// ==UserScript==
// @name         get-free-coupons
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  get free coupons
// @author       Coolman
// @match        https://prodev.m.jd.com/mall/active/2F3KrzC3cVRqVZNxoDoVgz5StZZ8/index.html*
// @grant        none
// ==/UserScript==
(() => {
    'use strict';

    // 生鲜好物低价购
    // https://prodev.m.jd.com/mall/active/2F3KrzC3cVRqVZNxoDoVgz5StZZ8/index.html
    const moument = '2019-11-08 20:00'; // 抢购时间

    const ms = +new Date(moument); // 抢购时间毫秒值
    const pre = +new Date(ms - 1000 * 5); // 提前 5 秒钟准备
    const end = +new Date(ms + 1000 * 60 * 1); // 一分钟之后结束

    // 获取服务器时间戳
    const getServerTime = async () => {
        return +new Date((await fetch(`?${ +new Date() }`, {
            method: 'head',
        }).then((res) => res.headers)).get("Date"));
    };

    const doTask = () => {
        const coupons = document.querySelectorAll('div.free_coupon a.coupon');
        for (let coupon of coupons) {
            console.log(coupon.innerText.replace('\n', ' '));
            if (coupon.classList.contains('coupon_today_receive')) {
                // 今日已领取
                console.log('今日已领取');
            } else if (coupon.classList.contains('coupon_today_empty')) {
                // 今日已抢完
                console.log('今日已抢完');
            } else if (coupon.classList.contains('coupon_receive')) {
                // 已领取
                console.log('已领取');
            } else if (coupon.classList.contains('coupon_empty')) {
                // 已抢完
                console.log('已抢完');
            } else {
                console.info('--- 抢它 ---')
                // coupon.click();
                // coupon.remove();
            }
        }
    };

    const intervalId = setInterval(() => {
        getServerTime().then(now => {
            console.log(`server time: ${ now }`);
            // 结束了
            if (now >= end) {
                console.info(`it's time to end.`);
                clearInterval(intervalId);
                return;
            }
            // 准备时间
            if (now >= pre) {
                console.log(`it's time to go...`);
                if (now >= ms) {
                    doTask();
                }
            } else {
                console.info(`it's too early.`);
                clearInterval(intervalId);
                return;
            }
        });
    }, 800);
})();