const express  = require('express');
const bcrypt   = require('bcryptjs');
const crypto   = require('crypto');
const multer   = require('multer');
const path     = require('path');
const fs       = require('fs');
const db       = require('../../db');
const { authenticate, requireAdmin } = require('../../middleware/auth');
const router   = express.Router();


const UPLOAD_DIR = process.env.UPLOAD_DIR || '/data/uploads';

function generateToken() { return crypto.randomBytes(20).toString('base64url'); }

function getOrCreateUploadFolder(userId) {
  let f = db.prepare("SELECT * FROM folders WHERE user_id=? AND is_upload_folder=1 LIMIT 1").get(userId);
  if (!f) {
    const r = db.prepare("INSERT INTO folders (user_id,name,is_upload_folder,created_at) VALUES (?,?,1,datetime('now','localtime'))").run(userId,'Upload');
    f = db.prepare('SELECT * FROM folders WHERE id=?').get(r.lastInsertRowid);
  }
  return f;
}

function canUseUploadShare(userId) {
  const u = db.prepare('SELECT role,allow_upload_share FROM users WHERE id=?').get(userId);
  return u && (u.role==='admin' || !!u.allow_upload_share);
}

// ── Eigene Shares ─────────────────────────────────────────────────────────────
router.get('/', authenticate, (req, res) => {
  if (!canUseUploadShare(req.user.id)) return res.status(403).json({ error:'Keine Berechtigung' });
  const folder = getOrCreateUploadFolder(req.user.id);
  const shares = db.prepare(`
    SELECT s.*, COUNT(l.id) as upload_count
    FROM upload_shares s
    LEFT JOIN upload_share_logs l ON l.share_id=s.id
    WHERE s.user_id=?
    GROUP BY s.id ORDER BY s.created_at DESC
  `).all(req.user.id);
  res.json({ shares, folder });
});

router.post('/', authenticate, (req, res) => {
  if (!canUseUploadShare(req.user.id)) return res.status(403).json({ error:'Keine Berechtigung' });
  const { password, expires_hours=24, max_size_mb=10 } = req.body;
  if (!password?.trim()) return res.status(400).json({ error:'Passwort erforderlich' });
  const folder  = getOrCreateUploadFolder(req.user.id);
  const token   = generateToken();
  const hash    = bcrypt.hashSync(password.trim(), 10);
  const expires = new Date(Date.now() + Number(expires_hours)*3600000).toISOString();
  const r = db.prepare(`
    INSERT INTO upload_shares (user_id,token,password_hash,expires_at,max_size_mb,folder_id,created_at)
    VALUES (?,?,?,?,?,?,datetime('now','localtime'))
  `).run(req.user.id, token, hash, expires, Number(max_size_mb), folder.id);
  res.json(db.prepare('SELECT * FROM upload_shares WHERE id=?').get(r.lastInsertRowid));
});

router.delete('/:id', authenticate, (req, res) => {
  const s = db.prepare('SELECT * FROM upload_shares WHERE id=? AND user_id=?').get(req.params.id, req.user.id);
  if (!s) return res.status(404).json({ error:'Nicht gefunden' });
  db.prepare("UPDATE upload_shares SET is_active=0, deactivated_reason='manual' WHERE id=?").run(s.id);
  res.json({ ok:true });
});

router.delete('/:id/remove', authenticate, (req, res) => {
  const s = db.prepare('SELECT * FROM upload_shares WHERE id=? AND user_id=?').get(req.params.id, req.user.id);
  if (!s) return res.status(404).json({ error:'Nicht gefunden' });
  db.prepare('DELETE FROM upload_shares WHERE id=?').run(s.id);
  res.json({ ok:true });
});

router.get('/logs', authenticate, (req, res) => {
  if (!canUseUploadShare(req.user.id)) return res.status(403).json({ error:'Keine Berechtigung' });
  const logs = db.prepare(`
    SELECT l.*, s.expires_at, s.max_size_mb
    FROM upload_share_logs l
    JOIN upload_shares s ON s.id=l.share_id
    WHERE l.user_id=? ORDER BY l.uploaded_at DESC LIMIT 100
  `).all(req.user.id);
  res.json(logs);
});

// ── Admin ─────────────────────────────────────────────────────────────────────
router.get('/admin/logs', authenticate, requireAdmin, (req, res) => {
  const logs = db.prepare(`
    SELECT l.*, s.expires_at, s.max_size_mb, u.username
    FROM upload_share_logs l
    JOIN upload_shares s ON s.id=l.share_id
    JOIN users u ON u.id=l.user_id
    ORDER BY l.uploaded_at DESC LIMIT 500
  `).all();
  res.json(logs);
});

router.get('/admin/shares', authenticate, requireAdmin, (req, res) => {
  const shares = db.prepare(`
    SELECT s.*, u.username, COUNT(l.id) as upload_count
    FROM upload_shares s JOIN users u ON u.id=s.user_id
    LEFT JOIN upload_share_logs l ON l.share_id=s.id
    GROUP BY s.id ORDER BY s.created_at DESC
  `).all();
  res.json(shares);
});

router.post('/admin/permission', authenticate, requireAdmin, (req, res) => {
  const { user_id, allow } = req.body;
  db.prepare('UPDATE users SET allow_upload_share=? WHERE id=?').run(allow?1:0, user_id);
  res.json({ ok:true });
});

// ── Öffentlich: Share-Info ────────────────────────────────────────────────────
router.get('/public/:token', (req, res) => {
  const s = db.prepare("SELECT id,expires_at,max_size_mb,is_active,failed_attempts,deactivated_reason FROM upload_shares WHERE token=?").get(req.params.token);
  if (!s || !s.is_active) return res.status(404).json({ error: s?.deactivated_reason==='too_many_attempts' ? 'Link wegen zu vieler Fehlversuche gesperrt' : 'Link ungültig oder deaktiviert' });
  if (new Date(s.expires_at) < new Date()) return res.status(410).json({ error:'Link abgelaufen' });
  res.json({ ok:true, max_size_mb:s.max_size_mb, expires_at:s.expires_at });
});

// ── Öffentlich: Passwort prüfen ───────────────────────────────────────────────
router.post('/public/:token/verify', (req, res) => {
  const s = db.prepare("SELECT * FROM upload_shares WHERE token=?").get(req.params.token);
  if (!s || !s.is_active) return res.status(404).json({ error:'Link ungültig' });
  if (new Date(s.expires_at) < new Date()) return res.status(410).json({ error:'Link abgelaufen' });

  if (!bcrypt.compareSync(req.body?.password || '', s.password_hash)) {
    const attempts = (s.failed_attempts||0) + 1;
    if (attempts >= 3) {
      // Link sperren
      db.prepare("UPDATE upload_shares SET is_active=0, failed_attempts=?, deactivated_reason='too_many_attempts' WHERE id=?").run(attempts, s.id);
      return res.status(401).json({ error:'Zu viele Fehlversuche – Link wurde gesperrt', locked:true });
    }
    db.prepare("UPDATE upload_shares SET failed_attempts=? WHERE id=?").run(attempts, s.id);
    return res.status(401).json({ error:'Falsches Passwort', attempts_left: 3-attempts });
  }

  // Erfolgreich – Fehlversuche zurücksetzen
  db.prepare("UPDATE upload_shares SET failed_attempts=0 WHERE id=?").run(s.id);
  res.json({ ok:true, max_size_mb:s.max_size_mb, expires_at:s.expires_at });
});

// ── Öffentlich: Upload ────────────────────────────────────────────────────────
router.post('/public/:token/upload', (req, res) => {
  const s = db.prepare("SELECT * FROM upload_shares WHERE token=?").get(req.params.token);
  if (!s || !s.is_active) return res.status(404).json({ error:'Link ungültig' });
  if (new Date(s.expires_at) < new Date()) return res.status(410).json({ error:'Link abgelaufen' });

  const pw = req.headers['x-upload-password'] || '';
  if (!bcrypt.compareSync(pw, s.password_hash)) return res.status(401).json({ error:'Nicht autorisiert' });

  const storage = multer.diskStorage({ destination: UPLOAD_DIR });
  const upload  = multer({ storage, limits:{ fileSize: s.max_size_mb*1024*1024 } }).single('file');

  upload(req, res, err => {
    if (err) {
      if (err.code==='LIMIT_FILE_SIZE') return res.status(413).json({ error:`Datei zu groß (max ${s.max_size_mb} MB)` });
      return res.status(500).json({ error:err.message });
    }
    if (!req.file) return res.status(400).json({ error:'Keine Datei' });
    try {
      db.prepare(`INSERT INTO files (user_id,filename,originalname,mimetype,size,folder_id,created_at) VALUES (?,?,?,?,?,?,datetime('now','localtime'))`).run(s.user_id,req.file.filename,req.file.originalname,req.file.mimetype,req.file.size,s.folder_id);
      db.prepare(`INSERT INTO upload_share_logs (share_id,user_id,originalname,size,ip_address,uploaded_at) VALUES (?,?,?,?,?,datetime('now','localtime'))`).run(s.id,s.user_id,req.file.originalname,req.file.size,req.ip||'');
      res.json({ ok:true, filename:req.file.originalname });
    } catch(e) {
      try { fs.unlinkSync(path.join(UPLOAD_DIR, req.file.filename)); } catch {}
      res.status(500).json({ error:e.message });
    }
  });
});

module.exports = router;