/* jshint laxbreak:true */
(function (window) {
    "use strict";

    var htmlEscapes = {
        "&": "&amp;",
        "<": "&lt;",
        ">": "&gt;",
        '"': "&quot;",
        "'": "&#x27;",
        "`": "&#x60;",
    };

    var escapeHtmlChar = function (chr) {
        return htmlEscapes[chr];
    };

    var reUnescapedHtml = /[&<>"'`]/g;
    var reHasUnescapedHtml = new RegExp(reUnescapedHtml.source);

    var escape = function (string) {
        return string && reHasUnescapedHtml.test(string) ? string.replace(reUnescapedHtml, escapeHtmlChar) : string;
    };

    /**
     * Sets up defaults for all the Template methods such as a default template
     *
     * @constructor
     */
    function Template() {
        this.defaultTemplate
            = '<li data-id="{{id}}" class="{{completed}}" data-priority="{{priority}}">'
            + '<div class="view">'
            + '<input class="toggle" type="checkbox" {{checked}}>'
            + "<label>{{title}}</label>"
            + '<button class="destroy"></button>'
            + "</div>"
            + "</li>";
    }

    /**
     * Creates an <li> HTML string and returns it for placement in your app.
     *
     * NOTE: In real life you should be using a templating engine such as Mustache
     * or Handlebars, however, this is a vanilla JS example.
     *
     * @param {object} data The object containing keys you want to find in the
     *                      template to replace.
     * @returns {string} HTML String of an <li> element
     *
     * @example
     * view.show({
     *    id: 1,
     *    title: "Hello World",
     *    completed: 0,
     * });
     */
    Template.prototype.show = function (data) {
        var i, l;
        var view = "";

        for (i = 0, l = data.length; i < l; i++) {
            var template = this.defaultTemplate;
            var completed = "";
            var checked = "";

            if (data[i].completed) {
                completed = "completed";
                checked = "checked";
            }

            template = template.replace("{{id}}", data[i].id);
            template = template.replace("{{title}}", escape(data[i].title));
            template = template.replace("{{completed}}", completed);
            template = template.replace("{{checked}}", checked);
            template = template.replace("{{priority}}", 4 - (i % 5));

            view = view + template;
        }

        return view;
    };

    /**
     * Displays a counter of how many to dos are left to complete
     *
     * @param {number} activeTodos The number of active todos.
     * @returns {string} String containing the count
     */
    Template.prototype.itemCounter = function (activeTodos) {
        var plural = activeTodos === 1 ? "" : "s";

        return `<strong>${activeTodos}</strong> item${plural} left`;
    };

    /**
     * Updates the text within the "Clear completed" button
     *
     * @param  {[type]} completedTodos The number of completed todos.
     * @returns {string} String containing the count
     */
    Template.prototype.clearCompletedButton = function (completedTodos) {
        if (completedTodos > 0)
            return "Clear completed";
        else
            return "";
    };

    // Export to window
    window.app = window.app || {};
    window.app.Template = Template;
})(window);
