/**
 * 小程序支付API
 * 对接真实微信支付接口
 * 
 * 配置来源: 用户规则
 * - 小程序AppID: wxb8bbb2b10dec74aa
 * - 商户号: 1318592501
 * - API密钥: wx3e31b068be59ddc131b068be59ddc2
 */

import { NextResponse } from 'next/server'
import crypto from 'crypto'
import { query, getConfig } from '@/lib/db'

// 微信支付配置 - 2026-01-25 更新
// 小程序支付绑定状态: 审核中（申请单ID: 201554696918）
const WECHAT_PAY_CONFIG = {
  appId: 'wxb8bbb2b10dec74aa',        // 小程序AppID
  appSecret: '3c1fb1f63e6e052222bbcead9d07fe0c', // 小程序AppSecret（已更新）
  mchId: '1318592501',                 // 商户号
  mchKey: 'wx3e31b068be59ddc131b068be59ddc2', // API密钥(v2)
  notifyUrl: 'https://soul.quwanzhi.com/api/miniprogram/pay/notify', // 支付回调地址
}

// 生成随机字符串
function generateNonceStr(): string {
  return crypto.randomBytes(16).toString('hex')
}

// 生成签名
function generateSign(params: Record<string, string>, key: string): string {
  const sortedKeys = Object.keys(params).sort()
  const signString = sortedKeys
    .filter((k) => params[k] && k !== 'sign')
    .map((k) => `${k}=${params[k]}`)
    .join('&')

  const signWithKey = `${signString}&key=${key}`
  return crypto.createHash('md5').update(signWithKey, 'utf8').digest('hex').toUpperCase()
}

// 对象转XML
function dictToXml(data: Record<string, string>): string {
  const xml = ['<xml>']
  for (const [key, value] of Object.entries(data)) {
    xml.push(`<${key}><![CDATA[${value}]]></${key}>`)
  }
  xml.push('</xml>')
  return xml.join('')
}

// XML转对象
function xmlToDict(xml: string): Record<string, string> {
  const result: Record<string, string> = {}
  const regex = /<(\w+)><!\[CDATA\[(.*?)\]\]><\/\1>/g
  let match
  while ((match = regex.exec(xml)) !== null) {
    result[match[1]] = match[2]
  }
  const simpleRegex = /<(\w+)>([^<]*)<\/\1>/g
  while ((match = simpleRegex.exec(xml)) !== null) {
    if (!result[match[1]]) {
      result[match[1]] = match[2]
    }
  }
  return result
}

// 生成订单号
function generateOrderSn(): string {
  const now = new Date()
  const timestamp = now.getFullYear().toString() +
    (now.getMonth() + 1).toString().padStart(2, '0') +
    now.getDate().toString().padStart(2, '0') +
    now.getHours().toString().padStart(2, '0') +
    now.getMinutes().toString().padStart(2, '0') +
    now.getSeconds().toString().padStart(2, '0')
  const random = Math.floor(Math.random() * 1000000).toString().padStart(6, '0')
  return `MP${timestamp}${random}`
}

/**
 * POST - 创建小程序支付订单
 */
export async function POST(request: Request) {
  try {
    const body = await request.json()
    const { openId, productType, productId, amount, description } = body

    if (!openId) {
      return NextResponse.json({
        success: false,
        error: '缺少openId参数，请先登录'
      }, { status: 400 })
    }

    if (!amount || amount <= 0) {
      return NextResponse.json({
        success: false,
        error: '支付金额无效'
      }, { status: 400 })
    }

    // === 根据推广配置计算好友优惠后的实际支付金额 ===
    let finalAmount = amount
    try {
      // 读取推广/分销配置，获取好友优惠比例（如 5 表示 5%）
      const referralConfig = await getConfig('referral_config')
      const userDiscount = referralConfig?.userDiscount ? Number(referralConfig.userDiscount) : 0

      // 若存在有效的推荐码且配置了优惠比例，则给好友打折
      if (userDiscount > 0 && body.referralCode) {
        const discountRate = userDiscount / 100
        const discounted = amount * (1 - discountRate)
        // 保证至少 0.01 元，并保留两位小数
        finalAmount = Math.max(0.01, Math.round(discounted * 100) / 100)
        console.log('[MiniPay] 应用好友优惠:', {
          originalAmount: amount,
          discountPercent: userDiscount,
          finalAmount,
          referralCode: body.referralCode,
        })
      }
    } catch (e) {
      console.warn('[MiniPay] 读取 referral_config.userDiscount 失败，使用原价金额:', e)
      finalAmount = amount
    }

    const orderSn = generateOrderSn()
    const totalFee = Math.round(finalAmount * 100) // 转换为分（单位分）
    const goodsBody = description || (productType === 'fullbook' ? '《一场Soul的创业实验》全书' : `章节购买-${productId}`)

    // 获取客户端IP
    const forwarded = request.headers.get('x-forwarded-for')
    const clientIp = forwarded ? forwarded.split(',')[0] : '127.0.0.1'

    // 构建统一下单参数
    const params: Record<string, string> = {
      appid: WECHAT_PAY_CONFIG.appId,
      mch_id: WECHAT_PAY_CONFIG.mchId,
      nonce_str: generateNonceStr(),
      body: goodsBody.slice(0, 128),
      out_trade_no: orderSn,
      total_fee: totalFee.toString(),
      spbill_create_ip: clientIp,
      notify_url: WECHAT_PAY_CONFIG.notifyUrl,
      trade_type: 'JSAPI',
      openid: openId,
      attach: JSON.stringify({ productType, productId, userId: body.userId || '' }),
    }

    // 生成签名
    params.sign = generateSign(params, WECHAT_PAY_CONFIG.mchKey)

    console.log('[MiniPay] 创建订单:', {
      orderSn,
      totalFee,
      openId: openId.slice(0, 10) + '...',
      productType,
      productId,
    })

    // === ✅ 1. 先插入订单到数据库（无论支付是否成功，都要有订单记录） ===
    const userId = body.userId || openId // 优先使用 userId，否则用 openId
    let orderCreated = false

    // 查询当前用户的有效推荐人（用于订单归属与分销）
    let referrerId: string | null = null
    try {
      const bindings = await query(`
        SELECT referrer_id
        FROM referral_bindings
        WHERE referee_id = ? AND status = 'active' AND expiry_date > NOW()
        ORDER BY binding_date DESC
        LIMIT 1
      `, [userId]) as any[]
      if (bindings.length > 0) {
        referrerId = bindings[0].referrer_id || null
        console.log('[MiniPay] 订单归属推荐人(绑定):', referrerId)
      }
      // 若绑定未查到且前端传了邀请码，按邀请码解析推荐人
      if (!referrerId && body.referralCode) {
        const refUsers = await query(`
          SELECT id FROM users WHERE referral_code = ? LIMIT 1
        `, [String(body.referralCode).trim()]) as any[]
        if (refUsers.length > 0) {
          referrerId = refUsers[0].id
          console.log('[MiniPay] 订单归属推荐人(邀请码):', referrerId)
        }
      }
    } catch (e) {
      console.warn('[MiniPay] 查询推荐人失败，继续创建订单:', e)
    }

    // 下单时使用的邀请码：优先用请求体，否则用推荐人当前邀请码（便于订单记录对账）
    let orderReferralCode: string | null = body.referralCode ? String(body.referralCode).trim() || null : null
    if (!orderReferralCode && referrerId) {
      try {
        const refRows = (await query(`SELECT referral_code FROM users WHERE id = ? LIMIT 1`, [referrerId]) as any[])
        if (refRows.length > 0 && refRows[0].referral_code) {
          orderReferralCode = refRows[0].referral_code
        }
      } catch (_) { /* 忽略 */ }
    }
    
    try {
      // 检查是否已有相同产品的已支付订单
      const existingOrders = await query(`
        SELECT id FROM orders 
        WHERE user_id = ? 
          AND product_type = ? 
          AND product_id = ?
          AND status = 'paid'
        LIMIT 1
      `, [userId, productType, productId || 'fullbook']) as any[]

      if (existingOrders.length > 0) {
        console.log('[MiniPay] ⚠️ 用户已购买该产品，但仍创建订单:', {
          userId,
          productType,
          productId
        })
      }

      // 插入订单（含 referrer_id、referral_code，便于分销归属与对账）
      try {
        await query(`
          INSERT INTO orders (
            id, order_sn, user_id, open_id,
            product_type, product_id, amount, description,
            status, transaction_id, referrer_id, referral_code, created_at, updated_at
          ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, NOW(), NOW())
        `, [
          orderSn, orderSn, userId, openId,
          productType, productId || 'fullbook', finalAmount, goodsBody,
          'created', null, referrerId, orderReferralCode
        ])
      } catch (insertErr: any) {
        // 兼容：若表尚无 referrer_id 或 referral_code 列
        const msg = (insertErr as any)?.message || ''
        const code = (insertErr as any)?.code || ''
        if (msg.includes('referrer_id') || msg.includes('referral_code') || code === 'ER_BAD_FIELD_ERROR') {
          try {
            await query(`
              INSERT INTO orders (
                id, order_sn, user_id, open_id,
                product_type, product_id, amount, description,
                status, transaction_id, referrer_id, created_at, updated_at
              ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, NOW(), NOW())
            `, [
              orderSn, orderSn, userId, openId,
              productType, productId || 'fullbook', finalAmount, goodsBody,
              'created', null, referrerId
            ])
            console.log('[MiniPay] 订单已插入(未含 referral_code，请执行 scripts/add_orders_referral_code.py)')
          } catch (e2: any) {
            if (e2?.message?.includes('referrer_id') || e2?.code === 'ER_BAD_FIELD_ERROR') {
              await query(`
                INSERT INTO orders (
                  id, order_sn, user_id, open_id,
                  product_type, product_id, amount, description,
                  status, transaction_id, created_at, updated_at
                ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, NOW(), NOW())
              `, [
                orderSn, orderSn, userId, openId,
                productType, productId || 'fullbook', finalAmount, goodsBody,
                'created', null
              ])
              console.log('[MiniPay] 订单已插入(未含 referrer_id/referral_code，请执行迁移脚本)')
            } else {
              throw e2
            }
          }
        } else {
          throw insertErr
        }
      }

      orderCreated = true
      console.log('[MiniPay] ✅ 订单已插入数据库:', { 
        orderSn, 
        userId, 
        productType, 
        productId,
        originalAmount: amount,
        finalAmount,
      })
    } catch (dbError) {
      console.error('[MiniPay] ❌ 插入订单失败:', dbError)
      // 订单创建失败，但不中断支付流程
      // 理由：微信支付成功后仍可以通过回调补记订单
    }

    // 调用微信统一下单接口
    const xmlData = dictToXml(params)
    const response = await fetch('https://api.mch.weixin.qq.com/pay/unifiedorder', {
      method: 'POST',
      headers: { 'Content-Type': 'application/xml' },
      body: xmlData,
    })

    const responseText = await response.text()
    const result = xmlToDict(responseText)

    console.log('[MiniPay] 微信响应:', {
      return_code: result.return_code,
      result_code: result.result_code,
      err_code: result.err_code,
      err_code_des: result.err_code_des,
    })

    // 检查返回结果
    if (result.return_code !== 'SUCCESS') {
      return NextResponse.json({
        success: false,
        error: `微信支付请求失败: ${result.return_msg || '未知错误'}`
      }, { status: 500 })
    }

    if (result.result_code !== 'SUCCESS') {
      return NextResponse.json({
        success: false,
        error: `微信支付失败: ${result.err_code_des || result.err_code || '未知错误'}`
      }, { status: 500 })
    }

    // 构建小程序支付参数
    const prepayId = result.prepay_id
    if (!prepayId) {
      return NextResponse.json({
        success: false,
        error: '微信支付返回数据异常'
      }, { status: 500 })
    }

    const timestamp = Math.floor(Date.now() / 1000).toString()
    const nonceStr = generateNonceStr()

    const payParams: Record<string, string> = {
      appId: WECHAT_PAY_CONFIG.appId,
      timeStamp: timestamp,
      nonceStr,
      package: `prepay_id=${prepayId}`,
      signType: 'MD5',
    }
    payParams.paySign = generateSign(payParams, WECHAT_PAY_CONFIG.mchKey)

    console.log('[MiniPay] 支付参数生成成功:', { orderSn, prepayId: prepayId.slice(0, 20) + '...' })

    return NextResponse.json({
      success: true,
      data: {
        orderSn,
        prepayId,
        payParams: {
          timeStamp: timestamp,
          nonceStr,
          package: `prepay_id=${prepayId}`,
          signType: 'MD5',
          paySign: payParams.paySign,
        }
      }
    })

  } catch (error) {
    console.error('[MiniPay] 创建订单失败:', error)
    return NextResponse.json({
      success: false,
      error: '创建支付订单失败'
    }, { status: 500 })
  }
}

/**
 * GET - 查询订单状态
 */
export async function GET(request: Request) {
  const { searchParams } = new URL(request.url)
  const orderSn = searchParams.get('orderSn')

  if (!orderSn) {
    return NextResponse.json({
      success: false,
      error: '缺少订单号'
    }, { status: 400 })
  }

  try {
    const params: Record<string, string> = {
      appid: WECHAT_PAY_CONFIG.appId,
      mch_id: WECHAT_PAY_CONFIG.mchId,
      out_trade_no: orderSn,
      nonce_str: generateNonceStr(),
    }
    params.sign = generateSign(params, WECHAT_PAY_CONFIG.mchKey)

    const xmlData = dictToXml(params)
    const response = await fetch('https://api.mch.weixin.qq.com/pay/orderquery', {
      method: 'POST',
      headers: { 'Content-Type': 'application/xml' },
      body: xmlData,
    })

    const responseText = await response.text()
    const result = xmlToDict(responseText)

    if (result.return_code !== 'SUCCESS' || result.result_code !== 'SUCCESS') {
      return NextResponse.json({
        success: true,
        data: { status: 'unknown', orderSn }
      })
    }

    const tradeState = result.trade_state
    let status = 'paying'
    if (tradeState === 'SUCCESS') status = 'paid'
    else if (['CLOSED', 'REVOKED', 'PAYERROR'].includes(tradeState)) status = 'failed'
    else if (tradeState === 'REFUND') status = 'refunded'

    return NextResponse.json({
      success: true,
      data: {
        status,
        orderSn,
        transactionId: result.transaction_id,
        totalFee: parseInt(result.total_fee || '0', 10),
      }
    })

  } catch (error) {
    console.error('[MiniPay] 查询订单失败:', error)
    return NextResponse.json({
      success: false,
      error: '查询订单失败'
    }, { status: 500 })
  }
}