jQuery(document).ready(function() {

    $.fn.likeButton = function(settings) {
        settings = $.extend({
            /**
             * URL to PHP script
             * @type {String}
             */
            url: '/LikeButton/',

            /**
             * Disable default button counter
             * @type {Boolean}
             */
            disableCounter: false,

            /**
             * Class name of element which will be updated with number of likes
             * @type {String}
             */
            customCounter: 'btn-like-custom-counter',

            /**
             * Function called before request
             * @param  {DOM Element} btn
             */
            before: function(btn) {},

            /**
             * Function called after each request
             * @param  {jQuery}   btn
             * @param  {Object}   response
             */
            after: function(btn, response) {}
        }, settings);

        var _ = {
            elements: this.selector,
            IDs: null,

            init: function() {
                _.getIDs(_.elements);

                // Load number of likes for each button
                if (_.IDs.length)
                    _.update();

                _.bindActions();
            },

            randomID: function() {
                var a, b = b || 16;
                return Array(a || 8).join(0).replace(/0/g, function() {
                    return (0 | Math.random() * b).toString(b)
                });
            },

            getIDs: function(selector) {
                _.IDs = $.map($(selector), function(el) {
                    return $(el).attr('data-item-id');
                });
            },

            counter: function(btn) {
                if (!btn)
                    return;

                var counter = $('.btn-like-counter[data-counter-id=' + btn.attr('data-counter-id') + ']').add('.' + settings.customCounter + '[data-counter-id=' + btn.attr('data-counter-id') + ']');

                return {
                    add: function() {
                        var counterID = _.randomID(),
                            position, type, url, title, counterDisabled;

                        $.each(btn, function() {
                            var btn = $(this);

                            attrs = {
                                'data-counter-id': counterID
                            };

                            position = btn.data('count') === 'vertical' ? 'before' : 'after';

                            type = 'btn-like-counter--' + (btn.data('count') || 'horizontal');

                            if (url = btn.attr('data-url'))
                                attrs.href = url;

                            if (title = btn.attr('data-title'))
                                attrs.title = title;

                            if (!btn.attr('data-counter-id')) {
                                btn.addClass('btn-like--' + (btn.data('count') || 'horizontal'))
                                btn.attr('data-counter-id', counterID);

                                $('.' + settings.customCounter).filter(function() {
                                    return $(this).attr('data-item-id') == btn.attr('data-item-id');
                                }).attr('data-counter-id', counterID);

                                btn.wrap($('<div/>').addClass('btn-like-wrap'));

                                counterDisabled =
                                    btn.data('disable-counter') === false ? false :
                                    btn.data('disable-counter') === true ? true : settings.disableCounter;

                                if (!counterDisabled) {
                                    btn[position](
                                        $('<' + (url ? 'a' : 'span') + '/>').addClass('btn-like-counter ' + type).attr(attrs)
                                    );
                                }
                            }
                        });

                        return _.counter(btn);
                    },

                    get: function() {
                        return counter;
                    },

                    update: function(value) {
                        counter.attr('data-value', value).text(value);

                        return _.counter(btn);
                    }
                }
            },

            bindActions: function() {
                $('body').delegate(_.elements, 'click', function() {
                    var btn = $('.btn-like[data-counter-id=' + $(this).data('counter-id') + ']');

                    // Add loader
                    _.counter(btn).update('');
                    _.counter(btn).get().addClass('is-loading');

                    settings.before($(this));

                    $.post(settings.url, {'lb-item-id': btn.attr('data-item-id')}, function (item) {
                        // Set counter and remove loader
                        _.counter(btn).update(item.count).get().removeClass('is-loading');

                        // Set active class
                        btn[item.isLiked ? 'addClass' : 'removeClass']('active');

                        settings.after(this, item);
                    });

                /**
                 * Additional method to update new buttons added to DOM
                 */
                }).delegate(_.elements, 'update', function() {
                    _.getIDs(this.selector);
                    _.update(_.IDs);
                });
            },

            update: function() {
                $.post(settings.url, {'lb-item-ids': _.IDs}, function (items) {
                    $.each(items, function() {
                        var btn = $(_.elements + '[data-item-id=' + this.id + ']');

                        // Add counter and update value
                        _.counter(btn).add().update(this.count);

                        // Set active class
                        btn[this.isLiked ? 'addClass' : 'removeClass']('active');

                        settings.after(btn, this);
                    });
                });
            }
        };

        _.init();

        return this;
    };

});