<?php

namespace app\service;

use app\model\UploadFile;

class VideoRenderService
{
    /**
     * 提取已生成镜头的最后一帧，作为下一镜头的真实视觉起点。
     */
    public static function extractLastFrame(int $videoUploadId, int $userId): int
    {
        $video = UploadFile::where('id', $videoUploadId)
            ->where('user_id', $userId)
            ->where('file_type', 'video')
            ->find();
        if (!$video) {
            throw new \RuntimeException('无法读取上一镜头视频');
        }

        $videoPath = rtrim(config('upload.path'), '/\\') . DIRECTORY_SEPARATOR
            . str_replace('/', DIRECTORY_SEPARATOR, (string) $video->file_path);
        if (!is_file($videoPath)) {
            throw new \RuntimeException('上一镜头视频文件不存在');
        }

        $subdir = date('Y/m/d');
        $storedBase = 'continuity_' . uniqid('', true) . '.jpg';
        $relativePath = $subdir . '/' . $storedBase;
        $fullDir = rtrim(config('upload.path'), '/\\') . DIRECTORY_SEPARATOR
            . str_replace('/', DIRECTORY_SEPARATOR, $subdir);
        if (!is_dir($fullDir) && !mkdir($fullDir, 0755, true) && !is_dir($fullDir)) {
            throw new \RuntimeException('无法创建镜头连续帧目录');
        }
        $outputPath = $fullDir . DIRECTORY_SEPARATOR . $storedBase;

        // H3 输出最后几帧有时会包含编码尾部黑帧，向前取 0.12 秒更稳定。
        [$exitCode, $error] = self::run([
            'ffmpeg', '-y', '-sseof', '-0.12', '-i', $videoPath,
            '-frames:v', '1', '-q:v', '2', $outputPath,
        ]);
        if ($exitCode !== 0 || !is_file($outputPath) || filesize($outputPath) === 0) {
            @unlink($outputPath);
            throw new \RuntimeException('提取镜头尾帧失败: ' . mb_substr(trim($error), -400));
        }

        $upload = UploadFile::create([
            'user_id' => $userId,
            'original_name' => 'continuity_last_frame.jpg',
            'stored_name' => $storedBase,
            'file_path' => $relativePath,
            'mime_type' => 'image/jpeg',
            'file_size' => (int) filesize($outputPath),
            'file_type' => 'image',
        ]);
        return (int) $upload->id;
    }

    /**
     * @param array<int,array<string,mixed>> $shots
     */
    public static function concatenate(
        array $shots,
        int $userId,
        bool $showSubtitles = false,
        string $aspectRatio = '9:16',
        string $screenTextLanguage = ShortDramaPlannerService::SCREEN_TEXT_LANGUAGE_NONE,
        string $quality = 'standard'
    ): int
    {
        $uploadIds = [];
        $durations = [];
        $renderShots = [];
        foreach ($shots as $shot) {
            $uploadId = (int) ($shot['output_upload_id'] ?? 0);
            if ($uploadId <= 0) {
                continue;
            }
            $uploadIds[] = $uploadId;
            $durations[] = max(1, min(30, (int) ($shot['duration_seconds'] ?? 5)));
            $renderShots[] = $shot;
        }
        if (!$uploadIds) {
            throw new \RuntimeException('没有可合成的视频镜头');
        }
        $overlayDocument = self::overlayDocument(
            $renderShots,
            $durations,
            $aspectRatio,
            $showSubtitles,
            $screenTextLanguage
        );
        if (count($uploadIds) === 1 && $overlayDocument === null) {
            return $uploadIds[0];
        }

        $uploads = UploadFile::whereIn('id', $uploadIds)
            ->where('user_id', $userId)
            ->select()
            ->column(null, 'id');
        $paths = [];
        foreach ($uploadIds as $uploadId) {
            $upload = $uploads[$uploadId] ?? null;
            if (!$upload) {
                throw new \RuntimeException('部分视频镜头文件已不存在');
            }
            $path = rtrim(config('upload.path'), '/\\') . DIRECTORY_SEPARATOR
                . str_replace('/', DIRECTORY_SEPARATOR, (string) $upload->file_path);
            if (!is_file($path)) {
                throw new \RuntimeException('视频镜头文件无法读取');
            }
            $paths[] = $path;
        }

        $subdir = date('Y/m/d');
        $storedBase = 'short_drama_' . uniqid('', true) . '.mp4';
        $relativePath = $subdir . '/' . $storedBase;
        $fullDir = rtrim(config('upload.path'), '/\\') . DIRECTORY_SEPARATOR
            . str_replace('/', DIRECTORY_SEPARATOR, $subdir);
        if (!is_dir($fullDir) && !mkdir($fullDir, 0755, true) && !is_dir($fullDir)) {
            throw new \RuntimeException('无法创建短剧成片目录');
        }
        $outputPath = $fullDir . DIRECTORY_SEPARATOR . $storedBase;
        $subtitlePath = null;
        if ($overlayDocument !== null) {
            $subtitlePath = $fullDir . DIRECTORY_SEPARATOR . 'subtitle_' . uniqid('', true) . '.ass';
            if (file_put_contents($subtitlePath, $overlayDocument) === false) {
                throw new \RuntimeException('无法创建文字合成文件');
            }
        }

        $command = ['ffmpeg', '-y'];
        foreach ($paths as $path) {
            $command[] = '-i';
            $command[] = $path;
        }
        $filters = [];
        $concatInputs = '';
        [$targetWidth, $targetHeight] = self::renderSize($aspectRatio, $quality);
        foreach ($durations as $index => $duration) {
            // 不同批次或重试镜头可能使用不同质量档位。concat 要求每路画面和
            // 音轨参数完全一致，因此先统一尺寸、SAR、帧率、像素格式和双声道。
            $filters[] = "[{$index}:v:0]trim=duration={$duration},setpts=PTS-STARTPTS,"
                . "scale={$targetWidth}:{$targetHeight}:force_original_aspect_ratio=decrease,"
                . "pad={$targetWidth}:{$targetHeight}:(ow-iw)/2:(oh-ih)/2:color=black,"
                . "setsar=1,fps=24,format=yuv420p[v{$index}]";
            $filters[] = "[{$index}:a:0]aresample=48000,"
                . "aformat=sample_fmts=fltp:sample_rates=48000:channel_layouts=stereo,"
                . "atrim=duration={$duration},asetpts=PTS-STARTPTS[a{$index}]";
            $concatInputs .= "[v{$index}][a{$index}]";
        }
        if (count($paths) === 1) {
            $videoOutput = '[v0]';
            $audioOutput = '[a0]';
        } else {
            $filters[] = $concatInputs . 'concat=n=' . count($paths) . ':v=1:a=1[vconcat][aout]';
            $videoOutput = '[vconcat]';
            $audioOutput = '[aout]';
        }
        if ($subtitlePath !== null) {
            $filters[] = $videoOutput . "ass=filename='" . self::escapeFilterPath($subtitlePath) . "'[vout]";
            $videoOutput = '[vout]';
        }
        array_push(
            $command,
            '-filter_complex', implode(';', $filters),
            '-map', $videoOutput, '-map', $audioOutput,
            '-c:v', 'libx264', '-preset', 'veryfast', '-crf', '20', '-pix_fmt', 'yuv420p',
            '-c:a', 'aac', '-b:a', '192k', '-ar', '48000',
            '-movflags', '+faststart', $outputPath
        );
        [$exitCode, $error] = self::run($command);
        if ($subtitlePath !== null) {
            @unlink($subtitlePath);
        }
        if ($exitCode !== 0 || !is_file($outputPath) || filesize($outputPath) === 0) {
            @unlink($outputPath);
            throw new \RuntimeException('视频合成失败: ' . mb_substr(trim($error), -600));
        }

        $size = (int) filesize($outputPath);
        $upload = UploadFile::create([
            'user_id' => $userId,
            'original_name' => 'short_drama_episode.mp4',
            'stored_name' => $storedBase,
            'file_path' => $relativePath,
            'mime_type' => 'video/mp4',
            'file_size' => $size,
            'file_type' => 'video',
        ]);
        return (int) $upload->id;
    }

    /**
     * 生成后期 ASS 文字层。字幕与场景文字都不交给视频模型直接绘制，避免乱码、漂移和闪烁。
     *
     * @param array<int,array<string,mixed>> $shots
     * @param int[] $durations
     */
    private static function overlayDocument(
        array $shots,
        array $durations,
        string $aspectRatio,
        bool $showSubtitles,
        string $screenTextLanguage
    ): ?string
    {
        $screenTextLanguage = ShortDramaPlannerService::normalizeScreenTextLanguage($screenTextLanguage);
        $portrait = $aspectRatio !== '16:9';
        $playResX = $portrait ? 1080 : 1920;
        $playResY = $portrait ? 1920 : 1080;
        $fontSize = $portrait ? 54 : 48;
        $marginV = $portrait ? 150 : 72;
        $lineLength = $portrait ? 17 : 28;
        $cursor = 0.0;
        $events = [];

        foreach ($shots as $index => $shot) {
            $duration = (float) ($durations[$index] ?? 5);
            $meta = is_array($shot['meta'] ?? null) ? $shot['meta'] : [];
            if (!$meta && is_string($shot['meta'] ?? null)) {
                $decoded = json_decode((string) $shot['meta'], true);
                $meta = is_array($decoded) ? $decoded : [];
            }
            $timeline = is_array($meta['timeline'] ?? null) ? $meta['timeline'] : [];
            $dialogue = $showSubtitles
                ? self::cleanSubtitleText((string) ($shot['dialogue'] ?? ''), $lineLength)
                : '';
            if ($dialogue !== '') {
                $placement = (string) ($timeline['voice_timing'] ?? 'start');
                $start = $cursor + 0.18;
                if ($placement === 'end') {
                    $start = $cursor + max(0.18, $duration - 2.8);
                }
                $end = max($start + 0.5, $cursor + $duration - 0.16);
                $events[] = 'Dialogue: 0,' . self::assTime($start) . ',' . self::assTime($end)
                    . ',Default,,0,0,0,,' . $dialogue;
            }
            $sceneText = $screenTextLanguage !== ShortDramaPlannerService::SCREEN_TEXT_LANGUAGE_NONE
                ? self::cleanSceneText((string) ($timeline['screen_text'] ?? ''), $portrait ? 14 : 24)
                : '';
            if ($sceneText !== '') {
                $start = $cursor + 0.35;
                $end = max($start + 0.6, $cursor + $duration - 0.25);
                $events[] = 'Dialogue: 1,' . self::assTime($start) . ',' . self::assTime($end)
                    . ',SceneText,,0,0,0,,' . $sceneText;
            }
            $cursor += $duration;
        }

        if (!$events) {
            return null;
        }

        return "[Script Info]\n"
            . "ScriptType: v4.00+\n"
            . "PlayResX: {$playResX}\n"
            . "PlayResY: {$playResY}\n"
            . "WrapStyle: 0\n"
            . "ScaledBorderAndShadow: yes\n\n"
            . "[V4+ Styles]\n"
            . "Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding\n"
            . "Style: Default,Noto Sans CJK SC,{$fontSize},&H00FFFFFF,&H00FFFFFF,&H50000000,&H78000000,-1,0,0,0,100,100,0,0,3,2,0,2,70,70,{$marginV},1\n"
            . 'Style: SceneText,Noto Sans CJK SC,' . ($portrait ? 62 : 54) . ',&H00FFFFFF,&H00FFFFFF,&H78000000,&HA0000000,-1,0,0,0,100,100,0,0,3,3,0,8,90,90,' . ($portrait ? 260 : 105) . ",1\n\n"
            . "[Events]\n"
            . "Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\n"
            . implode("\n", $events)
            . "\n";
    }

    private static function cleanSubtitleText(string $text, int $lineLength): string
    {
        $text = trim($text);
        $text = preg_replace('/^[^：:\n]{1,20}[：:]\s*/u', '', $text) ?? $text;
        $text = preg_replace('/\s+/u', ' ', $text) ?? $text;
        $text = trim($text);
        if ($text === '') {
            return '';
        }
        $text = mb_substr($text, 0, 80);
        $text = str_replace(['\\', '{', '}'], ['＼', '（', '）'], $text);
        $lines = [];
        for ($offset = 0, $length = mb_strlen($text); $offset < $length; $offset += $lineLength) {
            $lines[] = mb_substr($text, $offset, $lineLength);
        }
        return implode('\\N', array_slice($lines, 0, 3));
    }

    private static function cleanSceneText(string $text, int $lineLength): string
    {
        $text = preg_replace('/\s+/u', ' ', trim($text)) ?? trim($text);
        $text = preg_replace('/^[\s\"\'“”‘’]+|[\s\"\'“”‘’]+$/u', '', $text) ?? trim($text);
        if ($text === '') {
            return '';
        }
        $text = mb_substr($text, 0, 100);
        $text = str_replace(['\\', '{', '}'], ['＼', '（', '）'], $text);
        $lines = [];
        for ($offset = 0, $length = mb_strlen($text); $offset < $length; $offset += $lineLength) {
            $lines[] = mb_substr($text, $offset, $lineLength);
        }
        return implode('\\N', array_slice($lines, 0, 3));
    }

    private static function assTime(float $seconds): string
    {
        $centiseconds = max(0, (int) round($seconds * 100));
        $hours = intdiv($centiseconds, 360000);
        $minutes = intdiv($centiseconds % 360000, 6000);
        $secs = intdiv($centiseconds % 6000, 100);
        return sprintf('%d:%02d:%02d.%02d', $hours, $minutes, $secs, $centiseconds % 100);
    }

    private static function escapeFilterPath(string $path): string
    {
        return str_replace(['\\', "'", ':'], ['\\\\', "\\'", '\\:'], $path);
    }

    /** @return array{int,int} */
    private static function renderSize(string $aspectRatio, string $quality): array
    {
        $portrait = $aspectRatio !== '16:9';
        return match ($quality) {
            'high' => $portrait ? [768, 1344] : [1344, 768],
            'fast' => $portrait ? [512, 896] : [896, 512],
            default => $portrait ? [576, 1024] : [1024, 576],
        };
    }

    /** @return array{int,string} */
    private static function run(array $command): array
    {
        $pipes = [];
        $process = @proc_open($command, [
            0 => ['pipe', 'r'],
            1 => ['pipe', 'w'],
            2 => ['pipe', 'w'],
        ], $pipes);
        if (!is_resource($process)) {
            throw new \RuntimeException('服务器未安装或无法启动 FFmpeg');
        }
        fclose($pipes[0]);
        stream_get_contents($pipes[1]);
        fclose($pipes[1]);
        $error = (string) stream_get_contents($pipes[2]);
        fclose($pipes[2]);
        $code = proc_close($process);
        return [$code, $error];
    }
}