import { Router } from 'express';
import multer from 'multer';
import { join, extname, basename } from 'path';
import { existsSync, mkdirSync, readdirSync, statSync, unlinkSync, createReadStream, rmSync } from 'fs';
import { execFile } from 'child_process';
import { promisify } from 'util';
import {
  insertVideo, getVideoById, getVideoByPath, updateVideo, deleteVideoById,
  searchVideos, getOrCreateTag, getAllTags, setVideoTags, getVideoTags,
} from './db.js';

const execFileAsync = promisify(execFile);
const router = Router();

const VIDEOS_PATH = process.env.VIDEOS_PATH || '/data/videos';
const VIDEO_EXTS = new Set(['.mp4', '.mov', '.avi', '.webm', '.mkv', '.m4v', '.wmv', '.flv', '.ts']);

// Ensure videos dir exists
if (!existsSync(VIDEOS_PATH)) {
  mkdirSync(VIDEOS_PATH, { recursive: true });
}

// Multer config for uploads
const storage = multer.diskStorage({
  destination: (req, file, cb) => cb(null, VIDEOS_PATH),
  filename: (req, file, cb) => {
    // Preserve original name, avoid collisions
    let name = file.originalname;
    const filePath = join(VIDEOS_PATH, name);
    if (existsSync(filePath)) {
      const ext = extname(name);
      const base = basename(name, ext);
      name = `${base}_${Date.now()}${ext}`;
    }
    cb(null, name);
  },
});

const upload = multer({
  storage,
  fileFilter: (req, file, cb) => {
    const ext = extname(file.originalname).toLowerCase();
    if (VIDEO_EXTS.has(ext)) {
      cb(null, true);
    } else {
      cb(new Error(`Unsupported file type: ${ext}`));
    }
  },
  limits: { fileSize: 50 * 1024 * 1024 * 1024 }, // 50 GB
});

// --- ffprobe helper ---

async function probeVideo(filePath) {
  const { stdout } = await execFileAsync('ffprobe', [
    '-v', 'error',
    '-show_entries', 'format=duration,bit_rate',
    '-show_entries', 'stream=codec_name,width,height,r_frame_rate,codec_type',
    '-of', 'json',
    filePath,
  ], { timeout: 60000 });

  const info = JSON.parse(stdout);
  const videoStream = info.streams?.find(s => s.codec_type === 'video');
  const audioStream = info.streams?.find(s => s.codec_type === 'audio');
  const duration = parseFloat(info.format?.duration || '0');
  const bitrate = parseInt(info.format?.bit_rate || '0', 10);

  let fps = null;
  if (videoStream?.r_frame_rate) {
    const [num, den] = videoStream.r_frame_rate.split('/');
    if (den && parseInt(den, 10) > 0) {
      fps = Math.round((parseInt(num, 10) / parseInt(den, 10)) * 100) / 100;
    }
  }

  return {
    duration: duration || null,
    width: videoStream?.width || null,
    height: videoStream?.height || null,
    fps,
    codec: videoStream?.codec_name || null,
    bitrate: bitrate || null,
    has_audio: audioStream ? 1 : 0,
  };
}

// --- thumbnail generation ---

async function generateVideoThumbnail(filePath, outputPath) {
  const dir = join(VIDEOS_PATH, '.thumbnails');
  if (!existsSync(dir)) mkdirSync(dir, { recursive: true });

  // Seek 1s in for a better frame
  let duration = 0;
  try {
    const { stdout } = await execFileAsync('ffprobe', [
      '-v', 'error', '-show_entries', 'format=duration', '-of', 'csv=p=0', filePath,
    ], { timeout: 15000 });
    duration = parseFloat(stdout.trim()) || 0;
  } catch { /* ignore */ }

  const seekTime = duration > 2 ? '1' : '0';

  await execFileAsync('ffmpeg', [
    '-ss', seekTime,
    '-i', filePath,
    '-frames:v', '1',
    '-vf', 'scale=480:-1',
    '-q:v', '4',
    '-y',
    '-update', '1',
    outputPath,
  ], { timeout: 30000 });

  return outputPath;
}

// --- Scan state ---

let scanState = { running: false, total: 0, done: 0, added: 0, skipped: 0, errors: 0 };

// GET /api/videos — browse/search
router.get('/api/videos', (req, res, next) => {
  try {
    const { search, sort, offset, limit, minDuration, maxDuration, minWidth } = req.query;
    const tagsParam = req.query.tags;
    const tagsArr = tagsParam
      ? tagsParam.split(',').map(t => t.trim()).filter(Boolean)
      : undefined;

    const result = searchVideos({
      search: search || undefined,
      tags: tagsArr,
      minDuration: minDuration || undefined,
      maxDuration: maxDuration || undefined,
      minWidth: minWidth || undefined,
      sort: sort || 'latest',
      offset: parseInt(offset || '0', 10),
      limit: parseInt(limit || '48', 10),
    });

    // Attach tags to each video
    const videos = result.rows.map(v => ({
      ...v,
      tags: getVideoTags(v.id),
    }));

    res.json({ total: result.total, offset: parseInt(offset || '0', 10), videos });
  } catch (err) {
    next(err);
  }
});

// GET /api/videos/tags — all tags with counts
router.get('/api/videos/tags', (req, res, next) => {
  try {
    const { search } = req.query;
    const tags = getAllTags(search || undefined);
    res.json(tags);
  } catch (err) {
    next(err);
  }
});

// GET /api/videos/scan/status
router.get('/api/videos/scan/status', (req, res) => {
  res.json(scanState);
});

// GET /api/videos/:id
router.get('/api/videos/:id', (req, res, next) => {
  try {
    const video = getVideoById(parseInt(req.params.id, 10));
    if (!video) return res.status(404).json({ error: 'Video not found' });
    video.tags = getVideoTags(video.id);
    res.json(video);
  } catch (err) {
    next(err);
  }
});

// PUT /api/videos/:id — update title, description, tags
router.put('/api/videos/:id', (req, res, next) => {
  try {
    const id = parseInt(req.params.id, 10);
    const video = getVideoById(id);
    if (!video) return res.status(404).json({ error: 'Video not found' });

    const { title, description, tags } = req.body;
    const updates = {};
    if (title !== undefined) updates.title = title;
    if (description !== undefined) updates.description = description;

    if (Object.keys(updates).length > 0) {
      updateVideo(id, updates);
    }
    if (Array.isArray(tags)) {
      setVideoTags(id, tags);
    }

    const updated = getVideoById(id);
    updated.tags = getVideoTags(id);
    res.json(updated);
  } catch (err) {
    next(err);
  }
});

// DELETE /api/videos/:id
router.delete('/api/videos/:id', (req, res, next) => {
  try {
    const id = parseInt(req.params.id, 10);
    const video = getVideoById(id);
    if (!video) return res.status(404).json({ error: 'Video not found' });

    // Delete file
    if (existsSync(video.file_path)) {
      try { unlinkSync(video.file_path); } catch { /* ignore */ }
    }

    // Delete thumbnail
    if (video.thumbnail_path && existsSync(video.thumbnail_path)) {
      try { unlinkSync(video.thumbnail_path); } catch { /* ignore */ }
    }

    // Delete HLS cache
    const hlsCacheDir = join(VIDEOS_PATH, '.hls-cache', String(id));
    if (existsSync(hlsCacheDir)) {
      try { rmSync(hlsCacheDir, { recursive: true }); } catch { /* ignore */ }
    }

    deleteVideoById(id);
    res.json({ ok: true });
  } catch (err) {
    next(err);
  }
});

// POST /api/videos/upload — multipart file upload
router.post('/api/videos/upload', upload.single('video'), async (req, res) => {
  if (!req.file) {
    return res.status(400).json({ error: 'No video file provided' });
  }

  const filePath = req.file.path;
  const filename = req.file.filename;

  try {
    // Check for dupe
    const existing = getVideoByPath(filePath);
    if (existing) {
      return res.json({ video: existing, duplicate: true });
    }

    const stat = statSync(filePath);
    const probe = await probeVideo(filePath);

    // Generate thumbnail
    const thumbName = filename.replace(/\.[^.]+$/, '.jpg');
    const thumbPath = join(VIDEOS_PATH, '.thumbnails', thumbName);
    let thumbResult = null;
    try {
      thumbResult = await generateVideoThumbnail(filePath, thumbPath);
    } catch { /* ignore */ }

    const title = basename(filename, extname(filename))
      .replace(/[_.-]/g, ' ')
      .replace(/\s+/g, ' ')
      .trim();

    const videoId = insertVideo({
      title,
      filename,
      file_path: filePath,
      file_size: stat.size,
      ...probe,
      thumbnail_path: thumbResult || null,
      status: 'ready',
    });

    const video = getVideoById(videoId);
    video.tags = [];
    res.json({ video });
  } catch (err) {
    console.error('[videos] Upload processing failed:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// POST /api/videos/scan — scan VIDEOS_PATH for new files
router.post('/api/videos/scan', (req, res) => {
  if (scanState.running) {
    return res.json({ status: 'already_running', ...scanState });
  }

  scanState = { running: true, total: 0, done: 0, added: 0, skipped: 0, errors: 0 };
  res.json({ status: 'started' });

  setImmediate(async () => {
    try {
      // Collect all video files
      const videoFiles = [];
      const collectFiles = (dir) => {
        let entries;
        try { entries = readdirSync(dir, { withFileTypes: true }); } catch { return; }
        for (const entry of entries) {
          if (entry.name.startsWith('.')) continue;
          const fullPath = join(dir, entry.name);
          if (entry.isDirectory()) {
            collectFiles(fullPath);
          } else {
            const ext = extname(entry.name).toLowerCase();
            if (VIDEO_EXTS.has(ext)) {
              videoFiles.push(fullPath);
            }
          }
        }
      };
      collectFiles(VIDEOS_PATH);

      scanState.total = videoFiles.length;
      console.log(`[videos] Scan found ${videoFiles.length} video files`);

      for (const filePath of videoFiles) {
        try {
          // Skip if already indexed
          const existing = getVideoByPath(filePath);
          if (existing) {
            scanState.skipped++;
            scanState.done++;
            continue;
          }

          const stat = statSync(filePath);
          const filename = basename(filePath);

          // Probe metadata
          let probe;
          try {
            probe = await probeVideo(filePath);
          } catch (err) {
            console.error(`[videos] Probe failed for ${filename}:`, err.message);
            scanState.errors++;
            scanState.done++;
            continue;
          }

          // Generate thumbnail
          const thumbName = `${Date.now()}_${filename.replace(/\.[^.]+$/, '.jpg')}`;
          const thumbPath = join(VIDEOS_PATH, '.thumbnails', thumbName);
          let thumbResult = null;
          try {
            thumbResult = await generateVideoThumbnail(filePath, thumbPath);
          } catch { /* ignore */ }

          const title = basename(filename, extname(filename))
            .replace(/[_.-]/g, ' ')
            .replace(/\s+/g, ' ')
            .trim();

          insertVideo({
            title,
            filename,
            file_path: filePath,
            file_size: stat.size,
            ...probe,
            thumbnail_path: thumbResult || null,
            status: 'ready',
          });

          scanState.added++;
          scanState.done++;
        } catch (err) {
          console.error(`[videos] Scan error for ${filePath}:`, err.message);
          scanState.errors++;
          scanState.done++;
        }
      }

      console.log(`[videos] Scan complete: ${scanState.added} added, ${scanState.skipped} skipped, ${scanState.errors} errors`);
    } catch (err) {
      console.error('[videos] Scan failed:', err.message);
    } finally {
      scanState.running = false;
    }
  });
});

// GET /api/videos/:id/thumbnail
router.get('/api/videos/:id/thumbnail', (req, res) => {
  const id = parseInt(req.params.id, 10);
  const video = getVideoById(id);
  if (!video) return res.status(404).json({ error: 'Video not found' });

  if (video.thumbnail_path && existsSync(video.thumbnail_path)) {
    const stat = statSync(video.thumbnail_path);
    res.writeHead(200, {
      'Content-Type': 'image/jpeg',
      'Content-Length': stat.size,
      'Cache-Control': 'public, max-age=86400',
    });
    createReadStream(video.thumbnail_path).pipe(res);
  } else {
    // Return a placeholder
    res.status(404).json({ error: 'No thumbnail' });
  }
});

// GET /api/videos/:id/stream — direct file serve for grid wall playback
router.get('/api/videos/:id/stream', (req, res) => {
  const id = parseInt(req.params.id, 10);
  const video = getVideoById(id);
  if (!video) return res.status(404).json({ error: 'Video not found' });
  if (!existsSync(video.file_path)) return res.status(404).json({ error: 'File not found' });

  const stat = statSync(video.file_path);
  const ext = extname(video.file_path).toLowerCase();
  const mimeTypes = { '.mp4': 'video/mp4', '.webm': 'video/webm', '.mov': 'video/quicktime', '.mkv': 'video/x-matroska', '.m4v': 'video/mp4' };
  const contentType = mimeTypes[ext] || 'video/mp4';

  // Support range requests
  const range = req.headers.range;
  if (range) {
    const parts = range.replace(/bytes=/, '').split('-');
    const start = parseInt(parts[0], 10);
    const end = parts[1] ? parseInt(parts[1], 10) : stat.size - 1;
    res.writeHead(206, {
      'Content-Range': `bytes ${start}-${end}/${stat.size}`,
      'Accept-Ranges': 'bytes',
      'Content-Length': end - start + 1,
      'Content-Type': contentType,
    });
    createReadStream(video.file_path, { start, end }).pipe(res);
  } else {
    res.writeHead(200, {
      'Content-Length': stat.size,
      'Content-Type': contentType,
      'Accept-Ranges': 'bytes',
    });
    createReadStream(video.file_path).pipe(res);
  }
});

export default router;