num/cloudfunctions/applyWithdraw/index.js

const cloud = require('wx-server-sdk');
cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV });
const db = cloud.database();

// 提现申请（Phase 1：记录申请，平台手动打款）
exports.main = async (event) => {
  const { amount } = event;
  const { OPENID } = cloud.getWXContext();

  if (!amount || amount <= 0) {
    return { code: 400, error: '无效金额' };
  }

  try {
    const userRes = await db.collection('users').where({
      _openid: OPENID,
    }).get();

    if (userRes.data.length === 0) {
      return { code: 401, error: '用户不存在' };
    }

    // 检查可提现金额
    const commRes = await db.collection('commissions').where({
      toUser: OPENID,
      status: 'available',
    }).get();

    const availableTotal = (commRes.data || []).reduce((sum, c) => sum + (c.amount || 0), 0);
    if (amount > availableTotal) {
      return { code: 400, error: '可提现金额不足' };
    }

    if (amount < 10000) { // 单位：分，最低 ¥100
      return { code: 400, error: '未达到最低提现金额 ¥100' };
    }

    // 创建提现申请
    const applyRes = await db.collection('withdrawals').add({
      data: {
        userId: OPENID,
        amount,
        status: 'pending',
        createdAt: db.serverDate(),
        updatedAt: db.serverDate(),
      },
    });

    // 将佣金状态改为 processing
    let remaining = amount;
    const availableComms = commRes.data.sort((a, b) => a.createdAt - b.createdAt);
    for (const c of availableComms) {
      if (remaining <= 0) break;
      const deductAmount = Math.min(remaining, c.amount);
      remaining -= deductAmount;
      await db.collection('commissions').doc(c._id).update({
        data: {
          status: 'processing',
          withdrawId: applyRes._id,
          updatedAt: db.serverDate(),
        },
      });
    }

    return { code: 0, withdrawId: applyRes._id };
  } catch (err) {
    return { code: 500, error: err.message };
  }
};