import { Router } from 'express';
import { join } from 'path';
import { existsSync } from 'fs';
import { execFile, spawn } from 'child_process';
import { promisify } from 'util';
import { getSetting } from './db.js';

const execFileAsync = promisify(execFile);
const router = Router();
const MEDIA_PATH = process.env.MEDIA_PATH || './data/media';
const SEGMENT_DURATION = 10;

function isHlsEnabled() {
  return (getSetting('hls_enabled') || process.env.HLS_ENABLED) === 'true';
}

function validatePath(folder, filename) {
  if (folder.includes('..') || filename.includes('..')) return null;
  if (folder.includes('/') || folder.includes('\\')) return null;
  if (filename.includes('/') || filename.includes('\\')) return null;
  const filePath = join(MEDIA_PATH, folder, filename);
  if (!existsSync(filePath)) return null;
  return filePath;
}

// GET /api/hls/:folder/:filename/master.m3u8
router.get('/api/hls/:folder/:filename/master.m3u8', async (req, res) => {
  if (!isHlsEnabled()) {
    return res.status(404).json({ error: 'HLS not enabled' });
  }

  const { folder, filename } = req.params;
  const filePath = validatePath(folder, filename);
  if (!filePath) {
    return res.status(400).json({ error: 'Invalid path' });
  }

  try {
    const { stdout } = await execFileAsync('ffprobe', [
      '-v', 'error',
      '-show_entries', 'format=duration',
      '-of', 'csv=p=0',
      filePath,
    ]);

    const duration = parseFloat(stdout.trim());
    if (isNaN(duration) || duration <= 0) {
      return res.status(500).json({ error: 'Could not determine video duration' });
    }

    const segmentCount = Math.ceil(duration / SEGMENT_DURATION);
    let playlist = '#EXTM3U\n#EXT-X-VERSION:3\n';
    playlist += `#EXT-X-TARGETDURATION:${SEGMENT_DURATION}\n`;
    playlist += '#EXT-X-MEDIA-SEQUENCE:0\n';

    for (let i = 0; i < segmentCount; i++) {
      const remaining = duration - i * SEGMENT_DURATION;
      const segDuration = Math.min(SEGMENT_DURATION, remaining);
      playlist += `#EXTINF:${segDuration.toFixed(3)},\n`;
      playlist += `segment-${i}.ts\n`;
    }

    playlist += '#EXT-X-ENDLIST\n';

    res.setHeader('Content-Type', 'application/vnd.apple.mpegurl');
    res.send(playlist);
  } catch (err) {
    console.error('[hls] ffprobe error:', err.message);
    res.status(500).json({ error: 'Failed to probe video' });
  }
});

// GET /api/hls/:folder/:filename/segment-:index.ts
router.get('/api/hls/:folder/:filename/segment-:index.ts', (req, res) => {
  if (!isHlsEnabled()) {
    return res.status(404).json({ error: 'HLS not enabled' });
  }

  const { folder, filename, index } = req.params;
  const filePath = validatePath(folder, filename);
  if (!filePath) {
    return res.status(400).json({ error: 'Invalid path' });
  }

  const segIndex = parseInt(index, 10);
  if (isNaN(segIndex) || segIndex < 0) {
    return res.status(400).json({ error: 'Invalid segment index' });
  }

  const offset = segIndex * SEGMENT_DURATION;

  const ffmpeg = spawn('ffmpeg', [
    '-ss', String(offset),
    '-i', filePath,
    '-t', String(SEGMENT_DURATION),
    '-c', 'copy',
    '-f', 'mpegts',
    'pipe:1',
  ], { stdio: ['ignore', 'pipe', 'ignore'] });

  res.setHeader('Content-Type', 'video/MP2T');
  ffmpeg.stdout.pipe(res);

  req.on('close', () => {
    ffmpeg.kill('SIGKILL');
  });

  ffmpeg.on('error', (err) => {
    console.error('[hls] ffmpeg error:', err.message);
    if (!res.headersSent) {
      res.status(500).json({ error: 'Transcoding failed' });
    }
  });
});

export default router;