/**
 * This is an Optimizely script.
 *
 * It passes the url parameter from the main page to the iframe.
 * If a parameter exists in both urls (main page and iframe),
 * the parameter from the main page will be used.
 *
 * It also listens to messages with source="optiIframe", gets the document height
 * from the message and sets the <iframe> height in a style statement.
 *
 */
(function () {

    function appendParams(targetParams, sourceParams) {
        for (let p of sourceParams) {
            p = p.toString();
            var key = p.split(',')[0];
            var value = p.split(',')[1]
            if(!targetParams.has(key)) {
                targetParams.append(key, value);
            }
        }
    }

    window.addEventListener("DOMContentLoaded", function () {

        // Pass URL parameters from the parent window to the iframe
        var pageUrl = window.location.toString();
        var pageParams = pageUrl.split('?')[1];
        var iframe = document.getElementById("optiIframe");
        var iframeUrl = iframe.src.split('?')[0];
        var iframeParams = iframe.src.split('?')[1];


        var paramsFromMainPage = new URLSearchParams(pageParams);
        var paramsFromIFrame = new URLSearchParams(iframeParams);
        var paramsCombined = new URLSearchParams();

        appendParams(paramsCombined, paramsFromMainPage);
        appendParams(paramsCombined, paramsFromIFrame);

        if(paramsCombined.toString()) {
            iframe.src = iframeUrl + '?' + paramsCombined.toString();
        }

        // Update height of the iframe when message received
        window.addEventListener("message", function(event) {

            try {
                var postMessageEventData = JSON.parse(event.data);
                var source = postMessageEventData.source;
                var height = postMessageEventData.height;

                if (source === 'optiIFrame') {
                    iframe.style.height = height + "px";
                }

            } catch (err) {
                // Ignore.
            }

        });
    });
}());