const express = require('express');
const dbConnector = require('../utils/dbConnector');
const { adminRequired } = require('../middlewares/auth');
const { asyncHandler } = require('../middlewares/errorHandler');

const router = express.Router();

/**
 * 获取系统统计概览
 */
router.get('/statistics/overview', adminRequired, asyncHandler(async (req, res) => {
  // 获取总用户数
  const totalUsersResult = await dbConnector.query(
    'SELECT COUNT(*) as total FROM users WHERE status = 1'
  );

  // 获取今日新增用户数
  const newUsersTodayResult = await dbConnector.query(
    'SELECT COUNT(*) as total FROM users WHERE status = 1 AND DATE(created_at) = CURDATE()'
  );

  // 获取总订单数
  const totalOrdersResult = await dbConnector.query(
    'SELECT COUNT(*) as total FROM orders'
  );

  // 获取总收入
  const totalRevenueResult = await dbConnector.query(
    'SELECT COALESCE(SUM(total_amount), 0) as total FROM orders WHERE payment_status = 1'
  );

  // 获取总识别次数
  const totalIdentificationsResult = await dbConnector.query(
    'SELECT COUNT(*) as total FROM identifications'
  );

  // 获取今日活跃用户数
  const activeUsersTodayResult = await dbConnector.query(
    `SELECT COUNT(DISTINCT user_id) as total FROM (
      SELECT user_id FROM orders WHERE DATE(created_at) = CURDATE()
      UNION
      SELECT user_id FROM identifications WHERE DATE(created_at) = CURDATE()
    ) as active_users`
  );

  res.json({
    code: 200,
    message: '获取成功',
    data: {
      total_users: totalUsersResult[0].total,
      new_users_today: newUsersTodayResult[0].total,
      total_orders: totalOrdersResult[0].total,
      total_revenue: parseFloat(totalRevenueResult[0].total),
      total_identifications: totalIdentificationsResult[0].total,
      active_users_today: activeUsersTodayResult[0].total
    }
  });
}));

/**
 * 获取趋势数据
 */
router.get('/statistics/trend', adminRequired, asyncHandler(async (req, res) => {
  const { days = 7, type = 'users' } = req.query;
  const dayCount = parseInt(days);

  let query = '';
  let dataKey = '';

  switch (type) {
    case 'users':
      query = `
        SELECT DATE(created_at) as date, COUNT(*) as count
        FROM users 
        WHERE created_at >= DATE_SUB(CURDATE(), INTERVAL ? DAY)
        GROUP BY DATE(created_at)
        ORDER BY date
      `;
      dataKey = 'new_users';
      break;
    case 'orders':
      query = `
        SELECT DATE(created_at) as date, COUNT(*) as count
        FROM orders 
        WHERE created_at >= DATE_SUB(CURDATE(), INTERVAL ? DAY)
        GROUP BY DATE(created_at)
        ORDER BY date
      `;
      dataKey = 'new_orders';
      break;
    case 'revenue':
      query = `
        SELECT DATE(created_at) as date, COALESCE(SUM(total_amount), 0) as amount
        FROM orders 
        WHERE payment_status = 1 AND created_at >= DATE_SUB(CURDATE(), INTERVAL ? DAY)
        GROUP BY DATE(created_at)
        ORDER BY date
      `;
      dataKey = 'revenue';
      break;
    case 'identifications':
      query = `
        SELECT DATE(created_at) as date, COUNT(*) as count
        FROM identifications 
        WHERE created_at >= DATE_SUB(CURDATE(), INTERVAL ? DAY)
        GROUP BY DATE(created_at)
        ORDER BY date
      `;
      dataKey = 'identifications';
      break;
    default:
      return res.status(400).json({
        code: 400,
        message: '不支持的统计类型',
        data: null
      });
  }

  const trendData = await dbConnector.query(query, [dayCount]);

  res.json({
    code: 200,
    message: '获取成功',
    data: {
      type,
      days: dayCount,
      trend: trendData,
      total: trendData.reduce((sum, item) => sum + (item.count || item.amount || 0), 0)
    }
  });
}));

/**
 * 获取系统配置列表
 */
router.get('/config', adminRequired, asyncHandler(async (req, res) => {
  const configs = await dbConnector.query(
    'SELECT config_key, config_value, config_type, description FROM system_config ORDER BY config_key'
  );

  res.json({
    code: 200,
    message: '获取成功',
    data: configs
  });
}));

/**
 * 获取单个系统配置
 */
router.get('/config/:key', adminRequired, asyncHandler(async (req, res) => {
  const { key } = req.params;

  const configs = await dbConnector.query(
    'SELECT config_key, config_value, config_type, description FROM system_config WHERE config_key = ?',
    [key]
  );

  if (configs.length === 0) {
    return res.status(404).json({
      code: 404,
      message: '配置项不存在',
      data: null
    });
  }

  res.json({
    code: 200,
    message: '获取成功',
    data: configs[0]
  });
}));

/**
 * 更新系统配置
 */
router.put('/config/:key', adminRequired, asyncHandler(async (req, res) => {
  const { key } = req.params;
  const { value } = req.body;

  if (value === undefined) {
    return res.status(400).json({
      code: 400,
      message: '配置值不能为空',
      data: null
    });
  }

  const result = await dbConnector.query(
    'UPDATE system_config SET config_value = ?, updated_at = CURRENT_TIMESTAMP WHERE config_key = ?',
    [value, key]
  );

  if (result.affectedRows === 0) {
    return res.status(404).json({
      code: 404,
      message: '配置项不存在',
      data: null
    });
  }

  res.json({
    code: 200,
    message: '更新成功',
    data: null
  });
}));

/**
 * 获取操作日志
 */
router.get('/logs', adminRequired, asyncHandler(async (req, res) => {
  const { page = 1, limit = 20, module, action, username } = req.query;
  const offset = (page - 1) * limit;

  let whereClause = 'WHERE 1=1';
  let queryParams = [];

  if (module) {
    whereClause += ' AND module = ?';
    queryParams.push(module);
  }

  if (action) {
    whereClause += ' AND action = ?';
    queryParams.push(action);
  }

  if (username) {
    whereClause += ' AND username LIKE ?';
    queryParams.push(`%${username}%`);
  }

  // 获取日志列表
  const logs = await dbConnector.query(
    `SELECT id, user_id, username, user_type, module, action, target_id, 
     description, ip_address, user_agent, created_at
     FROM operation_logs ${whereClause}
     ORDER BY created_at DESC
     LIMIT ? OFFSET ?`,
    [...queryParams, parseInt(limit), offset]
  );

  // 获取总数
  const totalResult = await dbConnector.query(
    `SELECT COUNT(*) as total FROM operation_logs ${whereClause}`,
    queryParams
  );

  res.json({
    code: 200,
    message: '获取成功',
    data: {
      logs,
      pagination: {
        page: parseInt(page),
        limit: parseInt(limit),
        total: totalResult[0].total,
        pages: Math.ceil(totalResult[0].total / limit)
      }
    }
  });
}));

module.exports = router;