// ==UserScript==
// @name         记录上次查看时间
// @version      0.4.0
// @match      https://www.mcbbs.net/*
// @author       xmdhs
// @license MIT
// @description 记录上次查看时间。
// @namespace https://xmdhs.top
// @require https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/idb-keyval/6.1.0/umd.min.js
// @downloadURL none
// ==/UserScript==

(async function () {
    let tid = document.querySelector("#postlist .plc a[href^='forum.php?mod=viewthread&action=printable']")
    const customStore = idbKeyval.createStore('lastview-db-name', 'lastview-store-name');
    let data = localStorage.getItem("lastview")
    if (data) {
        let o = JSON.parse(data)
        for (const key in o) {
            await idbKeyval.set(String(key), String(o[key]), customStore)
        }
        localStorage.removeItem("lastview")
    }
    try {
        let temp = new URLSearchParams(tid.href)
        tid = temp.get("tid")
    } catch (error) { console.debug(error); }
    if (tid > 0) {
        idbKeyval.set(String(tid), String(new Date().getTime()), customStore)
    } else {
        const dl = document.querySelectorAll("tbody[id^='normalthread_'")
        for (const d of dl) {
            const dom = d.querySelector(".xst")
            let link = dom["href"]
            if (!link) {
                continue
            }
            let tid = link.match(/thread-([0-9]{1,10})-1-[0-9]{1,10}.html/)
            let atime
            if (tid != null && tid.length >= 2) {
                tid = tid[1]
                atime = await idbKeyval.get(tid, customStore)
            } else {
                let b = new URLSearchParams(link)
                let tidtemp = b.get("tid")
                if (tidtemp != "") {
                    atime = await idbKeyval.get(tidtemp, customStore)
                }
            }
            atime = new Number(atime)
            let lastTime;
            const tDom = d.querySelector("td.by > em > a > span[title]")
            if (tDom) {
                lastTime = Date.parse(tDom["title"])
            } else {
                lastTime = Date.parse(d.querySelector("td.by > em > a").textContent)
            }
            if (atime > 0) {
                let d = document.createElement("span")
                d.innerHTML = `<font style="color:#000000;"><b></b></font>`
                d.querySelector("b").textContent = `[${diffTime(new Date(atime), new Date())}]`
                if (lastTime > atime) {
                    d.querySelector("font").style.color = "red"
                }
                dom.insertBefore(d, dom.firstChild)
            }
        }
    }

})();

// https://www.jianshu.com/p/bdda96a1dcd8
function diffTime(startDate, endDate) {
    var diff = endDate.getTime() - startDate;//.getTime();//时间差的毫秒数

    //计算出相差天数
    var days = Math.floor(diff / (24 * 3600 * 1000));

    //计算出小时数
    var leave1 = diff % (24 * 3600 * 1000);    //计算天数后剩余的毫秒数
    var hours = Math.floor(leave1 / (3600 * 1000));
    //计算相差分钟数
    var leave2 = leave1 % (3600 * 1000);        //计算小时数后剩余的毫秒数
    var minutes = Math.floor(leave2 / (60 * 1000));

    //计算相差秒数
    var leave3 = leave2 % (60 * 1000);      //计算分钟数后剩余的毫秒数
    var seconds = Math.round(leave3 / 1000);

    var returnStr = seconds + "秒前";
    if (minutes > 0) {
        returnStr = minutes + "分钟前";//+ returnStr;
    }
    if (hours > 0) {
        returnStr = hours + "小时前";// + returnStr;
    }
    if (days > 0) {
        returnStr = days + "天前";//+ returnStr;
    }
    return returnStr;
}