if (typeof KOHA == "undefined" || !KOHA) {
    var KOHA = {};
}

/**
 * A namespace for Google related functions.
 */
KOHA.Google = {


    /**
     * Search all:
     *    <div title="biblionumber" id="isbn" class="gbs-thumbnail"></div>
     * or
     *    <div title="biblionumber" id="isbn" class="gbs-thumbnail-preview"></div>
     * and run a search with all collected isbns to Google Book Search.
     * The result is asynchronously returned by Google and catched by
     * gbsCallBack().
     */
    GetCoverFromIsbn: function(newWindow) {
        var bibkeys = [];
        $("[id^=gbs-thumbnail]").each(function(i) {
            bibkeys.push($(this).attr("class")); // id=isbn
        });
        bibkeys = bibkeys.join(',');
        var scriptElement = document.createElement("script");
        this.openInNewWindow=newWindow;
        scriptElement.setAttribute("id", "jsonScript");
        scriptElement.setAttribute("src",
            "https://books.google.com/books?bibkeys=" + escape(bibkeys) +
            "&jscmd=viewapi&callback=KOHA.Google.gbsCallBack");
        scriptElement.setAttribute("type", "text/javascript");
        document.documentElement.firstChild.appendChild(scriptElement);

    },

    /**
     * Add cover pages <div
     * and link to preview if div id is gbs-thumbnail-preview
     */
    gbsCallBack: function(booksInfo) {
         var target = '';
         if (this.openInNewWindow) {
            target = 'target="_blank" rel="noreferrer" ';
         }
         for (id in booksInfo) {
             var book = booksInfo[id];
             $("[id^=gbs-thumbnail]."+book.bib_key).each(function() {
                 if (typeof(book.thumbnail_url) != "undefined") {
                     if ( $(this).data('use-data-link') ) {
                         var a = document.createElement("a");
                         a.href = book.thumbnail_url;
                         var img = document.createElement("img");
                         img.src = book.thumbnail_url;
                         img.setAttribute('data-link', book.info_url);
                         a.append(img)
                         $(this).empty().append(a);
                     } else {
                         var img = document.createElement("img");
                         img.src = book.thumbnail_url;
                         $(this).empty().append(img);
                         var re = /^gbs-thumbnail-preview/;
                         if ( re.exec($(this).attr("id")) ) {
                             $(this).append(
                                 '<div class="google-books-preview">' +
                                 '<a '+target+'href="' +
                                 book.info_url +
                                 '"><img src="' +
                                 'https://books.google.com/intl/en/googlebooks/images/gbs_preview_sticker1.gif' +
                                 '"></a></div>'
                                 );
                         }
                     }
                 } else {
                     var message = document.createElement("span");
                     $(message).attr("class","no-image");
                     $(message).html(__("No cover image available"));
                     $(this).empty().append(message);
                 }
             });
        }
        this.done = 1;
    }
};