package com.replaymod.replay;

import com.google.common.io.Files;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.ListenableFutureTask;
import com.google.common.util.concurrent.SettableFuture;
import lombok.AccessLevel;
import lombok.Getter;
import lombok.RequiredArgsConstructor;
import net.minecraft.client.Minecraft;
import net.minecraft.client.renderer.GlStateManager;
import net.minecraft.util.ScreenShotHelper;
import org.apache.commons.io.FileUtils;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;

@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
@Getter
public class NoGuiScreenshot {
    private final BufferedImage image;
    private final int width;
    private final int height;

    public static ListenableFuture<NoGuiScreenshot> take(final Minecraft mc, final int width, final int height) {
        final SettableFuture<NoGuiScreenshot> future = SettableFuture.create();
        Runnable runnable = new Runnable() {
            @Override
            public void run() {
                if (future.isCancelled()) {
                    return;
                }

                final boolean guiHidden = mc.gameSettings.hideGUI;
                try {
                    mc.gameSettings.hideGUI = true;

                    // Render frame without GUI
                    GlStateManager.pushMatrix();
                    GlStateManager.clear(16640);
                    mc.getFramebuffer().bindFramebuffer(true);
                    GlStateManager.enableTexture2D();

                    mc.entityRenderer.updateCameraAndRender(mc.timer.renderPartialTicks, System.nanoTime());

                    mc.getFramebuffer().unbindFramebuffer();
                    GlStateManager.popMatrix();
                    GlStateManager.pushMatrix();
                    mc.getFramebuffer().framebufferRender(mc.displayWidth, mc.displayHeight);
                    GlStateManager.popMatrix();
                } catch (Throwable t) {
                    future.setException(t);
                    return;
                } finally {
                    // Reset GUI settings
                    mc.gameSettings.hideGUI = guiHidden;
                }

                // The frame without GUI has been rendered
                // Read it, create the screenshot and finish the future
                // We're using Minecraft's ScreenShotHelper even though it writes the screenshot to
                // disk for better maintainability
                File tmpFolder = Files.createTempDir();
                try {
                    ScreenShotHelper.saveScreenshot(tmpFolder, "tmp", mc.displayWidth, mc.displayHeight, mc.getFramebuffer());
                    File screenshotFile = new File(tmpFolder, "screenshots/tmp");
                    BufferedImage image = ImageIO.read(screenshotFile);
                    int imageWidth = image.getWidth();
                    int imageHeight = image.getHeight();

                    // First scale
                    float scaleFactor = Math.max((float) width / imageWidth, (float) height / imageHeight);
                    int scaledWidth = (int) (imageWidth * scaleFactor);
                    int scaledHeight = (int) (imageHeight * scaleFactor);
                    Image scaledImage = image.getScaledInstance(scaledWidth, scaledHeight, Image.SCALE_SMOOTH);

                    // Then crop
                    int resultX = (scaledWidth - width) / 2;
                    int resultY = (scaledHeight - height) / 2;
                    BufferedImage resultImage = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);
                    Graphics2D graphics = resultImage.createGraphics();
                    graphics.drawImage(scaledImage, 0, 0, width, height,
                            resultX, resultY, resultX + width, resultY + height, null);
                    graphics.dispose();

                    // Finish
                    future.set(new NoGuiScreenshot(resultImage, width, height));
                } catch (Throwable t) {
                    future.setException(t);
                } finally {
                    FileUtils.deleteQuietly(tmpFolder);
                }
            }
        };

        // Make sure we are not somewhere in the middle of the rendering process but always at the beginning
        // of the game loop. We cannot use the addScheduledTask method as it'll run the task if called
        // from the minecraft thread which is exactly what we want to avoid.
        synchronized (mc.scheduledTasks) {
            mc.scheduledTasks.add(ListenableFutureTask.create(runnable, null));
        }
        return future;
    }
}