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


router.get('/', async (req, res) => {
  try {
    const useId = req.query.user_id;
    const db = getDB();
    const query = `
      SELECT * FROM coupon_products
    `
    const [coupon] = await db.query(query);

    if (coupon.length === 0) {
      res.json({ message: '暂无优惠券' });
    }

    for(const item of coupon) {
      const query = `
        SELECT * FROM coupon_use WHERE user_id = ? AND coupon_id = ?
      `
      const [couponExist] = await db.query(query, [useId, item.id]);
      if (couponExist.length === 0) {
        item.got = false;
      } else {
        item.got = true;
      }
    }

    res.json({coupon, success: true});
  } catch (error) {
    res.status(500).json({ error: '获取优惠券失败' });
  }
});
router.get('/:id', async (req, res) => {
  try {
    const db = getDB();

    const userId = req.params.id;
    const receiveCouponId = req.query.coupon_id;

    const query = `
      SELECT * FROM coupon_use WHERE user_id = ? AND coupon_id = ?
    `
    const [couponExist] = await db.query(query, [userId, receiveCouponId]);

    if (couponExist.length === 0) {

      const insertQuery = `
        INSERT INTO coupon_use (user_id, coupon_id, get_time) VALUES (?, ?, now())
      `
      await db.query(insertQuery, [userId, receiveCouponId]);

      const updateQuery = `
        UPDATE coupon_products SET remain = remain - 1 WHERE id = ?
      `
      await db.query(updateQuery, [receiveCouponId]);

    } else {
      return res.status(500).json({ error: '已有该优惠券' });
    }

    res.json({success: true});
  } catch (error) {
    console.log(error);
    res.status(500).json({ error: '获取优惠券失败' });
  }
});

router.get('/user/:id', async (req, res) => {
  try {
    const db = getDB();
    const userId = req.params.id;

    const query = `
      SELECT * FROM coupon_use WHERE user_id = ?
    `
    const [coupon] = await db.query(query, [userId]);

    for (const item of coupon) {
      const query = `
        SELECT * FROM coupon_products WHERE id = ?
      `
      const [couponInfo] = await db.query(query, [item.coupon_id]);
      item.couponInfo = couponInfo[0];
      item.couponInfo.products = [];
      for (const product of item.couponInfo.products_id) {
        const query = `
          SELECT name FROM products WHERE id = ?
        `
        const [productInfo] = await db.query(query, [product]);
        item.couponInfo.products.push(productInfo[0]);
      }
    }
    
    res.json({success: true, coupon});
  } catch (error) {
    console.log(error);
    res.status(500).json({ error: '加载优惠券失败' });
  }
})

module.exports = router;