const express = require('express');
const cors = require('cors');
const dotenv = require('dotenv');
const fs = require('fs');
const os = require('os');
const path = require('path');
const http = require('http');
const WebSocket = require('ws');
const ffmpeg = require('fluent-ffmpeg');
const { S3Client, ListBucketsCommand, ListObjectsV2Command, GetObjectCommand } = require('@aws-sdk/client-s3');

dotenv.config();

const app = express();
const PORT = process.env.PORT || 3000;
const HOST = process.env.HOST || process.env.LISTEN_ADDRESS || '0.0.0.0';
const server = http.createServer(app);
const JELLYFIN_FFMPEG_PATH = process.env.JELLYFIN_FFMPEG_PATH || '/usr/lib/jellyfin-ffmpeg/ffmpeg';
const JELLYFIN_FFPROBE_PATH = process.env.JELLYFIN_FFPROBE_PATH || '/usr/lib/jellyfin-ffmpeg/ffprobe';

if (typeof ffmpeg.setFfmpegPath === 'function') {
    ffmpeg.setFfmpegPath(JELLYFIN_FFMPEG_PATH);
}
if (typeof ffmpeg.setFfprobePath === 'function') {
    ffmpeg.setFfprobePath(JELLYFIN_FFPROBE_PATH);
}

app.use(cors());
app.use(express.json());
app.use(express.static('public'));

const rawBucketAddress = process.env.S3_BUCKET_ADDRESS || process.env.S3_BUCKET_NAME || '';
let BUCKET_NAME = rawBucketAddress;

const parsedBucketUrl = rawBucketAddress.includes('://') ? (() => {
    try {
        const parsed = new URL(rawBucketAddress);
        const name = parsed.pathname.replace(/^\/+/, '');
        if (name) {
            BUCKET_NAME = name;
        }
        return parsed.origin;
    } catch (err) {
        return undefined;
    }
})() : undefined;

const defaultS3ClientConfig = {
    region: process.env.AWS_REGION || 'us-east-1',
    endpoint: process.env.S3_ENDPOINT || parsedBucketUrl,
    forcePathStyle: process.env.S3_FORCE_PATH_STYLE === 'true'
};

const createS3Client = (credentials) => {
    const clientConfig = { ...defaultS3ClientConfig };
    if (credentials && credentials.username && credentials.password) {
        clientConfig.credentials = {
            accessKeyId: credentials.username,
            secretAccessKey: credentials.password
        };
    } else if (process.env.AWS_ACCESS_KEY_ID && process.env.AWS_SECRET_ACCESS_KEY) {
        clientConfig.credentials = {
            accessKeyId: process.env.AWS_ACCESS_KEY_ID,
            secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY
        };
    }
    return new S3Client(clientConfig);
};

const progressMap = {};
const transcodeProcesses = new Map();
const wsSubscriptions = new Map();

const AVAILABLE_VIDEO_ENCODERS = [
    { value: 'libx264', label: 'libx264 (Software H.264)' },
    { value: 'libx265', label: 'libx265 (Software H.265)' },
    { value: 'h264_nvenc', label: 'h264_nvenc (NVIDIA H.264)' },
    { value: 'hevc_nvenc', label: 'hevc_nvenc (NVIDIA HEVC)' },
    { value: 'h264_qsv', label: 'h264_qsv (Intel QSV H.264)' },
    { value: 'hevc_qsv', label: 'hevc_qsv (Intel QSV HEVC)' },
    { value: 'h264_vaapi', label: 'h264_vaapi (VAAPI H.264)' },
    { value: 'hevc_vaapi', label: 'hevc_vaapi (VAAPI HEVC)' },
    { value: 'h264_rkmpp', label: 'h264_rkmpp (RKMPP H.264)' },
    { value: 'hevc_rkmpp', label: 'hevc_rkmpp (RKMPP HEVC)' },
    { value: 'mjpeg_rkmpp', label: 'mjpeg_rkmpp (RKMPP MJPEG)' }
];

const AVAILABLE_VIDEO_DECODERS = [
    { value: 'auto', label: 'Auto Select Decoder' },
    { value: 'av1_rkmpp', label: 'av1_rkmpp (RKMPP AV1)' },
    { value: 'h263_rkmpp', label: 'h263_rkmpp (RKMPP H.263)' },
    { value: 'h264_rkmpp', label: 'h264_rkmpp (RKMPP H.264)' },
    { value: 'hevc_rkmpp', label: 'hevc_rkmpp (RKMPP HEVC)' },
    { value: 'mjpeg_rkmpp', label: 'mjpeg_rkmpp (RKMPP MJPEG)' },
    { value: 'mpeg1_rkmpp', label: 'mpeg1_rkmpp (RKMPP MPEG-1)' },
    { value: 'mpeg2_rkmpp', label: 'mpeg2_rkmpp (RKMPP MPEG-2)' },
    { value: 'mpeg4_rkmpp', label: 'mpeg4_rkmpp (RKMPP MPEG-4)' },
    { value: 'vp8_rkmpp', label: 'vp8_rkmpp (RKMPP VP8)' },
    { value: 'vp9_rkmpp', label: 'vp9_rkmpp (RKMPP VP9)' }
];

const getProgressKey = (key) => key.split('/').map(segment => segment.replace(/[^a-zA-Z0-9_\-]/g, '_')).join('/');

const createStreamSessionId = () => `${Date.now()}-${Math.random().toString(36).slice(2, 10)}`;

const addWsClient = (progressKey, ws) => {
    if (!wsSubscriptions.has(progressKey)) {
        wsSubscriptions.set(progressKey, new Set());
    }
    wsSubscriptions.get(progressKey).add(ws);
    ws.currentKey = progressKey;
};

const removeWsClient = (ws) => {
    const key = ws.currentKey;
    if (!key) return;
    const set = wsSubscriptions.get(key);
    if (!set) return;
    set.delete(ws);
    if (set.size === 0) wsSubscriptions.delete(key);
};

const broadcastWs = (key, payload) => {
    const clients = wsSubscriptions.get(key);
    if (!clients) return;
    const message = JSON.stringify(payload);
    for (const client of clients) {
        if (client.readyState === WebSocket.OPEN) {
            client.send(message);
        }
    }
};

const createFfmpegOptions = (encoderName) => {
    const options = [];
    if (encoderName === 'libx264' || encoderName === 'libx265') {
        options.push('-preset', 'fast', '-crf', '23', '-threads', '0');
    } else if (/_nvenc$/.test(encoderName)) {
        options.push('-preset', 'fast', '-rc:v', 'vbr_hq', '-cq', '19');
    } else if (/_qsv$/.test(encoderName)) {
        options.push('-preset', 'fast', '-global_quality', '23');
    } else if (/_vaapi$/.test(encoderName)) {
        options.push('-qp', '23');
    } else if (/_rkmpp$/.test(encoderName)) {
        options.push('-qp_init', '23', '-pix_fmt', 'nv12');
    }
    return options;
};

const isRkmppCodec = (codecName) => /_rkmpp$/.test(codecName);
const isVaapiCodec = (codecName) => /_vaapi$/.test(codecName);
const availableEncoderValues = new Set(AVAILABLE_VIDEO_ENCODERS.map((item) => item.value));
const availableDecoderValues = new Set(AVAILABLE_VIDEO_DECODERS.map((item) => item.value));

const getRkmppDecoderName = (metadata) => {
    const videoStream = (metadata?.streams || []).find((stream) => stream.codec_type === 'video');
    const codecName = (videoStream?.codec_name || '').toLowerCase();
    const decoderMap = {
        av1: 'av1_rkmpp',
        h263: 'h263_rkmpp',
        h264: 'h264_rkmpp',
        hevc: 'hevc_rkmpp',
        mjpeg: 'mjpeg_rkmpp',
        mpeg1video: 'mpeg1_rkmpp',
        mpeg2video: 'mpeg2_rkmpp',
        mpeg4: 'mpeg4_rkmpp',
        vp8: 'vp8_rkmpp',
        vp9: 'vp9_rkmpp'
    };
    return decoderMap[codecName] || null;
};

const parseFpsValue = (fpsText) => {
    if (typeof fpsText !== 'string' || !fpsText.trim()) {
        return 0;
    }

    if (fpsText.includes('/')) {
        const [numeratorText, denominatorText] = fpsText.split('/');
        const numerator = parseFloat(numeratorText);
        const denominator = parseFloat(denominatorText);
        if (Number.isFinite(numerator) && Number.isFinite(denominator) && denominator !== 0) {
            return numerator / denominator;
        }
        return 0;
    }

    const numericValue = parseFloat(fpsText);
    return Number.isFinite(numericValue) ? numericValue : 0;
};

const getSeekFriendlyOutputOptions = (encoderName, metadata) => {
    const videoStream = (metadata?.streams || []).find((stream) => stream.codec_type === 'video') || {};
    const parsedFps = parseFpsValue(videoStream.avg_frame_rate) || parseFpsValue(videoStream.r_frame_rate) || 24;
    const normalizedFps = Math.min(Math.max(Math.round(parsedFps), 12), 60);
    const gopSize = Math.max(24, normalizedFps * 2);
    const options = [
        '-movflags', 'frag_keyframe+empty_moov+default_base_moof+faststart',
        '-frag_duration', '1000000',
        '-min_frag_duration', '1000000',
        '-g', gopSize.toString(),
        '-keyint_min', gopSize.toString()
    ];

    if (encoderName === 'libx264' || encoderName === 'libx265') {
        options.push('-sc_threshold', '0', '-force_key_frames', 'expr:gte(t,n_forced*2)');
    } else if (/_nvenc$/.test(encoderName)) {
        options.push('-forced-idr', '1', '-force_key_frames', 'expr:gte(t,n_forced*2)');
    } else if (/_qsv$/.test(encoderName)) {
        options.push('-idr_interval', '1');
    } else if (/_rkmpp$/.test(encoderName)) {
        options.push('-force_key_frames', 'expr:gte(t,n_forced*2)');
    }

    return options;
};

const shouldRetryWithSoftware = (message) => {
    if (!message) return false;
    return /Cannot load libcuda\.so\.1|Could not open encoder before EOF|Error while opening encoder|Operation not permitted|Invalid argument|mpp_create|rkmpp/i.test(message);
};

const probeFile = (filePath) => {
    return new Promise((resolve, reject) => {
        ffmpeg.ffprobe(filePath, (err, metadata) => {
            if (err) reject(err);
            else resolve(metadata);
        });
    });
};

const parseTimemarkToSeconds = (timemark) => {
    if (typeof timemark !== 'string' || !timemark.trim()) {
        return 0;
    }

    const parts = timemark.trim().split(':');
    if (parts.length !== 3) {
        const numericValue = parseFloat(timemark);
        return Number.isFinite(numericValue) ? numericValue : 0;
    }

    const [hoursPart, minutesPart, secondsPart] = parts;
    const hours = parseInt(hoursPart, 10);
    const minutes = parseInt(minutesPart, 10);
    const seconds = parseFloat(secondsPart);

    if (![hours, minutes, seconds].every(Number.isFinite)) {
        return 0;
    }

    return (hours * 3600) + (minutes * 60) + seconds;
};

const stopActiveTranscode = (progressKey) => {
    const activeProcess = transcodeProcesses.get(progressKey);
    if (!activeProcess?.command) {
        return false;
    }

    try {
        if (typeof activeProcess.command.removeAllListeners === 'function') {
            activeProcess.command.removeAllListeners('progress');
            activeProcess.command.removeAllListeners('stderr');
            activeProcess.command.removeAllListeners('end');
            activeProcess.command.removeAllListeners('error');
        }
        if (typeof activeProcess.command.kill === 'function') {
            activeProcess.command.kill('SIGKILL');
        }
    } catch (killError) {
        console.warn(`Failed to kill transcode process for ${progressKey}:`, killError);
    } finally {
        transcodeProcesses.delete(progressKey);
    }

    return true;
};

const extractS3Credentials = (req) => {
    const query = req.query || {};
    const username = req.headers['x-s3-username'] || req.body?.username || query.username || query.accessKeyId || '';
    const password = req.headers['x-s3-password'] || req.body?.password || query.password || query.secretAccessKey || '';
    return {
        username: typeof username === 'string' ? username.trim() : '',
        password: typeof password === 'string' ? password : ''
    };
};

const wss = new WebSocket.Server({ server });

wss.on('connection', (ws) => {
    ws.on('message', (raw) => {
        try {
            const message = JSON.parse(raw.toString());
            if (message.type === 'subscribe' && typeof message.key === 'string') {
                const progressKey = getProgressKey(message.key);
                if (ws.currentKey && ws.currentKey !== progressKey) {
                    removeWsClient(ws);
                }
                addWsClient(progressKey, ws);

                const currentProgress = progressMap[progressKey];
                if (currentProgress) {
                    if (typeof currentProgress.duration === 'number' && currentProgress.duration > 0) {
                        ws.send(JSON.stringify({ type: 'duration', key: message.key, duration: currentProgress.duration }));
                    }
                    ws.send(JSON.stringify({ type: 'progress', key: message.key, progress: currentProgress }));
                    if (currentProgress.status === 'finished' && currentProgress.mp4Url) {
                        ws.send(JSON.stringify({ type: 'ready', key: message.key, mp4Url: currentProgress.mp4Url }));
                    }
                }
            }
        } catch (error) {
            console.error('WebSocket parse error:', error);
        }
    });

    ws.on('close', () => removeWsClient(ws));
});


const clearDownloadCache = () => {
    const tmpDir = os.tmpdir();
    try {
        if (!fs.existsSync(tmpDir)) return;
        const files = fs.readdirSync(tmpDir);
        for (const file of files) {
            if (file.startsWith('s3-input-') && file.endsWith('.tmp')) {
                const filePath = path.join(tmpDir, file);
                fs.rmSync(filePath, { force: true });
            }
        }
    } catch (err) {
        console.error('Failed to clear download cache:', err);
        throw err;
    }
};


// Endpoint to list available buckets
app.get('/api/buckets', async (req, res) => {
    try {
        const auth = extractS3Credentials(req);
        const s3Client = createS3Client(auth);
        const command = new ListBucketsCommand({});
        const response = await s3Client.send(command);
        const buckets = response.Buckets || [];
        res.json({ buckets });
    } catch (error) {
        console.error('Error listing buckets:', error);
        res.status(500).json({ error: 'Failed to list buckets', detail: error.message });
    }
});

// Endpoint to list videos in the bucket
app.get('/api/videos', async (req, res) => {
    try {
        const bucket = req.query.bucket || BUCKET_NAME;
        if (!bucket) {
            return res.status(400).json({ error: 'Bucket name is required' });
        }
        const allObjects = [];
        const auth = extractS3Credentials(req);
        const s3Client = createS3Client(auth);
        let continuationToken;

        do {
            const command = new ListObjectsV2Command({
                Bucket: bucket,
                ContinuationToken: continuationToken,
            });
            const response = await s3Client.send(command);
            allObjects.push(...(response.Contents || []));
            continuationToken = response.IsTruncated ? response.NextContinuationToken : undefined;
        } while (continuationToken);

        // Filter for a broader set of common video formats
        const videoExtensions = [
            '.3gp', '.3g2', '.asf', '.avi', '.divx', '.flv', '.m2ts', '.m2v',
            '.m4v', '.mkv', '.mov', '.mp4', '.mpeg', '.mpg', '.mts', '.mxf',
            '.ogm', '.ogv', '.qt', '.rm', '.rmvb', '.ts', '.vob', '.vro',
            '.webm', '.wmv'
        ];
        const videos = allObjects
            .map(item => item.Key)
            .filter(key => {
                if (!key) return false;
                const lowerKey = key.toLowerCase();
                return videoExtensions.some(ext => lowerKey.endsWith(ext));
            });

        res.json({ videos });
    } catch (error) {
        console.error('Error fetching videos:', error);
        res.status(500).json({ error: 'Failed to fetch videos from S3', detail: error.message });
    }
});

app.get('/api/config', (req, res) => {
    const title = process.env.APP_TITLE || 'S3 Media Transcoder';
    res.json({
        title,
        ffmpegPath: JELLYFIN_FFMPEG_PATH,
        ffprobePath: JELLYFIN_FFPROBE_PATH,
        defaultVideoEncoder: 'h264_rkmpp',
        defaultVideoDecoder: 'auto',
        videoEncoders: AVAILABLE_VIDEO_ENCODERS,
        videoDecoders: AVAILABLE_VIDEO_DECODERS
    });
});

app.post('/api/clear-download-cache', (req, res) => {
    try {
        clearDownloadCache();
        res.json({ message: 'Download cache cleared' });
    } catch (error) {
        console.error('Error clearing download cache:', error);
        res.status(500).json({ error: 'Failed to clear download cache', detail: error.message });
    }
});

app.post('/api/stop-transcode', (req, res) => {
    try {
        const { key } = req.body;
        if (!key) {
            return res.status(400).json({ error: 'Video key is required' });
        }

        const progressKey = getProgressKey(key);
        if (!transcodeProcesses.has(progressKey)) {
            return res.status(404).json({ error: 'No active transcode found for this key' });
        }
        stopActiveTranscode(progressKey);
        progressMap[progressKey] = {
            status: 'cancelled',
            percent: 0,
            details: 'Transcode stopped by user',
            mp4Url: null
        };
        broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
        res.json({ message: 'Transcode stopped' });
    } catch (error) {
        console.error('Error stopping transcode:', error);
        res.status(500).json({ error: 'Failed to stop transcode', detail: error.message });
    }
});

const HLS_SEGMENT_TIME = 6;
const waitForSegment = async (hlsDir, segIndex, timeoutMs = 45000) => {
    const start = Date.now();
    const segPath = path.join(hlsDir, `segment_${segIndex}.ts`);
    const m3u8Path = path.join(hlsDir, `temp.m3u8`);
    
    while (Date.now() - start < timeoutMs) {
        if (fs.existsSync(m3u8Path)) {
            const m3u8Content = fs.readFileSync(m3u8Path, 'utf8');
            if (m3u8Content.includes(`segment_${segIndex}.ts`)) {
                return true;
            }
            if (m3u8Content.includes(`#EXT-X-ENDLIST`)) {
                if (fs.existsSync(segPath)) return true;
                return false; 
            }
        }
        await new Promise(r => setTimeout(r, 200));
    }
    return false;
};

app.get('/api/hls/playlist.m3u8', async (req, res) => {
    const bucket = req.query.bucket;
    const key = req.query.key;
    if (!bucket || !key) return res.status(400).send('Bad Request');
    
    const safeKeySegments = key.split('/').map(segment => segment.replace(/[^a-zA-Z0-9_\-]/g, '_'));
    const safeBucket = bucket.replace(/[^a-zA-Z0-9_\-]/g, '_');
    const tmpInputPath = path.join(os.tmpdir(), `s3-input-${safeBucket}-${safeKeySegments.join('-')}.tmp`);
    
    const auth = extractS3Credentials(req);
    const s3Client = createS3Client(auth);
    let totalBytes = 0;
    
    if (!fs.existsSync(tmpInputPath)) {
        try {
            const command = new GetObjectCommand({ Bucket: bucket, Key: key });
            const response = await s3Client.send(command);
            totalBytes = response.ContentLength;
            await new Promise((resolve, reject) => {
                const writeStream = fs.createWriteStream(tmpInputPath);
                response.Body.pipe(writeStream);
                writeStream.on('error', reject);
                writeStream.on('finish', resolve);
            });
        } catch(err) {
            return res.status(500).send('S3 Download Failed');
        }
    }
    
    let duration = 0;
    try {
        const metadata = await probeFile(tmpInputPath);
        duration = parseFloat(metadata.format?.duration || 0);
    } catch(err) {}

    if (duration <= 0) duration = 3600;
    
    const totalSegments = Math.ceil(duration / HLS_SEGMENT_TIME);
    
    let m3u8 = `#EXTM3U\n#EXT-X-VERSION:3\n#EXT-X-TARGETDURATION:${HLS_SEGMENT_TIME}\n#EXT-X-MEDIA-SEQUENCE:0\n#EXT-X-PLAYLIST-TYPE:VOD\n`;
    for (let i = 0; i < totalSegments; i++) {
        let segDur = HLS_SEGMENT_TIME;
        if (i === totalSegments - 1 && duration % HLS_SEGMENT_TIME !== 0) {
            segDur = (duration % HLS_SEGMENT_TIME) || HLS_SEGMENT_TIME;
        }
        m3u8 += `#EXTINF:${segDur.toFixed(6)},\nsegment.ts?bucket=${encodeURIComponent(bucket)}&key=${encodeURIComponent(key)}&seg=${i}&encoder=${req.query.encoder||'h264_rkmpp'}&decoder=${req.query.decoder||'auto'}\n`;
    }
    m3u8 += `#EXT-X-ENDLIST\n`;
    
    res.setHeader('Content-Type', 'application/vnd.apple.mpegurl');
    res.setHeader('Cache-Control', 'no-cache');
    res.send(m3u8);
});

const hlsProcesses = new Map();

app.get('/api/hls/segment.ts', async (req, res) => {
    const bucket = req.query.bucket;
    const key = req.query.key;
    const seg = parseInt(req.query.seg || '0');
    const requestedEncoder = req.query.encoder || 'h264_rkmpp';
    const requestedDecoder = req.query.decoder || 'auto';
    
    if (!bucket || !key || isNaN(seg)) return res.status(400).send('Bad Request');
    
    const safeKeySegments = key.split('/').map(segment => segment.replace(/[^a-zA-Z0-9_\-]/g, '_'));
    const safeBucket = bucket.replace(/[^a-zA-Z0-9_\-]/g, '_');
    const tmpInputPath = path.join(os.tmpdir(), `s3-input-${safeBucket}-${safeKeySegments.join('-')}.tmp`);
    
    const progressKey = safeKeySegments.join('/');
    const hlsDir = path.join(os.tmpdir(), `hls-${safeBucket}-${progressKey}`);
    if (!fs.existsSync(hlsDir)) fs.mkdirSync(hlsDir, { recursive: true });
    
    const targetSegPath = path.join(hlsDir, `segment_${seg}.ts`);
    let currentProcess = hlsProcesses.get(progressKey);
    const needsNewProcess = !currentProcess || (!fs.existsSync(targetSegPath) && Math.abs((currentProcess.currentSeg || 0) - seg) > 2);

    if (needsNewProcess) {
        if (currentProcess && currentProcess.command) {
            try { currentProcess.command.kill('SIGKILL'); } catch(e){}
        }
        
        const startTime = Math.max(0, seg * HLS_SEGMENT_TIME);
        
        let sourceMetadata = null;
        try { sourceMetadata = await probeFile(tmpInputPath); } catch(e){}
        
        const encoderName = availableEncoderValues.has(requestedEncoder) ? requestedEncoder : 'h264_rkmpp';
        const decoderName = availableDecoderValues.has(requestedDecoder) ? requestedDecoder : 'auto';
        
        const m3u8Path = path.join(hlsDir, `temp.m3u8`);
        if (fs.existsSync(m3u8Path)) fs.unlinkSync(m3u8Path);
        
        const ffmpegCommand = ffmpeg().input(tmpInputPath);
        if (startTime > 0) ffmpegCommand.seekInput(startTime);
        
        ffmpegCommand.videoCodec(encoderName).audioCodec('aac');
        
        if (isVaapiCodec(encoderName)) {
            ffmpegCommand.inputOptions(['-vaapi_device', '/dev/dri/renderD128']).videoFilters('format=nv12,hwupload');
        }
        const resolvedDecoderName = decoderName === 'auto' && isRkmppCodec(encoderName) ? getRkmppDecoderName(sourceMetadata) : decoderName;
        if (resolvedDecoderName && resolvedDecoderName !== 'auto') ffmpegCommand.inputOptions(['-c:v', resolvedDecoderName]);
        
        const segmentFilename = path.join(hlsDir, `segment_%d.ts`);
        const hlsOptions = createFfmpegOptions(encoderName).concat([
            '-f', 'hls',
            '-hls_time', HLS_SEGMENT_TIME.toString(),
            '-hls_list_size', '0', 
            '-hls_segment_filename', segmentFilename,
            '-start_number', seg.toString()
        ]);
        
        ffmpegCommand.outputOptions(hlsOptions).output(m3u8Path);
        ffmpegCommand.on('error', (err) => {
            console.error('HLS FFmpeg Error:', err.message);
        });
        
        ffmpegCommand.run();
        currentProcess = { command: ffmpegCommand, currentSeg: seg };
        hlsProcesses.set(progressKey, currentProcess);
    }
    
    const ready = await waitForSegment(hlsDir, seg);
    if (!ready) {
        return res.status(500).send('Segment generation timeout');
    }
    
    if (currentProcess) currentProcess.currentSeg = Math.max(currentProcess.currentSeg, seg);
    
    res.setHeader('Content-Type', 'video/MP2T');
    res.sendFile(targetSegPath);
});

app.get('/api/stream', async (req, res) => {
    const bucket = req.query.bucket;
    const key = req.query.key;
    const requestedDecoder = typeof req.query.decoder === 'string' ? req.query.decoder.trim() : 'auto';
    const requestedEncoder = typeof req.query.encoder === 'string' ? req.query.encoder.trim() : 'h264_rkmpp';
    const startSeconds = parseFloat(req.query.ss) || 0;
    const streamSessionId = typeof req.query.streamSessionId === 'string' && req.query.streamSessionId.trim()
        ? req.query.streamSessionId.trim()
        : createStreamSessionId();

    if (!bucket) {
        return res.status(400).json({ error: 'Bucket name is required' });
    }
    if (!key) {
        return res.status(400).json({ error: 'Video key is required' });
    }

    const videoEncoder = availableEncoderValues.has(requestedEncoder) ? requestedEncoder : 'h264_rkmpp';
    const requestedVideoDecoder = availableDecoderValues.has(requestedDecoder) ? requestedDecoder : 'auto';

    const safeKeySegments = key.split('/').map(segment => segment.replace(/[^a-zA-Z0-9_\-]/g, '_'));
    const progressKey = safeKeySegments.join('/');
    const safeBucket = bucket.replace(/[^a-zA-Z0-9_\-]/g, '_');
    const tmpInputPath = path.join(os.tmpdir(), `s3-input-${safeBucket}-${safeKeySegments.join('-')}.tmp`);
    const cacheExists = fs.existsSync(tmpInputPath);

    const auth = extractS3Credentials(req);
    const s3Client = createS3Client(auth);

    try {
        const replacedExistingStream = stopActiveTranscode(progressKey);
        if (replacedExistingStream && startSeconds > 0) {
            progressMap[progressKey] = {
                ...(progressMap[progressKey] || {}),
                status: 'transcoding',
                percent: Math.min(Math.max(Math.round((startSeconds / Math.max(progressMap[progressKey]?.duration || startSeconds || 1, 1)) * 100), 0), 100),
                startSeconds,
                streamSessionId,
                details: `Restarting transcode from ${startSeconds.toFixed(2)}s`,
                mp4Url: null
            };
            broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
        }

        let totalBytes = 0;
        let downloadedBytes = 0;

        if (!cacheExists) {
            const command = new GetObjectCommand({ Bucket: bucket, Key: key });
            const response = await s3Client.send(command);
            const s3Stream = response.Body;
            totalBytes = response.ContentLength || 0;

            progressMap[progressKey] = {
                status: 'downloading',
                percent: 0,
                downloadedBytes: 0,
                totalBytes,
                streamSessionId,
                details: 'Downloading full source before streaming...',
                mp4Url: null
            };
            broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });

            await new Promise((resolve, reject) => {
                const writeStream = fs.createWriteStream(tmpInputPath);
                s3Stream.on('data', (chunk) => {
                    downloadedBytes += chunk.length;
                    const percent = totalBytes ? Math.min(100, Math.round(downloadedBytes / totalBytes * 100)) : 0;
                    const downloadState = {
                        status: 'downloading',
                        percent,
                        downloadedBytes,
                        totalBytes,
                        streamSessionId,
                        details: totalBytes ? `Downloading source ${percent}%` : 'Downloading source...',
                        mp4Url: null
                    };
                    progressMap[progressKey] = downloadState;
                    broadcastWs(progressKey, { type: 'progress', key, progress: downloadState });
                });
                s3Stream.on('error', reject);
                writeStream.on('error', reject);
                writeStream.on('finish', resolve);
                s3Stream.pipe(writeStream);
            });

            progressMap[progressKey] = {
                status: 'downloaded',
                percent: 100,
                downloadedBytes,
                totalBytes,
                streamSessionId,
                details: 'Source download complete, starting real-time transcode...',
                mp4Url: null
            };
            broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
        } else {
            const stats = fs.statSync(tmpInputPath);
            totalBytes = stats.size;
            downloadedBytes = totalBytes;
            progressMap[progressKey] = {
                status: 'downloaded',
                percent: 100,
                downloadedBytes,
                totalBytes,
                streamSessionId,
                details: 'Source already downloaded locally, starting real-time transcode...',
                mp4Url: null
            };
            broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
        }

        // Probe file for duration and broadcast to clients
        let sourceMetadata = null;
        try {
            const metadata = await probeFile(tmpInputPath);
            sourceMetadata = metadata;
            const duration = metadata.format?.duration || 0;
            progressMap[progressKey] = {
                ...(progressMap[progressKey] || {}),
                duration: parseFloat(duration) || 0,
                streamSessionId
            };
            broadcastWs(progressKey, { type: 'duration', key, duration: parseFloat(duration) });
        } catch (probeErr) {
            console.error('Probe failed:', probeErr);
        }

        res.setHeader('Content-Type', 'video/mp4');
        res.setHeader('Cache-Control', 'no-cache');
        res.setHeader('Connection', 'keep-alive');

        let ffmpegCommand = null;

        const startStream = (encoderName, decoderName) => {
            const streamingOptions = createFfmpegOptions(encoderName).concat(getSeekFriendlyOutputOptions(encoderName, sourceMetadata));
            ffmpegCommand = ffmpeg()
                .input(tmpInputPath)
                .videoCodec(encoderName)
                .audioCodec('aac')
                .outputOptions(streamingOptions)
                .format('mp4');

            if (startSeconds > 0) {
                if (typeof ffmpegCommand.seekInput === 'function') {
                    ffmpegCommand.seekInput(startSeconds);
                } else {
                    ffmpegCommand.inputOptions(['-ss', startSeconds.toString()]);
                }
            }

            if (isVaapiCodec(encoderName)) {
                ffmpegCommand
                    .inputOptions(['-vaapi_device', '/dev/dri/renderD128'])
                    .videoFilters('format=nv12,hwupload');
            }

            const resolvedDecoderName = decoderName === 'auto' && isRkmppCodec(encoderName)
                ? getRkmppDecoderName(sourceMetadata)
                : decoderName;

            if (resolvedDecoderName && resolvedDecoderName !== 'auto') {
                ffmpegCommand.inputOptions(['-c:v', resolvedDecoderName]);
            }

            transcodeProcesses.set(progressKey, { command: ffmpegCommand, streamSessionId });

            ffmpegCommand
                .on('progress', (progress) => {
                    if (transcodeProcesses.get(progressKey)?.streamSessionId !== streamSessionId) {
                        return;
                    }
                    const effectiveDuration = Math.max(0, (progressMap[progressKey]?.duration || 0) - startSeconds);
                    const timemarkSeconds = parseTimemarkToSeconds(progress.timemark || '0');
                    const absoluteSeconds = startSeconds + (isFinite(timemarkSeconds) ? timemarkSeconds : 0);
                    const percent = effectiveDuration > 0
                        ? Math.min(Math.max(Math.round((absoluteSeconds / (progressMap[progressKey]?.duration || effectiveDuration)) * 100), 0), 100)
                        : Math.min(Math.max(Math.round(progress.percent || 0), 0), 100);
                    const progressState = {
                        status: 'transcoding',
                        percent,
                        frame: progress.frames || null,
                        fps: progress.currentFps || null,
                        bitrate: progress.currentKbps || null,
                        timemark: progress.timemark || null,
                        absoluteSeconds,
                        duration: progressMap[progressKey]?.duration || null,
                        startSeconds,
                        streamSessionId,
                        details: `Streaming transcode ${percent}%`,
                        mp4Url: null
                    };
                    progressMap[progressKey] = progressState;
                    broadcastWs(progressKey, { type: 'progress', key, progress: progressState });
                })
                .on('stderr', (stderrLine) => {
                    if (transcodeProcesses.get(progressKey)?.streamSessionId !== streamSessionId) {
                        return;
                    }
                    console.log(`ffmpeg stderr: ${stderrLine}`);
                })
                .on('end', () => {
                    if (transcodeProcesses.get(progressKey)?.streamSessionId !== streamSessionId) {
                        return;
                    }
                    transcodeProcesses.delete(progressKey);
                    progressMap[progressKey] = {
                        status: 'finished',
                        percent: 100,
                        duration: progressMap[progressKey]?.duration || null,
                        startSeconds,
                        streamSessionId,
                        details: 'Streaming transcode complete',
                        mp4Url: null
                    };
                    broadcastWs(progressKey, { type: 'progress', key, progress: progressMap[progressKey] });
                })
                .on('error', (err) => {
                    if (transcodeProcesses.get(progressKey)?.streamSessionId !== streamSessionId) {
                        return;
                    }
                    transcodeProcesses.delete(progressKey);
                    const failedState = {
                        status: 'failed',
                        percent: progressMap[progressKey]?.percent || 0,
                        duration: progressMap[progressKey]?.duration || null,
                        startSeconds,
                        streamSessionId,
                        details: err.message || 'Streaming transcode failed',
                        mp4Url: null
                    };
                    progressMap[progressKey] = failedState;
                    broadcastWs(progressKey, { type: 'progress', key, progress: failedState });
                    if (!res.headersSent) {
                        res.status(500).json({ error: 'Failed to stream transcoded video', detail: err.message });
                    } else {
                        res.destroy(err);
                    }
                });

            ffmpegCommand.pipe(res, { end: true });
        };

        res.on('close', () => {
            if (ffmpegCommand && typeof ffmpegCommand.kill === 'function') {
                try {
                    ffmpegCommand.kill('SIGKILL');
                } catch (_) {}
            }
            if (transcodeProcesses.get(progressKey)?.streamSessionId === streamSessionId) {
                transcodeProcesses.delete(progressKey);
            }
        });

        startStream(videoEncoder, requestedVideoDecoder);
    } catch (error) {
        console.error('Error in stream:', error);
        if (!res.headersSent) {
            res.status(500).json({ error: 'Failed to stream video', detail: error.message });
        } else {
            res.destroy(error);
        }
    }
});

server.listen(PORT, HOST, () => {
    console.log(`Server running on http://${HOST}:${PORT}`);
});