// ==UserScript==
// @name         记录上次查看时间
// @version      0.2.1
// @include      https://www.mcbbs.net/*
// @author       xmdhs
// @description 记录上次查看时间。
// @namespace https://xmdhs.top
// @downloadURL none
// ==/UserScript==

(function () {
    let tid = document.querySelector("#postlist > table:nth-child(1) > tbody > tr > td.plc.ptm.pbn.vwthd > div > a:nth-child(1)")
    try {
        let temp = new URLSearchParams(tid.href)
        tid = temp.get("tid")
    } catch (error) { console.debug(error); }
    if (tid > 0) {
        let date = localStorage.getItem("lastview")
        if (date == null) {
            date = {}
        } else {
            date = JSON.parse(date)
        }
        date[tid] = new Date().getTime()
        let tempdate = {}
        if (Object.keys(date).length > 1000) {
            let now = new Date().getTime()
            for (let i in date) {
                if ((now - date[i]) > 432000000) {
                    continue;
                }
                tempdate[i] = date[i]
            }
            date = tempdate
        }
        localStorage.setItem("lastview", JSON.stringify(date))
    } else {
        let date = localStorage.getItem("lastview")
        date = JSON.parse(date)
        let dl = document.querySelectorAll(".xst")
        for (const dom of dl) {
            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 = date[tid]
            } else {
                let b = new URLSearchParams(link)
                let tidtemp = b.get("tid")
                if (tidtemp != "") {
                    atime = date[tidtemp]
                }
            }
            if (atime > 0) {
                let d = document.createElement("span")
                d.innerHTML = `<font color="#000000"><b>[${diffTime(new Date(atime), new Date())}] </b></font>`
                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;
}