// ==UserScript==
// @name         志愿福建，日期自动填写脚本
// @namespace    https://penicillin.github.io/
// @description  对4个日期框做数据同步，修改起始日期会默认对结束日期+7。
// @version      0.1.3
// @match        http://www.fjvs.org/app/opp/*
// @downloadURL none
// ==/UserScript==
function addDate(date, days) {
     if (days == undefined || days == '') {
         days = 0;
     }
    return new Date(date.valueOf()+ days * 24 * 60 * 60 * 1000);

}

var userV1y=document.getElementById('opp_start_date_year');
var userV1m=document.getElementById('opp_start_date_month');
var userV1d=document.getElementById('opp_start_date_day');

var userV2y=document.getElementById('opp_end_date_year');
var userV2m=document.getElementById('opp_end_date_month');
var userV2d=document.getElementById('opp_end_date_day');

var userV3y=document.getElementById('opp_recruit_start_date_year');
var userV3m=document.getElementById('opp_recruit_start_date_month');
var userV3d=document.getElementById('opp_recruit_start_date_day');

var userV4y=document.getElementById('opp_recruit_end_date_year');
var userV4m=document.getElementById('opp_recruit_end_date_month');
var userV4d=document.getElementById('opp_recruit_end_date_day');

function setV2value(){
var calcDate=addDate(new Date(userV1y.value,userV1m.value-1,userV1d.value),6);
userV2y.value=calcDate.getFullYear()
userV2m.value=calcDate.getMonth()+1;
userV2d.value=calcDate.getDate();

userV4y.value=userV2y.value;
userV4m.value=userV2m.value;
userV4d.value=userV2d.value;
}

window.onload=function(){

userV3y.parentNode.style.opacity='0.3';

userV1y.onchange=function(){userV3y.value=userV1y.value;setV2value()};
userV1m.onchange=function(){userV3m.value=userV1m.value;setV2value()};
userV1d.onchange=function(){userV3d.value=userV1d.value;setV2value()};

var currentDate=new Date();
var startDate=addDate(currentDate, -currentDate.getDay());

if(userV1y.value==''){
userV1y.value=startDate.getFullYear();
userV1m.value=startDate.getMonth()+1;
userV1d.value=startDate.getDate();

setV2value();
}
userV2y.onchange=function(){userV4y.value=userV2y.value};
userV2m.onchange=function(){userV4m.value=userV2m.value};
userV2d.onchange=function(){userV4d.value=userV2d.value};

userV3y.value=userV1y.value;
userV3m.value=userV1m.value;
userV3d.value=userV1d.value;

userV4y.value=userV2y.value;
userV4m.value=userV2m.value;
userV4d.value=userV2d.value;
}