package com.doumee.service.business.collection;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.TimeUnit;

/**
 * 从视频指定时刻截取 JPEG 帧。
 */
@Slf4j
public final class MediaFrameUtil {

    private static final long SNAPSHOT_TIMEOUT_MINUTES = 10;

    private MediaFrameUtil() {
    }

    public static double probeDurationSec(String ffmpegPath, File source) {
        if (source == null || !source.exists() || source.length() <= 0) {
            return 0;
        }
        String ffprobe = resolveFfprobe(ffmpegPath);
        List<String> command = Arrays.asList(
                ffprobe,
                "-v", "error",
                "-show_entries", "format=duration",
                "-of", "default=noprint_wrappers=1:nokey=1",
                source.getAbsolutePath()
        );
        try {
            ProcessBuilder builder = new ProcessBuilder(command);
            builder.redirectErrorStream(true);
            Process process = builder.start();
            String output = readStream(process.getInputStream());
            boolean finished = process.waitFor(2, TimeUnit.MINUTES);
            if (!finished) {
                process.destroyForcibly();
                return 0;
            }
            if (process.exitValue() != 0 || StringUtils.isBlank(output)) {
                return 0;
            }
            return Double.parseDouble(output.trim());
        } catch (Exception e) {
            log.warn("ffprobe 读取时长失败: {}", e.getMessage());
            return 0;
        }
    }

    public static boolean extractFrame(String ffmpegPath, File source, File target, double second) {
        if (source == null || !source.exists() || source.length() <= 0) {
            return false;
        }
        if (second < 0) {
            second = 0;
        }
        String ffmpeg = resolveExecutable(ffmpegPath, "ffmpeg");
        String sec = formatSeconds(second);
        List<String> command = Arrays.asList(
                ffmpeg,
                "-y",
                "-ss", sec,
                "-i", source.getAbsolutePath(),
                "-frames:v", "1",
                "-q:v", "2",
                target.getAbsolutePath()
        );
        try {
            ProcessBuilder builder = new ProcessBuilder(command);
            builder.redirectErrorStream(true);
            Process process = builder.start();
            readStream(process.getInputStream());
            boolean finished = process.waitFor(SNAPSHOT_TIMEOUT_MINUTES, TimeUnit.MINUTES);
            if (!finished) {
                process.destroyForcibly();
                log.error("FFmpeg 截帧超时 source={} sec={}", source.getAbsolutePath(), sec);
                return false;
            }
            if (process.exitValue() != 0) {
                log.error("FFmpeg 截帧失败 exitCode={} source={} sec={}", process.exitValue(), source.getAbsolutePath(), sec);
                return false;
            }
            return target.exists() && target.length() > 0;
        } catch (Exception e) {
            log.error("FFmpeg 截帧异常 source={} sec={}: {}", source.getAbsolutePath(), sec, e.getMessage());
            return false;
        }
    }

    private static String formatSeconds(double second) {
        if (second <= 0) {
            return "0";
        }
        return String.format(Locale.US, "%.3f", second);
    }

    private static String readStream(java.io.InputStream in) throws Exception {
        StringBuilder sb = new StringBuilder();
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8))) {
            String line;
            while ((line = reader.readLine()) != null) {
                sb.append(line).append('\n');
            }
        }
        return sb.toString();
    }

    private static String resolveExecutable(String configuredPath, String defaultName) {
        if (StringUtils.isNotBlank(configuredPath)) {
            return configuredPath.trim();
        }
        return defaultName;
    }

    private static String resolveFfprobe(String ffmpegPath) {
        if (StringUtils.isBlank(ffmpegPath)) {
            return "ffprobe";
        }
        String path = ffmpegPath.trim();
        if (path.contains("/") || path.contains("\\")) {
            int slash = Math.max(path.lastIndexOf('/'), path.lastIndexOf('\\'));
            if (slash >= 0) {
                String dir = path.substring(0, slash + 1);
                String name = path.substring(slash + 1);
                if (name.toLowerCase().endsWith(".exe")) {
                    return dir + name.replaceAll("(?i)ffmpeg\\.exe$", "ffprobe.exe");
                }
                return dir + name.replaceAll("(?i)ffmpeg$", "ffprobe");
            }
            return path.replaceAll("(?i)ffmpeg", "ffprobe");
        }
        return "ffprobe";
    }
}