import express from 'express';
import User from '../models/User.js';
import Analysis from '../models/Analysis.js';
import AuditLog from '../models/AuditLog.js';
import { asyncHandler } from '../middleware/errorHandler.js';
import { requireAdmin, requireSuperAdmin } from '../middleware/auth.js';

const router = express.Router();

/**
 * GET /api/admin/dashboard
 * 管理者儀表板統計
 */
router.get('/dashboard', requireAdmin, asyncHandler(async (req, res) => {
  const stats = await Analysis.getStatistics();
  const userStats = await User.getAll(1, 1000); // 取得所有使用者

  const totalUsers = userStats.pagination.total;
  const activeUsers = userStats.data.filter(u => u.is_active).length;

  res.json({
    success: true,
    data: {
      totalUsers,
      activeUsers,
      totalAnalyses: stats.total,
      completedAnalyses: stats.completed,
      failedAnalyses: stats.failed,
      processingAnalyses: stats.processing,
      avgProcessingTime: Math.round(stats.avg_processing_time) || 0,
      successRate: stats.total > 0 ? ((stats.completed / stats.total) * 100).toFixed(1) : 0
    }
  });
}));

/**
 * GET /api/admin/users
 * 取得所有使用者
 */
router.get('/users', requireAdmin, asyncHandler(async (req, res) => {
  const page = parseInt(req.query.page) || 1;
  const limit = parseInt(req.query.limit) || 10;
  const filters = {
    role: req.query.role,
    is_active: req.query.is_active !== undefined ? req.query.is_active === 'true' : undefined,
    search: req.query.search
  };

  const result = await User.getAll(page, limit, filters);

  res.json({
    success: true,
    ...result
  });
}));

/**
 * POST /api/admin/users
 * 建立新使用者
 */
router.post('/users', requireAdmin, asyncHandler(async (req, res) => {
  const { employee_id, username, email, password, role, department, position } = req.body;

  // 驗證必填欄位
  if (!employee_id || !username || !email || !password) {
    return res.status(400).json({
      success: false,
      error: '請填寫所有必填欄位'
    });
  }

  // 驗證 role
  const validRoles = ['user', 'admin', 'super_admin'];
  if (role && !validRoles.includes(role)) {
    return res.status(400).json({
      success: false,
      error: '無效的權限等級'
    });
  }

  const newUser = await User.create({
    employee_id,
    username,
    email,
    password,
    role: role || 'user',
    department,
    position
  });

  // 記錄稽核日誌
  await AuditLog.logCreate(
    req.session.userId,
    'user',
    newUser.id,
    { username, email, role: newUser.role },
    req.ip,
    req.get('user-agent')
  );

  res.status(201).json({
    success: true,
    message: '使用者已建立',
    data: newUser
  });
}));

/**
 * PUT /api/admin/users/:id
 * 更新使用者
 */
router.put('/users/:id', requireAdmin, asyncHandler(async (req, res) => {
  const userId = parseInt(req.params.id);
  const { username, email, role, department, position, is_active } = req.body;

  const oldUser = await User.findById(userId);
  if (!oldUser) {
    return res.status(404).json({
      success: false,
      error: '使用者不存在'
    });
  }

  const updatedUser = await User.update(userId, {
    username,
    email,
    role,
    department,
    position,
    is_active
  });

  // 記錄稽核日誌
  await AuditLog.logUpdate(
    req.session.userId,
    'user',
    userId,
    { username: oldUser.username, role: oldUser.role },
    { username, role },
    req.ip,
    req.get('user-agent')
  );

  res.json({
    success: true,
    message: '使用者已更新',
    data: updatedUser
  });
}));

/**
 * DELETE /api/admin/users/:id
 * 停用/刪除使用者
 */
router.delete('/users/:id', requireSuperAdmin, asyncHandler(async (req, res) => {
  const userId = parseInt(req.params.id);
  const hard = req.query.hard === 'true';

  const user = await User.findById(userId);
  if (!user) {
    return res.status(404).json({
      success: false,
      error: '使用者不存在'
    });
  }

  // 不能刪除自己
  if (userId === req.session.userId) {
    return res.status(400).json({
      success: false,
      error: '無法刪除自己的帳號'
    });
  }

  if (hard) {
    await User.hardDelete(userId);
  } else {
    await User.delete(userId);
  }

  // 記錄稽核日誌
  await AuditLog.logDelete(
    req.session.userId,
    'user',
    userId,
    { username: user.username, email: user.email },
    req.ip,
    req.get('user-agent')
  );

  res.json({
    success: true,
    message: hard ? '使用者已刪除' : '使用者已停用'
  });
}));

/**
 * GET /api/admin/analyses
 * 取得所有分析記錄
 */
router.get('/analyses', requireAdmin, asyncHandler(async (req, res) => {
  const page = parseInt(req.query.page) || 1;
  const limit = parseInt(req.query.limit) || 10;
  const filters = {
    status: req.query.status,
    user_id: req.query.user_id,
    search: req.query.search
  };

  const result = await Analysis.getAll(page, limit, filters);

  res.json({
    success: true,
    ...result
  });
}));

/**
 * GET /api/admin/audit-logs
 * 取得稽核日誌
 */
router.get('/audit-logs', requireSuperAdmin, asyncHandler(async (req, res) => {
  const page = parseInt(req.query.page) || 1;
  const limit = parseInt(req.query.limit) || 50;
  const filters = {
    user_id: req.query.user_id,
    action: req.query.action,
    entity_type: req.query.entity_type,
    status: req.query.status,
    date_from: req.query.date_from,
    date_to: req.query.date_to
  };

  const result = await AuditLog.getAll(page, limit, filters);

  res.json({
    success: true,
    ...result
  });
}));

/**
 * GET /api/admin/statistics
 * 取得完整統計資料
 */
router.get('/statistics', requireSuperAdmin, asyncHandler(async (req, res) => {
  const overallStats = await Analysis.getStatistics();
  const users = await User.getAll(1, 1000);

  // 計算各部門統計
  const departmentStats = users.data.reduce((acc, user) => {
    const dept = user.department || '未分類';
    if (!acc[dept]) {
      acc[dept] = { total: 0, active: 0 };
    }
    acc[dept].total++;
    if (user.is_active) acc[dept].active++;
    return acc;
  }, {});

  // 計算權限統計
  const roleStats = users.data.reduce((acc, user) => {
    const role = user.role || 'user';
    acc[role] = (acc[role] || 0) + 1;
    return acc;
  }, {});

  res.json({
    success: true,
    data: {
      overall: overallStats,
      users: {
        total: users.pagination.total,
        byDepartment: departmentStats,
        byRole: roleStats
      }
    }
  });
}));

export default router;