/**

* Owl carousel
* @version 2.3.4
* @author Bartosz Wojciechowski
* @author David Deutsch
* @license The MIT License (MIT)
* @todo Lazy Load Icon
* @todo prevent animationend bubling
* @todo itemsScaleUp
* @todo Test Zepto
* @todo stagePadding calculate wrong active classes
*/

;(function($, window, document, undefined) {

/**
 * Creates a carousel.
 * @class The Owl Carousel.
 * @public
 * @param {HTMLElement|jQuery} element - The element to create the carousel for.
 * @param {Object} [options] - The options
 */
function Owl(element, options) {

        /**
         * Current settings for the carousel.
         * @public
         */
        this.settings = null;

        /**
         * Current options set by the caller including defaults.
         * @public
         */
        this.options = $.extend({}, Owl.Defaults, options);

        /**
         * Plugin element.
         * @public
         */
        this.$element = $(element);

        /**
         * Proxied event handlers.
         * @protected
         */
        this._handlers = {};

        /**
         * References to the running plugins of this carousel.
         * @protected
         */
        this._plugins = {};

        /**
         * Currently suppressed events to prevent them from being retriggered.
         * @protected
         */
        this._supress = {};

        /**
         * Absolute current position.
         * @protected
         */
        this._current = null;

        /**
         * Animation speed in milliseconds.
         * @protected
         */
        this._speed = null;

        /**
         * Coordinates of all items in pixel.
         * @todo The name of this member is missleading.
         * @protected
         */
        this._coordinates = [];

        /**
         * Current breakpoint.
         * @todo Real media queries would be nice.
         * @protected
         */
        this._breakpoint = null;

        /**
         * Current width of the plugin element.
         */
        this._width = null;

        /**
         * All real items.
         * @protected
         */
        this._items = [];

        /**
         * All cloned items.
         * @protected
         */
        this._clones = [];

        /**
         * Merge values of all items.
         * @todo Maybe this could be part of a plugin.
         * @protected
         */
        this._mergers = [];

        /**
         * Widths of all items.
         */
        this._widths = [];

        /**
         * Invalidated parts within the update process.
         * @protected
         */
        this._invalidated = {};

        /**
         * Ordered list of workers for the update process.
         * @protected
         */
        this._pipe = [];

        /**
         * Current state information for the drag operation.
         * @todo #261
         * @protected
         */
        this._drag = {
                time: null,
                target: null,
                pointer: null,
                stage: {
                        start: null,
                        current: null
                },
                direction: null
        };

        /**
         * Current state information and their tags.
         * @type {Object}
         * @protected
         */
        this._states = {
                current: {},
                tags: {
                        'initializing': [ 'busy' ],
                        'animating': [ 'busy' ],
                        'dragging': [ 'interacting' ]
                }
        };

        $.each([ 'onResize', 'onThrottledResize' ], $.proxy(function(i, handler) {
                this._handlers[handler] = $.proxy(this[handler], this);
        }, this));

        $.each(Owl.Plugins, $.proxy(function(key, plugin) {
                this._plugins[key.charAt(0).toLowerCase() + key.slice(1)]
                        = new plugin(this);
        }, this));

        $.each(Owl.Workers, $.proxy(function(priority, worker) {
                this._pipe.push({
                        'filter': worker.filter,
                        'run': $.proxy(worker.run, this)
                });
        }, this));

        this.setup();
        this.initialize();
}

/**
 * Default options for the carousel.
 * @public
 */
Owl.Defaults = {
        items: 3,
        loop: false,
        center: false,
        rewind: false,
        checkVisibility: true,

        mouseDrag: true,
        touchDrag: true,
        pullDrag: true,
        freeDrag: false,

        margin: 0,
        stagePadding: 0,

        merge: false,
        mergeFit: true,
        autoWidth: false,

        startPosition: 0,
        rtl: false,

        smartSpeed: 250,
        fluidSpeed: false,
        dragEndSpeed: false,

        responsive: {},
        responsiveRefreshRate: 200,
        responsiveBaseElement: window,

        fallbackEasing: 'swing',
        slideTransition: '',

        info: false,

        nestedItemSelector: false,
        itemElement: 'div',
        stageElement: 'div',

        refreshClass: 'owl-refresh',
        loadedClass: 'owl-loaded',
        loadingClass: 'owl-loading',
        rtlClass: 'owl-rtl',
        responsiveClass: 'owl-responsive',
        dragClass: 'owl-drag',
        itemClass: 'owl-item',
        stageClass: 'owl-stage',
        stageOuterClass: 'owl-stage-outer',
        grabClass: 'owl-grab'
};

/**
 * Enumeration for width.
 * @public
 * @readonly
 * @enum {String}
 */
Owl.Width = {
        Default: 'default',
        Inner: 'inner',
        Outer: 'outer'
};

/**
 * Enumeration for types.
 * @public
 * @readonly
 * @enum {String}
 */
Owl.Type = {
        Event: 'event',
        State: 'state'
};

/**
 * Contains all registered plugins.
 * @public
 */
Owl.Plugins = {};

/**
 * List of workers involved in the update process.
 */
Owl.Workers = [ {
        filter: [ 'width', 'settings' ],
        run: function() {
                this._width = this.$element.width();
        }
}, {
        filter: [ 'width', 'items', 'settings' ],
        run: function(cache) {
                cache.current = this._items && this._items[this.relative(this._current)];
        }
}, {
        filter: [ 'items', 'settings' ],
        run: function() {
                this.$stage.children('.cloned').remove();
        }
}, {
        filter: [ 'width', 'items', 'settings' ],
        run: function(cache) {
                var margin = this.settings.margin || '',
                        grid = !this.settings.autoWidth,
                        rtl = this.settings.rtl,
                        css = {
                                'width': 'auto',
                                'margin-left': rtl ? margin : '',
                                'margin-right': rtl ? '' : margin
                        };

                !grid && this.$stage.children().css(css);

                cache.css = css;
        }
}, {
        filter: [ 'width', 'items', 'settings' ],
        run: function(cache) {
                var width = (this.width() / this.settings.items).toFixed(3) - this.settings.margin,
                        merge = null,
                        iterator = this._items.length,
                        grid = !this.settings.autoWidth,
                        widths = [];

                cache.items = {
                        merge: false,
                        width: width
                };

                while (iterator--) {
                        merge = this._mergers[iterator];
                        merge = this.settings.mergeFit && Math.min(merge, this.settings.items) || merge;

                        cache.items.merge = merge > 1 || cache.items.merge;

                        widths[iterator] = !grid ? this._items[iterator].width() : width * merge;
                }

                this._widths = widths;
        }
}, {
        filter: [ 'items', 'settings' ],
        run: function() {
                var clones = [],
                        items = this._items,
                        settings = this.settings,
                        // TODO: Should be computed from number of min width items in stage
                        view = Math.max(settings.items * 2, 4),
                        size = Math.ceil(items.length / 2) * 2,
                        repeat = settings.loop && items.length ? settings.rewind ? view : Math.max(view, size) : 0,
                        append = '',
                        prepend = '';

                repeat /= 2;

                while (repeat > 0) {
                        // Switch to only using appended clones
                        clones.push(this.normalize(clones.length / 2, true));
                        append = append + items[clones[clones.length - 1]][0].outerHTML;
                        clones.push(this.normalize(items.length - 1 - (clones.length - 1) / 2, true));
                        prepend = items[clones[clones.length - 1]][0].outerHTML + prepend;
                        repeat -= 1;
                }

                this._clones = clones;

                $(append).addClass('cloned').appendTo(this.$stage);
                $(prepend).addClass('cloned').prependTo(this.$stage);
        }
}, {
        filter: [ 'width', 'items', 'settings' ],
        run: function() {
                var rtl = this.settings.rtl ? 1 : -1,
                        size = this._clones.length + this._items.length,
                        iterator = -1,
                        previous = 0,
                        current = 0,
                        coordinates = [];

                while (++iterator < size) {
                        previous = coordinates[iterator - 1] || 0;
                        current = this._widths[this.relative(iterator)] + this.settings.margin;
                        coordinates.push(previous + current * rtl);
                }

                this._coordinates = coordinates;
        }
}, {
        filter: [ 'width', 'items', 'settings' ],
        run: function() {
                var padding = this.settings.stagePadding,
                        coordinates = this._coordinates,
                        css = {
                                'width': Math.ceil(Math.abs(coordinates[coordinates.length - 1])) + padding * 2,
                                'padding-left': padding || '',
                                'padding-right': padding || ''
                        };

                this.$stage.css(css);
        }
}, {
        filter: [ 'width', 'items', 'settings' ],
        run: function(cache) {
                var iterator = this._coordinates.length,
                        grid = !this.settings.autoWidth,
                        items = this.$stage.children();

                if (grid && cache.items.merge) {
                        while (iterator--) {
                                cache.css.width = this._widths[this.relative(iterator)];
                                items.eq(iterator).css(cache.css);
                        }
                } else if (grid) {
                        cache.css.width = cache.items.width;
                        items.css(cache.css);
                }
        }
}, {
        filter: [ 'items' ],
        run: function() {
                this._coordinates.length < 1 && this.$stage.removeAttr('style');
        }
}, {
        filter: [ 'width', 'items', 'settings' ],
        run: function(cache) {
                cache.current = cache.current ? this.$stage.children().index(cache.current) : 0;
                cache.current = Math.max(this.minimum(), Math.min(this.maximum(), cache.current));
                this.reset(cache.current);
        }
}, {
        filter: [ 'position' ],
        run: function() {
                this.animate(this.coordinates(this._current));
        }
}, {
        filter: [ 'width', 'position', 'items', 'settings' ],
        run: function() {
                var rtl = this.settings.rtl ? 1 : -1,
                        padding = this.settings.stagePadding * 2,
                        begin = this.coordinates(this.current()) + padding,
                        end = begin + this.width() * rtl,
                        inner, outer, matches = [], i, n;

                for (i = 0, n = this._coordinates.length; i < n; i++) {
                        inner = this._coordinates[i - 1] || 0;
                        outer = Math.abs(this._coordinates[i]) + padding * rtl;

                        if ((this.op(inner, '<=', begin) && (this.op(inner, '>', end)))
                                || (this.op(outer, '<', begin) && this.op(outer, '>', end))) {
                                matches.push(i);
                        }
                }

                this.$stage.children('.active').removeClass('active');
                this.$stage.children(':eq(' + matches.join('), :eq(') + ')').addClass('active');

                this.$stage.children('.center').removeClass('center');
                if (this.settings.center) {
                        this.$stage.children().eq(this.current()).addClass('center');
                }
        }
} ];

/**
 * Create the stage DOM element
 */
Owl.prototype.initializeStage = function() {
        this.$stage = this.$element.find('.' + this.settings.stageClass);

        // if the stage is already in the DOM, grab it and skip stage initialization
        if (this.$stage.length) {
                return;
        }

        this.$element.addClass(this.options.loadingClass);

        // create stage
        this.$stage = $('<' + this.settings.stageElement + '>', {
                "class": this.settings.stageClass
        }).wrap( $( '<div/>', {
                "class": this.settings.stageOuterClass
        }));

        // append stage
        this.$element.append(this.$stage.parent());
};

/**
 * Create item DOM elements
 */
Owl.prototype.initializeItems = function() {
        var $items = this.$element.find('.owl-item');

        // if the items are already in the DOM, grab them and skip item initialization
        if ($items.length) {
                this._items = $items.get().map(function(item) {
                        return $(item);
                });

                this._mergers = this._items.map(function() {
                        return 1;
                });

                this.refresh();

                return;
        }

        // append content
        this.replace(this.$element.children().not(this.$stage.parent()));

        // check visibility
        if (this.isVisible()) {
                // update view
                this.refresh();
        } else {
                // invalidate width
                this.invalidate('width');
        }

        this.$element
                .removeClass(this.options.loadingClass)
                .addClass(this.options.loadedClass);
};

/**
 * Initializes the carousel.
 * @protected
 */
Owl.prototype.initialize = function() {
        this.enter('initializing');
        this.trigger('initialize');

        this.$element.toggleClass(this.settings.rtlClass, this.settings.rtl);

        if (this.settings.autoWidth && !this.is('pre-loading')) {
                var imgs, nestedSelector, width;
                imgs = this.$element.find('img');
                nestedSelector = this.settings.nestedItemSelector ? '.' + this.settings.nestedItemSelector : undefined;
                width = this.$element.children(nestedSelector).width();

                if (imgs.length && width <= 0) {
                        this.preloadAutoWidthImages(imgs);
                }
        }

        this.initializeStage();
        this.initializeItems();

        // register event handlers
        this.registerEventHandlers();

        this.leave('initializing');
        this.trigger('initialized');
};

/**
 * @returns {Boolean} visibility of $element
 *                    if you know the carousel will always be visible you can set `checkVisibility` to `false` to
 *                    prevent the expensive browser layout forced reflow the $element.is(':visible') does
 */
Owl.prototype.isVisible = function() {
        return this.settings.checkVisibility
                ? this.$element.is(':visible')
                : true;
};

/**
 * Setups the current settings.
 * @todo Remove responsive classes. Why should adaptive designs be brought into IE8?
 * @todo Support for media queries by using `matchMedia` would be nice.
 * @public
 */
Owl.prototype.setup = function() {
        var viewport = this.viewport(),
                overwrites = this.options.responsive,
                match = -1,
                settings = null;

        if (!overwrites) {
                settings = $.extend({}, this.options);
        } else {
                $.each(overwrites, function(breakpoint) {
                        if (breakpoint <= viewport && breakpoint > match) {
                                match = Number(breakpoint);
                        }
                });

                settings = $.extend({}, this.options, overwrites[match]);
                if (typeof settings.stagePadding === 'function') {
                        settings.stagePadding = settings.stagePadding();
                }
                delete settings.responsive;

                // responsive class
                if (settings.responsiveClass) {
                        this.$element.attr('class',
                                this.$element.attr('class').replace(new RegExp('(' + this.options.responsiveClass + '-)\\S+\\s', 'g'), '$1' + match)
                        );
                }
        }

        this.trigger('change', { property: { name: 'settings', value: settings } });
        this._breakpoint = match;
        this.settings = settings;
        this.invalidate('settings');
        this.trigger('changed', { property: { name: 'settings', value: this.settings } });
};

/**
 * Updates option logic if necessery.
 * @protected
 */
Owl.prototype.optionsLogic = function() {
        if (this.settings.autoWidth) {
                this.settings.stagePadding = false;
                this.settings.merge = false;
        }
};

/**
 * Prepares an item before add.
 * @todo Rename event parameter `content` to `item`.
 * @protected
 * @returns {jQuery|HTMLElement} - The item container.
 */
Owl.prototype.prepare = function(item) {
        var event = this.trigger('prepare', { content: item });

        if (!event.data) {
                event.data = $('<' + this.settings.itemElement + '/>')
                        .addClass(this.options.itemClass).append(item)
        }

        this.trigger('prepared', { content: event.data });

        return event.data;
};

/**
 * Updates the view.
 * @public
 */
Owl.prototype.update = function() {
        var i = 0,
                n = this._pipe.length,
                filter = $.proxy(function(p) { return this[p] }, this._invalidated),
                cache = {};

        while (i < n) {
                if (this._invalidated.all || $.grep(this._pipe[i].filter, filter).length > 0) {
                        this._pipe[i].run(cache);
                }
                i++;
        }

        this._invalidated = {};

        !this.is('valid') && this.enter('valid');
};

/**
 * Gets the width of the view.
 * @public
 * @param {Owl.Width} [dimension=Owl.Width.Default] - The dimension to return.
 * @returns {Number} - The width of the view in pixel.
 */
Owl.prototype.width = function(dimension) {
        dimension = dimension || Owl.Width.Default;
        switch (dimension) {
                case Owl.Width.Inner:
                case Owl.Width.Outer:
                        return this._width;
                default:
                        return this._width - this.settings.stagePadding * 2 + this.settings.margin;
        }
};

/**
 * Refreshes the carousel primarily for adaptive purposes.
 * @public
 */
Owl.prototype.refresh = function() {
        this.enter('refreshing');
        this.trigger('refresh');

        this.setup();

        this.optionsLogic();

        this.$element.addClass(this.options.refreshClass);

        this.update();

        this.$element.removeClass(this.options.refreshClass);

        this.leave('refreshing');
        this.trigger('refreshed');
};

/**
 * Checks window `resize` event.
 * @protected
 */
Owl.prototype.onThrottledResize = function() {
        window.clearTimeout(this.resizeTimer);
        this.resizeTimer = window.setTimeout(this._handlers.onResize, this.settings.responsiveRefreshRate);
};

/**
 * Checks window `resize` event.
 * @protected
 */
Owl.prototype.onResize = function() {
        if (!this._items.length) {
                return false;
        }

        if (this._width === this.$element.width()) {
                return false;
        }

        if (!this.isVisible()) {
                return false;
        }

        this.enter('resizing');

        if (this.trigger('resize').isDefaultPrevented()) {
                this.leave('resizing');
                return false;
        }

        this.invalidate('width');

        this.refresh();

        this.leave('resizing');
        this.trigger('resized');
};

/**
 * Registers event handlers.
 * @todo Check `msPointerEnabled`
 * @todo #261
 * @protected
 */
Owl.prototype.registerEventHandlers = function() {
        if ($.support.transition) {
                this.$stage.on($.support.transition.end + '.owl.core', $.proxy(this.onTransitionEnd, this));
        }

        if (this.settings.responsive !== false) {
                this.on(window, 'resize', this._handlers.onThrottledResize);
        }

        if (this.settings.mouseDrag) {
                this.$element.addClass(this.options.dragClass);
                this.$stage.on('mousedown.owl.core', $.proxy(this.onDragStart, this));
                this.$stage.on('dragstart.owl.core selectstart.owl.core', function() { return false });
        }

        if (this.settings.touchDrag){
                this.$stage.on('touchstart.owl.core', $.proxy(this.onDragStart, this));
                this.$stage.on('touchcancel.owl.core', $.proxy(this.onDragEnd, this));
        }
};

/**
 * Handles `touchstart` and `mousedown` events.
 * @todo Horizontal swipe threshold as option
 * @todo #261
 * @protected
 * @param {Event} event - The event arguments.
 */
Owl.prototype.onDragStart = function(event) {
        var stage = null;

        if (event.which === 3) {
                return;
        }

        if ($.support.transform) {
                stage = this.$stage.css('transform').replace(/.*\(|\)| /g, '').split(',');
                stage = {
                        x: stage[stage.length === 16 ? 12 : 4],
                        y: stage[stage.length === 16 ? 13 : 5]
                };
        } else {
                stage = this.$stage.position();
                stage = {
                        x: this.settings.rtl ?
                                stage.left + this.$stage.width() - this.width() + this.settings.margin :
                                stage.left,
                        y: stage.top
                };
        }

        if (this.is('animating')) {
                $.support.transform ? this.animate(stage.x) : this.$stage.stop()
                this.invalidate('position');
        }

        this.$element.toggleClass(this.options.grabClass, event.type === 'mousedown');

        this.speed(0);

        this._drag.time = new Date().getTime();
        this._drag.target = $(event.target);
        this._drag.stage.start = stage;
        this._drag.stage.current = stage;
        this._drag.pointer = this.pointer(event);

        $(document).on('mouseup.owl.core touchend.owl.core', $.proxy(this.onDragEnd, this));

        $(document).one('mousemove.owl.core touchmove.owl.core', $.proxy(function(event) {
                var delta = this.difference(this._drag.pointer, this.pointer(event));

                $(document).on('mousemove.owl.core touchmove.owl.core', $.proxy(this.onDragMove, this));

                if (Math.abs(delta.x) < Math.abs(delta.y) && this.is('valid')) {
                        return;
                }

                event.preventDefault();

                this.enter('dragging');
                this.trigger('drag');
        }, this));
};

/**
 * Handles the `touchmove` and `mousemove` events.
 * @todo #261
 * @protected
 * @param {Event} event - The event arguments.
 */
Owl.prototype.onDragMove = function(event) {
        var minimum = null,
                maximum = null,
                pull = null,
                delta = this.difference(this._drag.pointer, this.pointer(event)),
                stage = this.difference(this._drag.stage.start, delta);

        if (!this.is('dragging')) {
                return;
        }

        event.preventDefault();

        if (this.settings.loop) {
                minimum = this.coordinates(this.minimum());
                maximum = this.coordinates(this.maximum() + 1) - minimum;
                stage.x = (((stage.x - minimum) % maximum + maximum) % maximum) + minimum;
        } else {
                minimum = this.settings.rtl ? this.coordinates(this.maximum()) : this.coordinates(this.minimum());
                maximum = this.settings.rtl ? this.coordinates(this.minimum()) : this.coordinates(this.maximum());
                pull = this.settings.pullDrag ? -1 * delta.x / 5 : 0;
                stage.x = Math.max(Math.min(stage.x, minimum + pull), maximum + pull);
        }

        this._drag.stage.current = stage;

        this.animate(stage.x);
};

/**
 * Handles the `touchend` and `mouseup` events.
 * @todo #261
 * @todo Threshold for click event
 * @protected
 * @param {Event} event - The event arguments.
 */
Owl.prototype.onDragEnd = function(event) {
        var delta = this.difference(this._drag.pointer, this.pointer(event)),
                stage = this._drag.stage.current,
                direction = delta.x > 0 ^ this.settings.rtl ? 'left' : 'right';

        $(document).off('.owl.core');

        this.$element.removeClass(this.options.grabClass);

        if (delta.x !== 0 && this.is('dragging') || !this.is('valid')) {
                this.speed(this.settings.dragEndSpeed || this.settings.smartSpeed);
                this.current(this.closest(stage.x, delta.x !== 0 ? direction : this._drag.direction));
                this.invalidate('position');
                this.update();

                this._drag.direction = direction;

                if (Math.abs(delta.x) > 3 || new Date().getTime() - this._drag.time > 300) {
                        this._drag.target.one('click.owl.core', function() { return false; });
                }
        }

        if (!this.is('dragging')) {
                return;
        }

        this.leave('dragging');
        this.trigger('dragged');
};

/**
 * Gets absolute position of the closest item for a coordinate.
 * @todo Setting `freeDrag` makes `closest` not reusable. See #165.
 * @protected
 * @param {Number} coordinate - The coordinate in pixel.
 * @param {String} direction - The direction to check for the closest item. Ether `left` or `right`.
 * @return {Number} - The absolute position of the closest item.
 */
Owl.prototype.closest = function(coordinate, direction) {
        var position = -1,
                pull = 30,
                width = this.width(),
                coordinates = this.coordinates();

        if (!this.settings.freeDrag) {
                // check closest item
                $.each(coordinates, $.proxy(function(index, value) {
                        // on a left pull, check on current index
                        if (direction === 'left' && coordinate > value - pull && coordinate < value + pull) {
                                position = index;
                        // on a right pull, check on previous index
                        // to do so, subtract width from value and set position = index + 1
                        } else if (direction === 'right' && coordinate > value - width - pull && coordinate < value - width + pull) {
                                position = index + 1;
                        } else if (this.op(coordinate, '<', value)
                                && this.op(coordinate, '>', coordinates[index + 1] !== undefined ? coordinates[index + 1] : value - width)) {
                                position = direction === 'left' ? index + 1 : index;
                        }
                        return position === -1;
                }, this));
        }

        if (!this.settings.loop) {
                // non loop boundries
                if (this.op(coordinate, '>', coordinates[this.minimum()])) {
                        position = coordinate = this.minimum();
                } else if (this.op(coordinate, '<', coordinates[this.maximum()])) {
                        position = coordinate = this.maximum();
                }
        }

        return position;
};

/**
 * Animates the stage.
 * @todo #270
 * @public
 * @param {Number} coordinate - The coordinate in pixels.
 */
Owl.prototype.animate = function(coordinate) {
        var animate = this.speed() > 0;

        this.is('animating') && this.onTransitionEnd();

        if (animate) {
                this.enter('animating');
                this.trigger('translate');
        }

        if ($.support.transform3d && $.support.transition) {
                this.$stage.css({
                        transform: 'translate3d(' + coordinate + 'px,0px,0px)',
                        transition: (this.speed() / 1000) + 's' + (
                                this.settings.slideTransition ? ' ' + this.settings.slideTransition : ''
                        )
                });
        } else if (animate) {
                this.$stage.animate({
                        left: coordinate + 'px'
                }, this.speed(), this.settings.fallbackEasing, $.proxy(this.onTransitionEnd, this));
        } else {
                this.$stage.css({
                        left: coordinate + 'px'
                });
        }
};

/**
 * Checks whether the carousel is in a specific state or not.
 * @param {String} state - The state to check.
 * @returns {Boolean} - The flag which indicates if the carousel is busy.
 */
Owl.prototype.is = function(state) {
        return this._states.current[state] && this._states.current[state] > 0;
};

/**
 * Sets the absolute position of the current item.
 * @public
 * @param {Number} [position] - The new absolute position or nothing to leave it unchanged.
 * @returns {Number} - The absolute position of the current item.
 */
Owl.prototype.current = function(position) {
        if (position === undefined) {
                return this._current;
        }

        if (this._items.length === 0) {
                return undefined;
        }

        position = this.normalize(position);

        if (this._current !== position) {
                var event = this.trigger('change', { property: { name: 'position', value: position } });

                if (event.data !== undefined) {
                        position = this.normalize(event.data);
                }

                this._current = position;

                this.invalidate('position');

                this.trigger('changed', { property: { name: 'position', value: this._current } });
        }

        return this._current;
};

/**
 * Invalidates the given part of the update routine.
 * @param {String} [part] - The part to invalidate.
 * @returns {Array.<String>} - The invalidated parts.
 */
Owl.prototype.invalidate = function(part) {
        if ($.type(part) === 'string') {
                this._invalidated[part] = true;
                this.is('valid') && this.leave('valid');
        }
        return $.map(this._invalidated, function(v, i) { return i });
};

/**
 * Resets the absolute position of the current item.
 * @public
 * @param {Number} position - The absolute position of the new item.
 */
Owl.prototype.reset = function(position) {
        position = this.normalize(position);

        if (position === undefined) {
                return;
        }

        this._speed = 0;
        this._current = position;

        this.suppress([ 'translate', 'translated' ]);

        this.animate(this.coordinates(position));

        this.release([ 'translate', 'translated' ]);
};

/**
 * Normalizes an absolute or a relative position of an item.
 * @public
 * @param {Number} position - The absolute or relative position to normalize.
 * @param {Boolean} [relative=false] - Whether the given position is relative or not.
 * @returns {Number} - The normalized position.
 */
Owl.prototype.normalize = function(position, relative) {
        var n = this._items.length,
                m = relative ? 0 : this._clones.length;

        if (!this.isNumeric(position) || n < 1) {
                position = undefined;
        } else if (position < 0 || position >= n + m) {
                position = ((position - m / 2) % n + n) % n + m / 2;
        }

        return position;
};

/**
 * Converts an absolute position of an item into a relative one.
 * @public
 * @param {Number} position - The absolute position to convert.
 * @returns {Number} - The converted position.
 */
Owl.prototype.relative = function(position) {
        position -= this._clones.length / 2;
        return this.normalize(position, true);
};

/**
 * Gets the maximum position for the current item.
 * @public
 * @param {Boolean} [relative=false] - Whether to return an absolute position or a relative position.
 * @returns {Number}
 */
Owl.prototype.maximum = function(relative) {
        var settings = this.settings,
                maximum = this._coordinates.length,
                iterator,
                reciprocalItemsWidth,
                elementWidth;

        if (settings.loop) {
                maximum = this._clones.length / 2 + this._items.length - 1;
        } else if (settings.autoWidth || settings.merge) {
                iterator = this._items.length;
                if (iterator) {
                        reciprocalItemsWidth = this._items[--iterator].width();
                        elementWidth = this.$element.width();
                        while (iterator--) {
                                reciprocalItemsWidth += this._items[iterator].width() + this.settings.margin;
                                if (reciprocalItemsWidth > elementWidth) {
                                        break;
                                }
                        }
                }
                maximum = iterator + 1;
        } else if (settings.center) {
                maximum = this._items.length - 1;
        } else {
                maximum = this._items.length - settings.items;
        }

        if (relative) {
                maximum -= this._clones.length / 2;
        }

        return Math.max(maximum, 0);
};

/**
 * Gets the minimum position for the current item.
 * @public
 * @param {Boolean} [relative=false] - Whether to return an absolute position or a relative position.
 * @returns {Number}
 */
Owl.prototype.minimum = function(relative) {
        return relative ? 0 : this._clones.length / 2;
};

/**
 * Gets an item at the specified relative position.
 * @public
 * @param {Number} [position] - The relative position of the item.
 * @return {jQuery|Array.<jQuery>} - The item at the given position or all items if no position was given.
 */
Owl.prototype.items = function(position) {
        if (position === undefined) {
                return this._items.slice();
        }

        position = this.normalize(position, true);
        return this._items[position];
};

/**
 * Gets an item at the specified relative position.
 * @public
 * @param {Number} [position] - The relative position of the item.
 * @return {jQuery|Array.<jQuery>} - The item at the given position or all items if no position was given.
 */
Owl.prototype.mergers = function(position) {
        if (position === undefined) {
                return this._mergers.slice();
        }

        position = this.normalize(position, true);
        return this._mergers[position];
};

/**
 * Gets the absolute positions of clones for an item.
 * @public
 * @param {Number} [position] - The relative position of the item.
 * @returns {Array.<Number>} - The absolute positions of clones for the item or all if no position was given.
 */
Owl.prototype.clones = function(position) {
        var odd = this._clones.length / 2,
                even = odd + this._items.length,
                map = function(index) { return index % 2 === 0 ? even + index / 2 : odd - (index + 1) / 2 };

        if (position === undefined) {
                return $.map(this._clones, function(v, i) { return map(i) });
        }

        return $.map(this._clones, function(v, i) { return v === position ? map(i) : null });
};

/**
 * Sets the current animation speed.
 * @public
 * @param {Number} [speed] - The animation speed in milliseconds or nothing to leave it unchanged.
 * @returns {Number} - The current animation speed in milliseconds.
 */
Owl.prototype.speed = function(speed) {
        if (speed !== undefined) {
                this._speed = speed;
        }

        return this._speed;
};

/**
 * Gets the coordinate of an item.
 * @todo The name of this method is missleanding.
 * @public
 * @param {Number} position - The absolute position of the item within `minimum()` and `maximum()`.
 * @returns {Number|Array.<Number>} - The coordinate of the item in pixel or all coordinates.
 */
Owl.prototype.coordinates = function(position) {
        var multiplier = 1,
                newPosition = position - 1,
                coordinate;

        if (position === undefined) {
                return $.map(this._coordinates, $.proxy(function(coordinate, index) {
                        return this.coordinates(index);
                }, this));
        }

        if (this.settings.center) {
                if (this.settings.rtl) {
                        multiplier = -1;
                        newPosition = position + 1;
                }

                coordinate = this._coordinates[position];
                coordinate += (this.width() - coordinate + (this._coordinates[newPosition] || 0)) / 2 * multiplier;
        } else {
                coordinate = this._coordinates[newPosition] || 0;
        }

        coordinate = Math.ceil(coordinate);

        return coordinate;
};

/**
 * Calculates the speed for a translation.
 * @protected
 * @param {Number} from - The absolute position of the start item.
 * @param {Number} to - The absolute position of the target item.
 * @param {Number} [factor=undefined] - The time factor in milliseconds.
 * @returns {Number} - The time in milliseconds for the translation.
 */
Owl.prototype.duration = function(from, to, factor) {
        if (factor === 0) {
                return 0;
        }

        return Math.min(Math.max(Math.abs(to - from), 1), 6) * Math.abs((factor || this.settings.smartSpeed));
};

/**
 * Slides to the specified item.
 * @public
 * @param {Number} position - The position of the item.
 * @param {Number} [speed] - The time in milliseconds for the transition.
 */
Owl.prototype.to = function(position, speed) {
        var current = this.current(),
                revert = null,
                distance = position - this.relative(current),
                direction = (distance > 0) - (distance < 0),
                items = this._items.length,
                minimum = this.minimum(),
                maximum = this.maximum();

        if (this.settings.loop) {
                if (!this.settings.rewind && Math.abs(distance) > items / 2) {
                        distance += direction * -1 * items;
                }

                position = current + distance;
                revert = ((position - minimum) % items + items) % items + minimum;

                if (revert !== position && revert - distance <= maximum && revert - distance > 0) {
                        current = revert - distance;
                        position = revert;
                        this.reset(current);
                }
        } else if (this.settings.rewind) {
                maximum += 1;
                position = (position % maximum + maximum) % maximum;
        } else {
                position = Math.max(minimum, Math.min(maximum, position));
        }

        this.speed(this.duration(current, position, speed));
        this.current(position);

        if (this.isVisible()) {
                this.update();
        }
};

/**
 * Slides to the next item.
 * @public
 * @param {Number} [speed] - The time in milliseconds for the transition.
 */
Owl.prototype.next = function(speed) {
        speed = speed || false;
        this.to(this.relative(this.current()) + 1, speed);
};

/**
 * Slides to the previous item.
 * @public
 * @param {Number} [speed] - The time in milliseconds for the transition.
 */
Owl.prototype.prev = function(speed) {
        speed = speed || false;
        this.to(this.relative(this.current()) - 1, speed);
};

/**
 * Handles the end of an animation.
 * @protected
 * @param {Event} event - The event arguments.
 */
Owl.prototype.onTransitionEnd = function(event) {

        // if css2 animation then event object is undefined
        if (event !== undefined) {
                event.stopPropagation();

                // Catch only owl-stage transitionEnd event
                if ((event.target || event.srcElement || event.originalTarget) !== this.$stage.get(0)) {
                        return false;
                }
        }

        this.leave('animating');
        this.trigger('translated');
};

/**
 * Gets viewport width.
 * @protected
 * @return {Number} - The width in pixel.
 */
Owl.prototype.viewport = function() {
        var width;
        if (this.options.responsiveBaseElement !== window) {
                width = $(this.options.responsiveBaseElement).width();
        } else if (window.innerWidth) {
                width = window.innerWidth;
        } else if (document.documentElement && document.documentElement.clientWidth) {
                width = document.documentElement.clientWidth;
        } else {
                console.warn('Can not detect viewport width.');
        }
        return width;
};

/**
 * Replaces the current content.
 * @public
 * @param {HTMLElement|jQuery|String} content - The new content.
 */
Owl.prototype.replace = function(content) {
        this.$stage.empty();
        this._items = [];

        if (content) {
                content = (content instanceof jQuery) ? content : $(content);
        }

        if (this.settings.nestedItemSelector) {
                content = content.find('.' + this.settings.nestedItemSelector);
        }

        content.filter(function() {
                return this.nodeType === 1;
        }).each($.proxy(function(index, item) {
                item = this.prepare(item);
                this.$stage.append(item);
                this._items.push(item);
                this._mergers.push(item.find('[data-merge]').addBack('[data-merge]').attr('data-merge') * 1 || 1);
        }, this));

        this.reset(this.isNumeric(this.settings.startPosition) ? this.settings.startPosition : 0);

        this.invalidate('items');
};

/**
 * Adds an item.
 * @todo Use `item` instead of `content` for the event arguments.
 * @public
 * @param {HTMLElement|jQuery|String} content - The item content to add.
 * @param {Number} [position] - The relative position at which to insert the item otherwise the item will be added to the end.
 */
Owl.prototype.add = function(content, position) {
        var current = this.relative(this._current);

        position = position === undefined ? this._items.length : this.normalize(position, true);
        content = content instanceof jQuery ? content : $(content);

        this.trigger('add', { content: content, position: position });

        content = this.prepare(content);

        if (this._items.length === 0 || position === this._items.length) {
                this._items.length === 0 && this.$stage.append(content);
                this._items.length !== 0 && this._items[position - 1].after(content);
                this._items.push(content);
                this._mergers.push(content.find('[data-merge]').addBack('[data-merge]').attr('data-merge') * 1 || 1);
        } else {
                this._items[position].before(content);
                this._items.splice(position, 0, content);
                this._mergers.splice(position, 0, content.find('[data-merge]').addBack('[data-merge]').attr('data-merge') * 1 || 1);
        }

        this._items[current] && this.reset(this._items[current].index());

        this.invalidate('items');

        this.trigger('added', { content: content, position: position });
};

/**
 * Removes an item by its position.
 * @todo Use `item` instead of `content` for the event arguments.
 * @public
 * @param {Number} position - The relative position of the item to remove.
 */
Owl.prototype.remove = function(position) {
        position = this.normalize(position, true);

        if (position === undefined) {
                return;
        }

        this.trigger('remove', { content: this._items[position], position: position });

        this._items[position].remove();
        this._items.splice(position, 1);
        this._mergers.splice(position, 1);

        this.invalidate('items');

        this.trigger('removed', { content: null, position: position });
};

/**
 * Preloads images with auto width.
 * @todo Replace by a more generic approach
 * @protected
 */
Owl.prototype.preloadAutoWidthImages = function(images) {
        images.each($.proxy(function(i, element) {
                this.enter('pre-loading');
                element = $(element);
                $(new Image()).one('load', $.proxy(function(e) {
                        element.attr('src', e.target.src);
                        element.css('opacity', 1);
                        this.leave('pre-loading');
                        !this.is('pre-loading') && !this.is('initializing') && this.refresh();
                }, this)).attr('src', element.attr('src') || element.attr('data-src') || element.attr('data-src-retina'));
        }, this));
};

/**
 * Destroys the carousel.
 * @public
 */
Owl.prototype.destroy = function() {

        this.$element.off('.owl.core');
        this.$stage.off('.owl.core');
        $(document).off('.owl.core');

        if (this.settings.responsive !== false) {
                window.clearTimeout(this.resizeTimer);
                this.off(window, 'resize', this._handlers.onThrottledResize);
        }

        for (var i in this._plugins) {
                this._plugins[i].destroy();
        }

        this.$stage.children('.cloned').remove();

        this.$stage.unwrap();
        this.$stage.children().contents().unwrap();
        this.$stage.children().unwrap();
        this.$stage.remove();
        this.$element
                .removeClass(this.options.refreshClass)
                .removeClass(this.options.loadingClass)
                .removeClass(this.options.loadedClass)
                .removeClass(this.options.rtlClass)
                .removeClass(this.options.dragClass)
                .removeClass(this.options.grabClass)
                .attr('class', this.$element.attr('class').replace(new RegExp(this.options.responsiveClass + '-\\S+\\s', 'g'), ''))
                .removeData('owl.carousel');
};

/**
 * Operators to calculate right-to-left and left-to-right.
 * @protected
 * @param {Number} [a] - The left side operand.
 * @param {String} [o] - The operator.
 * @param {Number} [b] - The right side operand.
 */
Owl.prototype.op = function(a, o, b) {
        var rtl = this.settings.rtl;
        switch (o) {
                case '<':
                        return rtl ? a > b : a < b;
                case '>':
                        return rtl ? a < b : a > b;
                case '>=':
                        return rtl ? a <= b : a >= b;
                case '<=':
                        return rtl ? a >= b : a <= b;
                default:
                        break;
        }
};

/**
 * Attaches to an internal event.
 * @protected
 * @param {HTMLElement} element - The event source.
 * @param {String} event - The event name.
 * @param {Function} listener - The event handler to attach.
 * @param {Boolean} capture - Wether the event should be handled at the capturing phase or not.
 */
Owl.prototype.on = function(element, event, listener, capture) {
        if (element.addEventListener) {
                element.addEventListener(event, listener, capture);
        } else if (element.attachEvent) {
                element.attachEvent('on' + event, listener);
        }
};

/**
 * Detaches from an internal event.
 * @protected
 * @param {HTMLElement} element - The event source.
 * @param {String} event - The event name.
 * @param {Function} listener - The attached event handler to detach.
 * @param {Boolean} capture - Wether the attached event handler was registered as a capturing listener or not.
 */
Owl.prototype.off = function(element, event, listener, capture) {
        if (element.removeEventListener) {
                element.removeEventListener(event, listener, capture);
        } else if (element.detachEvent) {
                element.detachEvent('on' + event, listener);
        }
};

/**
 * Triggers a public event.
 * @todo Remove `status`, `relatedTarget` should be used instead.
 * @protected
 * @param {String} name - The event name.
 * @param {*} [data=null] - The event data.
 * @param {String} [namespace=carousel] - The event namespace.
 * @param {String} [state] - The state which is associated with the event.
 * @param {Boolean} [enter=false] - Indicates if the call enters the specified state or not.
 * @returns {Event} - The event arguments.
 */
Owl.prototype.trigger = function(name, data, namespace, state, enter) {
        var status = {
                item: { count: this._items.length, index: this.current() }
        }, handler = $.camelCase(
                $.grep([ 'on', name, namespace ], function(v) { return v })
                        .join('-').toLowerCase()
        ), event = $.Event(
                [ name, 'owl', namespace || 'carousel' ].join('.').toLowerCase(),
                $.extend({ relatedTarget: this }, status, data)
        );

        if (!this._supress[name]) {
                $.each(this._plugins, function(name, plugin) {
                        if (plugin.onTrigger) {
                                plugin.onTrigger(event);
                        }
                });

                this.register({ type: Owl.Type.Event, name: name });
                this.$element.trigger(event);

                if (this.settings && typeof this.settings[handler] === 'function') {
                        this.settings[handler].call(this, event);
                }
        }

        return event;
};

/**
 * Enters a state.
 * @param name - The state name.
 */
Owl.prototype.enter = function(name) {
        $.each([ name ].concat(this._states.tags[name] || []), $.proxy(function(i, name) {
                if (this._states.current[name] === undefined) {
                        this._states.current[name] = 0;
                }

                this._states.current[name]++;
        }, this));
};

/**
 * Leaves a state.
 * @param name - The state name.
 */
Owl.prototype.leave = function(name) {
        $.each([ name ].concat(this._states.tags[name] || []), $.proxy(function(i, name) {
                this._states.current[name]--;
        }, this));
};

/**
 * Registers an event or state.
 * @public
 * @param {Object} object - The event or state to register.
 */
Owl.prototype.register = function(object) {
        if (object.type === Owl.Type.Event) {
                if (!$.event.special[object.name]) {
                        $.event.special[object.name] = {};
                }

                if (!$.event.special[object.name].owl) {
                        var _default = $.event.special[object.name]._default;
                        $.event.special[object.name]._default = function(e) {
                                if (_default && _default.apply && (!e.namespace || e.namespace.indexOf('owl') === -1)) {
                                        return _default.apply(this, arguments);
                                }
                                return e.namespace && e.namespace.indexOf('owl') > -1;
                        };
                        $.event.special[object.name].owl = true;
                }
        } else if (object.type === Owl.Type.State) {
                if (!this._states.tags[object.name]) {
                        this._states.tags[object.name] = object.tags;
                } else {
                        this._states.tags[object.name] = this._states.tags[object.name].concat(object.tags);
                }

                this._states.tags[object.name] = $.grep(this._states.tags[object.name], $.proxy(function(tag, i) {
                        return $.inArray(tag, this._states.tags[object.name]) === i;
                }, this));
        }
};

/**
 * Suppresses events.
 * @protected
 * @param {Array.<String>} events - The events to suppress.
 */
Owl.prototype.suppress = function(events) {
        $.each(events, $.proxy(function(index, event) {
                this._supress[event] = true;
        }, this));
};

/**
 * Releases suppressed events.
 * @protected
 * @param {Array.<String>} events - The events to release.
 */
Owl.prototype.release = function(events) {
        $.each(events, $.proxy(function(index, event) {
                delete this._supress[event];
        }, this));
};

/**
 * Gets unified pointer coordinates from event.
 * @todo #261
 * @protected
 * @param {Event} - The `mousedown` or `touchstart` event.
 * @returns {Object} - Contains `x` and `y` coordinates of current pointer position.
 */
Owl.prototype.pointer = function(event) {
        var result = { x: null, y: null };

        event = event.originalEvent || event || window.event;

        event = event.touches && event.touches.length ?
                event.touches[0] : event.changedTouches && event.changedTouches.length ?
                        event.changedTouches[0] : event;

        if (event.pageX) {
                result.x = event.pageX;
                result.y = event.pageY;
        } else {
                result.x = event.clientX;
                result.y = event.clientY;
        }

        return result;
};

/**
 * Determines if the input is a Number or something that can be coerced to a Number
 * @protected
 * @param {Number|String|Object|Array|Boolean|RegExp|Function|Symbol} - The input to be tested
 * @returns {Boolean} - An indication if the input is a Number or can be coerced to a Number
 */
Owl.prototype.isNumeric = function(number) {
        return !isNaN(parseFloat(number));
};

/**
 * Gets the difference of two vectors.
 * @todo #261
 * @protected
 * @param {Object} - The first vector.
 * @param {Object} - The second vector.
 * @returns {Object} - The difference.
 */
Owl.prototype.difference = function(first, second) {
        return {
                x: first.x - second.x,
                y: first.y - second.y
        };
};

/**
 * The jQuery Plugin for the Owl Carousel
 * @todo Navigation plugin `next` and `prev`
 * @public
 */
$.fn.owlCarousel = function(option) {
        var args = Array.prototype.slice.call(arguments, 1);

        return this.each(function() {
                var $this = $(this),
                        data = $this.data('owl.carousel');

                if (!data) {
                        data = new Owl(this, typeof option == 'object' && option);
                        $this.data('owl.carousel', data);

                        $.each([
                                'next', 'prev', 'to', 'destroy', 'refresh', 'replace', 'add', 'remove'
                        ], function(i, event) {
                                data.register({ type: Owl.Type.Event, name: event });
                                data.$element.on(event + '.owl.carousel.core', $.proxy(function(e) {
                                        if (e.namespace && e.relatedTarget !== this) {
                                                this.suppress([ event ]);
                                                data[event].apply(this, [].slice.call(arguments, 1));
                                                this.release([ event ]);
                                        }
                                }, data));
                        });
                }

                if (typeof option == 'string' && option.charAt(0) !== '_') {
                        data[option].apply(data, args);
                }
        });
};

/**
 * The constructor for the jQuery Plugin
 * @public
 */
$.fn.owlCarousel.Constructor = Owl;

})(window.Zepto || window.jQuery, window, document);