const express = require('express');
const router = express.Router();
const dbConnector = require('../utils/dbConnector');

// 发起支付
router.post('/orders/:order_no', async (req, res) => {
  try {
    const { order_no } = req.params;
    const userId = req.user.id;
    
    // 查询订单信息
    const order = await dbConnector.query(`
      SELECT o.*, u.openid 
      FROM orders o 
      JOIN users u ON o.user_id = u.id 
      WHERE o.order_no = ? AND o.user_id = ?
    `, [order_no, userId]);
    
    if (order.length === 0) {
      return res.status(404).json({
        code: 404,
        message: '订单不存在'
      });
    }
    
    // 检查订单状态
    if (order[0].payment_status !== 0) {
      return res.status(400).json({
        code: 400,
        message: '订单已支付或已取消'
      });
    }
    
    // 模拟微信支付参数生成（实际项目中需要调用微信支付API）
    const paymentParams = {
      timeStamp: Math.floor(Date.now() / 1000).toString(),
      nonceStr: generateNonceStr(),
      package: `prepay_id=wx${generateNonceStr(28)}`,
      signType: 'MD5',
      paySign: generateNonceStr(32)
    };
    
    // 记录支付请求
    await dbConnector.query(
      `INSERT INTO payments 
       (order_id, payment_method, amount, status, created_at, updated_at) 
       VALUES (?, 'wechat', ?, 'pending', NOW(), NOW())`,
      [order[0].id, order[0].total_amount]
    );
    
    res.json({
      code: 200,
      message: '支付参数生成成功',
      data: {
        payment_params: paymentParams
      }
    });
  } catch (error) {
    console.error('发起支付失败:', error);
    res.status(500).json({
      code: 500,
      message: '服务器内部错误',
      error: error.message
    });
  }
});

// 查询支付结果
router.get('/orders/:order_no/status', async (req, res) => {
  try {
    const { order_no } = req.params;
    const userId = req.user.id;
    
    // 查询订单和支付信息
    const result = await dbConnector.query(`
      SELECT o.order_no, o.payment_status, p.amount as paid_amount, p.paid_at
      FROM orders o
      LEFT JOIN payments p ON o.id = p.order_id
      WHERE o.order_no = ? AND o.user_id = ?
      ORDER BY p.created_at DESC LIMIT 1
    `, [order_no, userId]);
    
    if (result.length === 0) {
      return res.status(404).json({
        code: 404,
        message: '订单不存在'
      });
    }
    
    const paymentStatus = result[0].payment_status === 1 ? 'paid' : 'pending';
    
    res.json({
      code: 200,
      message: '查询成功',
      data: {
        order_no: result[0].order_no,
        payment_status: paymentStatus,
        paid_amount: result[0].paid_amount || 0,
        paid_at: result[0].paid_at
      }
    });
  } catch (error) {
    console.error('查询支付状态失败:', error);
    res.status(500).json({
      code: 500,
      message: '服务器内部错误',
      error: error.message
    });
  }
});

// 支付回调（微信支付回调接口）
router.post('/notify/wechat', async (req, res) => {
  try {
    // 这里应该验证微信支付回调的签名
    const { out_trade_no, transaction_id, total_fee, time_end } = req.body;
    
    // 更新订单支付状态
    await dbConnector.query(`
      UPDATE orders SET payment_status = 1, updated_at = NOW() 
      WHERE order_no = ? AND payment_status = 0
    `, [out_trade_no]);
    
    // 更新支付记录
    await dbConnector.query(`
      UPDATE payments SET status = 'paid', transaction_id = ?, paid_at = NOW() 
      WHERE order_id = (SELECT id FROM orders WHERE order_no = ?)
    `, [transaction_id, out_trade_no]);
    
    // 返回成功响应给微信
    res.send('<xml><return_code><![CDATA[SUCCESS]]></return_code><return_msg><![CDATA[OK]]></return_msg></xml>');
  } catch (error) {
    console.error('支付回调处理失败:', error);
    res.status(500).send('<xml><return_code><![CDATA[FAIL]]></return_code><return_msg><![CDATA[处理失败]]></return_msg></xml>');
  }
});

// 生成随机字符串
function generateNonceStr(length = 16) {
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
  let nonceStr = '';
  for (let i = 0; i < length; i++) {
    nonceStr += chars.charAt(Math.floor(Math.random() * chars.length));
  }
  return nonceStr;
}

module.exports = router;