(function () {
        
    this.MenuAccess = function () {
        var defaults = {
            links : null,
            shortcut : [50, 51, 52, 53, 54, 55, 56, 57]
        };

        if (arguments[0] && typeof arguments[0] === "object") {
            this.options = extendDefaults(defaults, arguments[0]);
        }
    }


    MenuAccess.prototype.init = function() {
        this.createTrigger();
        this.createPanel();
        this.createShortcutList();
        this.createToolsButtons();

        listenerDocumentKeyDown(this.options.shortcut, this.options.links);

        if (sessionStorage.getItem('menuAcessContrast')) {
            document.body.setAttribute('data-contrast', 'contrast-1');
        }
    }


    MenuAccess.prototype.createShortcutList = function () {
        

        var shortcutList, li, panel;
        panel = document.getElementById('menuAcessPanel');

        shortcutList = document.createElement('ol');
        shortcutList.className = 'menu-acess-shortcut-list';

        for (var i = 0; i < this.options.links.length; i++) {
            li = document.createElement('li');
            li.innerHTML = '<a href="'+this.options.links[i].url+'" title="'+this.options.links[i].lbl+'" tabindex="'+ (i+3) +'">'+this.options.links[i].lbl + ' <small>[ALT+' + (i+2) + ']</small>' +'</a>';
            shortcutList.appendChild(li);
        }

        panel.appendChild(shortcutList);
    }


    MenuAccess.prototype.createToolsButtons = function () {
        

        var toolsList, li,button, panel;
        panel = document.getElementById('menuAcessPanel');

        toolsList = document.createElement('ol');
        toolsList.className = 'menu-acess-tools-list';


        /*
        *  DECREASE FONT-SIZE
        * * * */
        li = document.createElement('li');
        button = document.createElement('button');
        button.innerHTML = '<i class="icon-fontsize"></i> Diminuir Fonte';
        button.addEventListener('click', decreaseFontSize);
        button.setAttribute('disabled', 'decreaseFontSize');
        button.setAttribute('id', 'btnDecreaseFontSize');
        button.setAttribute('tabindex', '12');
        li.appendChild(button);
        toolsList.appendChild(li);


        /*
        *  INCREASE FONT-SIZE
        * * * */
        li = document.createElement('li');
        button = document.createElement('button');
        button.innerHTML = '<i class="icon-fontsize"></i> Aumentar Fonte';
        button.addEventListener('click', increaseFontSize);
        button.setAttribute('id', 'btnIncreaseFontSize');
        button.setAttribute('tabindex', '13');
        li.appendChild(button);
        toolsList.appendChild(li);


        /*
        *  CONTRAST
        * * * */
        li = document.createElement('li');
        button = document.createElement('button');
        button.innerHTML = '<i class="icon-ajust"></i> Alto Contraste';
        button.addEventListener('click', contrast);
        button.setAttribute('id', 'btnContrast');
        button.setAttribute('tabindex', '14');
        li.appendChild(button);
        toolsList.appendChild(li);


        panel.appendChild(toolsList);
    }


    MenuAccess.prototype.createPanel = function () {
        

        var panel, panelHead, buttonClose;

        panel = document.createElement('div');
        panel.setAttribute('id', 'menuAcessPanel');
        panel.className = 'menu-acess-panel';

        panelHead = document.createElement('div');
        panelHead.className = 'menu-acess-panel-head';
        panelHead.innerHTML = '<h1 class="menu-acess-panel-title" id="menuAcessTitle" tabindex="1">Menu Acess\u00edvel</h1>';

        buttonClose = document.createElement('button');
        buttonClose.className = 'menu-acess-panel-button-close';
        buttonClose.innerHTML = '[FECHAR - ALT+1]';
        buttonClose.setAttribute('title', 'Fechar Menu Acess\u00edvel');
        buttonClose.setAttribute('tabindex', '2');
        buttonClose.addEventListener('click', toggleMenuAcess);

        panelHead.appendChild(buttonClose);
        panel.appendChild(panelHead);
        document.body.appendChild(panel);
    }


    MenuAccess.prototype.createTrigger = function () {
        

        var trigger;
        trigger = document.createElement('button');
        trigger.innerHTML = '<i class="icon-wheelchair"></i>';
        trigger.className = 'menu-acess-trigger-open-menu';

        trigger.addEventListener('click', toggleMenuAcess);

        document.body.appendChild(trigger);
    }

    function extendDefaults(source, properties) {
        var property;

        for (property in properties) {
            if (properties.hasOwnProperty(property)) {
                source[property] = properties[property];
            }
        }
        return source;
    }


    function toggleMenuAcess() {
        var panel;
        panel = document.getElementById('menuAcessPanel');

        if (panel.className.indexOf('open') > -1) {
            panel.classList.remove('open');
        } else {
            panel.classList.add('open');
            document.getElementById('menuAcessTitle').focus();
        }
    }


    function listenerDocumentKeyDown(shortcuts, links) {
        document.addEventListener("keydown", function (e) {

            if (shortcuts.indexOf(e.keyCode) > -1 && (e.altKey)) {
                if (links[shortcuts.indexOf(e.keyCode)]) {
                    e.preventDefault();
                    location.href = links[shortcuts.indexOf(e.keyCode)].url;
                }

            } else if (e.keyCode === 49 && (e.altKey)) {
                toggleMenuAcess();
            }
        });
    }


    function increaseFontSize() {
        var size;

        if (!document.body.getAttribute('data-fontincrease')) {
            document.body.setAttribute('data-fontincrease', 'sm');
            document.getElementById('btnDecreaseFontSize').removeAttribute('disabled');
            return;
        }

        size = document.body.getAttribute('data-fontincrease');

        switch (size) {
        case 'sm':
            document.body.setAttribute('data-fontincrease', 'md');
            break;

        case 'md':
            document.body.setAttribute('data-fontincrease', 'lg');
            break;

        case 'lg':
            document.body.setAttribute('data-fontincrease', 'xlg');
            document.getElementById('btnIncreaseFontSize').setAttribute('disabled', 'disabled');
            break;
        }

        document.getElementById('btnDecreaseFontSize').removeAttribute('disabled');
        return;
    }


    function decreaseFontSize() {
        var size;

        if (document.body.getAttribute('data-fontincrease')) {
            size = document.body.getAttribute('data-fontincrease');

            switch (size) {
            case 'xlg':
                document.body.setAttribute('data-fontincrease', 'lg');
                break;

            case 'lg':
                document.body.setAttribute('data-fontincrease', 'md');
                break;

            case 'md':
                document.body.setAttribute('data-fontincrease', 'sm');
                break;

            case 'sm':
                document.body.removeAttribute('data-fontincrease');
                document.getElementById('btnDecreaseFontSize').setAttribute('disabled', 'disabled');
                break;
            }

            document.getElementById('btnIncreaseFontSize').removeAttribute('disabled');
            return;
        }
    }


    function contrast() {
        if (!document.body.getAttribute('data-contrast')) {
            sessionStorage.setItem('menuAcessContrast', true);
            document.body.setAttribute('data-contrast', 'contrast-1');
        } else {
            sessionStorage.clear('menuAcessContrast');
            document.body.removeAttribute('data-contrast');
        }
    }
    
}());