(function (root, factory) {
    if (typeof module === "object" && module.exports) {
        module.exports = factory();
        return;
    }

    root.PartnerMarquee = factory();
}(typeof self !== "undefined" ? self : this, function () {
    "use strict";

    function calculateCopies(viewportWidth, baseWidth) {
        if (!viewportWidth || !baseWidth) {
            return 2;
        }

        return Math.max(1, Math.ceil((viewportWidth + 1) / baseWidth));
    }

    function calculateDuration(segmentWidth) {
        var minDuration = 18;
        var pixelsPerSecond = 90;

        if (!segmentWidth) {
            return minDuration;
        }

        return Math.max(minDuration, Math.round((segmentWidth / pixelsPerSecond) * 10) / 10);
    }

    function buildSegmentMarkup(baseMarkup, copies) {
        return new Array(copies + 1).join(baseMarkup);
    }

    function syncTrack(track) {
        var marquee = track.parentNode;
        var firstSet = track.querySelector(".partner-track-set");
        var viewportWidth;
        var baseWidth;
        var copies;
        var segmentMarkup;
        var firstSegment;
        var secondSegment;

        if (!marquee || !firstSet) {
            return;
        }

        if (!track.getAttribute("data-base-markup")) {
            track.setAttribute("data-base-markup", firstSet.innerHTML.trim());
        }

        track.innerHTML = "";

        firstSet = document.createElement("div");
        firstSet.className = "partner-track-set";
        firstSet.setAttribute("aria-hidden", "true");
        firstSet.innerHTML = track.getAttribute("data-base-markup");
        track.appendChild(firstSet);

        viewportWidth = marquee.clientWidth;
        baseWidth = firstSet.scrollWidth;
        copies = calculateCopies(viewportWidth, baseWidth);
        segmentMarkup = buildSegmentMarkup(track.getAttribute("data-base-markup"), copies);

        track.innerHTML = "";

        firstSegment = document.createElement("div");
        firstSegment.className = "partner-track-set";
        firstSegment.innerHTML = segmentMarkup;

        secondSegment = document.createElement("div");
        secondSegment.className = "partner-track-set";
        secondSegment.setAttribute("aria-hidden", "true");
        secondSegment.innerHTML = segmentMarkup;

        track.appendChild(firstSegment);
        track.appendChild(secondSegment);
        track.style.animationDuration = calculateDuration(firstSegment.scrollWidth) + "s";
    }

    function syncAll() {
        var tracks = document.querySelectorAll(".partner-track");
        var i;

        for (i = 0; i < tracks.length; i += 1) {
            syncTrack(tracks[i]);
        }
    }

    function debounce(fn, wait) {
        var timer = null;

        return function () {
            clearTimeout(timer);
            timer = setTimeout(fn, wait);
        };
    }

    function init() {
        if (!document.querySelector(".partner-track")) {
            return;
        }

        syncAll();
        window.addEventListener("resize", debounce(syncAll, 120));
    }

    if (typeof window !== "undefined" && typeof document !== "undefined") {
        if (document.readyState === "loading") {
            document.addEventListener("DOMContentLoaded", init);
        } else {
            init();
        }
    }

    return {
        buildSegmentMarkup: buildSegmentMarkup,
        calculateCopies: calculateCopies,
        calculateDuration: calculateDuration
    };
}));