jQuery(document).ready(function ($) {
    
    var timelines = $('.cd-horizontal-timeline'),
            eventsMinDistance = 60;

    (timelines.length > 0) && initTimeline(timelines);

    function initTimeline(timelines) {
        timelines.each(function () {
            var timeline = $(this),
                    timelineComponents = {};
            //cache timeline components 
            timelineComponents['timelineWrapper'] = timeline.find('.events-wrapper');
            timelineComponents['eventsWrapper'] = timelineComponents['timelineWrapper'].children('.events');
            timelineComponents['fillingLine'] = timelineComponents['eventsWrapper'].children('.filling-line');
            timelineComponents['timelineEvents'] = timelineComponents['eventsWrapper'].find('a');
            timelineComponents['timelineDates'] = parseDate(timelineComponents['timelineEvents']);
            timelineComponents['eventsMinLapse'] = minLapse(timelineComponents['timelineDates']);
            timelineComponents['timelineNavigation'] = timeline.find('.cd-timeline-navigation');
            timelineComponents['eventsContent'] = timeline.children('.events-content');

            //assign a left postion to the single events along the timeline
            setDatePosition(timelineComponents, eventsMinDistance);
            //assign a width to the timeline
            var timelineTotWidth = setTimelineWidth(timelineComponents, eventsMinDistance);
            //the timeline has been initialize - show it
            timeline.addClass('loaded');

            //detect click on the next arrow
            timelineComponents['timelineNavigation'].on('click', '.next', function (event) {
                event.preventDefault();
                updateSlide(timelineComponents, timelineTotWidth, 'next');
            });
            //detect click on the prev arrow
            timelineComponents['timelineNavigation'].on('click', '.prev', function (event) {
                event.preventDefault();
                updateSlide(timelineComponents, timelineTotWidth, 'prev');
            });
            //detect click on the a single event - show new event content
            timelineComponents['eventsWrapper'].on('click', 'a', function (event) {
                event.preventDefault();
                timelineComponents['timelineEvents'].removeClass('selected');
                $(this).addClass('selected');
                updateOlderEvents($(this));
                updateFilling($(this), timelineComponents['fillingLine'], timelineTotWidth);
                updateVisibleContent($(this), timelineComponents['eventsContent']);
            });

            //on swipe, show next/prev event content
            timelineComponents['eventsContent'].on('swipeleft', function () {
                var mq = checkMQ();
                (mq == 'mobile') && showNewContent(timelineComponents, timelineTotWidth, 'next');
            });
            timelineComponents['eventsContent'].on('swiperight', function () {
                var mq = checkMQ();
                (mq == 'mobile') && showNewContent(timelineComponents, timelineTotWidth, 'prev');
            });

            //keyboard navigation
            $(document).keyup(function (event) {
                if (event.which == '37' && elementInViewport(timeline.get(0))) {
                    showNewContent(timelineComponents, timelineTotWidth, 'prev');
                } else if (event.which == '39' && elementInViewport(timeline.get(0))) {
                    showNewContent(timelineComponents, timelineTotWidth, 'next');
                }
            });
        });
    }

    function updateSlide(timelineComponents, timelineTotWidth, string) {
        //retrieve translateX value of timelineComponents['eventsWrapper']
        var translateValue = getTranslateValue(timelineComponents['eventsWrapper']),
                wrapperWidth = Number(timelineComponents['timelineWrapper'].css('width').replace('px', ''));
        //translate the timeline to the left('next')/right('prev') 
        (string == 'next')
                ? translateTimeline(timelineComponents, translateValue - wrapperWidth + eventsMinDistance, wrapperWidth - timelineTotWidth)
                : translateTimeline(timelineComponents, translateValue + wrapperWidth - eventsMinDistance);
    }

    function showNewContent(timelineComponents, timelineTotWidth, string) {
        //go from one event to the next/previous one
        var visibleContent = timelineComponents['eventsContent'].find('.selected'),
                newContent = (string == 'next') ? visibleContent.next() : visibleContent.prev();

        if (newContent.length > 0) { //if there's a next/prev event - show it
            var selectedDate = timelineComponents['eventsWrapper'].find('.selected'),
                    newEvent = (string == 'next') ? selectedDate.parent('li').next('li').children('a') : selectedDate.parent('li').prev('li').children('a');

            updateFilling(newEvent, timelineComponents['fillingLine'], timelineTotWidth);
            updateVisibleContent(newEvent, timelineComponents['eventsContent']);
            newEvent.addClass('selected');
            selectedDate.removeClass('selected');
            updateOlderEvents(newEvent);
            updateTimelinePosition(string, newEvent, timelineComponents);
        }
    }

    function updateTimelinePosition(string, event, timelineComponents) {
        //translate timeline to the left/right according to the position of the selected event
        var eventStyle = window.getComputedStyle(event.get(0), null),
                eventLeft = Number(eventStyle.getPropertyValue("left").replace('px', '')),
                timelineWidth = Number(timelineComponents['timelineWrapper'].css('width').replace('px', '')),
                timelineTotWidth = Number(timelineComponents['eventsWrapper'].css('width').replace('px', ''));
        var timelineTranslate = getTranslateValue(timelineComponents['eventsWrapper']);

        if ((string == 'next' && eventLeft > timelineWidth - timelineTranslate) || (string == 'prev' && eventLeft < -timelineTranslate)) {
            translateTimeline(timelineComponents, -eventLeft + timelineWidth / 2, timelineWidth - timelineTotWidth);
        }
    }

    function translateTimeline(timelineComponents, value, totWidth) {
        var eventsWrapper = timelineComponents['eventsWrapper'].get(0);
        value = (value > 0) ? 0 : value; //only negative translate value
        value = (!(typeof totWidth === 'undefined') && value < totWidth) ? totWidth : value; //do not translate more than timeline width
        setTransformValue(eventsWrapper, 'translateX', value + 'px');
        //update navigation arrows visibility
        (value == 0) ? timelineComponents['timelineNavigation'].find('.prev').addClass('inactive') : timelineComponents['timelineNavigation'].find('.prev').removeClass('inactive');
        (value == totWidth) ? timelineComponents['timelineNavigation'].find('.next').addClass('inactive') : timelineComponents['timelineNavigation'].find('.next').removeClass('inactive');
    }

    function updateFilling(selectedEvent, filling, totWidth) {
        //change .filling-line length according to the selected event
        var eventStyle = window.getComputedStyle(selectedEvent.get(0), null),
                eventLeft = eventStyle.getPropertyValue("left"),
                eventWidth = eventStyle.getPropertyValue("width");
        eventLeft = Number(eventLeft.replace('px', '')) + Number(eventWidth.replace('px', '')) / 2;
        var scaleValue = eventLeft / totWidth;
        setTransformValue(filling.get(0), 'scaleX', scaleValue);
    }

    function setDatePosition(timelineComponents, min) {
        for (i = 0; i < timelineComponents['timelineDates'].length; i++) {
            var distance = daydiff(timelineComponents['timelineDates'][0], timelineComponents['timelineDates'][i]),
                    distanceNorm = Math.round(distance / timelineComponents['eventsMinLapse']) + 2;
            timelineComponents['timelineEvents'].eq(i).css('left', distanceNorm * min + 'px');
        }
    }

    function setTimelineWidth(timelineComponents, width) {
        var timeSpan = daydiff(timelineComponents['timelineDates'][0], timelineComponents['timelineDates'][timelineComponents['timelineDates'].length - 1]),
                timeSpanNorm = timeSpan / timelineComponents['eventsMinLapse'],
                timeSpanNorm = Math.round(timeSpanNorm) + 4,
                totalWidth = timeSpanNorm * width;
        timelineComponents['eventsWrapper'].css('width', totalWidth + 'px');
        updateFilling(timelineComponents['eventsWrapper'].find('a.selected'), timelineComponents['fillingLine'], totalWidth);
        updateTimelinePosition('next', timelineComponents['eventsWrapper'].find('a.selected'), timelineComponents);

        return totalWidth;
    }

    function updateVisibleContent(event, eventsContent) {
        var eventDate = event.data('date'),
                visibleContent = eventsContent.find('.selected'),
                selectedContent = eventsContent.find('[data-date="' + eventDate + '"]'),
                selectedContentHeight = selectedContent.height();

        if (selectedContent.index() > visibleContent.index()) {
            var classEnetering = 'selected enter-right',
                    classLeaving = 'leave-left';
        } else {
            var classEnetering = 'selected enter-left',
                    classLeaving = 'leave-right';
        }

        selectedContent.attr('class', classEnetering);
        visibleContent.attr('class', classLeaving).one('webkitAnimationEnd oanimationend msAnimationEnd animationend', function () {
            visibleContent.removeClass('leave-right leave-left');
            selectedContent.removeClass('enter-left enter-right');
        });
        eventsContent.css('height', selectedContentHeight + 'px');
    }

    function updateOlderEvents(event) {
        event.parent('li').prevAll('li').children('a').addClass('older-event').end().end().nextAll('li').children('a').removeClass('older-event');
    }

    function getTranslateValue(timeline) {
        var timelineStyle = window.getComputedStyle(timeline.get(0), null),
                timelineTranslate = timelineStyle.getPropertyValue("-webkit-transform") ||
                timelineStyle.getPropertyValue("-moz-transform") ||
                timelineStyle.getPropertyValue("-ms-transform") ||
                timelineStyle.getPropertyValue("-o-transform") ||
                timelineStyle.getPropertyValue("transform");

        if (timelineTranslate.indexOf('(') >= 0) {
            var timelineTranslate = timelineTranslate.split('(')[1];
            timelineTranslate = timelineTranslate.split(')')[0];
            timelineTranslate = timelineTranslate.split(',');
            var translateValue = timelineTranslate[4];
        } else {
            var translateValue = 0;
        }

        return Number(translateValue);
    }

    function setTransformValue(element, property, value) {
        element.style["-webkit-transform"] = property + "(" + value + ")";
        element.style["-moz-transform"] = property + "(" + value + ")";
        element.style["-ms-transform"] = property + "(" + value + ")";
        element.style["-o-transform"] = property + "(" + value + ")";
        element.style["transform"] = property + "(" + value + ")";
    }

    //based on http://stackoverflow.com/questions/542938/how-do-i-get-the-number-of-days-between-two-dates-in-javascript
    function parseDate(events) {
        var dateArrays = [];
        events.each(function () {
            var singleDate = $(this),
                    dateComp = singleDate.data('date').split('T');
            if (dateComp.length > 1) { //both DD/MM/YEAR and time are provided
                var dayComp = dateComp[0].split('/'),
                        timeComp = dateComp[1].split(':');
            } else if (dateComp[0].indexOf(':') >= 0) { //only time is provide
                var dayComp = ["2000", "0", "0"],
                        timeComp = dateComp[0].split(':');
            } else { //only DD/MM/YEAR
                var dayComp = dateComp[0].split('/'),
                        timeComp = ["0", "0"];
            }
            var newDate = new Date(dayComp[2], dayComp[1] - 1, dayComp[0], timeComp[0], timeComp[1]);
            dateArrays.push(newDate);
        });
        return dateArrays;
    }

    function daydiff(first, second) {
        return Math.round((second - first));
    }

    function minLapse(dates) {
        //determine the minimum distance among events
        var dateDistances = [];
        for (i = 1; i < dates.length; i++) {
            var distance = daydiff(dates[i - 1], dates[i]);
            dateDistances.push(distance);
        }
        return Math.min.apply(null, dateDistances);
    }

    /*
     How to tell if a DOM element is visible in the current viewport?
     http://stackoverflow.com/questions/123999/how-to-tell-if-a-dom-element-is-visible-in-the-current-viewport
     */
    function elementInViewport(el) {
        var top = el.offsetTop;
        var left = el.offsetLeft;
        var width = el.offsetWidth;
        var height = el.offsetHeight;

        while (el.offsetParent) {
            el = el.offsetParent;
            top += el.offsetTop;
            left += el.offsetLeft;
        }

        return (
                top < (window.pageYOffset + window.innerHeight) &&
                left < (window.pageXOffset + window.innerWidth) &&
                (top + height) > window.pageYOffset &&
                (left + width) > window.pageXOffset
                );
    }

    function checkMQ() {
        //check if mobile or desktop device
        return window.getComputedStyle(document.querySelector('.cd-horizontal-timeline'), '::before').getPropertyValue('content').replace(/'/g, "").replace(/"/g, "");
    }
});