/// <reference path="modernizr-2.6.2.js" />

(function () {

    var checkboxes = [],
        details = [],
        progress, bonus, fallback, prefix;

    function findCheckboxes() {

        var inputs = document.getElementsByTagName('input');

        for (var i = 0; i < inputs.length; i++) {

            if (inputs[i].type === 'checkbox') {
                checkboxes.push(inputs[i]);
            }
        }

        details = document.getElementsByTagName('em');
    }
    
    function initialize() {

        bonus = document.getElementsByTagName("mark")[0];
        progress = document.getElementsByTagName("progress")[0];
        fallback = (progress.firstElementChild || progress.firstChild);
        prefix = location.pathname.substr(1);

        var max = 0;

        for (var i = 0; i < checkboxes.length; i++) {

            var checkbox = checkboxes[i];
            checkbox.onchange = calculateProgress;

            if (Modernizr.localstorage) {
                var value = localStorage.getItem(prefix + checkbox.id) === "true";
                checkbox.checked = value;
            }

            if (checkbox.parentNode.className !== "optional")
                max++;
        }

        for (var d = 0; d < details.length; d++) {
            details[d].onclick = openDetails;
        }

        for (var j = 0; j < details.length; j++) {
            var detail = details[j];
            if (Modernizr.localstorage && localStorage.getItem(prefix + detail.id))
                openDetailsElement(detail);
        }
        progress.max = max;
    }

    function openDetails(e) {

        if (!e) e = window.event;
        var detail = (e.target || e.srcElement);
        openDetailsElement(detail);

        for (i = 0; i < details.length; i++) {

            var detail = details[i];

            if (detail.className === 'open') {
                localStorage && localStorage.setItem(prefix + detail.id, true);
            }
            else {
                localStorage && localStorage.removeItem(prefix + detail.id);
            }
        }
    }
    function openDetailsElement(detail) {

        var ul = (detail.nextElementSibling || detail.nextSibling);

        for (var i = 0; i < details.length; i++) {

            if (details[i] !== detail) {
                var d = (details[i].nextElementSibling || details[i].nextSibling);
                d.style.maxHeight = "0";
            }

            details[i].className = 'info';
        }

        if (ul.style.maxHeight !== '100px') {
            ul.style.maxHeight = '100px';
            detail.className = 'open';
        }
        else {
            ul.style.maxHeight = '0';
        }
    }

    function calculateProgress() {

        var count = 0,
            optional = 0;

        for (var i = 0; i < checkboxes.length; i++) {

            var checkbox = checkboxes[i];

            if (checkbox.checked)
                localStorage && localStorage.setItem(prefix + checkbox.id, checkbox.checked);
            else
                localStorage && localStorage.removeItem(prefix + checkbox.id);

            if (checkbox.parentNode.className !== "optional") {

                if (checkbox.checked) {
                    count++;
                }
            }
            else {
                if (checkbox.checked) {
                    optional++;
                }
            }
        }
       
        bonus.innerHTML = optional.toString();
        setProgressValue(count);
    }

    function setProgressValue(value) {
        progress.value = value;

        var max = parseInt(progress.max, 10);
        fallback.style.width = (value * 100 / max) + "%";
    }

    function clearAll() {

        document.getElementById("clearall").onclick = function () {

            for (var i = 0; i < checkboxes.length; i++) {
                checkboxes[i].checked = false;
            }

            localStorage && localStorage.clear();
            calculateProgress();

            return false;
        };
    }

    window.onload = function () {
        findCheckboxes();
        initialize();
        calculateProgress();
        clearAll();
     
        if (localStorage.length === 0)
            details[0].click();
    };

})();