// ==UserScript==
// @name          University of Toronto Arts & Science Exam Schedule Filter
// @namespace     https://alxu.ca/
// @match         http://www.artsci.utoronto.ca/current/exams/*
// @version       1.1
// @grant         none
// @downloadURL   https://alxu.ca/uoft-artsci-exam-filter.user.js
// @require       https://www.kryogenix.org/code/browser/sorttable/sorttable.js#sha512=33bdc388d816cab2190ee33918143074a3d1bc8da315b0d6117eb8233d8a7ed51752aa26419296c06120c6faee6053d4589fca2a7590846139d69e84cb600808
// @run-at        document-end
// ==/UserScript==

/*
 * Copyright 2017 Alex Xu, released under GPLv3 or later
 *
 * Firefox: Install Greasemonkey: https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/ then (re-)open this file.
 * Chrome: Install Tampermonkey: https://chrome.google.com/webstore/detail/tampermonkey/dhdgffkkebhmkfjojejmpbldmpobfkfo then (re-)open this file.
 * Note that installing this script directly will also work, but sorting will not be supported, and in addition, on Windows and Mac the script will be automatically and permanently disabled once Chrome restarts.
 */

(function () {
"use strict";

if (document.title.indexOf("Timetable") === -1)
    return;

// hopefully won't change, these queries are expensive-ish
var tbl = document.getElementsByClassName("vertical")[0],

if (!tbl)
    return;

var trs = tbl.querySelectorAll("tr:not(:first-child)");

if (!trs.length)
    return;

var storage = localStorage.getItem("filterinfo");
if (storage)
    try {
        storage = JSON.parse(storage);
    } catch (e) {
        if (!(e instanceof SyntaxError))
            throw e;
    }

if (!storage)
    storage = {};

var parseCourses = function (mycoursesstr) {
    // ignore leading, trailing, consecutive delimiters
    var mycourses = mycoursesstr.split(/[ ,;]/).filter(function (v) { return v; }).map(function (c) {
        var cspl = c.split(/[\/:]+/);
        return {
            name: cspl[0].toUpperCase(),
            section: cspl.length > 1 ? cspl[1].toUpperCase() : null
        };
    });
    return mycourses;
};

var dofilter = function (myname, mycourses) {
    var getCourse = function (name) {
        return mycourses.find(function (c) {
            return c && name.indexOf(c.name) > -1;
        });
    };

    var checkCourse = function (tr) {
        var ch = tr.children,
            s = ch[1].innerHTML;

        // if we don't have any courses, match everything instead of nothing
        if (mycourses.length) {
            var course = getCourse(ch[0].innerHTML);
            if (!course)
                return false;

            if (course.section) {
                var l = s.match(/L?[0-9]+/);
                if (l && l[0].indexOf(course.section) === -1)
                    return false;
            }
        }

        // same with name
        if (myname) {
            var nr = s.match(/([A-Z]+) - ([A-Z]+)/);
            if (nr && (myname < nr[1] || myname > nr[2]))
                return false;
        }

        return true;
    };

    for (var i = trs.length - 1; i >= 0; i--) {
        trs[i].style.display = checkCourse(trs[i]) ? '' : 'none';
    }
};

var ourctnr = document.createElement("div");
ourctnr.appendChild(document.createTextNode("Filter by name: "));

var makeInput = function (attr, size) {
    var input = document.createElement("input");
    input.type = "text";
    input.size = size;
    if (storage[attr])
        input.value = storage[attr];
    input.addEventListener("input", function () {
        storage[attr] = this.value.toUpperCase();
        // in theory we could cache this, but it's fast enough
        dofilter(storage.name, parseCourses(storage.courses));
        localStorage.setItem("filterinfo", JSON.stringify(storage));
    }, false);
    ourctnr.appendChild(input);
};

makeInput("name", "4");

ourctnr.appendChild(document.createTextNode(", courses: "));

makeInput("courses", "50");

ourctnr.appendChild(document.createElement("br"));
ourctnr.appendChild(document.createTextNode("Courses should be separated by spaces and sections preceded by slash."));
ourctnr.appendChild(document.createElement("br"));
ourctnr.appendChild(document.createTextNode("Example: ABC101 XYZ201/L0301"));

tbl.parentNode.insertBefore(ourctnr, tbl);

if (storage.name || storage.courses)
    window.requestAnimationFrame(function () {
        dofilter(storage.name, parseCourses(storage.courses));

        if (typeof sorttable !== "undefined") {
            sorttable.init();
            sorttable.makeSortable(tbl);
            sorttable.innerSortFunction.apply(tbl.getElementsByTagName("th")[2], []);
        }
    });

if (typeof sorttable !== "undefined")
    for (var i = trs.length - 1; i >= 0; i--) {
        var dateEl = trs[i].children[2],
            dateSplit = dateEl.innerHTML.split(" "); // ["MON", "1", "JAN"]
        dateEl.setAttribute("sorttable_customkey", dateSplit[2] + dateSplit[1]); // "JAN1"
    }

}());