// ==UserScript==
// @name		天数倒计时
// @namespace	https://bbs.tampermonkey.net.cn/
// @version		0.8
// @description	每天提醒你距离目标日期的天数
// @author		Exisi
// @crontab    * 7-23 once * *
// @grant		GM_notification
// @grant		GM_getValue
// @homepage   https://scriptcat.org/script-show-page/372
// @supportURL  https://exi.ink
// ==/UserScript==

/* ==UserConfig==
设置:
    Notice:
        title: 标题
        description: 请输入通知标题
    Timeout:
        title: 通知时间
        description: 请输入每次通知保持的时长，默认 3 秒
    Year:
        title: 年
        description: 请输入年份，默认当前年份
    Month:
        title: 月
        description: 请输入年份，默认当前月份
    Day:
        title: 日
        description: 请输入天数，默认无
 ==/UserConfig== */

function getTotalDay(year, month) {
    let date = new Date(year, month, 0);
    return date.getDate();
}

function getDiffDay(date, aim_date){
    let diff = (aim_date - date) / 1000 / 3600 / 24;
    return diff;
}

function error(target){
    GM_notification({
        title   :  target.notice,
        text    :  '日期错误，请重新设置时间',
        timeout :  GM_getValue('设置.Timeout') !='' ? GM_getValue('设置.Timeout') : 3000,
    });
}

return new Promise((resolve, reject) => {
    let date = new Date();
    let aim_date = new Date();
    let current = {
        year   :  date.getFullYear(),
        month  :  date.getMonth() + 1,
        day    :  date.getDate(),
    }
    let target = {
        notice :  GM_getValue('设置.Notice') != '' ? GM_getValue('设置.Notice') :  '天数倒计时',
        year   :  GM_getValue('设置.Year')   != '' && GM_getValue('设置.Year') != null ? GM_getValue('设置.Year')   :  current.year,
        month  :  GM_getValue('设置.Month')  != '' && GM_getValue('设置.Month') != null ? GM_getValue('设置.Month')  :  current.month,
        day    :  GM_getValue('设置.Day'),
    }
    let total_day = getTotalDay(target.year, target.month); 
    let real = {
        month  : 0 < target.month && target.month <= 12,
        day    : 0 < target.day && target.day <= total_day,
    }
    if(!(real.month && real.day)){
        resolve('日期错误，请重新设置时间');
        return error(target);
    }
    let over = {
        all    : target.year  > current.year,
        year   :  target.year == current.year,
        month  :  target.month == current.month,
        fmonth  :  target.month > current.month,
        day    :  target.day >= current.day,
    }
    if ( over.all || (over.year && over.month && over.day) || (over.year && over.fmonth)) {
        aim_date.setFullYear(target.year, target.month - 1 , target.day);
        let diff = getDiffDay(date, aim_date);
        GM_notification({
            title   :  target.notice,
            text    :  '剩余天数：'+ diff,
            timeout :  GM_getValue('设置.Timeout') !='' ? GM_getValue('设置.Timeout') : 3000,
        });
        resolve();
    } else {
        resolve('倒计时完成，自动停止');
    }
});