package com.fuyuanshen.web.util;

import lombok.extern.slf4j.Slf4j;
import org.bytedeco.javacv.FFmpegFrameGrabber;
import org.bytedeco.javacv.Frame;
import org.bytedeco.javacv.Java2DFrameUtils;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.List;

/**
 * 视频处理工具类
 */
@Slf4j
@Component
public class VideoProcessUtil {

    private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();

    /**
     * 创建临时视频文件
     */
    public File createTempVideoFile(MultipartFile file) throws Exception {
        File tempFile = Files.createTempFile("upload-", ".mp4").toFile();
        file.transferTo(tempFile);
        log.debug("创建临时视频文件: {}", tempFile.getAbsolutePath());
        return tempFile;
    }

    /**
     * 处理视频并转换为Hex字符串列表
     */
    public List<String> processVideoToHex(File videoFile, int frameRate, int duration, int width, int height) throws Exception {
        // 1. 提取视频帧
        List<BufferedImage> frames = extractFramesFromVideo(videoFile, frameRate, duration, width, height);

        // 2. 转换为RGB565格式
        byte[] binaryData = convertFramesToRGB565(frames);

        // 3. 转换为Hex字符串列表
        return bytesToHexList(binaryData);
    }

    /**
     * 从视频中提取帧
     */
    private List<BufferedImage> extractFramesFromVideo(File videoFile, int frameRate, int duration, int width, int height) throws Exception {
        List<BufferedImage> frames = new ArrayList<>();
        int totalFramesToExtract = frameRate * duration;

        try (FFmpegFrameGrabber grabber = FFmpegFrameGrabber.createDefault(videoFile)) {
            grabber.start();

            long totalFramesInVideo = grabber.getLengthInFrames();
            int fps = (int) Math.round(grabber.getFrameRate());
            if (fps <= 0) fps = 30;

            double durationSeconds = (double) totalFramesInVideo / fps;
            if (durationSeconds < duration) {
                throw new IllegalArgumentException("视频太短，至少需要 " + duration + " 秒");
            }

            double frameInterval = (double) totalFramesInVideo / totalFramesToExtract;

            for (int i = 0; i < totalFramesToExtract; i++) {
                int targetFrameNumber = (int) Math.round(i * frameInterval);

                if (targetFrameNumber >= totalFramesInVideo) {
                    throw new IllegalArgumentException("目标帧超出范围: " + targetFrameNumber);
                }

                grabber.setFrameNumber(targetFrameNumber);
                Frame frame = grabber.grab();

                if (frame != null && frame.image != null) {
                    BufferedImage bufferedImage = Java2DFrameUtils.toBufferedImage(frame);
                    frames.add(cropImage(bufferedImage, width, height));
                } else {
                    throw new IllegalArgumentException("无法获取第 " + targetFrameNumber + "帧");
                }
            }

            grabber.stop();
        }

        log.debug("从视频中提取了 {} 帧", frames.size());
        return frames;
    }

    /**
     * 将所有帧转换为 RGB565 格式字节数组
     */
    private byte[] convertFramesToRGB565(List<BufferedImage> frames) throws Exception {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        for (BufferedImage image : frames) {
            byte[] rgb565Bytes = convertToRGB565(image);
            byteArrayOutputStream.write(rgb565Bytes);
        }

        byte[] result = byteArrayOutputStream.toByteArray();
        log.debug("转换RGB565数据完成，总字节数: {}", result.length);
        return result;
    }

    /**
     * 将字节数组转换为Hex字符串列表
     */
    private List<String> bytesToHexList(byte[] bytes) {
        List<String> hexList = new ArrayList<>();
        for (byte b : bytes) {
            int value = b & 0xFF;
            char high = HEX_ARRAY[value >>> 4];
            char low = HEX_ARRAY[value & 0x0F];
            hexList.add(String.valueOf(high) + low);
        }
        return hexList;
    }

    /**
     * 删除临时文件
     */
    public void deleteTempFile(File file) {
        if (file != null && file.exists()) {
            if (file.delete()) {
                log.debug("删除临时文件成功: {}", file.getAbsolutePath());
            } else {
                log.warn("无法删除临时文件: {}", file.getAbsolutePath());
            }
        }
    }

    /**
     * 裁剪图像到目标尺寸
     */
    private BufferedImage cropImage(BufferedImage img, int targetWidth, int targetHeight) {
        int w = Math.min(img.getWidth(), targetWidth);
        int h = Math.min(img.getHeight(), targetHeight);
        return img.getSubimage(0, 0, w, h);
    }

    /**
     * 将 BufferedImage 转换为 RGB565 格式的字节数组
     */
    private byte[] convertToRGB565(BufferedImage image) {
        int width = image.getWidth();
        int height = image.getHeight();
        byte[] result = new byte[width * height * 2];
        int index = 0;

        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                int rgb = image.getRGB(x, y);
                int r = ((rgb >> 16) & 0xFF) >> 3;
                int g = ((rgb >> 8) & 0xFF) >> 2;
                int b = (rgb & 0xFF) >> 3;
                short pixel = (short) ((r << 11) | (g << 5) | b);

                result[index++] = (byte) (pixel >> 8);
                result[index++] = (byte) pixel;
            }
        }

        return result;
    }

    /**
     * 保存帧到本地（用于调试）
     */
    public void saveFramesToLocal(List<BufferedImage> frames, String prefix) {
        File outputDir = new File("output_frames");
        if (!outputDir.exists()) {
            outputDir.mkdirs();
        }

        int index = 0;
        for (BufferedImage frame : frames) {
            try {
                File outputImage = new File(outputDir, prefix + "_" + (index++) + ".png");
                ImageIO.write(frame, "png", outputImage);
                log.debug("保存帧图片成功: {}", outputImage.getAbsolutePath());
            } catch (Exception e) {
                log.error("保存帧图片失败", e);
            }
        }
    }
}