const API = require("../../lib/API");
const db = require("../../plugin/DataBase/db");
const { BaseStdResponse } = require("../../BaseStdResponse");

// 获取产品列表
class GetProductList extends API {
    constructor() {
        super();

        this.setPath('/Goods/List')
        this.setMethod('post')
    }

    async onRequest(req, res) {
        let { keyword, pagesize, current } = req.body;

        if ([pagesize, current].some(value => value === '' || value === null || value === undefined))
            return res.json({
                ...BaseStdResponse.MISSING_PARAMETER
            })

        // 校验分页参数
        if (isNaN(pagesize) || pagesize <= 0) {
            return res.json({
                ...BaseStdResponse.ERR,
                msg: '参数错误'
            })
        }

        if (isNaN(current) || current <= 0) {
            return res.json({
                ...BaseStdResponse.ERR,
                msg: '参数错误'
            })
        }

        // 计算分页的 offset
        const offset = (current - 1) * pagesize

        let sql = `
            SELECT
                id,
                name,
                price,
                num
            FROM
                goods
            WHERE state = 1 
        `

        let countSql = `
            SELECT COUNT(*) AS total
            FROM goods
            WHERE 1 = 1
        `

        let params = []
        let countParams = []

        if (keyword) {
            sql += ` AND name LIKE ?`
            countSql += ` AND name LIKE ?`
            params.push(`%${keyword}%`)
            countParams.push(`%${keyword}%`)
        }

        sql += `
            ORDER BY 
                id DESC
            LIMIT ? OFFSET ?;
        `
        params.push(String(pagesize), String(offset))

        let rows = await db.query(sql, params)
        let countResult = await db.query(countSql, countParams)

        if (!rows || !countResult)
            return res.json({
                ...BaseStdResponse.ERR,
                msg: '获取商品失败！'
            })

        let total = countResult[0].total
        const totalPages = Math.ceil(total / pagesize)

        res.json({
            ...BaseStdResponse.OK,
            data: rows,
            pagination: {
                current: current,
                pagesize: pagesize,
                total: total,
                totalPages: totalPages
            }
        })
    }
}

module.exports.GetProductList = GetProductList;