import { Router } from 'express';
import bcrypt from 'bcryptjs';
import jwt from 'jsonwebtoken';
import crypto from 'crypto';
import {
  getSetting, setSetting,
  getAppUserCount, createAppUser, getAppUserByUsername, getAppUserById,
  getAllAppUsers, updateAppUser, deleteAppUser,
  getUserFolderAccess, setUserFolderAccess,
  getUserRouteAccess, setUserRouteAccess,
  getAllIndexedFolders,
} from './db.js';

const router = Router();
const TOKEN_COOKIE = 'ofapp_token';
const TOKEN_EXPIRY = undefined; // no expiration

function getJwtSecret() {
  let secret = getSetting('jwt_secret');
  if (!secret) {
    secret = crypto.randomBytes(48).toString('hex');
    setSetting('jwt_secret', secret);
    console.log('[auth] Generated new JWT secret');
  }
  return secret;
}

function signToken(userId) {
  return jwt.sign({ userId }, getJwtSecret(), { expiresIn: TOKEN_EXPIRY });
}

function setTokenCookie(res, token) {
  res.cookie(TOKEN_COOKIE, token, {
    httpOnly: true,
    sameSite: 'lax',
    maxAge: 10 * 365 * 24 * 60 * 60 * 1000, // ~10 years
    secure: false, // allow HTTP (self-signed HTTPS + local network)
  });
}

function userPayload(user, routes, folders) {
  return {
    id: user.id,
    username: user.username,
    display_name: user.display_name,
    role: user.role,
    enabled: user.enabled,
    routes,
    folders: user.role === 'admin' ? null : folders, // null = all access
  };
}

// --- Middleware ---

export function requireAuth(req, res, next) {
  // Setup mode: if no users exist, allow all requests as synthetic admin
  const userCount = getAppUserCount();
  if (userCount === 0) {
    req.user = { id: 0, username: 'setup', role: 'admin', enabled: 1 };
    return next();
  }

  const token = req.cookies?.[TOKEN_COOKIE];
  if (!token) {
    return res.status(401).json({ error: 'Authentication required' });
  }

  try {
    const decoded = jwt.verify(token, getJwtSecret());
    const user = getAppUserById(decoded.userId);
    if (!user || !user.enabled) {
      return res.status(401).json({ error: 'Account disabled or not found' });
    }

    req.user = user;

    next();
  } catch (err) {
    return res.status(401).json({ error: 'Invalid or expired token' });
  }
}

export function requireAdmin(req, res, next) {
  if (req.user?.role !== 'admin') {
    return res.status(403).json({ error: 'Admin access required' });
  }
  next();
}

// Route permission map: API path prefix -> route key
const ROUTE_PERMISSION_MAP = {
  '/api/feed':          'feed',
  '/api/subscriptions': 'users',
  '/api/users':         'users',
  '/api/download':      'downloads',
  '/api/gallery':       'gallery',
  '/api/hls':           'gallery',
  '/api/scrape':        'scrape',
  '/api/settings':      'settings',
  '/api/auth':          'settings',
  '/api/dashboard':     'dashboard',
  '/api/health':        'dashboard',
  '/api/videos':        'videos',
  '/api/video-hls':     'videos',
  '/api/drm':           null,
  '/api/media-proxy':   null,
  '/api/me':            null,
  '/api/admin':         null, // handled by requireAdmin
  '/api/app-auth':      null, // public
};

export function checkRoutePermission(req, res, next) {
  // Admins bypass all route checks
  if (req.user?.role === 'admin') return next();

  // Find matching route key
  const path = req.path;
  let routeKey = undefined;
  for (const [prefix, key] of Object.entries(ROUTE_PERMISSION_MAP)) {
    if (path.startsWith(prefix)) {
      routeKey = key;
      break;
    }
  }

  // null = always allowed for authenticated users
  if (routeKey === null || routeKey === undefined) return next();

  // Check user's route access
  const userRoutes = getUserRouteAccess(req.user.id);
  if (!userRoutes.includes(routeKey)) {
    return res.status(403).json({ error: 'Access denied' });
  }

  next();
}

// --- Public endpoints (no auth required) ---

// GET /api/app-auth/status — check if setup is needed
router.get('/api/app-auth/status', (req, res) => {
  const count = getAppUserCount();
  res.json({ setupRequired: count === 0 });
});

// POST /api/app-auth/setup — create initial admin (only when 0 users exist)
router.post('/api/app-auth/setup', (req, res) => {
  const count = getAppUserCount();
  if (count > 0) {
    return res.status(400).json({ error: 'Setup already completed' });
  }

  const { username, password } = req.body;
  if (!username || !password) {
    return res.status(400).json({ error: 'Username and password required' });
  }
  if (password.length < 4) {
    return res.status(400).json({ error: 'Password must be at least 4 characters' });
  }

  const hash = bcrypt.hashSync(password, 10);
  const userId = createAppUser(username.trim(), hash, 'admin', username.trim());
  const user = getAppUserById(userId);
  const token = signToken(userId);
  setTokenCookie(res, token);

  res.json({
    ok: true,
    user: userPayload(user, [], null),
  });
});

// POST /api/app-auth/login — validate creds, set JWT cookie
router.post('/api/app-auth/login', (req, res) => {
  const { username, password } = req.body;
  if (!username || !password) {
    return res.status(400).json({ error: 'Username and password required' });
  }

  const user = getAppUserByUsername(username.trim());
  if (!user) {
    return res.status(401).json({ error: 'Invalid username or password' });
  }
  if (!user.enabled) {
    return res.status(401).json({ error: 'Account is disabled' });
  }
  if (!bcrypt.compareSync(password, user.password_hash)) {
    return res.status(401).json({ error: 'Invalid username or password' });
  }

  const routes = getUserRouteAccess(user.id);
  const folders = getUserFolderAccess(user.id);
  const token = signToken(user.id);
  setTokenCookie(res, token);

  res.json({
    ok: true,
    user: userPayload(user, routes, folders),
  });
});

// POST /api/app-auth/logout — clear JWT cookie
router.post('/api/app-auth/logout', (req, res) => {
  res.clearCookie(TOKEN_COOKIE);
  res.json({ ok: true });
});

// --- Authenticated endpoints ---

// GET /api/app-auth/me — current user + permissions
router.get('/api/app-auth/me', requireAuth, (req, res) => {
  if (!req.user || req.user.id === 0) {
    return res.json({ setupRequired: true });
  }

  const routes = getUserRouteAccess(req.user.id);
  const folders = getUserFolderAccess(req.user.id);
  res.json({ user: userPayload(req.user, routes, folders) });
});

// --- Admin-only endpoints ---

// GET /api/admin/users — list all users with permissions
router.get('/api/admin/users', requireAuth, requireAdmin, (req, res) => {
  const users = getAllAppUsers();
  const result = users.map((u) => ({
    ...u,
    routes: getUserRouteAccess(u.id),
    folders: getUserFolderAccess(u.id),
  }));
  res.json(result);
});

// POST /api/admin/users — create user
router.post('/api/admin/users', requireAuth, requireAdmin, (req, res) => {
  const { username, password, role, display_name, routes, folders } = req.body;
  if (!username || !password) {
    return res.status(400).json({ error: 'Username and password required' });
  }
  if (password.length < 4) {
    return res.status(400).json({ error: 'Password must be at least 4 characters' });
  }

  const existing = getAppUserByUsername(username.trim());
  if (existing) {
    return res.status(400).json({ error: 'Username already exists' });
  }

  const hash = bcrypt.hashSync(password, 10);
  const userId = createAppUser(username.trim(), hash, role || 'user', display_name || username.trim());

  if (routes && Array.isArray(routes)) {
    setUserRouteAccess(userId, routes);
  }
  if (folders && Array.isArray(folders)) {
    setUserFolderAccess(userId, folders);
  }

  const user = getAppUserById(userId);
  res.json({
    ...user,
    routes: getUserRouteAccess(userId),
    folders: getUserFolderAccess(userId),
  });
});

// PUT /api/admin/users/:id — update user
router.put('/api/admin/users/:id', requireAuth, requireAdmin, (req, res) => {
  const id = parseInt(req.params.id, 10);
  const target = getAppUserById(id);
  if (!target) {
    return res.status(404).json({ error: 'User not found' });
  }

  const { username, password, role, display_name, enabled, routes, folders } = req.body;

  // Prevent demoting/disabling last admin
  if (target.role === 'admin' && (role === 'user' || enabled === 0)) {
    const allUsers = getAllAppUsers();
    const adminCount = allUsers.filter(u => u.role === 'admin' && u.enabled).length;
    if (adminCount <= 1) {
      return res.status(400).json({ error: 'Cannot demote or disable the last admin' });
    }
  }

  const fields = {};
  if (username !== undefined) fields.username = username.trim();
  if (display_name !== undefined) fields.display_name = display_name;
  if (role !== undefined) fields.role = role;
  if (enabled !== undefined) fields.enabled = enabled;
  if (password) {
    if (password.length < 4) {
      return res.status(400).json({ error: 'Password must be at least 4 characters' });
    }
    fields.password_hash = bcrypt.hashSync(password, 10);
  }

  if (Object.keys(fields).length > 0) {
    updateAppUser(id, fields);
  }

  if (routes !== undefined && Array.isArray(routes)) {
    setUserRouteAccess(id, routes);
  }
  if (folders !== undefined && Array.isArray(folders)) {
    setUserFolderAccess(id, folders);
  }

  const updated = getAppUserById(id);
  res.json({
    id: updated.id,
    username: updated.username,
    display_name: updated.display_name,
    role: updated.role,
    enabled: updated.enabled,
    created_at: updated.created_at,
    updated_at: updated.updated_at,
    routes: getUserRouteAccess(id),
    folders: getUserFolderAccess(id),
  });
});

// DELETE /api/admin/users/:id — delete user
router.delete('/api/admin/users/:id', requireAuth, requireAdmin, (req, res) => {
  const id = parseInt(req.params.id, 10);
  const target = getAppUserById(id);
  if (!target) {
    return res.status(404).json({ error: 'User not found' });
  }

  // Cannot delete self
  if (req.user.id === id) {
    return res.status(400).json({ error: 'Cannot delete your own account' });
  }

  // Cannot delete last admin
  if (target.role === 'admin') {
    const allUsers = getAllAppUsers();
    const adminCount = allUsers.filter(u => u.role === 'admin').length;
    if (adminCount <= 1) {
      return res.status(400).json({ error: 'Cannot delete the last admin' });
    }
  }

  deleteAppUser(id);
  res.json({ ok: true });
});

// GET /api/admin/available-folders — all gallery folders
router.get('/api/admin/available-folders', requireAuth, requireAdmin, (req, res) => {
  const folders = getAllIndexedFolders();
  res.json(folders);
});

export default router;