new CPacketResourcePackStatus(hash, CPacketResourcePackStatus.Action.FAILED_DOWNLOAD));
+                mc.getConnection().sendPacket(new CPacketResourcePackStatus(CPacketResourcePackStatus.Action.FAILED_DOWNLOAD));
             }
         });
     }
@@ -186,7 +190,7 @@ public class ResourcePackRecorder {
 
             Futures.getUnchecked(mc.addScheduledTask(() -> mc.displayGuiScreen(guiScreen)));
 
-            Map<String, String> sessionInfo = Minecraft.getSessionInfo();
+            Map<String, String> sessionInfo = ResourcePackRepository.getDownloadHeaders();
             repo.downloadingPacks = HttpUtil.downloadResourcePack(file, url, sessionInfo, 50 * 1024 * 1024, guiScreen, mc.getProxy());
             Futures.addCallback(repo.downloadingPacks, new FutureCallback<Object>() {
                 @Override

src/main/java/com/replaymod/render/gui/GuiRenderSettings.java

@@ -80,8 +80,8 @@ public class GuiRenderSettings extends GuiScreen implements Closeable {
                 }
             }).setMinSize(new Dimension(0, 20)).setValues(RenderSettings.EncodingPreset.values());
 
-    public final GuiNumberField videoWidth = new GuiNumberField().setSize(50, 20).setMinValue(1);
-    public final GuiNumberField videoHeight = new GuiNumberField().setSize(50, 20).setMinValue(1);
+    public final GuiNumberField videoWidth = new GuiNumberField().setSize(50, 20).setMinValue(1).setValidateOnFocusChange(true);
+    public final GuiNumberField videoHeight = new GuiNumberField().setSize(50, 20).setMinValue(1).setValidateOnFocusChange(true);
     public final GuiSlider frameRateSlider = new GuiSlider().onValueChanged(new Runnable() {
         @Override
         public void run() {
@@ -93,7 +93,7 @@ public class GuiRenderSettings extends GuiScreen implements Closeable {
             .setLayout(new HorizontalLayout(HorizontalLayout.Alignment.RIGHT).setSpacing(2))
             .addElements(new HorizontalLayout.Data(0.5), videoWidth, new GuiLabel().setText("*"), videoHeight);
 
-    public final GuiNumberField bitRateField = new GuiNumberField().setValue(10).setSize(50, 20);
+    public final GuiNumberField bitRateField = new GuiNumberField().setValue(10).setSize(50, 20).setValidateOnFocusChange(true);
     public final GuiDropdownMenu<String> bitRateUnit = new GuiDropdownMenu<String>()
             .setSize(50, 20).setValues("bps", "kbps", "mbps").setSelected("mbps");
 

src/main/java/com/replaymod/replay/InputReplayTimer.java

@@ -147,7 +147,7 @@ public class InputReplayTimer extends WrappedTimer {
                 // TODO: Translate magic values to Keyboard.KEY_ constants
 
                 if (key == 32 && Keyboard.isKeyDown(61) && mc.ingameGUI != null) {
-                    mc.ingameGUI.getChatGUI().clearChatMessages();
+                    mc.ingameGUI.getChatGUI().clearChatMessages(false);
                 }
 
                 if (key == 31 && Keyboard.isKeyDown(61)) {

src/main/java/com/replaymod/replay/ReplayHandler.java

@@ -128,7 +128,7 @@ public class ReplayHandler {
     }
 
     private void setup() {
-        mc.ingameGUI.getChatGUI().clearChatMessages();
+        mc.ingameGUI.getChatGUI().clearChatMessages(true);
 
         NetworkManager networkManager = new NetworkManager(EnumPacketDirection.CLIENTBOUND) {
             @Override

src/main/java/com/replaymod/replay/ReplaySender.java

@@ -22,8 +22,8 @@ import net.minecraft.network.*;
 import net.minecraft.network.play.server.*;
 import net.minecraft.util.text.ITextComponent;
 import net.minecraft.world.EnumDifficulty;
+import net.minecraft.world.GameType;
 import net.minecraft.world.World;
-import net.minecraft.world.WorldSettings.GameType;
 import net.minecraft.world.WorldType;
 import net.minecraftforge.common.MinecraftForge;
 import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;

src/main/java/com/replaymod/replay/camera/CameraEntity.java

@@ -252,6 +252,15 @@ public class CameraEntity extends EntityPlayerSP {
         return false;
     }
 
+    @Override
+    public boolean isInvisible() {
+        Entity view = mc.getRenderViewEntity();
+        if (view != this) {
+            return view.isInvisible();
+        }
+        return super.isInvisible();
+    }
+
     @Override
     public ResourceLocation getLocationSkin() {
         Entity view = mc.getRenderViewEntity();

src/main/java/com/replaymod/replay/gui/overlay/GuiEditMarkerPopup.java

@@ -16,6 +16,10 @@ import org.lwjgl.input.Keyboard;
 import org.lwjgl.util.ReadablePoint;
 
 public class GuiEditMarkerPopup extends AbstractGuiPopup<GuiEditMarkerPopup> implements Typeable {
+    private static GuiNumberField newGuiNumberField() {
+        return new GuiNumberField().setSize(150, 20).setValidateOnFocusChange(true);
+    }
+
     private final ReplayHandler replayHandler;
     private final Marker marker;
 
@@ -23,15 +27,15 @@ public class GuiEditMarkerPopup extends AbstractGuiPopup<GuiEditMarkerPopup> imp
 
     public final GuiTextField nameField = new GuiTextField().setSize(150, 20);
     // TODO: Replace with a min/sec/msec field
-    public final GuiNumberField timeField = new GuiNumberField().setSize(150, 20).setPrecision(0);
+    public final GuiNumberField timeField = newGuiNumberField().setPrecision(0);
 
-    public final GuiNumberField xField = new GuiNumberField().setSize(150, 20).setPrecision(10);
-    public final GuiNumberField yField = new GuiNumberField().setSize(150, 20).setPrecision(10);
-    public final GuiNumberField zField = new GuiNumberField().setSize(150, 20).setPrecision(10);
+    public final GuiNumberField xField = newGuiNumberField().setPrecision(10);
+    public final GuiNumberField yField = newGuiNumberField().setPrecision(10);
+    public final GuiNumberField zField = newGuiNumberField().setPrecision(10);
 
-    public final GuiNumberField yawField = new GuiNumberField().setSize(150, 20).setPrecision(5);
-    public final GuiNumberField pitchField = new GuiNumberField().setSize(150, 20).setPrecision(5);
-    public final GuiNumberField rollField = new GuiNumberField().setSize(150, 20).setPrecision(5);
+    public final GuiNumberField yawField = newGuiNumberField().setPrecision(5);
+    public final GuiNumberField pitchField = newGuiNumberField().setPrecision(5);
+    public final GuiNumberField rollField = newGuiNumberField().setPrecision(5);
 
     public final GuiPanel inputs = GuiPanel.builder()
             .layout(new GridLayout().setColumns(2).setSpacingX(7).setSpacingY(3))

src/main/java/com/replaymod/replay/mixin/MixinViewFrustum.java

@@ -31,7 +31,7 @@ public abstract class MixinViewFrustum {
     }
 
     /**
-     * Instead of calling {@link RenderChunk#setOrigin(int, int, int)} we recreate the render chunk
+     * Instead of calling {@link RenderChunk#setPosition(int, int, int)} we recreate the render chunk
      * which seems to solve the problem that chunks are invisible when you leave an area and return
      * to it.
      * Any better fixes are welcome.
@@ -59,7 +59,7 @@ public abstract class MixinViewFrustum {
                         // Recreate render chunk instead of setting its position
                         (renderChunks[(j1 * this.countChunksY + l1) * this.countChunksX + l] =
                                 renderChunkFactory.create(world, renderGlobal, 0)
-                        ).setOrigin(blockpos.getX(), blockpos.getY(), blockpos.getZ());
+                        ).setPosition(blockpos.getX(), blockpos.getY(), blockpos.getZ());
                     }
                 }
             }

src/main/java/com/replaymod/simplepathing/InterpolatorType.java

@@ -0,0 +1,54 @@
+package com.replaymod.simplepathing;
+
+import com.replaymod.replaystudio.pathing.interpolation.CatmullRomSplineInterpolator;
+import com.replaymod.replaystudio.pathing.interpolation.CubicSplineInterpolator;
+import com.replaymod.replaystudio.pathing.interpolation.Interpolator;
+import com.replaymod.replaystudio.pathing.interpolation.LinearInterpolator;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+import java.util.function.Supplier;
+
+@AllArgsConstructor
+public enum InterpolatorType {
+    DEFAULT("default", null, null),
+    CATMULL_ROM("catmullrom", CatmullRomSplineInterpolator.class, () -> new CatmullRomSplineInterpolator(0.5)),
+    CUBIC("cubic", CubicSplineInterpolator.class, CubicSplineInterpolator::new),
+    LINEAR("linear", LinearInterpolator.class, LinearInterpolator::new);
+
+    @Getter
+    private String localizationKey;
+
+    @Getter
+    private Class<? extends Interpolator> interpolatorClass;
+
+    private Supplier<Interpolator> interpolatorConstructor;
+
+    public String getI18nName() {
+        return String.format("replaymod.gui.editkeyframe.interpolator.%1$s.name", localizationKey);
+    }
+
+    public String getI18nDescription() {
+        return String.format("replaymod.gui.editkeyframe.interpolator.%1$s.desc", localizationKey);
+    }
+
+    public static InterpolatorType fromString(String string) {
+        for (InterpolatorType t : values()) {
+            if (t.getI18nName().equals(string)) return t;
+        }
+        return CATMULL_ROM; //the default
+    }
+
+    public static InterpolatorType fromClass(Class<? extends Interpolator> cls) {
+        for (InterpolatorType type : values()) {
+            if (cls.equals(type.getInterpolatorClass())) {
+                return type;
+            }
+        }
+        return DEFAULT;
+    }
+
+    public Interpolator newInstance() {
+        return interpolatorConstructor.get();
+    }
+}

src/main/java/com/replaymod/simplepathing/ReplayModSimplePathing.java

@@ -1,36 +1,25 @@
 package com.replaymod.simplepathing;
 
-import com.google.gson.stream.JsonReader;
-import com.google.gson.stream.JsonWriter;
 import com.replaymod.core.ReplayMod;
 import com.replaymod.core.events.SettingsChangedEvent;
-import com.replaymod.pathing.properties.CameraProperties;
-import com.replaymod.pathing.properties.SpectatorProperty;
-import com.replaymod.pathing.properties.TimestampProperty;
 import com.replaymod.replay.events.ReplayCloseEvent;
 import com.replaymod.replay.events.ReplayOpenEvent;
-import com.replaymod.replaystudio.pathing.PathingRegistry;
-import com.replaymod.replaystudio.pathing.impl.TimelineImpl;
-import com.replaymod.replaystudio.pathing.interpolation.CubicSplineInterpolator;
-import com.replaymod.replaystudio.pathing.interpolation.Interpolator;
-import com.replaymod.replaystudio.pathing.interpolation.LinearInterpolator;
 import com.replaymod.replaystudio.pathing.path.Keyframe;
-import com.replaymod.replaystudio.pathing.path.Timeline;
+import com.replaymod.simplepathing.SPTimeline.SPPath;
 import com.replaymod.simplepathing.gui.GuiPathing;
 import com.replaymod.simplepathing.preview.PathPreview;
+import lombok.Getter;
 import net.minecraftforge.common.MinecraftForge;
 import net.minecraftforge.fml.common.Mod;
 import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
 import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
 import org.apache.logging.log4j.Logger;
 
-import java.io.IOException;
-
 @Mod(modid = ReplayModSimplePathing.MOD_ID,
         version = "@MOD_VERSION@",
         acceptedMinecraftVersions = "@MC_VERSION@",
         useMetadata = true)
-public class ReplayModSimplePathing implements PathingRegistry {
+public class ReplayModSimplePathing {
     public static final String MOD_ID = "replaymod-simplepathing";
 
     private ReplayMod core;
@@ -54,84 +43,60 @@ public class ReplayModSimplePathing implements PathingRegistry {
 
     @SubscribeEvent
     public void postReplayOpen(ReplayOpenEvent.Post event) {
+        currentTimeline = new SPTimeline();
         guiPathing = new GuiPathing(core, this, event.getReplayHandler());
     }
 
     @SubscribeEvent
     public void onReplayClose(ReplayCloseEvent.Post event) {
+        currentTimeline = null;
         guiPathing = null;
-        currentTimeline = createTimeline();
-        currentTimeline.createPath();
-        currentTimeline.createPath();
-        selectedKeyframe = null;
+        selectedPath = null;
     }
 
     @SubscribeEvent
     public void onSettingsChanged(SettingsChangedEvent event) {
-        if (event.getKey() == Setting.LINEAR_INTERPOLATION) {
+        if (event.getKey() == Setting.DEFAULT_INTERPOLATION) {
             if (currentTimeline != null && guiPathing != null) {
-                currentTimeline.applyChange(guiPathing.updateInterpolators());
+                updateDefaultInterpolatorType();
             }
         }
     }
 
-    private Timeline currentTimeline = createTimeline(); { currentTimeline.createPath(); currentTimeline.createPath(); }
-    private Keyframe selectedKeyframe;
+    private SPTimeline currentTimeline;
 
-    public Keyframe getSelectedKeyframe() {
-        return selectedKeyframe;
+    @Getter
+    private SPPath selectedPath;
+    @Getter
+    private long selectedTime;
+
+    public boolean isSelected(Keyframe keyframe) {
+        return selectedPath != null && currentTimeline.getKeyframe(selectedPath, selectedTime) == keyframe;
     }
 
-    public void setSelectedKeyframe(Keyframe selected) {
-        this.selectedKeyframe = selected;
+    public void setSelected(SPPath path, long time) {
+        selectedPath = path;
+        selectedTime = time;
     }
 
-    public void setCurrentTimeline(Timeline currentTimeline) {
-        if (this.currentTimeline != currentTimeline) {
-            selectedKeyframe = null;
-        }
-        this.currentTimeline = currentTimeline;
+    public void setCurrentTimeline(SPTimeline newTimeline) {
+        selectedPath = null;
+        currentTimeline = newTimeline;
     }
 
-    public Timeline getCurrentTimeline() {
+    public void clearCurrentTimeline() {
+        setCurrentTimeline(new SPTimeline());
+        updateDefaultInterpolatorType();
+    }
+
+    public SPTimeline getCurrentTimeline() {
         return currentTimeline;
     }
 
-    @Override
-    public Timeline createTimeline() {
-        Timeline timeline = new TimelineImpl();
-
-        timeline.registerProperty(TimestampProperty.PROPERTY);
-        timeline.registerProperty(CameraProperties.POSITION);
-        timeline.registerProperty(CameraProperties.ROTATION);
-        timeline.registerProperty(SpectatorProperty.PROPERTY);
-
-        return timeline;
-    }
-
-    @Override
-    public void serializeInterpolator(JsonWriter writer, Interpolator interpolator) throws IOException {
-        if (interpolator instanceof LinearInterpolator) {
-            writer.value("linear");
-        } else if (interpolator instanceof CubicSplineInterpolator) {
-            writer.value("cubic-spline");
-        } else {
-            throw new IOException("Unknown interpolator type: " + interpolator);
-        }
-    }
-
-    @Override
-    public Interpolator deserializeInterpolator(JsonReader reader) throws IOException {
-        String type = reader.nextString();
-        switch (type) {
-            case "linear":
-                return new LinearInterpolator();
-            case "cubic-spline":
-                return new CubicSplineInterpolator();
-            default:
-                throw new IOException("Unknown interpolation type: " + type);
-
-        }
+    private void updateDefaultInterpolatorType() {
+        InterpolatorType newDefaultType =
+                InterpolatorType.fromString(core.getSettingsRegistry().get(Setting.DEFAULT_INTERPOLATION));
+        currentTimeline.setDefaultInterpolatorType(newDefaultType);
     }
 
     public ReplayMod getCore() {

src/main/java/com/replaymod/simplepathing/SPTimeline.java

@@ -0,0 +1,669 @@
+package com.replaymod.simplepathing;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Iterables;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import com.replaymod.pathing.properties.CameraProperties;
+import com.replaymod.pathing.properties.SpectatorProperty;
+import com.replaymod.pathing.properties.TimestampProperty;
+import com.replaymod.replaystudio.pathing.PathingRegistry;
+import com.replaymod.replaystudio.pathing.change.AddKeyframe;
+import com.replaymod.replaystudio.pathing.change.Change;
+import com.replaymod.replaystudio.pathing.change.CombinedChange;
+import com.replaymod.replaystudio.pathing.change.SetInterpolator;
+import com.replaymod.replaystudio.pathing.change.UpdateKeyframeProperties;
+import com.replaymod.replaystudio.pathing.impl.TimelineImpl;
+import com.replaymod.replaystudio.pathing.interpolation.CatmullRomSplineInterpolator;
+import com.replaymod.replaystudio.pathing.interpolation.CubicSplineInterpolator;
+import com.replaymod.replaystudio.pathing.interpolation.Interpolator;
+import com.replaymod.replaystudio.pathing.interpolation.LinearInterpolator;
+import com.replaymod.replaystudio.pathing.path.Keyframe;
+import com.replaymod.replaystudio.pathing.path.Path;
+import com.replaymod.replaystudio.pathing.path.PathSegment;
+import com.replaymod.replaystudio.pathing.path.Timeline;
+import com.replaymod.replaystudio.pathing.property.Property;
+import com.replaymod.replaystudio.util.EntityPositionTracker;
+import com.replaymod.replaystudio.util.Location;
+import com.replaymod.simplepathing.properties.ExplicitInterpolationProperty;
+import lombok.Getter;
+import net.minecraft.crash.CrashReport;
+import net.minecraft.crash.CrashReportCategory;
+import net.minecraft.util.ReportedException;
+import org.apache.commons.lang3.ObjectUtils;
+import org.apache.commons.lang3.Validate;
+import org.apache.commons.lang3.tuple.Triple;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringReader;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.IdentityHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+
+import static com.replaymod.replaystudio.pathing.change.RemoveKeyframe.create;
+import static com.replaymod.simplepathing.ReplayModSimplePathing.LOGGER;
+
+/**
+ * Simplified timeline abstraction used in the SimplePathing module.
+ */
+public class SPTimeline implements PathingRegistry {
+    public enum SPPath {
+        TIME,
+        POSITION,
+    }
+
+    @Getter
+    private final Timeline timeline;
+    @Getter
+    private final Path timePath;
+    @Getter
+    private final Path positionPath;
+
+    @Getter
+    private EntityPositionTracker entityTracker;
+    private InterpolatorType defaultInterpolatorType = InterpolatorType.fromString("invalid string returns default");
+
+    public SPTimeline() {
+        this(createInitialTimeline());
+    }
+
+    public SPTimeline(Timeline timeline) {
+        this.timeline = timeline;
+        this.timePath = timeline.getPaths().get(SPPath.TIME.ordinal());
+        this.positionPath = timeline.getPaths().get(SPPath.POSITION.ordinal());
+    }
+
+    public Path getPath(SPPath path) {
+        switch (path) {
+            case TIME:
+                return getTimePath();
+            case POSITION:
+                return getPositionPath();
+        }
+        throw new IllegalArgumentException("Unknown path " + path);
+    }
+
+    public Keyframe getKeyframe(SPPath path, long keyframe) {
+        return getPath(path).getKeyframe(keyframe);
+    }
+
+    public void setEntityTracker(EntityPositionTracker entityTracker) {
+        Preconditions.checkState(this.entityTracker == null, "Entity tracker already set");
+        this.entityTracker = entityTracker;
+    }
+
+    public void setDefaultInterpolatorType(InterpolatorType defaultInterpolatorType) {
+        Validate.isTrue(defaultInterpolatorType != InterpolatorType.DEFAULT, "Must not be DEFAULT");
+        this.defaultInterpolatorType = Validate.notNull(defaultInterpolatorType);
+
+        if (entityTracker != null) {
+            timeline.pushChange(updateInterpolators());
+        }
+    }
+
+    public Change setDefaultInterpolator(Interpolator interpolator) {
+        Preconditions.checkState(defaultInterpolatorType != null, "Default interpolator type not set.");
+        Validate.isInstanceOf(defaultInterpolatorType.getInterpolatorClass(), interpolator);
+
+        registerPositionInterpolatorProperties(interpolator);
+
+        Change change = CombinedChange.create(
+                positionPath.getSegments().stream()
+                        // Ignore explicitly set segments
+                        .filter(s -> !s.getStartKeyframe().getValue(ExplicitInterpolationProperty.PROPERTY).isPresent())
+                        // Ignore spectator segments
+                        .filter(s -> !isSpectatorSegment(s))
+                        // Update interpolator for every remaining segment
+                        // This will create a fragmented interpolator which is split by the updateInterpolators call
+                        .map(s -> SetInterpolator.create(s, interpolator)).toArray(Change[]::new)
+        );
+        change.apply(timeline);
+        return CombinedChange.createFromApplied(change, updateInterpolators());
+    }
+
+    public boolean isTimeKeyframe(long time) {
+        return timePath.getKeyframe(time) != null;
+    }
+
+    public boolean isPositionKeyframe(long time) {
+        return positionPath.getKeyframe(time) != null;
+    }
+
+    public boolean isSpectatorKeyframe(long time) {
+        Keyframe keyframe = positionPath.getKeyframe(time);
+        return keyframe != null && keyframe.getValue(SpectatorProperty.PROPERTY).isPresent();
+    }
+
+    public void addPositionKeyframe(long time, double posX, double posY, double posZ,
+                                    float yaw, float pitch, float roll, int spectated) {
+        LOGGER.debug("Adding position keyframe at {} pos {}/{}/{} rot {}/{}/{} entId {}",
+                time, posX, posY, posZ, yaw, pitch, roll, spectated);
+
+        Path path = positionPath;
+
+        Preconditions.checkState(positionPath.getKeyframe(time) == null, "Keyframe already exists");
+
+        Change change = AddKeyframe.create(path, time);
+        change.apply(timeline);
+        Keyframe keyframe = path.getKeyframe(time);
+
+        UpdateKeyframeProperties.Builder builder = UpdateKeyframeProperties.create(path, keyframe);
+        builder.setValue(CameraProperties.POSITION, Triple.of(posX, posY, posZ));
+        builder.setValue(CameraProperties.ROTATION, Triple.of(yaw, pitch, roll));
+        if (spectated != -1) {
+            builder.setValue(SpectatorProperty.PROPERTY, spectated);
+        }
+        UpdateKeyframeProperties updateChange = builder.done();
+        updateChange.apply(timeline);
+        change = CombinedChange.createFromApplied(change, updateChange);
+
+        // If this new keyframe formed the first segment of the path
+        if (path.getSegments().size() == 1) {
+            // then create an initial interpolator of default type
+            PathSegment segment = path.getSegments().iterator().next();
+            Interpolator interpolator = createDefaultInterpolator();
+            SetInterpolator setInterpolator = SetInterpolator.create(segment, interpolator);
+            setInterpolator.apply(timeline);
+            change = CombinedChange.createFromApplied(change, setInterpolator);
+        }
+
+        // Update interpolators for spectator keyframes
+        // while this is overkill, it is far simpler than updating differently for every possible case
+        change = CombinedChange.createFromApplied(change, updateInterpolators());
+
+        Change specPosUpdate = updateSpectatorPositions();
+        specPosUpdate.apply(timeline);
+        change = CombinedChange.createFromApplied(change, specPosUpdate);
+
+        timeline.pushChange(change);
+    }
+
+    public Change updatePositionKeyframe(long time, double posX, double posY, double posZ,
+                                    float yaw, float pitch, float roll) {
+        LOGGER.debug("Updating position keyframe at {} to pos {}/{}/{} rot {}/{}/{}",
+                time, posX, posY, posZ, yaw, pitch, roll);
+
+        Keyframe keyframe = positionPath.getKeyframe(time);
+
+        Preconditions.checkState(keyframe != null, "Keyframe does not exists");
+        Preconditions.checkState(!keyframe.getValue(SpectatorProperty.PROPERTY).isPresent(), "Cannot update spectator keyframe");
+
+        Change change = UpdateKeyframeProperties.create(positionPath, keyframe)
+                .setValue(CameraProperties.POSITION, Triple.of(posX, posY, posZ))
+                .setValue(CameraProperties.ROTATION, Triple.of(yaw, pitch, roll))
+                .done();
+        change.apply(timeline);
+        return change;
+    }
+
+    public void removePositionKeyframe(long time) {
+        LOGGER.debug("Removing position keyframe at {}", time);
+
+        Path path = positionPath;
+        Keyframe keyframe = path.getKeyframe(time);
+
+        Preconditions.checkState(keyframe != null, "No keyframe at that time");
+
+        Change change = create(path, keyframe);
+        change.apply(timeline);
+
+        // Update interpolators for spectator keyframes
+        // while this is overkill, it is far simpler than updating differently for every possible case
+        change = CombinedChange.createFromApplied(change, updateInterpolators());
+
+        Change specPosUpdate = updateSpectatorPositions();
+        specPosUpdate.apply(timeline);
+        change = CombinedChange.createFromApplied(change, specPosUpdate);
+
+        timeline.pushChange(change);
+    }
+
+    public void addTimeKeyframe(long time, int replayTime) {
+        LOGGER.debug("Adding time keyframe at {} time {}", time, replayTime);
+
+        Path path = timePath;
+
+        Preconditions.checkState(path.getKeyframe(time) == null, "Keyframe already exists");
+
+        Change change = AddKeyframe.create(path, time);
+        change.apply(timeline);
+        Keyframe keyframe = path.getKeyframe(time);
+
+        UpdateKeyframeProperties updateChange = UpdateKeyframeProperties.create(path, keyframe)
+                .setValue(TimestampProperty.PROPERTY, replayTime)
+                .done();
+        updateChange.apply(timeline);
+        change = CombinedChange.createFromApplied(change, updateChange);
+
+        // If this new keyframe formed the first segment of the path
+        if (path.getSegments().size() == 1) {
+            // then create an initial interpolator
+            PathSegment segment = path.getSegments().iterator().next();
+            Interpolator interpolator = new LinearInterpolator();
+            interpolator.registerProperty(TimestampProperty.PROPERTY);
+            SetInterpolator setInterpolator = SetInterpolator.create(segment, interpolator);
+            setInterpolator.apply(timeline);
+            change = CombinedChange.createFromApplied(change, setInterpolator);
+        }
+
+        Change specPosUpdate = updateSpectatorPositions();
+        specPosUpdate.apply(timeline);
+        change = CombinedChange.createFromApplied(change, specPosUpdate);
+
+        timeline.pushChange(change);
+    }
+
+    public Change updateTimeKeyframe(long time, int replayTime) {
+        LOGGER.debug("Updating time keyframe at {} to time {}", time, replayTime);
+
+        Keyframe keyframe = timePath.getKeyframe(time);
+
+        Preconditions.checkState(keyframe != null, "Keyframe does not exists");
+
+        Change change = UpdateKeyframeProperties.create(timePath, keyframe)
+                .setValue(TimestampProperty.PROPERTY, replayTime)
+                .done();
+        change.apply(timeline);
+        return change;
+    }
+
+    public void removeTimeKeyframe(long time) {
+        LOGGER.debug("Removing time keyframe at {}", time);
+
+        Path path = timePath;
+        Keyframe keyframe = path.getKeyframe(time);
+
+        Preconditions.checkState(keyframe != null, "No keyframe at that time");
+
+        Change change = create(path, keyframe);
+        change.apply(timeline);
+
+        Change specPosUpdate = updateSpectatorPositions();
+        specPosUpdate.apply(timeline);
+        change = CombinedChange.createFromApplied(change, specPosUpdate);
+
+        timeline.pushChange(change);
+    }
+
+    public Change setInterpolatorToDefault(long time) {
+        LOGGER.debug("Setting interpolator of position keyframe at {} to the default", time);
+
+        Keyframe keyframe = positionPath.getKeyframe(time);
+
+        Preconditions.checkState(keyframe != null, "Keyframe does not exists");
+
+        Change change = UpdateKeyframeProperties.create(positionPath, keyframe)
+                .removeProperty(ExplicitInterpolationProperty.PROPERTY)
+                .done();
+        change.apply(timeline);
+        return CombinedChange.createFromApplied(change, updateInterpolators());
+    }
+
+    public Change setInterpolator(long time, Interpolator interpolator) {
+        LOGGER.debug("Setting interpolator of position keyframe at {} to {}", time, interpolator);
+
+        Keyframe keyframe = positionPath.getKeyframe(time);
+        Preconditions.checkState(keyframe != null, "Keyframe does not exists");
+        PathSegment segment = positionPath.getSegments().stream().filter(s -> s.getStartKeyframe() == keyframe)
+                .findFirst().orElseThrow(() -> new IllegalStateException("Keyframe has no following segment."));
+
+        registerPositionInterpolatorProperties(interpolator);
+
+        Change change = CombinedChange.create(
+                UpdateKeyframeProperties.create(positionPath, keyframe)
+                        .setValue(ExplicitInterpolationProperty.PROPERTY, ObjectUtils.NULL)
+                        .done(),
+                SetInterpolator.create(segment, interpolator)
+        );
+        change.apply(timeline);
+        return CombinedChange.createFromApplied(change, updateInterpolators());
+    }
+
+    public Change moveKeyframe(SPPath spPath, long oldTime, long newTime) {
+        LOGGER.debug("Moving keyframe on {} from {} to {}", spPath, oldTime, newTime);
+        Path path = getPath(spPath);
+        Keyframe keyframe = path.getKeyframe(oldTime);
+
+        Preconditions.checkState(keyframe != null, "No keyframe at specified time");
+
+        // Interpolator of the first segment might be required later if it is the only one
+        Optional<Interpolator> firstInterpolator =
+                path.getSegments().stream().findFirst().map(PathSegment::getInterpolator);
+
+        // The interpolator of the previous segment
+        Optional<Interpolator> interpolatorBefore =
+                path.getSegments().stream().filter(s -> s.getEndKeyframe() == keyframe).findFirst().map(PathSegment::getInterpolator);
+
+        // The interpolator of the following segment
+        Optional<Interpolator> interpolatorAfter =
+                path.getSegments().stream().filter(s -> s.getStartKeyframe() == keyframe).findFirst().map(PathSegment::getInterpolator);
+
+        // First remove the old keyframe
+        Change removeChange = create(path, keyframe);
+        removeChange.apply(timeline);
+
+        // and add a new one at the correct time
+        Change addChange = AddKeyframe.create(path, newTime);
+        addChange.apply(timeline);
+
+        // Then copy over all properties
+        UpdateKeyframeProperties.Builder builder = UpdateKeyframeProperties.create(path, path.getKeyframe(newTime));
+        for (Property property : keyframe.getProperties()) {
+            copyProperty(property, keyframe, builder);
+        }
+        Change propertyChange = builder.done();
+        propertyChange.apply(timeline);
+
+
+        Change restoreInterpolatorChange;
+        Keyframe newKf = path.getKeyframe(newTime);
+        if (Iterables.getLast(path.getKeyframes()) != newKf) { // Unless this is the last keyframe
+            // the interpolator of the following segment has been lost and needs to be restored
+            restoreInterpolatorChange = interpolatorAfter.<Change>flatMap(interpolator ->
+                    path.getSegments().stream().filter(s -> s.getStartKeyframe() == newKf).findFirst().map(segment ->
+                            SetInterpolator.create(segment, interpolator)
+                    )
+            ).orElseGet(CombinedChange::create);
+        } else { // If it is the last keyframe however,
+            // the interpolator of the previous segment has been lost and needs to be restored
+            restoreInterpolatorChange = interpolatorBefore.<Change>flatMap(interpolator ->
+                    path.getSegments().stream().filter(s -> s.getEndKeyframe() == newKf).findFirst().map(segment ->
+                            SetInterpolator.create(segment, interpolator)
+                    )
+            ).orElseGet(CombinedChange::create);
+        }
+        restoreInterpolatorChange.apply(timeline);
+
+        // Finally update the interpolators
+        Change interpolatorUpdateChange;
+        if (spPath == SPPath.POSITION) {
+            // Position / Spectator keyframes need special handling
+            interpolatorUpdateChange = updateInterpolators();
+        } else {
+            // Time keyframes only need updating when only one segment of them exists
+            if (path.getSegments().size() == 1) {
+                assert firstInterpolator.isPresent() : "One segment should have existed before as well";
+                interpolatorUpdateChange = SetInterpolator.create(path.getSegments().iterator().next(), firstInterpolator.get());
+            } else {
+                interpolatorUpdateChange = CombinedChange.create(); // Noop change
+            }
+            interpolatorUpdateChange.apply(timeline);
+        }
+
+        // and update spectator positions
+        Change spectatorChange = updateSpectatorPositions();
+        spectatorChange.apply(timeline);
+
+        return CombinedChange.createFromApplied(removeChange, addChange, propertyChange,
+                restoreInterpolatorChange, interpolatorUpdateChange, spectatorChange);
+    }
+
+    // Helper method because generics cannot be defined on blocks
+    private <T> void copyProperty(Property<T> property, Keyframe from, UpdateKeyframeProperties.Builder to) {
+        from.getValue(property).ifPresent(value -> to.setValue(property, value));
+    }
+
+    private Change updateInterpolators() {
+        Collection<PathSegment> pathSegments = positionPath.getSegments();
+        // Contains updated pathsegment-interpolator mappings, may be changed multiple times over the course of this method
+        Map<PathSegment, Interpolator> updates = new HashMap<>();
+
+        // First, setup spectator interpolators
+        Interpolator interpolator = null;
+        // Iterate through all segments
+        for (PathSegment segment : pathSegments) {
+            if (isSpectatorSegment(segment)) {
+                // If the last segment was a spectator segment, then use its interpolator for this segment as well
+                if (interpolator == null) {
+                    // otherwise create a new interpolator
+                    interpolator = new LinearInterpolator();
+                    interpolator.registerProperty(SpectatorProperty.PROPERTY);
+                }
+                // Now that we have an interpolator, set it for the current segment
+                updates.put(segment, interpolator);
+            } else {
+                // Not a spectator segment, make sure we don't re-use the last interpolator (it would not be continuous)
+                interpolator = null;
+            }
+        }
+
+        // Then, if required, replace old default interpolators with new ones
+        pathSegments.stream()
+                // Ignore explicitly set segments
+                .filter(s -> !s.getStartKeyframe().getValue(ExplicitInterpolationProperty.PROPERTY).isPresent())
+                // Ignore spectator segments
+                .filter(s -> !isSpectatorSegment(s))
+                // Ignore already correct segments, should ignore all if default hasn't changed
+                .filter(s -> !s.getInterpolator().getClass().equals(defaultInterpolatorType.getInterpolatorClass()))
+                // Finally, set the interpolators
+                // This will create one interpolator per segment, they will be merged later
+                .forEach(segment -> updates.put(segment, createDefaultInterpolator()));
+
+        // All interpolators should now be set appropriately but may still be fragmented.
+        // Cleaning that up is a two step process
+
+        // Firstly, all interpolators that are not continuous need to be split up
+        Interpolator lastInterpolator = null;
+        Set<Interpolator> used = Collections.newSetFromMap(new IdentityHashMap<>());
+        for (PathSegment segment : pathSegments) {
+            if (isSpectatorSegment(segment)) {
+                lastInterpolator = null;
+                continue; // Chain broken by spectator segment
+            }
+
+            Interpolator currentInterpolator = updates.getOrDefault(segment, segment.getInterpolator());
+            if (lastInterpolator == currentInterpolator) {
+                continue; // All fine, interpolator is still continuous
+            }
+
+            // New interpolator, make sure it hasn't been used before
+            if (!used.add(interpolator)) {
+                // It has been used before, we need to clone it and use the clone instead
+                // This will create a new interpolator for each segment which will be merged later
+                currentInterpolator = cloneInterpolator(currentInterpolator);
+                updates.put(segment, currentInterpolator);
+            }
+            lastInterpolator = currentInterpolator;
+        }
+
+        // Secondly, all neighbouring interpolators that are equal need to be merged
+        lastInterpolator = null;
+        String lastInterpolatorSerialized = null;
+        for (PathSegment segment : pathSegments) {
+            if (isSpectatorSegment(segment)) {
+                lastInterpolator = null;
+                lastInterpolatorSerialized = null;
+                continue; // Spectator segments are continuous by construction
+            }
+            Interpolator currentInterpolator = updates.getOrDefault(segment, segment.getInterpolator());
+            String serialized = serializeInterpolator(currentInterpolator);
+            if (lastInterpolator != currentInterpolator && serialized.equals(lastInterpolatorSerialized)) {
+                // This interpolator is equal to the last one but not the same, needs merging
+                updates.put(segment, lastInterpolator);
+                continue;
+            }
+            // New interpolator, not related to the previous one, merged by definition
+            lastInterpolator = currentInterpolator;
+            lastInterpolatorSerialized = serialized;
+        }
+
+        Change change = CombinedChange.create(updates.entrySet().stream()
+                .map(e -> SetInterpolator.create(e.getKey(), e.getValue())).toArray(Change[]::new));
+        change.apply(timeline);
+        return change;
+    }
+
+    private boolean isSpectatorSegment(PathSegment segment) {
+        return segment.getStartKeyframe().getValue(SpectatorProperty.PROPERTY).isPresent()
+                && segment.getEndKeyframe().getValue(SpectatorProperty.PROPERTY).isPresent();
+    }
+
+    private Change updateSpectatorPositions() {
+        List<Change> changes = new ArrayList<>();
+        timePath.updateAll();
+        for (Keyframe keyframe : positionPath.getKeyframes()) {
+            Optional<Integer> spectator = keyframe.getValue(SpectatorProperty.PROPERTY);
+            if (spectator.isPresent()) {
+                Optional<Integer> time = timePath.getValue(TimestampProperty.PROPERTY, keyframe.getTime());
+                if (!time.isPresent()) {
+                    continue; // No time keyframes set at this video time, cannot determine replay time
+                }
+                Location expected = entityTracker.getEntityPositionAtTimestamp(spectator.get(), time.get());
+                if (expected == null) {
+                    continue; // We don't have any data on this entity for some reason
+                }
+                Triple<Double, Double, Double> pos = keyframe.getValue(CameraProperties.POSITION).orElse(Triple.of(0D, 0D, 0D));
+                Triple<Float, Float, Float> rot = keyframe.getValue(CameraProperties.ROTATION).orElse(Triple.of(0F, 0F, 0F));
+                Location actual = new Location(pos.getLeft(), pos.getMiddle(), pos.getRight(), rot.getLeft(), rot.getRight());
+                if (!expected.equals(actual)) {
+                    changes.add(UpdateKeyframeProperties.create(positionPath, keyframe)
+                            .setValue(CameraProperties.POSITION, Triple.of(expected.getX(), expected.getY(), expected.getZ()))
+                            .setValue(CameraProperties.ROTATION, Triple.of(expected.getYaw(), expected.getPitch(), 0f)).done()
+                    );
+                }
+            }
+        }
+        return CombinedChange.create(changes.toArray(new Change[changes.size()]));
+    }
+
+    private Interpolator createDefaultInterpolator() {
+        return registerPositionInterpolatorProperties(defaultInterpolatorType.newInstance());
+    }
+
+    private Interpolator registerPositionInterpolatorProperties(Interpolator interpolator) {
+        interpolator.registerProperty(CameraProperties.POSITION);
+        interpolator.registerProperty(CameraProperties.ROTATION);
+        return interpolator;
+    }
+
+    @Override
+    public Timeline createTimeline() {
+        return createTimelineStatic();
+    }
+
+    private static Timeline createInitialTimeline() {
+        Timeline timeline = createTimelineStatic();
+        timeline.createPath();
+        timeline.createPath();
+        return timeline;
+    }
+
+    private static Timeline createTimelineStatic() {
+        Timeline timeline = new TimelineImpl();
+
+        timeline.registerProperty(TimestampProperty.PROPERTY);
+        timeline.registerProperty(CameraProperties.POSITION);
+        timeline.registerProperty(CameraProperties.ROTATION);
+        timeline.registerProperty(SpectatorProperty.PROPERTY);
+        timeline.registerProperty(ExplicitInterpolationProperty.PROPERTY);
+
+        return timeline;
+    }
+
+    @Override
+    public void serializeInterpolator(JsonWriter writer, Interpolator interpolator) throws IOException {
+        if (interpolator instanceof LinearInterpolator) {
+            writer.value("linear");
+        } else if (interpolator instanceof CubicSplineInterpolator) {
+            writer.value("cubic-spline");
+        } else if (interpolator instanceof CatmullRomSplineInterpolator) {
+            writer.beginObject();
+            writer.name("type").value("catmull-rom-spline");
+            writer.name("alpha").value(((CatmullRomSplineInterpolator) interpolator).getAlpha());
+            writer.endObject();
+        } else {
+            throw new IOException("Unknown interpolator type: " + interpolator);
+        }
+    }
+
+    @Override
+    public Interpolator deserializeInterpolator(JsonReader reader) throws IOException {
+        String type;
+        JsonObject args;
+        switch (reader.peek()) {
+            case STRING:
+                type = reader.nextString();
+                args = null;
+                break;
+            case BEGIN_OBJECT:
+                args = new JsonParser().parse(reader).getAsJsonObject();
+                type = args.get("type").getAsString();
+                break;
+            default:
+                throw new IOException("Unexpected token: " + reader.peek());
+        }
+        switch (type) {
+            case "linear":
+                return new LinearInterpolator();
+            case "cubic-spline":
+                return new CubicSplineInterpolator();
+            case "catmull-rom-spline":
+                if (args == null || !args.has("alpha")) {
+                    throw new IOException("Missing alpha value for catmull-rom-spline.");
+                }
+                return new CatmullRomSplineInterpolator(args.get("alpha").getAsDouble());
+            default:
+                throw new IOException("Unknown interpolation type: " + type);
+
+        }
+    }
+
+    /**
+     * Clones an interpolator by de- and re-serializing it.
+     * @param interpolator The interpolator to clone
+     * @return The cloned interpolator
+     */
+    private Interpolator cloneInterpolator(Interpolator interpolator) {
+        Interpolator cloned = deserializeInterpolator(serializeInterpolator(interpolator));
+        interpolator.getKeyframeProperties().forEach(cloned::registerProperty);
+        return cloned;
+    }
+
+    /**
+     * Serializes the specific interpolator to String.
+     * Does <b>not</b> serialize the registered keyframe properties.
+     * @param interpolator The interpolator to serialize.
+     * @return The serialized interpolator
+     */
+    private String serializeInterpolator(Interpolator interpolator) {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+        JsonWriter jsonWriter = new JsonWriter(new PrintWriter(baos));
+        try {
+            jsonWriter.beginArray();
+            serializeInterpolator(jsonWriter, interpolator);
+            jsonWriter.endArray();
+            jsonWriter.flush();
+        } catch (IOException e) {
+            CrashReport crash = CrashReport.makeCrashReport(e, "Serializing interpolator");
+            CrashReportCategory category = crash.makeCategory("Serializing interpolator");
+            category.setDetail("Interpolator", interpolator::toString);
+            throw new ReportedException(crash);
+        }
+
+        return baos.toString();
+    }
+
+    private Interpolator deserializeInterpolator(String json) {
+        JsonReader jsonReader = new JsonReader(new StringReader(json));
+        try {
+            jsonReader.beginArray();
+            return deserializeInterpolator(jsonReader);
+        } catch (IOException e) {
+            CrashReport crash = CrashReport.makeCrashReport(e, "De-serializing interpolator");
+            CrashReportCategory category = crash.makeCategory("De-serializing interpolator");
+            category.addCrashSection("Interpolator", json);
+            throw new ReportedException(crash);
+        }
+    }
+}

src/main/java/com/replaymod/simplepathing/Setting.java

@@ -2,9 +2,25 @@ package com.replaymod.simplepathing;
 
 import com.replaymod.core.SettingsRegistry;
 
+import java.util.Arrays;
+import java.util.stream.Collectors;
+
 public final class Setting<T> extends SettingsRegistry.SettingKeys<T> {
     public static final Setting<Boolean> PATH_PREVIEW = make("pathpreview", "pathpreview", true);
-    public static final Setting<Boolean> LINEAR_INTERPOLATION = make("linear_interpolation", "linearinterpolation", false);
+    public static final SettingsRegistry.MultipleChoiceSettingKeys<String> DEFAULT_INTERPOLATION;
+
+    static {
+        String format = "replaymod.gui.editkeyframe.interpolator.%s.name";
+        DEFAULT_INTERPOLATION = new SettingsRegistry.MultipleChoiceSettingKeys<>(
+                "simplepathing", "interpolator", "replaymod.gui.settings.interpolator",
+                String.format(format, InterpolatorType.fromString("invalid returns default").getLocalizationKey())
+        );
+        DEFAULT_INTERPOLATION.setChoices(
+                Arrays.stream(InterpolatorType.values()).filter(i -> i != InterpolatorType.DEFAULT)
+                        .map(i -> String.format(format, i.getLocalizationKey()))
+                        .collect(Collectors.toList())
+        );
+    }
 
     private static <T> Setting<T> make(String key, String displayName, T defaultValue) {
         return new Setting<>(key, displayName, defaultValue);

src/main/java/com/replaymod/simplepathing/gui/GuiEditKeyframe.java

@@ -5,14 +5,27 @@ import com.replaymod.pathing.properties.TimestampProperty;
 import com.replaymod.replay.ReplayModReplay;
 import com.replaymod.replaystudio.pathing.change.Change;
 import com.replaymod.replaystudio.pathing.change.CombinedChange;
-import com.replaymod.replaystudio.pathing.change.UpdateKeyframeProperties;
+import com.replaymod.replaystudio.pathing.interpolation.CatmullRomSplineInterpolator;
+import com.replaymod.replaystudio.pathing.interpolation.CubicSplineInterpolator;
+import com.replaymod.replaystudio.pathing.interpolation.Interpolator;
+import com.replaymod.replaystudio.pathing.interpolation.LinearInterpolator;
 import com.replaymod.replaystudio.pathing.path.Keyframe;
 import com.replaymod.replaystudio.pathing.path.Path;
+import com.replaymod.replaystudio.pathing.path.PathSegment;
+import com.replaymod.simplepathing.InterpolatorType;
+import com.replaymod.simplepathing.SPTimeline;
+import com.replaymod.simplepathing.SPTimeline.SPPath;
+import com.replaymod.simplepathing.Setting;
+import com.replaymod.simplepathing.properties.ExplicitInterpolationProperty;
+import de.johni0702.minecraft.gui.container.AbstractGuiContainer;
 import de.johni0702.minecraft.gui.container.GuiPanel;
 import de.johni0702.minecraft.gui.element.GuiButton;
 import de.johni0702.minecraft.gui.element.GuiLabel;
 import de.johni0702.minecraft.gui.element.GuiNumberField;
+import de.johni0702.minecraft.gui.element.GuiTooltip;
+import de.johni0702.minecraft.gui.element.IGuiClickable;
 import de.johni0702.minecraft.gui.element.IGuiLabel;
+import de.johni0702.minecraft.gui.element.advanced.GuiDropdownMenu;
 import de.johni0702.minecraft.gui.function.Typeable;
 import de.johni0702.minecraft.gui.layout.GridLayout;
 import de.johni0702.minecraft.gui.layout.HorizontalLayout;
@@ -20,10 +33,16 @@ import de.johni0702.minecraft.gui.layout.VerticalLayout;
 import de.johni0702.minecraft.gui.popup.AbstractGuiPopup;
 import de.johni0702.minecraft.gui.utils.Colors;
 import de.johni0702.minecraft.gui.utils.Consumer;
-import org.apache.commons.lang3.tuple.Triple;
+import lombok.Getter;
+import net.minecraft.client.resources.I18n;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.lwjgl.input.Keyboard;
 import org.lwjgl.util.ReadablePoint;
 
+import java.util.Map;
+import java.util.Optional;
+
 import static de.johni0702.minecraft.gui.utils.Utils.link;
 
 public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends AbstractGuiPopup<T> implements Typeable {
@@ -31,6 +50,11 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
         return new GuiNumberField().setPrecision(0).setValidateOnFocusChange(true);
     }
 
+    protected static final Logger logger = LogManager.getLogger();
+
+    protected final GuiPathing guiPathing;
+
+    protected final long time;
     protected final Keyframe keyframe;
     protected final Path path;
 
@@ -66,12 +90,13 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
                 .addElements(new VerticalLayout.Data(0.5, false), title, inputs, timePanel, buttons);
     }
 
-    public GuiEditKeyframe(GuiPathing gui, Path path, Keyframe keyframe, String type) {
+    public GuiEditKeyframe(GuiPathing gui, SPPath path, long time, String type) {
         super(ReplayModReplay.instance.getReplayHandler().getOverlay());
-        this.keyframe = keyframe;
-        this.path = path;
+        this.guiPathing = gui;
+        this.time = time;
+        this.path = gui.getMod().getCurrentTimeline().getPath(path);
+        this.keyframe = this.path.getKeyframe(time);
 
-        long time = keyframe.getTime();
         Consumer<String> updateSaveButtonState = s -> saveButton.setEnabled(canSave());
         timeMinField.setValue(time / 1000 / 60).onTextChanged(updateSaveButtonState);
         timeSecField.setValue(time / 1000 % 60).onTextChanged(updateSaveButtonState);
@@ -81,10 +106,11 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
         saveButton.onClick(() -> {
             Change change = save();
             long newTime = (timeMinField.getInteger() * 60 + timeSecField.getInteger()) * 1000 + timeMSecField.getInteger();
-            if (newTime != keyframe.getTime()) {
-                change = CombinedChange.createFromApplied(change, gui.moveKeyframe(path, keyframe, newTime));
+            if (newTime != time) {
+                change = CombinedChange.createFromApplied(change,
+                        gui.getMod().getCurrentTimeline().moveKeyframe(path, time, newTime));
             }
-            path.getTimeline().pushChange(change);
+            gui.getMod().getCurrentTimeline().getTimeline().pushChange(change);
             close();
         });
     }
@@ -114,7 +140,7 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
     protected abstract Change save();
 
     public static class Spectator extends GuiEditKeyframe<Spectator> {
-        public Spectator(GuiPathing gui, Path path, Keyframe keyframe) {
+        public Spectator(GuiPathing gui, SPPath path, long keyframe) {
             super(gui, path, keyframe, "spec");
 
             link(timeMinField, timeSecField, timeMSecField);
@@ -147,10 +173,10 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
                             timestampMSecField, new GuiLabel().setI18nText("replaymod.gui.milliseconds"));
         }
 
-        public Time(GuiPathing gui, Path path, Keyframe keyframe) {
+        public Time(GuiPathing gui, SPPath path, long keyframe) {
             super(gui, path, keyframe, "time");
 
-            keyframe.getValue(TimestampProperty.PROPERTY).ifPresent(time -> {
+            this.keyframe.getValue(TimestampProperty.PROPERTY).ifPresent(time -> {
                 timestampMinField.setValue(time / 1000 / 60);
                 timestampSecField.setValue(time / 1000 % 60);
                 timestampMSecField.setValue(time % 1000);
@@ -165,11 +191,7 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
         protected Change save() {
             int time = (timestampMinField.getInteger() * 60 + timestampSecField.getInteger()) * 1000
                     + timestampMSecField.getInteger();
-            Change change = UpdateKeyframeProperties.create(path, keyframe)
-                    .setValue(TimestampProperty.PROPERTY, time)
-                    .done();
-            change.apply(path.getTimeline());
-            return change;
+            return guiPathing.getMod().getCurrentTimeline().updateTimeKeyframe(keyframe.getTime(), time);
         }
 
         @Override
@@ -187,8 +209,11 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
         public final GuiNumberField pitchField = newGuiNumberField().setSize(60, 20).setPrecision(5);
         public final GuiNumberField rollField = newGuiNumberField().setSize(60, 20).setPrecision(5);
 
+        public final InterpolationPanel interpolationPanel = new InterpolationPanel();
+
         {
-            inputs.setLayout(new GridLayout().setCellsEqualSize(false).setColumns(4).setSpacingX(3).setSpacingY(5))
+            GuiPanel positionInputs = new GuiPanel()
+                    .setLayout(new GridLayout().setCellsEqualSize(false).setColumns(4).setSpacingX(3).setSpacingY(5))
                     .addElements(new GridLayout.Data(1, 0.5),
                             new GuiLabel().setI18nText("replaymod.gui.editkeyframe.xpos"), xField,
                             new GuiLabel().setI18nText("replaymod.gui.editkeyframe.camyaw"), yawField,
@@ -196,17 +221,20 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
                             new GuiLabel().setI18nText("replaymod.gui.editkeyframe.campitch"), pitchField,
                             new GuiLabel().setI18nText("replaymod.gui.editkeyframe.zpos"), zField,
                             new GuiLabel().setI18nText("replaymod.gui.editkeyframe.camroll"), rollField);
+
+            inputs.setLayout(new VerticalLayout().setSpacing(10)).addElements(new VerticalLayout.Data(0.5, false),
+                    positionInputs, interpolationPanel);
         }
 
-        public Position(GuiPathing gui, Path path, Keyframe keyframe) {
+        public Position(GuiPathing gui, SPPath path, long keyframe) {
             super(gui, path, keyframe, "pos");
 
-            keyframe.getValue(CameraProperties.POSITION).ifPresent(pos -> {
+            this.keyframe.getValue(CameraProperties.POSITION).ifPresent(pos -> {
                 xField.setValue(pos.getLeft());
                 yField.setValue(pos.getMiddle());
                 zField.setValue(pos.getRight());
             });
-            keyframe.getValue(CameraProperties.ROTATION).ifPresent(rot -> {
+            this.keyframe.getValue(CameraProperties.ROTATION).ifPresent(rot -> {
                 yawField.setValue(rot.getLeft());
                 pitchField.setValue(rot.getMiddle());
                 rollField.setValue(rot.getRight());
@@ -219,17 +247,176 @@ public abstract class GuiEditKeyframe<T extends GuiEditKeyframe<T>> extends Abst
 
         @Override
         protected Change save() {
-            Change change = UpdateKeyframeProperties.create(path, keyframe)
-                    .setValue(CameraProperties.POSITION, Triple.of(xField.getDouble(), yField.getDouble(), zField.getDouble()))
-                    .setValue(CameraProperties.ROTATION, Triple.of(yawField.getFloat(), pitchField.getFloat(), rollField.getFloat()))
-                    .done();
-            change.apply(path.getTimeline());
-            return change;
+            SPTimeline timeline = guiPathing.getMod().getCurrentTimeline();
+            Change positionChange = timeline.updatePositionKeyframe(time,
+                    xField.getDouble(), yField.getDouble(), zField.getDouble(),
+                    yawField.getFloat(), pitchField.getFloat(), rollField.getFloat()
+            );
+            Interpolator interpolator = interpolationPanel.getSettingsPanel().createInterpolator();
+            if (interpolationPanel.getInterpolatorType() == InterpolatorType.DEFAULT) {
+                return CombinedChange.createFromApplied(positionChange, timeline.setInterpolatorToDefault(time),
+                        timeline.setDefaultInterpolator(interpolator));
+            } else {
+                return CombinedChange.createFromApplied(positionChange, timeline.setInterpolator(time, interpolator));
+            }
         }
 
         @Override
         protected Position getThis() {
             return this;
         }
+
+        public class InterpolationPanel extends AbstractGuiContainer<InterpolationPanel> {
+
+            @Getter
+            private SettingsPanel settingsPanel;
+
+            private GuiDropdownMenu<InterpolatorType> dropdown;
+
+            public InterpolationPanel() {
+                setLayout(new VerticalLayout());
+
+                dropdown = new GuiDropdownMenu<InterpolatorType>()
+                        .setToString(s -> I18n.format(s.getI18nName()))
+                        .setValues(InterpolatorType.values()).setHeight(20)
+                        .onSelection(i -> setSettingsPanel(dropdown.getSelectedValue()));
+
+                // set hover tooltips
+                for (Map.Entry<InterpolatorType, IGuiClickable> e : dropdown.getDropdownEntries().entrySet()) {
+                    e.getValue().setTooltip(new GuiTooltip().setI18nText(e.getKey().getI18nDescription()));
+                }
+
+                GuiPanel dropdownPanel = new GuiPanel()
+                        .setLayout(new GridLayout().setCellsEqualSize(false).setColumns(2).setSpacingX(3).setSpacingY(5))
+                        .addElements(new GridLayout.Data(1, 0.5),
+                                new GuiLabel().setI18nText("replaymod.gui.editkeyframe.interpolator"), dropdown);
+
+
+                addElements(new VerticalLayout.Data(0.5, false), dropdownPanel);
+
+                Optional<PathSegment> segment = path.getSegments().stream()
+                        .filter(s -> s.getStartKeyframe() == keyframe).findFirst();
+                if (segment.isPresent()) {
+                    Interpolator interpolator = segment.get().getInterpolator();
+                    InterpolatorType type = InterpolatorType.fromClass(interpolator.getClass());
+                    if (keyframe.getValue(ExplicitInterpolationProperty.PROPERTY).isPresent()) {
+                        dropdown.setSelected(type); // trigger the callback once to display settings panel
+                    } else {
+                        setSettingsPanel(InterpolatorType.DEFAULT);
+                    }
+                    if (getInterpolatorTypeNoDefault(type).getInterpolatorClass().isInstance(interpolator)) {
+                        //noinspection unchecked
+                        settingsPanel.loadSettings(interpolator);
+                    }
+                } else {
+                    // Disable dropdown if this is the last keyframe
+                    dropdown.setDisabled();
+                }
+            }
+
+            public void setSettingsPanel(InterpolatorType type) {
+                removeElement(this.settingsPanel);
+
+                switch (getInterpolatorTypeNoDefault(type)) {
+                    case CATMULL_ROM:
+                        settingsPanel = new CatmullRomSettingsPanel();
+                        break;
+                    case CUBIC:
+                        settingsPanel = new CubicSettingsPanel();
+                        break;
+                    case LINEAR:
+                        settingsPanel = new LinearSettingsPanel();
+                        break;
+                }
+
+                addElements(new GridLayout.Data(0.5, 0.5), settingsPanel);
+            }
+
+            protected InterpolatorType getInterpolatorTypeNoDefault(InterpolatorType interpolatorType) {
+                if (interpolatorType == InterpolatorType.DEFAULT || interpolatorType == null) {
+                    InterpolatorType defaultType = InterpolatorType.fromString(
+                            guiPathing.getMod().getCore().getSettingsRegistry().get(Setting.DEFAULT_INTERPOLATION));
+                    return defaultType;
+                }
+                return interpolatorType;
+            }
+
+            public InterpolatorType getInterpolatorType() {
+                return dropdown.getSelectedValue();
+            }
+
+            @Override
+            protected InterpolationPanel getThis() {
+                return this;
+            }
+
+            public abstract class SettingsPanel<I extends Interpolator, T extends SettingsPanel<I, T>> extends AbstractGuiContainer<T> {
+
+                public abstract void loadSettings(I interpolator);
+
+                public abstract I createInterpolator();
+            }
+
+            public class CatmullRomSettingsPanel extends SettingsPanel<CatmullRomSplineInterpolator, CatmullRomSettingsPanel> {
+                public final GuiLabel alphaLabel = new GuiLabel().setColor(Colors.BLACK)
+                        .setI18nText("replaymod.gui.editkeyframe.interpolator.catmullrom.alpha");
+                public final GuiNumberField alphaField = new GuiNumberField().setSize(100, 20).setPrecision(5)
+                        .setMinValue(0).setValidateOnFocusChange(true);
+
+                {
+                    setLayout(new HorizontalLayout(HorizontalLayout.Alignment.CENTER));
+                    addElements(new HorizontalLayout.Data(0.5), alphaLabel, alphaField);
+                }
+
+                @Override
+                public void loadSettings(CatmullRomSplineInterpolator interpolator) {
+                    alphaField.setValue(interpolator.getAlpha());
+                }
+
+                @Override
+                public CatmullRomSplineInterpolator createInterpolator() {
+                    return new CatmullRomSplineInterpolator(alphaField.getDouble());
+                }
+
+                @Override
+                protected CatmullRomSettingsPanel getThis() {
+                    return this;
+                }
+            }
+
+            public class CubicSettingsPanel extends SettingsPanel<CubicSplineInterpolator, CubicSettingsPanel> {
+
+                @Override
+                public void loadSettings(CubicSplineInterpolator interpolator) {
+                }
+
+                @Override
+                public CubicSplineInterpolator createInterpolator() {
+                    return new CubicSplineInterpolator();
+                }
+
+                @Override
+                protected CubicSettingsPanel getThis() {
+                    return this;
+                }
+            }
+
+            public class LinearSettingsPanel extends SettingsPanel<LinearInterpolator, LinearSettingsPanel> {
+
+                @Override
+                public void loadSettings(LinearInterpolator interpolator) {
+                }
+
+                @Override
+                public LinearInterpolator createInterpolator() {
+                    return new LinearInterpolator();
+                }
+
+                @Override
+                protected LinearSettingsPanel getThis() {
+                    return this;
+                }
+            }
+        }
     }
 }

src/main/java/com/replaymod/simplepathing/gui/GuiKeyframeTimeline.java

@@ -1,7 +1,5 @@
 package com.replaymod.simplepathing.gui;
 
-import com.google.common.base.Function;
-import com.google.common.collect.Iterables;
 import com.replaymod.core.ReplayMod;
 import com.replaymod.pathing.properties.CameraProperties;
 import com.replaymod.pathing.properties.SpectatorProperty;
@@ -11,9 +9,10 @@ import com.replaymod.replaystudio.pathing.change.Change;
 import com.replaymod.replaystudio.pathing.path.Keyframe;
 import com.replaymod.replaystudio.pathing.path.Path;
 import com.replaymod.replaystudio.pathing.path.PathSegment;
-import com.replaymod.replaystudio.pathing.path.Timeline;
 import com.replaymod.replaystudio.pathing.property.Property;
 import com.replaymod.simplepathing.ReplayModSimplePathing;
+import com.replaymod.simplepathing.SPTimeline;
+import com.replaymod.simplepathing.SPTimeline.SPPath;
 import de.johni0702.minecraft.gui.GuiRenderer;
 import de.johni0702.minecraft.gui.element.advanced.AbstractGuiTimeline;
 import de.johni0702.minecraft.gui.function.Draggable;
@@ -23,7 +22,6 @@ import org.lwjgl.util.Point;
 import org.lwjgl.util.ReadableDimension;
 import org.lwjgl.util.ReadablePoint;
 
-import javax.annotation.Nullable;
 import java.util.Comparator;
 import java.util.Optional;
 
@@ -37,14 +35,14 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
     private final GuiPathing gui;
 
     /**
-     * The keyframe that was last clicked on using the left mouse button.
+     * The keyframe (time on timeline) that was last clicked on using the left mouse button.
      */
-    private Keyframe lastClickedKeyframe;
+    private long lastClickedKeyframe;
 
     /**
-     * Id of the path of {@link #lastClickedKeyframe}.
+     * Path of {@link #lastClickedKeyframe}.
      */
-    private int lastClickedPath;
+    private SPPath lastClickedPath;
 
     /**
      * The time at which {@link #lastClickedKeyframe} was updated.
@@ -89,18 +87,13 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
 
         renderer.bindTexture(ReplayMod.TEXTURE);
 
-        for (Keyframe keyframe : Iterables.concat(Iterables.transform(mod.getCurrentTimeline().getPaths(), new Function<Path, Iterable<Keyframe>>() {
-            @Nullable
-            @Override
-            public Iterable<Keyframe> apply(@Nullable Path input) {
-                assert input != null;
-                return input.getKeyframes();
-            }
-        }))) {
+        SPTimeline timeline = mod.getCurrentTimeline();
+
+        timeline.getTimeline().getPaths().stream().flatMap(path -> path.getKeyframes().stream()).forEach(keyframe -> {
             if (keyframe.getTime() >= startTime && keyframe.getTime() <= endTime) {
                 double relativeTime = keyframe.getTime() - startTime;
                 int positonX = BORDER_LEFT + (int) (relativeTime / visibleTime * visibleWidth) - KEYFRAME_SIZE / 2;
-                int u = KEYFRAME_TEXTURE_X + (mod.getSelectedKeyframe() == keyframe ? KEYFRAME_SIZE : 0);
+                int u = KEYFRAME_TEXTURE_X + (mod.isSelected(keyframe) ? KEYFRAME_SIZE : 0);
                 int v = KEYFRAME_TEXTURE_Y;
                 if (keyframe.getValue(CameraProperties.POSITION).isPresent()) {
                     if (keyframe.getValue(SpectatorProperty.PROPERTY).isPresent()) {
@@ -113,10 +106,10 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
                     renderer.drawTexturedRect(positonX, BORDER_TOP + KEYFRAME_SIZE, u, v, KEYFRAME_SIZE, KEYFRAME_SIZE);
                 }
             }
-        }
+        });
 
         // Draw colored quads on spectator path segments
-        for (PathSegment segment : mod.getCurrentTimeline().getPaths().get(GuiPathing.POSITION_PATH).getSegments()) {
+        for (PathSegment segment : timeline.getPositionPath().getSegments()) {
             if (segment.getInterpolator() == null
                     || !segment.getInterpolator().getKeyframeProperties().contains(SpectatorProperty.PROPERTY)) {
                 continue; // Not a spectator segment
@@ -125,7 +118,7 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
         }
 
         // Draw red quads on time path segments that would require time going backwards
-        for (PathSegment segment : mod.getCurrentTimeline().getPaths().get(GuiPathing.TIME_PATH).getSegments()) {
+        for (PathSegment segment : timeline.getTimePath().getSegments()) {
             long startTimestamp = segment.getStartKeyframe().getValue(TimestampProperty.PROPERTY).orElseThrow(IllegalStateException::new);
             long endTimestamp = segment.getEndKeyframe().getValue(TimestampProperty.PROPERTY).orElseThrow(IllegalStateException::new);
             if (endTimestamp >= startTimestamp) {
@@ -162,29 +155,28 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
      * @param position The raw position
      * @return Pair of path id and keyframe or null when no keyframe was clicked
      */
-    private Pair<Integer, Keyframe> getKeyframe(ReadablePoint position) {
+    private Pair<SPPath, Long> getKeyframe(ReadablePoint position) {
         int time = getTimeAt(position.getX(), position.getY());
         if (time != -1) {
             Point mouse = new Point(position);
             getContainer().convertFor(this, mouse);
             int mouseY = mouse.getY();
             if (mouseY > BORDER_TOP && mouseY < BORDER_TOP + 2 * KEYFRAME_SIZE) {
-                Timeline timeline = gui.getMod().getCurrentTimeline();
-                int path;
+                SPPath path;
                 if (mouseY <= BORDER_TOP + KEYFRAME_SIZE) {
                     // Position keyframe
-                    path = GuiPathing.POSITION_PATH;
+                    path = SPPath.POSITION;
                 } else {
                     // Time keyframe
-                    path = GuiPathing.TIME_PATH;
+                    path = SPPath.TIME;
                 }
                 int visibleTime = (int) (getZoom() * getLength());
-                int tolerance = visibleTime * KEYFRAME_SIZE / (size.getWidth() - BORDER_LEFT - BORDER_RIGHT) / 2;
-                Optional<Keyframe> keyframe = timeline.getPaths().get(path).getKeyframes().stream()
+                int tolerance = visibleTime * KEYFRAME_SIZE / (getLastSize().getWidth() - BORDER_LEFT - BORDER_RIGHT) / 2;
+                Optional<Keyframe> keyframe = gui.getMod().getCurrentTimeline().getPath(path).getKeyframes().stream()
                         .filter(k -> Math.abs(k.getTime() - time) <= tolerance)
                         .sorted(Comparator.comparing(k -> Math.abs(k.getTime() - time)))
                         .findFirst();
-                return Pair.of(path, keyframe.orElse(null));
+                return Pair.of(path, keyframe.map(Keyframe::getTime).orElse(null));
             }
         }
         return Pair.of(null, null);
@@ -193,30 +185,31 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
     @Override
     public boolean mouseClick(ReadablePoint position, int button) {
         int time = getTimeAt(position.getX(), position.getY());
-        Pair<Integer, Keyframe> pathKeyframePair = getKeyframe(position);
+        Pair<SPPath, Long> pathKeyframePair = getKeyframe(position);
         if (pathKeyframePair.getRight() != null) {
+            SPPath path = pathKeyframePair.getLeft();
             // Clicked on keyframe
-            Keyframe keyframe = pathKeyframePair.getRight();
+            long keyframeTime = pathKeyframePair.getRight();
             if (button == 0) { // Left click
                 long now = Minecraft.getSystemTime();
-                if (lastClickedKeyframe == keyframe) {
+                if (lastClickedKeyframe == keyframeTime) {
                     // Clicked the same keyframe again, potentially a double click
                     if (now - lastClickedTime < DOUBLE_CLICK_INTERVAL) {
                         // Yup, double click, open the edit keyframe gui
-                        Path path = gui.getMod().getCurrentTimeline().getPaths().get(pathKeyframePair.getLeft());
-                        gui.openEditKeyframePopup(path, keyframe);
+                        gui.openEditKeyframePopup(path, keyframeTime);
                         return true;
                     }
                 }
                 // Not a double click, just update the click time and selection
                 lastClickedTime = now;
-                lastClickedKeyframe = keyframe;
-                lastClickedPath = pathKeyframePair.getLeft();
-                gui.getMod().setSelectedKeyframe(lastClickedKeyframe);
+                lastClickedKeyframe = keyframeTime;
+                lastClickedPath = path;
+                gui.getMod().setSelected(lastClickedPath, lastClickedKeyframe);
                 // We might be dragging
                 draggingStartX = position.getX();
                 dragging = true;
             } else if (button == 1) { // Right click
+                Keyframe keyframe = gui.getMod().getCurrentTimeline().getKeyframe(path, keyframeTime);
                 for (Property property : keyframe.getProperties()) {
                     applyPropertyToGame(property, keyframe);
                 }
@@ -226,12 +219,11 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
             // Clicked on timeline but not on any keyframe
             if (button == 0) { // Left click
                 setCursorPosition(time);
-                gui.getMod().setSelectedKeyframe(null);
+                gui.getMod().setSelected(null, 0);
             } else if (button == 1) { // Right click
                 if (pathKeyframePair.getLeft() != null) {
                     // Apply the value of the clicked path at the clicked position
-                    Timeline timeline = gui.getMod().getCurrentTimeline();
-                    Path path = timeline.getPaths().get(pathKeyframePair.getLeft());
+                    Path path = gui.getMod().getCurrentTimeline().getPath(pathKeyframePair.getLeft());
                     path.getKeyframes().stream().flatMap(k -> k.getProperties().stream()).distinct().forEach(
                             p -> applyPropertyToGame(p, path, time));
                 }
@@ -280,12 +272,13 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
             }
         }
         if (actuallyDragging) {
+            if (!gui.ensureEntityTracker(() -> mouseDrag(position, button, timeSinceLastCall))) return true;
             // Threshold passed
-            Path path = gui.getMod().getCurrentTimeline().getPaths().get(lastClickedPath);
+            SPTimeline timeline = gui.getMod().getCurrentTimeline();
             Point mouse = new Point(position);
             getContainer().convertFor(this, mouse);
             int mouseX = mouse.getX();
-            int width = size.getWidth();
+            int width = getLastSize().getWidth();
             int bodyWidth = width - BORDER_LEFT - BORDER_RIGHT;
             double segmentLength = getLength() * getZoom();
             double segmentTime =  segmentLength * (mouseX - BORDER_LEFT) / bodyWidth;
@@ -295,24 +288,21 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
             }
 
             // If there already is a keyframe at the target time, then increase the time by one until there is none
-            while (path.getKeyframe(newTime) != null) {
+            while (timeline.getKeyframe(lastClickedPath, newTime) != null) {
                 newTime++;
             }
 
             // First undo any previous changes
             if (draggingChange != null) {
-                draggingChange.undo(gui.getMod().getCurrentTimeline());
+                draggingChange.undo(timeline.getTimeline());
             }
 
             // Move keyframe to new position and
             // store change for later undoing / pushing to history
-            draggingChange = gui.moveKeyframe(path, lastClickedKeyframe, newTime);
+            draggingChange = timeline.moveKeyframe(lastClickedPath, lastClickedKeyframe, newTime);
 
             // Selected keyframe has been replaced
-            gui.getMod().setSelectedKeyframe(path.getKeyframe(newTime));
-
-            // Path has been changed
-            path.updateAll();
+            gui.getMod().setSelected(lastClickedPath, newTime);
         }
         return true;
     }
@@ -321,7 +311,7 @@ public class GuiKeyframeTimeline extends AbstractGuiTimeline<GuiKeyframeTimeline
     public boolean mouseRelease(ReadablePoint position, int button) {
         if (dragging) {
             if (actuallyDragging) {
-                gui.getMod().getCurrentTimeline().pushChange(draggingChange);
+                gui.getMod().getCurrentTimeline().getTimeline().pushChange(draggingChange);
                 draggingChange = null;
                 actuallyDragging = false;
             }

src/main/java/com/replaymod/simplepathing/gui/GuiPathing.java

@@ -14,25 +14,26 @@ import com.replaymod.render.gui.GuiRenderSettings;
 import com.replaymod.replay.ReplayHandler;
 import com.replaymod.replay.camera.CameraEntity;
 import com.replaymod.replay.gui.overlay.GuiReplayOverlay;
-import com.replaymod.replaystudio.pathing.change.*;
-import com.replaymod.replaystudio.pathing.interpolation.CubicSplineInterpolator;
-import com.replaymod.replaystudio.pathing.interpolation.Interpolator;
-import com.replaymod.replaystudio.pathing.interpolation.LinearInterpolator;
 import com.replaymod.replaystudio.pathing.path.Keyframe;
 import com.replaymod.replaystudio.pathing.path.Path;
-import com.replaymod.replaystudio.pathing.path.PathSegment;
 import com.replaymod.replaystudio.pathing.path.Timeline;
-import com.replaymod.replaystudio.pathing.property.Property;
 import com.replaymod.replaystudio.pathing.serialize.TimelineSerialization;
 import com.replaymod.replaystudio.util.EntityPositionTracker;
-import com.replaymod.replaystudio.util.Location;
 import com.replaymod.simplepathing.ReplayModSimplePathing;
-import com.replaymod.simplepathing.Setting;
+import com.replaymod.simplepathing.SPTimeline;
+import com.replaymod.simplepathing.SPTimeline.SPPath;
 import de.johni0702.minecraft.gui.GuiRenderer;
 import de.johni0702.minecraft.gui.RenderInfo;
 import de.johni0702.minecraft.gui.container.GuiContainer;
 import de.johni0702.minecraft.gui.container.GuiPanel;
-import de.johni0702.minecraft.gui.element.*;
+import de.johni0702.minecraft.gui.element.AbstractGuiClickable;
+import de.johni0702.minecraft.gui.element.AbstractGuiElement;
+import de.johni0702.minecraft.gui.element.GuiElement;
+import de.johni0702.minecraft.gui.element.GuiHorizontalScrollbar;
+import de.johni0702.minecraft.gui.element.GuiLabel;
+import de.johni0702.minecraft.gui.element.GuiTexturedButton;
+import de.johni0702.minecraft.gui.element.GuiTooltip;
+import de.johni0702.minecraft.gui.element.IGuiClickable;
 import de.johni0702.minecraft.gui.element.advanced.GuiProgressBar;
 import de.johni0702.minecraft.gui.element.advanced.GuiTimelineTime;
 import de.johni0702.minecraft.gui.layout.CustomLayout;
@@ -43,9 +44,7 @@ import de.johni0702.minecraft.gui.popup.GuiInfoPopup;
 import de.johni0702.minecraft.gui.popup.GuiYesNoPopup;
 import de.johni0702.minecraft.gui.utils.Colors;
 import net.minecraft.crash.CrashReport;
-import net.minecraft.entity.Entity;
 import net.minecraftforge.fml.common.Loader;
-import org.apache.commons.lang3.tuple.Triple;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.lwjgl.input.Keyboard;
@@ -57,10 +56,7 @@ import org.lwjgl.util.WritablePoint;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import java.io.IOException;
-import java.util.ArrayList;
 import java.util.Collections;
-import java.util.List;
-import java.util.Optional;
 import java.util.function.Consumer;
 
 import static com.replaymod.core.utils.Utils.error;
@@ -71,9 +67,6 @@ import static com.replaymod.simplepathing.ReplayModSimplePathing.LOGGER;
  * Gui plug-in to the GuiReplayOverlay for simple pathing.
  */
 public class GuiPathing {
-    public static final int TIME_PATH = 0;
-    public static final int POSITION_PATH = 1;
-
     private static final Logger logger = LogManager.getLogger();
 
     public final GuiTexturedButton playPauseButton = new GuiTexturedButton() {
@@ -99,10 +92,11 @@ public class GuiPathing {
             if (!preparePathsForPlayback()) return;
 
             // Clone the timeline passed to the settings gui as it may be stored for later rendering in a queue
-            Timeline timeline = mod.getCurrentTimeline();
+            SPTimeline spTimeline = mod.getCurrentTimeline();
+            Timeline timeline;
             try {
-                TimelineSerialization serialization = new TimelineSerialization(mod, null);
-                String serialized = serialization.serialize(Collections.singletonMap("", timeline));
+                TimelineSerialization serialization = new TimelineSerialization(spTimeline, null);
+                String serialized = serialization.serialize(Collections.singletonMap("", spTimeline.getTimeline()));
                 timeline = serialization.deserialize(serialized).get("");
             } catch (Throwable t) {
                 error(LOGGER, replayHandler.getOverlay(), CrashReport.makeCrashReport(t, "Cloning timeline"), () -> {});
@@ -296,27 +290,28 @@ public class GuiPathing {
                 if (player.isActive()) {
                     player.getFuture().cancel(false);
                 } else {
-                    Timeline timeline = mod.getCurrentTimeline();
-                    Path timePath = timeline.getPaths().get(TIME_PATH);
+                    Path timePath = mod.getCurrentTimeline().getTimePath();
 
                     if (!preparePathsForPlayback()) return;
 
                     timePath.setActive(!Keyboard.isKeyDown(Keyboard.KEY_LSHIFT));
                     // Start from cursor time unless the control key is pressed (then start from beginning)
                     int startTime = Keyboard.isKeyDown(Keyboard.KEY_LCONTROL)? 0 : GuiPathing.this.timeline.getCursorPosition();
-                    ListenableFuture<Void> future = player.start(timeline, startTime);
+                    ListenableFuture<Void> future = player.start(mod.getCurrentTimeline().getTimeline(), startTime);
                     overlay.setCloseable(false);
                     overlay.setMouseVisible(true);
                     Futures.addCallback(future, new FutureCallback<Void>() {
                         @Override
                         public void onSuccess(@Nullable Void result) {
                             overlay.setCloseable(true);
+                            timePath.setActive(true);
                         }
 
                         @Override
                         public void onFailure(Throwable t) {
                             t.printStackTrace();
                             overlay.setCloseable(true);
+                            timePath.setActive(true);
                         }
                     });
                 }
@@ -326,26 +321,28 @@ public class GuiPathing {
         positionKeyframeButton.setTexturePosH(new ReadablePoint() {
             @Override
             public int getX() {
-                Keyframe keyframe = mod.getSelectedKeyframe();
-                if (keyframe == null || !keyframe.getValue(CameraProperties.POSITION).isPresent()) {
+                SPPath keyframePath = mod.getSelectedPath();
+                long keyframeTime = mod.getSelectedTime();
+                if (keyframePath != SPPath.POSITION) {
                     // No keyframe or wrong path
-                    keyframe = mod.getCurrentTimeline().getPaths().get(POSITION_PATH).getKeyframe(timeline.getCursorPosition());
+                    keyframeTime = timeline.getCursorPosition();
+                    keyframePath = mod.getCurrentTimeline().isPositionKeyframe(keyframeTime) ? SPPath.POSITION : null;
                 }
-                if (keyframe == null) {
+                if (keyframePath != SPPath.POSITION) {
                     return replayHandler.isCameraView() ? 0 : 40;
                 } else {
-                    return keyframe.getValue(SpectatorProperty.PROPERTY).isPresent() ? 40 : 0;
+                    return mod.getCurrentTimeline().isSpectatorKeyframe(keyframeTime) ? 40 : 0;
                 }
             }
 
             @Override
             public int getY() {
-                Keyframe keyframe = mod.getSelectedKeyframe();
-                if (keyframe == null || !keyframe.getValue(CameraProperties.POSITION).isPresent()) {
+                SPPath keyframePath = mod.getSelectedPath();
+                if (keyframePath != SPPath.POSITION) {
                     // No keyframe selected but there might be one at exactly the position of the cursor
-                    keyframe = mod.getCurrentTimeline().getPaths().get(POSITION_PATH).getKeyframe(timeline.getCursorPosition());
+                    keyframePath = mod.getCurrentTimeline().isPositionKeyframe(timeline.getCursorPosition()) ? SPPath.POSITION : null;
                 }
-                return keyframe != null && keyframe.getValue(CameraProperties.POSITION).isPresent() ? 60 : 40;
+                return keyframePath == SPPath.POSITION ? 60 : 40;
             }
 
             @Override
@@ -355,7 +352,7 @@ public class GuiPathing {
         }).onClick(new Runnable() {
             @Override
             public void run() {
-                updateKeyframe(false);
+                updateKeyframe(SPPath.POSITION);
             }
         });
 
@@ -367,12 +364,12 @@ public class GuiPathing {
 
             @Override
             public int getY() {
-                Keyframe keyframe = mod.getSelectedKeyframe();
-                if (keyframe == null || !keyframe.getValue(TimestampProperty.PROPERTY).isPresent()) {
+                SPPath keyframePath = mod.getSelectedPath();
+                if (keyframePath != SPPath.TIME) {
                     // No keyframe selected but there might be one at exactly the position of the cursor
-                    keyframe = mod.getCurrentTimeline().getPaths().get(TIME_PATH).getKeyframe(timeline.getCursorPosition());
+                    keyframePath = mod.getCurrentTimeline().isTimeKeyframe(timeline.getCursorPosition()) ? SPPath.TIME : null;
                 }
-                return keyframe != null && keyframe.getValue(TimestampProperty.PROPERTY).isPresent() ? 100 : 80;
+                return keyframePath == SPPath.TIME ? 100 : 80;
             }
 
             @Override
@@ -382,7 +379,7 @@ public class GuiPathing {
         }).onClick(new Runnable() {
             @Override
             public void run() {
-                updateKeyframe(true);
+                updateKeyframe(SPPath.TIME);
             }
         });
 
@@ -404,12 +401,12 @@ public class GuiPathing {
                 }
                 try {
                     GuiKeyframeRepository gui = new GuiKeyframeRepository(
-                            mod, replayHandler.getReplayFile(), mod.getCurrentTimeline());
+                            mod.getCurrentTimeline(), replayHandler.getReplayFile(), mod.getCurrentTimeline().getTimeline());
                     Futures.addCallback(gui.getFuture(), new FutureCallback<Timeline>() {
                         @Override
                         public void onSuccess(Timeline result) {
                             if (result != null) {
-                                mod.setCurrentTimeline(result);
+                                mod.setCurrentTimeline(new SPTimeline(result));
                             }
                         }
 
@@ -435,10 +432,10 @@ public class GuiPathing {
                 @Override
                 public void onSuccess(Boolean delete) {
                     if (delete) {
-                        Timeline timeline = mod.createTimeline();
-                        timeline.createPath();
-                        timeline.createPath();
-                        mod.setCurrentTimeline(timeline);
+                        mod.clearCurrentTimeline();
+                        if (entityTracker != null) {
+                            mod.getCurrentTimeline().setEntityTracker(entityTracker);
+                        }
                     }
                 }
 
@@ -455,7 +452,7 @@ public class GuiPathing {
             // Position of the cursor
             int cursor = timeline.getCursorPosition();
             // Get the last time keyframe before the cursor
-            mod.getCurrentTimeline().getPaths().get(TIME_PATH).getKeyframes().stream()
+            mod.getCurrentTimeline().getTimePath().getKeyframes().stream()
                     .filter(it -> it.getTime() <= cursor).reduce((__, last) -> last).ifPresent(keyframe -> {
                 // Cursor position at the keyframe
                 int keyframeCursor = (int) keyframe.getTime();
@@ -471,7 +468,7 @@ public class GuiPathing {
                 // Move cursor to new position
                 timeline.setCursorPosition(keyframeCursor + cursorPassed);
                 // Deselect keyframe to allow the user to add a new one right away
-                mod.setSelectedKeyframe(null);
+                mod.setSelected(null, 0);
             });
         });
 
@@ -479,8 +476,8 @@ public class GuiPathing {
             if (!overlay.isVisible()) {
                 return;
             }
-            if (mod.getSelectedKeyframe() != null) {
-                updateKeyframe(mod.getSelectedKeyframe().getValue(TimestampProperty.PROPERTY).isPresent());
+            if (mod.getSelectedPath() != null) {
+                updateKeyframe(mod.getSelectedPath());
             }
         });
 
@@ -511,13 +508,12 @@ public class GuiPathing {
     }
 
     private boolean preparePathsForPlayback() {
-        Timeline timeline = mod.getCurrentTimeline();
-        timeline.getPaths().get(TIME_PATH).updateAll();
-        timeline.getPaths().get(POSITION_PATH).updateAll();
+        SPTimeline timeline = mod.getCurrentTimeline();
+        timeline.getTimeline().getPaths().forEach(Path::updateAll);
 
         // Make sure time keyframes's values are monotonically increasing
         int lastTime = 0;
-        for (Keyframe keyframe : timeline.getPaths().get(TIME_PATH).getKeyframes()) {
+        for (Keyframe keyframe : timeline.getTimePath().getKeyframes()) {
             int time = keyframe.getValue(TimestampProperty.PROPERTY).orElseThrow(IllegalStateException::new);
             if (time < lastTime) {
                 // We are going backwards in time
@@ -531,8 +527,8 @@ public class GuiPathing {
         }
 
         // Make sure there are at least two position- and two time-keyframes
-        if (timeline.getPaths().get(POSITION_PATH).getSegments().isEmpty()
-                || timeline.getPaths().get(TIME_PATH).getSegments().isEmpty()) {
+        if (timeline.getPositionPath().getSegments().isEmpty()
+                || timeline.getTimePath().getSegments().isEmpty()) {
             GuiInfoPopup.open(replayHandler.getOverlay(), "replaymod.chat.morekeyframes");
             return false;
         }
@@ -544,19 +540,19 @@ public class GuiPathing {
         scrollbar.setZoom(scrollbar.getZoom() * factor);
     }
 
-    /**
-     * Called when either one of the property buttons is pressed.
-     * @param isTime {@code true} for the time property button, {@code false} for the place property button
-     */
-    private void updateKeyframe(final boolean isTime) {
+    public boolean ensureEntityTracker(Runnable withDelayedTracker) {
         if (entityTracker == null) {
+            LOGGER.debug("Entity tracker not yet loaded, delaying...");
             LoadEntityTrackerPopup popup = new LoadEntityTrackerPopup(replayHandler.getOverlay());
             entityTrackerLoadingProgress = p -> popup.progressBar.setProgress(p.floatValue());
             Futures.addCallback(entityTrackerFuture, new FutureCallback<Void>() {
                 @Override
                 public void onSuccess(@Nullable Void result) {
                     popup.close();
-                    updateKeyframe(isTime);
+                    if (mod.getCurrentTimeline().getEntityTracker() == null) {
+                        mod.getCurrentTimeline().setEntityTracker(entityTracker);
+                    }
+                    withDelayedTracker.run();
                 }
 
                 @Override
@@ -564,184 +560,63 @@ public class GuiPathing {
                     popup.close();
                 }
             });
-            return;
+            return false;
         }
+        if (mod.getCurrentTimeline().getEntityTracker() == null) {
+            mod.getCurrentTimeline().setEntityTracker(entityTracker);
+        }
+        return true;
+    }
+
+    /**
+     * Called when either one of the property buttons is pressed.
+     * @param path {@code TIME} for the time property button, {@code POSITION} for the place property button
+     */
+    private void updateKeyframe(SPPath path) {
+        LOGGER.debug("Updating keyframe on path {}" + path);
+        if (!ensureEntityTracker(() -> updateKeyframe(path))) return;
 
         int time = timeline.getCursorPosition();
-        Timeline timeline = mod.getCurrentTimeline();
-        Path path = timeline.getPaths().get(isTime ? TIME_PATH : POSITION_PATH);
+        SPTimeline timeline = mod.getCurrentTimeline();
 
-        Keyframe keyframe = mod.getSelectedKeyframe();
-        if (keyframe != null && keyframe.getValue(TimestampProperty.PROPERTY).isPresent() ^ isTime) {
-            // Keyframe is on the wrong timeline
-            keyframe = null;
-        }
-        if (keyframe == null) {
-            // No keyframe selected but there may still be one at this exact time
-            keyframe = path.getKeyframe(time);
-        }
-        Change change;
-        if (keyframe == null) {
-            change = AddKeyframe.create(path, time);
-            change.apply(timeline);
-            keyframe = path.getKeyframe(time);
-        } else {
-            change = RemoveKeyframe.create(path, keyframe);
-            change.apply(timeline);
-            keyframe = null;
-        }
-
-        if (keyframe != null) {
-            UpdateKeyframeProperties.Builder builder = UpdateKeyframeProperties.create(path, keyframe);
-            if (isTime) {
-                builder.setValue(TimestampProperty.PROPERTY, replayHandler.getReplaySender().currentTimeStamp());
-            } else {
-                CameraEntity camera = replayHandler.getCameraEntity();
-                builder.setValue(CameraProperties.POSITION, Triple.of(camera.posX, camera.posY, camera.posZ));
-                builder.setValue(CameraProperties.ROTATION, Triple.of(camera.rotationYaw, camera.rotationPitch, camera.roll));
-                if (!replayHandler.isCameraView()) {
-                    Entity spectated = replayHandler.getOverlay().getMinecraft().getRenderViewEntity();
-                    builder.setValue(SpectatorProperty.PROPERTY, spectated.getEntityId());
+        switch (path) {
+            case TIME:
+                if (mod.getSelectedPath() == path) {
+                    LOGGER.debug("Selected keyframe is time keyframe -> removing keyframe");
+                    timeline.removeTimeKeyframe(mod.getSelectedTime());
+                    mod.setSelected(null, 0);
+                } else if (timeline.isTimeKeyframe(time)) {
+                    LOGGER.debug("Keyframe at cursor position is time keyframe -> removing keyframe");
+                    timeline.removeTimeKeyframe(time);
+                    mod.setSelected(null, 0);
+                } else {
+                    LOGGER.debug("No time keyframe found -> adding new keyframe");
+                    timeline.addTimeKeyframe(time, replayHandler.getReplaySender().currentTimeStamp());
+                    mod.setSelected(path, time);
                 }
-            }
-            UpdateKeyframeProperties updateChange = builder.done();
-            updateChange.apply(timeline);
-            change = CombinedChange.createFromApplied(change, updateChange);
-
-            // If this new keyframe formed the first segment of the time path
-            if (isTime && path.getSegments().size() == 1) {
-                PathSegment segment = path.getSegments().iterator().next();
-                Interpolator interpolator = new LinearInterpolator();
-                interpolator.registerProperty(TimestampProperty.PROPERTY);
-                SetInterpolator setInterpolator = SetInterpolator.create(segment, interpolator);
-                setInterpolator.apply(timeline);
-                change = CombinedChange.createFromApplied(change, setInterpolator);
-            }
-        }
-
-        // Update interpolators for spectator keyframes
-        // while this is overkill, it is far simpler than updating differently for every possible case
-        if (!isTime) {
-            Change interpolators = updateInterpolators();
-            interpolators.apply(timeline);
-            change = CombinedChange.createFromApplied(change, interpolators);
-        }
-
-        Change specPosUpdate = updateSpectatorPositions();
-        specPosUpdate.apply(timeline);
-        change = CombinedChange.createFromApplied(change, specPosUpdate);
-
-        timeline.pushChange(change);
-
-        mod.setSelectedKeyframe(keyframe);
-    }
-
-    public Change updateInterpolators() {
-        boolean linearInterpolation = mod.getCore().getSettingsRegistry().get(Setting.LINEAR_INTERPOLATION);
-        List<Change> changes = new ArrayList<>();
-        Interpolator interpolator = null;
-        boolean isSpectatorInterpolator = false;
-        for (PathSegment segment : mod.getCurrentTimeline().getPaths().get(POSITION_PATH).getSegments()) {
-            if (segment.getStartKeyframe().getValue(SpectatorProperty.PROPERTY).isPresent()
-                    && segment.getEndKeyframe().getValue(SpectatorProperty.PROPERTY).isPresent()) {
-                // Spectator segment
-                if (!isSpectatorInterpolator) {
-                    isSpectatorInterpolator = true;
-                    interpolator = new LinearInterpolator();
-                    interpolator.registerProperty(SpectatorProperty.PROPERTY);
+                break;
+            case POSITION:
+                if (mod.getSelectedPath() == path) {
+                    LOGGER.debug("Selected keyframe is position keyframe -> removing keyframe");
+                    timeline.removePositionKeyframe(mod.getSelectedTime());
+                    mod.setSelected(null, 0);
+                } else if (timeline.isPositionKeyframe(time)) {
+                    LOGGER.debug("Keyframe at cursor position is position keyframe -> removing keyframe");
+                    timeline.removePositionKeyframe(time);
+                    mod.setSelected(null, 0);
+                } else {
+                    LOGGER.debug("No position keyframe found -> adding new keyframe");
+                    CameraEntity camera = replayHandler.getCameraEntity();
+                    int spectatedId = -1;
+                    if (!replayHandler.isCameraView()) {
+                        spectatedId = replayHandler.getOverlay().getMinecraft().getRenderViewEntity().getEntityId();
+                    }
+                    timeline.addPositionKeyframe(time, camera.posX, camera.posY, camera.posZ,
+                            camera.rotationYaw, camera.rotationPitch, camera.roll, spectatedId);
+                    mod.setSelected(path, time);
                 }
-                changes.add(SetInterpolator.create(segment, interpolator));
-            } else {
-                // Normal segment
-                if (isSpectatorInterpolator || interpolator == null) {
-                    isSpectatorInterpolator = false;
-                    interpolator = linearInterpolation ? new LinearInterpolator() : new CubicSplineInterpolator();
-                    interpolator.registerProperty(CameraProperties.POSITION);
-                    interpolator.registerProperty(CameraProperties.ROTATION);
-                }
-                changes.add(SetInterpolator.create(segment, interpolator));
-            }
+                break;
         }
-        return CombinedChange.create(changes.toArray(new Change[changes.size()]));
-    }
-
-    public Change updateSpectatorPositions() {
-        List<Change> changes = new ArrayList<>();
-        Path positionPath = mod.getCurrentTimeline().getPaths().get(POSITION_PATH);
-        Path timePath = mod.getCurrentTimeline().getPaths().get(TIME_PATH);
-        timePath.updateAll();
-        for (Keyframe keyframe : positionPath.getKeyframes()) {
-            Optional<Integer> spectator = keyframe.getValue(SpectatorProperty.PROPERTY);
-            if (spectator.isPresent()) {
-                Optional<Integer> time = timePath.getValue(TimestampProperty.PROPERTY, keyframe.getTime());
-                if (!time.isPresent()) {
-                    continue; // No time keyframes set at this video time, cannot determine replay time
-                }
-                Location expected = entityTracker.getEntityPositionAtTimestamp(spectator.get(), time.get());
-                if (expected == null) {
-                    continue; // We don't have any data on this entity for some reason
-                }
-                Triple<Double, Double, Double> pos = keyframe.getValue(CameraProperties.POSITION).orElse(Triple.of(0D, 0D, 0D));
-                Triple<Float, Float, Float> rot = keyframe.getValue(CameraProperties.ROTATION).orElse(Triple.of(0F, 0F, 0F));
-                Location actual = new Location(pos.getLeft(), pos.getMiddle(), pos.getRight(), rot.getLeft(), rot.getRight());
-                if (!expected.equals(actual)) {
-                    changes.add(UpdateKeyframeProperties.create(positionPath, keyframe)
-                            .setValue(CameraProperties.POSITION, Triple.of(expected.getX(), expected.getY(), expected.getZ()))
-                            .setValue(CameraProperties.ROTATION, Triple.of(expected.getYaw(), expected.getPitch(), 0f)).done()
-                    );
-                }
-            }
-        }
-        return CombinedChange.create(changes.toArray(new Change[changes.size()]));
-    }
-
-    public Change moveKeyframe(Path path, Keyframe keyframe, long newTime) {
-        Timeline timeline = mod.getCurrentTimeline();
-        // Interpolator might be required later (only if path is the time path)
-        Optional<Interpolator> interpolator =
-                path.getSegments().stream().findFirst().map(PathSegment::getInterpolator);
-
-        // First remove the old keyframe
-        Change removeChange = RemoveKeyframe.create(path, keyframe);
-        removeChange.apply(timeline);
-
-        // and add a new one at the correct time
-        Change addChange = AddKeyframe.create(path, newTime);
-        addChange.apply(timeline);
-        path.getKeyframe(newTime);
-
-        // Then copy over all properties
-        UpdateKeyframeProperties.Builder builder = UpdateKeyframeProperties.create(path, path.getKeyframe(newTime));
-        for (Property property : keyframe.getProperties()) {
-            copyProperty(property, keyframe, builder);
-        }
-        Change propertyChange = builder.done();
-        propertyChange.apply(timeline);
-
-        // Finally set the interpolators
-        Change interpolatorChange;
-        if (path.getTimeline().getPaths().indexOf(path) == GuiPathing.POSITION_PATH) {
-            // Position / Spectator keyframes need special handling
-            interpolatorChange = updateInterpolators();
-        } else {
-            // Time keyframes only need updating when only one segment of them exists
-            if (path.getSegments().size() == 1) {
-                interpolatorChange = SetInterpolator.create(path.getSegments().iterator().next(), interpolator.get());
-            } else {
-                interpolatorChange = CombinedChange.create(); // Noop change
-            }
-        }
-        interpolatorChange.apply(timeline);
-        // and update spectator positions
-        Change spectatorChange = updateSpectatorPositions();
-        spectatorChange.apply(timeline);
-
-        return CombinedChange.createFromApplied(removeChange, addChange, propertyChange, interpolatorChange, spectatorChange);
-    }
-
-    // Helper method because generics cannot be defined on blocks
-    private <T> void copyProperty(Property<T> property, Keyframe from, UpdateKeyframeProperties.Builder to) {
-        from.getValue(property).ifPresent(value -> to.setValue(property, value));
     }
 
     public ReplayModSimplePathing getMod() {
@@ -752,13 +627,15 @@ public class GuiPathing {
         return entityTracker;
     }
 
-    public void openEditKeyframePopup(Path path, Keyframe keyframe) {
+    public void openEditKeyframePopup(SPPath path, long time) {
+        if (!ensureEntityTracker(() -> openEditKeyframePopup(path, time))) return;
+        Keyframe keyframe = mod.getCurrentTimeline().getKeyframe(path, time);
         if (keyframe.getProperties().contains(SpectatorProperty.PROPERTY)) {
-            new GuiEditKeyframe.Spectator(this, path, keyframe).open();
+            new GuiEditKeyframe.Spectator(this, path, keyframe.getTime()).open();
         } else if (keyframe.getProperties().contains(CameraProperties.POSITION)) {
-            new GuiEditKeyframe.Position(this, path, keyframe).open();
+            new GuiEditKeyframe.Position(this, path, keyframe.getTime()).open();
         } else {
-            new GuiEditKeyframe.Time(this, path, keyframe).open();
+            new GuiEditKeyframe.Time(this, path, keyframe.getTime()).open();
         }
     }
 

src/main/java/com/replaymod/simplepathing/preview/PathPreviewRenderer.java

@@ -9,10 +9,10 @@ import com.replaymod.replaystudio.pathing.interpolation.Interpolator;
 import com.replaymod.replaystudio.pathing.path.Keyframe;
 import com.replaymod.replaystudio.pathing.path.Path;
 import com.replaymod.replaystudio.pathing.path.PathSegment;
-import com.replaymod.replaystudio.pathing.path.Timeline;
 import com.replaymod.replaystudio.util.EntityPositionTracker;
 import com.replaymod.replaystudio.util.Location;
 import com.replaymod.simplepathing.ReplayModSimplePathing;
+import com.replaymod.simplepathing.SPTimeline;
 import com.replaymod.simplepathing.gui.GuiPathing;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.GlStateManager;
@@ -68,11 +68,11 @@ public class PathPreviewRenderer {
         if (guiPathing == null) return;
         EntityPositionTracker entityTracker = guiPathing.getEntityTracker();
 
-        Timeline timeline = mod.getCurrentTimeline();
+        SPTimeline timeline = mod.getCurrentTimeline();
         if (timeline == null) return;
-        Path path = timeline.getPaths().get(GuiPathing.POSITION_PATH);
+        Path path = timeline.getPositionPath();
         if (path.getKeyframes().isEmpty()) return;
-        Path timePath = timeline.getPaths().get(GuiPathing.TIME_PATH);
+        Path timePath = timeline.getTimePath();
 
         path.update();
 
@@ -97,8 +97,8 @@ public class PathPreviewRenderer {
                 if (spectator && entityTracker == null) {
                     continue; // Cannot render spectator positions when entity tracker is not yet loaded
                 }
-                // Spectator segments have 20 lines per second whereas normal segments have a fixed 100
-                long steps = spectator ? diff / 50 : 100;
+                // Spectator segments have 20 lines per second (at least 10) whereas normal segments have a fixed 100
+                long steps = spectator ? Math.max(diff / 50, 10) : 100;
                 Triple<Double, Double, Double> prevPos = null;
                 for (int i = 0; i <= steps; i++) {
                     long time = start.getTime() + diff * i / steps;
@@ -240,7 +240,7 @@ public class PathPreviewRenderer {
         float posY = 0f;
         float size = 10f / ReplayMod.TEXTURE_SIZE;
 
-        if (keyframe == mod.getSelectedKeyframe()) {
+        if (mod.isSelected(keyframe)) {
             posY += size;
         }
 

src/main/java/com/replaymod/simplepathing/properties/ExplicitInterpolationProperty.java

@@ -0,0 +1,44 @@
+package com.replaymod.simplepathing.properties;
+
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import com.replaymod.replaystudio.pathing.property.AbstractProperty;
+import com.replaymod.replaystudio.pathing.property.PropertyPart;
+import lombok.NonNull;
+import org.apache.commons.lang3.ObjectUtils;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Collections;
+
+/**
+ * Property indicating that the next path segment's interpolator is fixed
+ */
+public class ExplicitInterpolationProperty extends AbstractProperty<Object> {
+    public static final ExplicitInterpolationProperty PROPERTY = new ExplicitInterpolationProperty();
+
+    private ExplicitInterpolationProperty() {
+        super("interpolationFixed", "<internal>", null, new Object());
+    }
+
+    @Override
+    public Collection<PropertyPart<Object>> getParts() {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public void applyToGame(Object value, @NonNull Object replayHandler) {
+        // dummy property, do nothing
+    }
+
+    @Override
+    public void toJson(JsonWriter writer, Object value) throws IOException {
+        writer.nullValue();
+    }
+
+    @Override
+    public Object fromJson(JsonReader reader) throws IOException {
+        reader.nextNull();
+        return ObjectUtils.NULL;
+    }
+}

src/main/resources/META-INF/replaymod_at.cfg

@@ -1,7 +1,7 @@
 # To apply changes in this file run: ./gradlew clean setupDecompWorkspace idea
 
 # Minecraft
-public net.minecraft.client.Minecraft field_71428_T # timer
+public-f net.minecraft.client.Minecraft field_71428_T # timer
 public net.minecraft.client.Minecraft field_83002_am # debugCrashKeyPressTime
 public net.minecraft.client.Minecraft field_71467_ac # rightClickDelayTimer
 public net.minecraft.client.Minecraft field_71423_H # systemTime
@@ -95,10 +95,10 @@ public net.minecraft.client.entity.EntityOtherPlayerMP *
 public net.minecraft.server.integrated.IntegratedServer field_71348_o # isGamePaused
 
 # GameSettings
-public net.minecraft.client.settings.GameSettings field_186714_aM # soundLevels
+public-f net.minecraft.client.settings.GameSettings field_186714_aM # soundLevels
 
 # Frustum
-public net.minecraft.client.renderer.culling.Frustum field_78552_a # clippingHelper
+public-f net.minecraft.client.renderer.culling.Frustum field_78552_a # clippingHelper
 
 # CrashReportCategory
 public net.minecraft.crash.CrashReportCategory field_85077_c # children

src/main/resources/assets/replaymod/lang/en_US.lang

@@ -292,6 +292,7 @@ replaymod.gui.settings.title=Replay Mod Settings
 
 replaymod.gui.settings.interpolation.linear=Linear
 replaymod.gui.settings.interpolation.cubic=Cubic
+replaymod.gui.settings.interpolation.catmullrom=Catmull Rom
 
 replaymod.gui.settings.bitrate=Video Bitrate
 replaymod.gui.settings.framerate=Video Framerate
@@ -309,6 +310,7 @@ replaymod.gui.settings.keyframecleancallback=Clear Confirmation
 replaymod.gui.settings.renderinvisible=Render invisible Entities
 replaymod.gui.settings.camera=Camera
 replaymod.gui.settings.showchat=Show Chat
+replaymod.gui.settings.interpolator=Default Interpolator
 
 replaymod.gui.settings.warning.linea=WARNING: Recording settings will be
 replaymod.gui.settings.warning.lineb=applied the next time you join a world.
@@ -372,6 +374,17 @@ replaymod.gui.editkeyframe.spec.method.shoulder.pitch=Pitch Offset
 replaymod.gui.editkeyframe.spec.method.shoulder.yaw=Rotation Angle
 replaymod.gui.editkeyframe.spec.method.shoulder.smoothness=Path Smoothness
 
+replaymod.gui.editkeyframe.interpolator=Interpolator
+replaymod.gui.editkeyframe.interpolator.default.name=Default Interpolator
+replaymod.gui.editkeyframe.interpolator.default.desc=Uses the default interpolator defined in the Replay Mod Settings.
+replaymod.gui.editkeyframe.interpolator.catmullrom.name=Catmull Rom Spline Interpolator
+replaymod.gui.editkeyframe.interpolator.catmullrom.desc=Calculates a catmull rom spline with customizable alpha value for precise tightness and smoothness of the camera path.
+replaymod.gui.editkeyframe.interpolator.catmullrom.alpha=Alpha:
+replaymod.gui.editkeyframe.interpolator.cubic.name=Cubic Spline Interpolator
+replaymod.gui.editkeyframe.interpolator.cubic.desc=Calculates a cubic equation matrix for all points for a smooth camera path.
+replaymod.gui.editkeyframe.interpolator.linear.name=Linear Interpolator
+replaymod.gui.editkeyframe.interpolator.linear.desc=Draws straight lines between the keyframes.
+
 #Render Settings GUI
 replaymod.gui.rendersettings.title=Rendering Options
 replaymod.gui.rendersettings.renderer=Rendering Method

src/main/resources/dst_root_ca_x3.pem

@@ -0,0 +1,20 @@
+-----BEGIN CERTIFICATE-----
+MIIDSjCCAjKgAwIBAgIQRK+wgNajJ7qJMDmGLvhAazANBgkqhkiG9w0BAQUFADA/
+MSQwIgYDVQQKExtEaWdpdGFsIFNpZ25hdHVyZSBUcnVzdCBDby4xFzAVBgNVBAMT
+DkRTVCBSb290IENBIFgzMB4XDTAwMDkzMDIxMTIxOVoXDTIxMDkzMDE0MDExNVow
+PzEkMCIGA1UEChMbRGlnaXRhbCBTaWduYXR1cmUgVHJ1c3QgQ28uMRcwFQYDVQQD
+Ew5EU1QgUm9vdCBDQSBYMzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEB
+AN+v6ZdQCINXtMxiZfaQguzH0yxrMMpb7NnDfcdAwRgUi+DoM3ZJKuM/IUmTrE4O
+rz5Iy2Xu/NMhD2XSKtkyj4zl93ewEnu1lcCJo6m67XMuegwGMoOifooUMM0RoOEq
+OLl5CjH9UL2AZd+3UWODyOKIYepLYYHsUmu5ouJLGiifSKOeDNoJjj4XLh7dIN9b
+xiqKqy69cK3FCxolkHRyxXtqqzTWMIn/5WgTe1QLyNau7Fqckh49ZLOMxt+/yUFw
+7BZy1SbsOFU5Q9D8/RhcQPGX69Wam40dutolucbY38EVAjqr2m7xPi71XAicPNaD
+aeQQmxkqtilX4+U9m5/wAl0CAwEAAaNCMEAwDwYDVR0TAQH/BAUwAwEB/zAOBgNV
+HQ8BAf8EBAMCAQYwHQYDVR0OBBYEFMSnsaR7LHH62+FLkHX/xBVghYkQMA0GCSqG
+SIb3DQEBBQUAA4IBAQCjGiybFwBcqR7uKGY3Or+Dxz9LwwmglSBd49lZRNI+DT69
+ikugdB/OEIKcdBodfpga3csTS7MgROSR6cz8faXbauX+5v3gTt23ADq1cEmv8uXr
+AvHRAosZy5Q6XkjEGB5YGV8eAlrwDPGxrancWYaLbumR9YbK+rlmM6pZW87ipxZz
+R8srzJmwN0jP41ZL9c8PDHIyh8bwRLtTcm1D9SZImlJnt1ir/md2cXjbDaJWFBM5
+JDGFoqgCWjBH4d1QB7wCCZAA62RjYJsWvIjJEubSfZGL+T0yjWW06XyxV3bqxbYo
+Ob8VZRzI9neWagqNdwvYkQsEjgfbKbYK7p2CNTUQ
+-----END CERTIFICATE-----

src/test/java/com/replaymod/simplepathing/SPTimelineTest.java

@@ -0,0 +1,626 @@
+package com.replaymod.simplepathing;
+
+import com.google.common.collect.Iterables;
+import com.replaymod.pathing.properties.CameraProperties;
+import com.replaymod.pathing.properties.SpectatorProperty;
+import com.replaymod.pathing.properties.TimestampProperty;
+import com.replaymod.replaystudio.pathing.change.Change;
+import com.replaymod.replaystudio.pathing.interpolation.CatmullRomSplineInterpolator;
+import com.replaymod.replaystudio.pathing.interpolation.Interpolator;
+import com.replaymod.replaystudio.pathing.interpolation.LinearInterpolator;
+import com.replaymod.replaystudio.pathing.path.Keyframe;
+import com.replaymod.replaystudio.pathing.path.Path;
+import com.replaymod.replaystudio.pathing.path.PathSegment;
+import com.replaymod.replaystudio.pathing.path.Timeline;
+import com.replaymod.replaystudio.util.EntityPositionTracker;
+import com.replaymod.replaystudio.util.Location;
+import com.replaymod.simplepathing.SPTimeline.SPPath;
+import org.apache.commons.lang3.tuple.Triple;
+import org.apache.logging.log4j.LogManager;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.IdentityHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+
+public class SPTimelineTest {
+    private SPTimeline impl;
+    private Timeline timeline;
+
+    @BeforeClass
+    public static void setupLogger() {
+        ReplayModSimplePathing.LOGGER = LogManager.getLogger();
+    }
+
+    @Before
+    public void setup() {
+        impl = new SPTimeline();
+        impl.setDefaultInterpolatorType(InterpolatorType.CUBIC);
+        impl.setEntityTracker(new EntityPositionTrackerMock());
+        timeline = impl.getTimeline();
+    }
+
+    @Test
+    public void testGetPath() {
+        assertSame(impl.getTimeline().getPaths().get(0), impl.getTimePath());
+        assertSame(impl.getTimeline().getPaths().get(0), impl.getPath(SPPath.TIME));
+        assertSame(impl.getTimeline().getPaths().get(1), impl.getPositionPath());
+        assertSame(impl.getTimeline().getPaths().get(1), impl.getPath(SPPath.POSITION));
+    }
+
+    @Test
+    public void testGetKeyframe() {
+        assertSame(timeline.getPaths().get(0).insert(123), impl.getKeyframe(SPPath.TIME, 123));
+        assertSame(timeline.getPaths().get(1).insert(456), impl.getKeyframe(SPPath.POSITION, 456));
+    }
+
+    @Test
+    public void testIsTimeKeyframe() {
+        impl.getTimePath().insert(123);
+        impl.getPositionPath().insert(456);
+        impl.getPositionPath().insert(42).setValue(SpectatorProperty.PROPERTY, 42);
+        assertTrue(impl.isTimeKeyframe(123));
+        assertFalse(impl.isTimeKeyframe(456));
+        assertFalse(impl.isTimeKeyframe(789));
+        assertFalse(impl.isTimeKeyframe(42));
+    }
+
+    @Test
+    public void testIsPositionKeyframe() {
+        impl.getTimePath().insert(123);
+        impl.getPositionPath().insert(456);
+        impl.getPositionPath().insert(42).setValue(SpectatorProperty.PROPERTY, 42);
+        assertFalse(impl.isPositionKeyframe(123));
+        assertTrue(impl.isPositionKeyframe(456));
+        assertFalse(impl.isPositionKeyframe(789));
+        assertTrue(impl.isSpectatorKeyframe(42));
+    }
+
+    @Test
+    public void testIsSpectatorKeyframe() {
+        impl.getTimePath().insert(123);
+        impl.getPositionPath().insert(456);
+        impl.getPositionPath().insert(42).setValue(SpectatorProperty.PROPERTY, 42);
+        assertFalse(impl.isSpectatorKeyframe(123));
+        assertFalse(impl.isSpectatorKeyframe(456));
+        assertFalse(impl.isSpectatorKeyframe(789));
+        assertTrue(impl.isSpectatorKeyframe(42));
+    }
+
+    @Test
+    public void testAddPositionKeyframe() {
+        assertNull(timeline.peekUndoStack());
+        impl.addPositionKeyframe(0, 1, 2, 3, 4, 5, 6, -1);
+        assertNotNull(timeline.peekUndoStack());
+        Keyframe keyframe = impl.getKeyframe(SPPath.POSITION, 0);
+        assertNotNull(keyframe);
+        assertEquals(keyframe.getValue(CameraProperties.POSITION), Optional.of(Triple.of(1d, 2d, 3d)));
+        assertEquals(keyframe.getValue(CameraProperties.ROTATION), Optional.of(Triple.of(4f, 5f, 6f)));
+        assertFalse(keyframe.getValue(SpectatorProperty.PROPERTY).isPresent());
+        timeline.undoLastChange();
+        assertNull(timeline.peekUndoStack());
+        assertNull(impl.getKeyframe(SPPath.POSITION, 0));
+    }
+
+    @Test
+    public void testAddPositionKeyframeSpectator() {
+        assertNull(timeline.peekUndoStack());
+        impl.addPositionKeyframe(0, 1, 2, 3, 4, 5, 6, 7);
+        assertNotNull(timeline.peekUndoStack());
+        Keyframe keyframe = impl.getKeyframe(SPPath.POSITION, 0);
+        assertNotNull(keyframe);
+        assertEquals(keyframe.getValue(CameraProperties.POSITION), Optional.of(Triple.of(1d, 2d, 3d)));
+        assertEquals(keyframe.getValue(CameraProperties.ROTATION), Optional.of(Triple.of(4f, 5f, 6f)));
+        assertEquals(keyframe.getValue(SpectatorProperty.PROPERTY), Optional.of(7));
+        timeline.undoLastChange();
+        assertNull(timeline.peekUndoStack());
+        assertNull(impl.getKeyframe(SPPath.POSITION, 0));
+    }
+
+    @Test
+    public void testPositionKeyframeSpectatorPosition() {
+        Keyframe keyframe;
+        impl.addTimeKeyframe(0, 0);
+        impl.addTimeKeyframe(9, 9);
+
+        impl.addPositionKeyframe(4, 1, 2, 3, 4, 5, 6, 1);
+        keyframe = impl.getKeyframe(SPPath.POSITION, 4);
+        assertEquals(keyframe.getValue(CameraProperties.POSITION), Optional.of(Triple.of(1d, 2d, 3d)));
+        assertEquals(keyframe.getValue(CameraProperties.ROTATION), Optional.of(Triple.of(4f, 5f, 6f)));
+
+        impl.addPositionKeyframe(6, 1, 2, 3, 4, 5, 6, 42);
+        keyframe = impl.getKeyframe(SPPath.POSITION, 6);
+        assertEquals(keyframe.getValue(CameraProperties.POSITION), Optional.of(Triple.of(12d, 0d, 0d)));
+        assertEquals(keyframe.getValue(CameraProperties.ROTATION), Optional.of(Triple.of(0f, 0f, 0f)));
+
+        impl.addPositionKeyframe(8, 1, 2, 3, 4, 5, 6, 42);
+        keyframe = impl.getKeyframe(SPPath.POSITION, 8);
+        assertEquals(keyframe.getValue(CameraProperties.POSITION), Optional.of(Triple.of(16d, 0d, 0d)));
+        assertEquals(keyframe.getValue(CameraProperties.ROTATION), Optional.of(Triple.of(0f, 0f, 0f)));
+
+        impl.addPositionKeyframe(10, 1, 2, 3, 4, 5, 6, 42);
+        keyframe = impl.getKeyframe(SPPath.POSITION, 10);
+        assertEquals(keyframe.getValue(CameraProperties.POSITION), Optional.of(Triple.of(1d, 2d, 3d)));
+        assertEquals(keyframe.getValue(CameraProperties.ROTATION), Optional.of(Triple.of(4f, 5f, 6f)));
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testAddPositionKeyframeDuplicate() {
+        impl.addPositionKeyframe(0, 1, 2, 3, 4, 5, 6, -1);
+        impl.addPositionKeyframe(0, 1, 2, 3, 4, 5, 6, -1);
+    }
+
+    @Test
+    public void testUpdatePositionKeyframe() {
+        impl.addPositionKeyframe(0, 1, 2, 3, 4, 5, 6, -1);
+        Change change = impl.updatePositionKeyframe(0, 7, 8, 9, 10, 11, 12);
+        assertNotNull(change);
+        Keyframe keyframe = impl.getKeyframe(SPPath.POSITION, 0);
+        assertEquals(keyframe.getValue(CameraProperties.POSITION), Optional.of(Triple.of(7d, 8d, 9d)));
+        assertEquals(keyframe.getValue(CameraProperties.ROTATION), Optional.of(Triple.of(10f, 11f, 12f)));
+        assertFalse(keyframe.getValue(SpectatorProperty.PROPERTY).isPresent());
+        change.undo(timeline);
+        keyframe = impl.getKeyframe(SPPath.POSITION, 0);
+        assertEquals(keyframe.getValue(CameraProperties.POSITION), Optional.of(Triple.of(1d, 2d, 3d)));
+        assertEquals(keyframe.getValue(CameraProperties.ROTATION), Optional.of(Triple.of(4f, 5f, 6f)));
+        assertFalse(keyframe.getValue(SpectatorProperty.PROPERTY).isPresent());
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testUpdatePositionKeyframeNoKeyframe() {
+        impl.updatePositionKeyframe(0, 1, 2, 3, 4, 5, 6);
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testUpdatePositionKeyframeSpectatorKeyframe() {
+        impl.addPositionKeyframe(0, 1, 2, 3, 4, 5, 6, 7);
+        impl.updatePositionKeyframe(0, 1, 2, 3, 4, 5, 6);
+    }
+
+    @Test
+    public void testRemovePositionKeyframe() {
+        impl.addPositionKeyframe(0, 1, 2, 3, 4, 5, 6, -1);
+        impl.removePositionKeyframe(0);
+        assertNull(impl.getKeyframe(SPPath.POSITION, 0));
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testRemovePositionKeyframeNoKeyframe() {
+        impl.removePositionKeyframe(0);
+    }
+
+    @Test
+    public void testAddTimeKeyframe() {
+        assertNull(timeline.peekUndoStack());
+        impl.addTimeKeyframe(0, 1);
+        assertNotNull(timeline.peekUndoStack());
+        Keyframe keyframe = impl.getKeyframe(SPPath.TIME, 0);
+        assertNotNull(keyframe);
+        assertEquals(keyframe.getValue(TimestampProperty.PROPERTY), Optional.of(1));
+        timeline.undoLastChange();
+        assertNull(timeline.peekUndoStack());
+        assertNull(impl.getKeyframe(SPPath.TIME, 0));
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testAddTimeKeyframeDuplicate() {
+        impl.addTimeKeyframe(0, 1);
+        impl.addTimeKeyframe(0, 1);
+    }
+
+    @Test
+    public void testUpdateTimeKeyframe() {
+        impl.addTimeKeyframe(0, 1);
+        Change change = impl.updateTimeKeyframe(0, 2);
+        assertNotNull(change);
+        assertEquals(impl.getKeyframe(SPPath.TIME, 0).getValue(TimestampProperty.PROPERTY), Optional.of(2));
+        change.undo(timeline);
+        assertEquals(impl.getKeyframe(SPPath.TIME, 0).getValue(TimestampProperty.PROPERTY), Optional.of(1));
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testUpdateTimeKeyframeNoKeyframe() {
+        impl.updateTimeKeyframe(0, 1);
+    }
+
+    @Test
+    public void testRemoveTimeKeyframe() {
+        impl.addTimeKeyframe(0, 1);
+        impl.removeTimeKeyframe(0);
+        assertNull(impl.getKeyframe(SPPath.TIME, 0));
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testRemoveTimeKeyframeNoKeyframe() {
+        impl.removeTimeKeyframe(0);
+    }
+
+    /**
+     * Checks all interpolators to make sure that they are continuous and not fragmented.
+     */
+    private void assertValidInterpolators(SPPath path, int expectedNumberOfInterpolators) {
+        String str = prettyPrintInterpolators(impl, path);
+        List<Interpolator> interpolators = impl.getPath(path).getSegments().stream().map(PathSegment::getInterpolator)
+                .distinct().collect(Collectors.toList());
+        assertFalse("Not all interpolators set: " + str, interpolators.contains(null));
+        assertEquals("Mismatched interpolator number: " + str, expectedNumberOfInterpolators, interpolators.size());
+        int i = 0;
+        for (Interpolator interpolator : interpolators) {
+            Keyframe lastKeyframe = null;
+            for (PathSegment segment : interpolator.getSegments().stream()
+                    .sorted(Comparator.comparing(s -> s.getStartKeyframe().getTime())).collect(Collectors.toList())) {
+                String message = "Fragmentation in interpolator " + i + ": " + str;
+                assertTrue(message, lastKeyframe == null || segment.getStartKeyframe() == lastKeyframe);
+                lastKeyframe = segment.getEndKeyframe();
+            }
+            i++;
+        }
+    }
+
+    @Test
+    public void testAddPositionKeyframeAppend() {
+        addPosition(0, 0);
+        addPosition(1, 1);
+        addPosition(2, 1);
+        addPosition(3, 1);
+        addPosition(4, 1);
+    }
+
+    @Test
+    public void testAddPositionKeyframePrepend() {
+        addPosition(4, 0);
+        addPosition(3, 1);
+        addPosition(2, 1);
+        addPosition(1, 1);
+        addPosition(0, 1);
+    }
+
+    @Test
+    public void testAddPositionKeyframeMixed() {
+        addPosition(2, 0);
+        addPosition(4, 1);
+        addPosition(3, 1);
+        addPosition(0, 1);
+        addPosition(1, 1);
+    }
+
+    @Test
+    public void testAddPositionSpectatorKeyframe() {
+        addPosition(0, 0);
+        addSpectator(1, 1);
+        addSpectator(2, 2);
+        addPosition(4, 3);
+        addPosition(7, 3);
+        addPosition(8, 3);
+        addSpectator(3, 3);
+        addSpectator(5, 3);
+        addSpectator(6, 5);
+    }
+
+    @Test
+    public void testRemovePositionKeyframeFromStart() {
+        addPosition(0, 0);
+        addPosition(1, 1);
+        addPosition(2, 1);
+        addPosition(3, 1);
+        removePosition(0, 1);
+        removePosition(1, 1);
+        removePosition(2, 0);
+        removePosition(3, 0);
+    }
+
+    @Test
+    public void testRemovePositionKeyframeFromEnd() {
+        addPosition(0, 0);
+        addPosition(1, 1);
+        addPosition(2, 1);
+        addPosition(3, 1);
+        removePosition(3, 1);
+        removePosition(2, 1);
+        removePosition(1, 0);
+        removePosition(0, 0);
+    }
+
+    @Test
+    public void testRemovePositionKeyframeFromMiddle() {
+        addPosition(0, 0);
+        addPosition(1, 1);
+        addPosition(2, 1);
+        addPosition(3, 1);
+        removePosition(1, 1);
+        removePosition(2, 1);
+        removePosition(0, 0);
+        removePosition(3, 0);
+    }
+
+    @Test
+    public void testRemovePositionSpectatorKeyframe() {
+        addPosition(0, 0);
+        addPosition(1, 1);
+        addPosition(2, 1);
+        addSpectator(3, 1);
+        addSpectator(4, 2);
+        addSpectator(5, 2);
+        addPosition(6, 3);
+        addPosition(7, 3);
+        addSpectator(8, 3);
+        addSpectator(9, 4);
+        removePosition(4, 4);
+        removePosition(9, 3);
+        removePosition(6, 3);
+        removePosition(7, 2);
+        removePosition(0, 2);
+        removePosition(1, 2);
+        removePosition(3, 2);
+        removePosition(2, 1);
+        removePosition(5, 0);
+        removePosition(8, 0);
+    }
+
+    @Test
+    public void testAddTimeKeyframeAppend() {
+        addTime(0, 0);
+        addTime(1, 1);
+        addTime(2, 1);
+        addTime(3, 1);
+        addTime(4, 1);
+    }
+
+    @Test
+    public void testAddTimeKeyframePrepend() {
+        addTime(4, 0);
+        addTime(3, 1);
+        addTime(2, 1);
+        addTime(1, 1);
+        addTime(0, 1);
+    }
+
+    @Test
+    public void testAddTimeKeyframeMixed() {
+        addTime(2, 0);
+        addTime(4, 1);
+        addTime(3, 1);
+        addTime(0, 1);
+        addTime(1, 1);
+    }
+
+    @Test
+    public void testRemoveTimeKeyframeFromStart() {
+        addTime(0, 0);
+        addTime(1, 1);
+        addTime(2, 1);
+        addTime(3, 1);
+        removeTime(0, 1);
+        removeTime(1, 1);
+        removeTime(2, 0);
+        removeTime(3, 0);
+    }
+
+    @Test
+    public void testRemoveTimeKeyframeFromEnd() {
+        addTime(0, 0);
+        addTime(1, 1);
+        addTime(2, 1);
+        addTime(3, 1);
+        removeTime(3, 1);
+        removeTime(2, 1);
+        removeTime(1, 0);
+        removeTime(0, 0);
+    }
+
+    @Test
+    public void testRemoveTimeKeyframeFromMiddle() {
+        addTime(0, 0);
+        addTime(1, 1);
+        addTime(2, 1);
+        addTime(3, 1);
+        removeTime(1, 1);
+        removeTime(2, 1);
+        removeTime(0, 0);
+        removeTime(3, 0);
+    }
+
+    @Test
+    public void testSetInterpolator() {
+        addPosition(0, 0);
+        addPosition(1, 1);
+        addPosition(2, 1);
+        setInterpolator(1, new LinearInterpolator(), 2);
+        assertIsLinear(1);
+        Interpolator interpolator = Iterables.get(impl.getPositionPath().getSegments(), 1).getInterpolator();
+        assertTrue(interpolator.getKeyframeProperties().contains(CameraProperties.POSITION));
+        assertTrue(interpolator.getKeyframeProperties().contains(CameraProperties.ROTATION));
+        addPosition(3, 3);
+        addPosition(4, 3);
+        addPosition(5, 3);
+        setInterpolator(3, new LinearInterpolator(), 5);
+        assertIsLinear(3);
+        removePosition(2, 3);
+        removePosition(3, 3);
+        removePosition(0, 2);
+        removePosition(1, 1);
+        removePosition(4, 0);
+        removePosition(5, 0);
+    }
+
+    private void assertIsLinear(int index) {
+        assertTrue("Expected segment " + index + " to have linear interpolator: " + prettyPrintInterpolators(impl, SPPath.POSITION),
+                Iterables.get(impl.getPositionPath().getSegments(), index).getInterpolator() instanceof LinearInterpolator);
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testSetInterpolatorNoKeyframe() {
+        addTime(0, 0);
+        impl.setInterpolator(0, new LinearInterpolator());
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testSetInterpolatorToDefaultNoKeyframe() {
+        addTime(0, 0);
+        impl.setInterpolatorToDefault(0);
+    }
+
+    @Test
+    public void testMoveKeyframe() {
+        addPosition(1, 0);
+        addPosition(3, 1);
+        addPosition(5, 1);
+        addPosition(7, 1);
+        addSpectator(9, 1);
+        addSpectator(11, 2);
+        addSpectator(13, 2);
+        addPosition(15, 3);
+        addPosition(17, 3);
+        addPosition(19, 3);
+        setInterpolator(3, new LinearInterpolator(), 5);
+        assertIsLinear(1);
+        setInterpolator(5, new LinearInterpolator(), 5);
+        assertIsLinear(2);
+        // [P 1] C0 [P 3] L1 [P 5] L1 [P 7] C2 [S 9] L3 [S 11] L3 [S 13] C4 [P 15] C4 [P 17] C4 [P 19]
+
+        impl.moveKeyframe(SPPath.POSITION, 5, 0);
+        assertValidInterpolators(SPPath.POSITION, 6);
+        assertIsLinear(0);
+        impl.moveKeyframe(SPPath.POSITION, 0, 5);
+        assertValidInterpolators(SPPath.POSITION, 5);
+        assertIsLinear(2);
+
+        impl.moveKeyframe(SPPath.POSITION, 3, 12);
+        assertValidInterpolators(SPPath.POSITION, 7);
+        assertIsLinear(5);
+        impl.moveKeyframe(SPPath.POSITION, 12, 3);
+        assertValidInterpolators(SPPath.POSITION, 5);
+        assertIsLinear(1);
+
+        impl.moveKeyframe(SPPath.POSITION, 7, 14);
+        assertValidInterpolators(SPPath.POSITION, 4);
+        impl.moveKeyframe(SPPath.POSITION, 14, 20);
+        assertValidInterpolators(SPPath.POSITION, 4);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testSetDefaultInterpolatorDifferentType() {
+        addPosition(0, 0);
+        addPosition(1, 1);
+        impl.setDefaultInterpolator(new CatmullRomSplineInterpolator(42));
+    }
+
+    @Test
+    public void testSetDefaultInterpolatorSameType() {
+        impl.setDefaultInterpolatorType(InterpolatorType.CATMULL_ROM);
+        addPosition(0, 0);
+        addSpectator(1, 1);
+        addSpectator(2, 2);
+        addPosition(3, 3);
+        addPosition(4, 3);
+        impl.setDefaultInterpolator(new CatmullRomSplineInterpolator(42));
+        assertValidInterpolators(SPPath.POSITION, 3);
+        assertIsCatmullRom(0, 42);
+        assertIsCatmullRom(2, 42);
+        assertIsCatmullRom(3, 42);
+    }
+
+    private void assertIsCatmullRom(int index, double alpha) {
+        String str = prettyPrintInterpolators(impl, SPPath.POSITION);
+        Interpolator interpolator = Iterables.get(impl.getPositionPath().getSegments(), index).getInterpolator();
+        assertTrue("Expected segment " + index + " to be catmull rom interpolator: " + str,
+                 interpolator instanceof CatmullRomSplineInterpolator);
+        assertTrue("Expected interpolator of segment segment " + index + " to have alpha " + alpha + ": " + str,
+                ((CatmullRomSplineInterpolator) interpolator).getAlpha() == 42);
+    }
+
+    private void addPosition(int time, int expectedNumberOfInterpolators) {
+        impl.addPositionKeyframe(time, 1, 2, 3, 4, 5, 6, -1);
+        assertNotNull(impl.getKeyframe(SPPath.POSITION, time));
+        assertValidInterpolators(SPPath.POSITION, expectedNumberOfInterpolators);
+    }
+
+    private void addSpectator(int time, int expectedNumberOfInterpolators) {
+        impl.addPositionKeyframe(time, 1, 2, 3, 4, 5, 6, 42);
+        assertNotNull(impl.getKeyframe(SPPath.POSITION, time));
+        assertTrue(impl.isSpectatorKeyframe(time));
+        assertValidInterpolators(SPPath.POSITION, expectedNumberOfInterpolators);
+    }
+
+    private void addTime(int time, int expectedNumberOfInterpolators) {
+        impl.addTimeKeyframe(time, 1);
+        assertNotNull(impl.getKeyframe(SPPath.TIME, time));
+        assertValidInterpolators(SPPath.TIME, expectedNumberOfInterpolators);
+    }
+
+    private void removePosition(int time, int expectedNumberOfInterpolators) {
+        impl.removePositionKeyframe(time);
+        assertNull(impl.getKeyframe(SPPath.POSITION, time));
+        assertValidInterpolators(SPPath.POSITION, expectedNumberOfInterpolators);
+    }
+
+    private void removeTime(int time, int expectedNumberOfInterpolators) {
+        impl.removeTimeKeyframe(time);
+        assertNull(impl.getKeyframe(SPPath.TIME, time));
+        assertValidInterpolators(SPPath.TIME, expectedNumberOfInterpolators);
+    }
+
+    private void setInterpolator(int time, Interpolator interpolator, int expectedNumberOfInterpolators) {
+        impl.setInterpolator(time, interpolator);
+        assertValidInterpolators(SPPath.POSITION, expectedNumberOfInterpolators);
+    }
+
+    private void assertPositionState(String expected) {
+        assertEquals(expected, prettyPrintInterpolators(impl, SPPath.POSITION));
+    }
+
+    // Tracks only entity 42 which always is at x=time*2, y,z=0
+    private class EntityPositionTrackerMock extends EntityPositionTracker {
+        public EntityPositionTrackerMock() {
+            super(null);
+        }
+
+        @Override
+        public Location getEntityPositionAtTimestamp(int entityID, long timestamp) {
+            if (entityID == 42) {
+                return new Location(timestamp * 2, 0 ,0, 0, 0);
+            } else {
+                return null;
+            }
+        }
+    }
+
+    public static String prettyPrintInterpolators(SPTimeline timeline, SPPath spPath) {
+        return prettyPrintInterpolators(timeline, spPath, Collections.emptyMap());
+    }
+
+    public static String prettyPrintInterpolators(SPTimeline timeline, SPPath spPath, Map<PathSegment, Interpolator> updates) {
+        Map<Interpolator, String> interpolatorIdMap = new IdentityHashMap<>();
+        Path path = timeline.getPath(spPath);
+        StringBuilder sb = new StringBuilder();
+        for (Keyframe keyframe : path.getKeyframes()) {
+            if (spPath == SPPath.TIME) {
+                sb.append("[T ").append(keyframe.getTime()).append("]");
+            } else if (keyframe.getValue(SpectatorProperty.PROPERTY).isPresent()) {
+                sb.append("[S ").append(keyframe.getTime()).append("]");
+            } else {
+                sb.append("[P ").append(keyframe.getTime()).append("]");
+            }
+            path.getSegments().stream().filter(s -> s.getStartKeyframe() == keyframe).findFirst().ifPresent(segment -> {
+                Interpolator interpolator = updates.getOrDefault(segment, segment.getInterpolator());
+                String id = interpolatorIdMap.computeIfAbsent(interpolator, i ->
+                        (i instanceof LinearInterpolator ? "L" : "C") + interpolatorIdMap.size());
+                sb.append(' ').append(id).append(' ');
+            });
+        }
+        return sb.toString();
+    }
+}