// ==UserScript==
// @name         Better Luogu Problem Searcher
// @namespace    n/a
// @version      0
// @description  洛谷题目跳转器优化
// @author       iotang
// @match        https://www.luogu.org
// @match        https://www.luogu.org/
// @match        https://www.luogu.org/#feed
// @match        https://www.luogu.org/#feed/
// @match        http://www.luogu.org
// @match        http://www.luogu.org/
// @match        http://www.luogu.org/#feed
// @match        http://www.luogu.org/#feed/
// @grant        none
// @downloadURL none
// ==/UserScript==

(function()
{
    'use strict';

    function searchfn()
    {
        var target = document.getElementsByClassName("am-form-field")[0].value;
        if(target === "")return;

        var targetu = target.toUpperCase();
        var go = "";

        if(target.match(/^[0-9]+$/) == target)
        {
            go = "https://www.luogu.org/fe/problem/P" + target;
        }
        else if(targetu.match(/^[0-9]+[A-Z]?[0-9]?$/) == targetu)
        {
            go = "https://www.luogu.org/fe/problem/CF" + targetu;
        }
        else if(targetu.match(/^(?:P|CF|SP|AT|UVA)[0-9]+[A-Z]?[0-9]?$/) == targetu)
        {
            go = "https://www.luogu.org/fe/problem/" + targetu;
        }
        else
        {
            go = "https://www.luogu.org/fe/problem/list?keyword=" + target;
        }

        location.href = go;
    }

    var locations =
        document.getElementsByClassName("lg-index-content")[0]
    .getElementsByClassName("lg-article lg-index-stat")[0]
    .getElementsByClassName("am-btn am-btn-primary am-btn-sm")[0]
    .parentNode;

    var button = document.createElement("button");
    button.className = "am-btn am-btn-success am-btn-sm";
    button.name = "gotosearch";
    button.id = "gotosearch";
    button.innerHTML = "搜索";
    button.onclick = function(){searchfn();}

    locations.appendChild(button);

    document.getElementsByClassName("am-form-field")[0].placeholder = "输入题号或者题目名字";
    document.getElementsByClassName("am-form-field")[0].onkeyup = function(event){if(event.keyCode === 13){searchfn();}}

    document.getElementsByClassName("lg-article lg-index-stat")[0].getElementsByTagName("h2")[0].innerHTML = "问题搜索";
})();