const express = require('express');
const router = express.Router();
const { getDB } = require('../database');
const { agentAuth } = require('../middleware/agentAuth');
const { logger } = require('../config/logger');

/**
 * 获取代理下级用户列表
 * GET /api/users
 */
router.get('/', agentAuth, async (req, res) => {
  try {
    const agentId = req.agent.id;
    const { 
      page = 1, 
      limit = 20, 
      search, 
      role, 
      sort_by = 'created_at', 
      sort_order = 'desc',
      city,
      district
    } = req.query;

    const pageNum = parseInt(page) || 1;
    const limitNum = parseInt(limit) || 20;
    const offset = (pageNum - 1) * limitNum;

    // 构建查询条件
    let whereConditions = ['am.agent_id = ?'];
    let queryParams = [agentId];

    if (search) {
      whereConditions.push('(u.username LIKE ? OR u.real_name LIKE ? OR u.phone LIKE ?)');
      queryParams.push(`%${search}%`, `%${search}%`, `%${search}%`);
    }

    if (role) {
      whereConditions.push('u.role = ?');
      queryParams.push(role);
    }

    if (city) {
      whereConditions.push('u.city = ?');
      queryParams.push(city);
    }

    if (district) {
      whereConditions.push('u.district = ?');
      queryParams.push(district);
    }

    const whereClause = whereConditions.join(' AND ');

    // 验证排序字段
    const allowedSortFields = ['created_at', 'updated_at', 'balance', 'username', 'real_name'];
    const sortBy = allowedSortFields.includes(sort_by) ? sort_by : 'created_at';
    const sortOrder = sort_order.toLowerCase() === 'asc' ? 'ASC' : 'DESC';

    // 查询用户列表
    const usersQuery = `
      SELECT 
        u.id,
        u.username,
        u.real_name,
        u.phone,
        u.email,
        u.avatar,
        u.role,
        u.city,
        u.balance,
        u.points,
        u.created_at,
        u.updated_at,
        am.created_at as join_date,
        (
          SELECT CAST(COALESCE(SUM(amount), 0) AS DECIMAL(10,2))
          FROM transfers 
          WHERE from_user_id = u.id 
            AND DATE(created_at) = CURDATE()
        ) as today_transfer_out,
        (
          SELECT CAST(COALESCE(SUM(amount), 0) AS DECIMAL(10,2))
          FROM transfers 
          WHERE to_user_id = u.id 
            AND DATE(created_at) = CURDATE()
        ) as today_transfer_in
      FROM agent_merchants am
      LEFT JOIN users u ON am.merchant_id = u.id
      WHERE ${whereClause}
      ORDER BY u.${sortBy} ${sortOrder}
      LIMIT ${limitNum} OFFSET ${offset}
    `;

    const [users] = await getDB().execute(usersQuery, queryParams);

    // 查询总数
    const countQuery = `
      SELECT COUNT(*) as total
      FROM agent_merchants am
      LEFT JOIN users u ON am.merchant_id = u.id
      WHERE ${whereClause}
    `;
    
    const [countResult] = await getDB().execute(countQuery, queryParams);
    const total = countResult[0]?.total || 0;

    // 查询统计信息
    const [statsResult] = await getDB().execute(`
      SELECT 
        COUNT(*) as total_users,
        COUNT(CASE WHEN u.audit_status = 'approved' THEN 1 END) as active_users,
        CAST(COALESCE(SUM(u.balance), 0) AS DECIMAL(10,2)) as total_balance,
        COUNT(CASE WHEN DATE(am.created_at) = CURDATE() THEN 1 END) as today_new_users
      FROM agent_merchants am
      LEFT JOIN users u ON am.merchant_id = u.id
      WHERE am.agent_id = ?
    `, [agentId]);

    const stats = statsResult[0] || {
      total_users: 0,
      active_users: 0,
      total_balance: '0.00',
      today_new_users: 0
    };

    res.json({
      success: true,
      data: {
        users,
        pagination: {
          current_page: pageNum,
          per_page: limitNum,
          total,
          total_pages: Math.ceil(total / limitNum)
        },
        stats
      }
    });

  } catch (error) {
    logger.error('获取用户列表失败', {
      error: error.message,
      stack: error.stack,
      agentId: req.agent?.id
    });
    
    res.status(500).json({
      success: false,
      message: '获取用户列表失败'
    });
  }
});

/**
 * 获取单个用户详情
 * GET /api/users/:id
 */
router.get('/:id', agentAuth, async (req, res) => {
  try {
    const agentId = req.agent.id;
    const userId = req.params.id;

    // 验证用户是否属于当前代理
    const [users] = await getDB().execute(`
      SELECT 
        u.id,
        u.username,
        u.real_name,
        u.phone,
        u.email,
        u.avatar,
        u.role,
        u.city,
        u.district,
        u.balance,
        u.points,
        u.id_card,
        u.business_license,
        u.payment_qr_code,
        u.created_at,
        u.updated_at,
        am.created_at as join_date
      FROM agent_merchants am
      LEFT JOIN users u ON am.merchant_id = u.id
      WHERE am.agent_id = ? AND u.id = ?
    `, [agentId, userId]);

    if (users.length === 0) {
      return res.status(404).json({
        success: false,
        message: '用户不存在或不属于当前代理'
      });
    }

    const user = users[0];

    // 获取用户转账统计
    const [transferStats] = await getDB().execute(`
      SELECT 
        COUNT(*) as total_transfers,
        CAST(COALESCE(SUM(CASE WHEN from_user_id = ? THEN amount ELSE 0 END), 0) AS DECIMAL(10,2)) as total_transfer_out,
        CAST(COALESCE(SUM(CASE WHEN to_user_id = ? THEN amount ELSE 0 END), 0) AS DECIMAL(10,2)) as total_transfer_in,
        COUNT(CASE WHEN DATE(created_at) = CURDATE() THEN 1 END) as today_transfers,
        CAST(COALESCE(SUM(CASE WHEN from_user_id = ? AND DATE(created_at) = CURDATE() THEN amount ELSE 0 END), 0) AS DECIMAL(10,2)) as today_transfer_out,
        CAST(COALESCE(SUM(CASE WHEN to_user_id = ? AND DATE(created_at) = CURDATE() THEN amount ELSE 0 END), 0) AS DECIMAL(10,2)) as today_transfer_in
      FROM transfers 
      WHERE from_user_id = ? OR to_user_id = ?
    `, [userId, userId, userId, userId, userId, userId]);

    user.transfer_stats = transferStats[0] || {
      total_transfers: 0,
      total_transfer_out: '0.00',
      total_transfer_in: '0.00',
      today_transfers: 0,
      today_transfer_out: '0.00',
      today_transfer_in: '0.00'
    };

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

  } catch (error) {
    logger.error('获取用户详情失败', {
      error: error.message,
      stack: error.stack,
      agentId: req.agent?.id,
      userId: req.params.id
    });
    
    res.status(500).json({
      success: false,
      message: '获取用户详情失败'
    });
  }
});

/**
 * 导出用户数据
 * GET /api/users/export
 */
router.get('/export/data', agentAuth, async (req, res) => {
  try {
    const agentId = req.agent.id;
    const { format = 'json', search, role, city, district } = req.query;

    // 构建查询条件
    let whereConditions = ['am.agent_id = ?'];
    let queryParams = [agentId];

    if (search) {
      whereConditions.push('(u.username LIKE ? OR u.real_name LIKE ? OR u.phone LIKE ?)');
      queryParams.push(`%${search}%`, `%${search}%`, `%${search}%`);
    }

    if (role) {
      whereConditions.push('u.role = ?');
      queryParams.push(role);
    }

    if (city) {
      whereConditions.push('u.city = ?');
      queryParams.push(city);
    }

    if (district) {
      whereConditions.push('u.district = ?');
      queryParams.push(district);
    }

    const whereClause = whereConditions.join(' AND ');

    // 查询用户数据
    const [users] = await getDB().execute(`
      SELECT 
        u.id,
        u.username,
        u.real_name,
        u.phone,
        u.email,
        u.role,
        u.city,
        u.balance,
        u.points,
        u.created_at,
        am.created_at as join_date
      FROM agent_merchants am
      LEFT JOIN users u ON am.merchant_id = u.id
      WHERE ${whereClause}
      ORDER BY u.created_at DESC
    `, queryParams);

    if (format === 'csv') {
      // 生成CSV格式
      const csvHeader = 'ID,用户名,真实姓名,手机号,邮箱,角色,城市,地区,账户类型,余额,积分,状态,注册时间,加入时间\n';
      const csvData = users.map(user => {
        return [
          user.id,
          user.username || '',
          user.real_name || '',
          user.phone || '',
          user.email || '',
          user.role || '',
          user.city || '',
          user.district || '',
          user.account_type || '',
          user.balance || '0.00',
          user.points || 0,
          user.status || '',
          user.created_at || '',
          user.join_date || ''
        ].join(',');
      }).join('\n');

      res.setHeader('Content-Type', 'text/csv; charset=utf-8');
      res.setHeader('Content-Disposition', `attachment; filename="users_${Date.now()}.csv"`);
      res.send(csvHeader + csvData);
    } else {
      // 默认JSON格式
      res.json({
        success: true,
        data: users,
        exported_at: new Date().toISOString(),
        total: users.length
      });
    }

  } catch (error) {
    logger.error('导出用户数据失败', {
      error: error.message,
      stack: error.stack,
      agentId: req.agent?.id
    });
    
    res.status(500).json({
      success: false,
      message: '导出用户数据失败'
    });
  }
});

module.exports = router;