/** 2356 Google Book Preview */
/** require prototype.js */
var TOL_GBP_GoogleAPIUrl = 'http://books.google.com/books?jscmd=viewapi';

var TOL_GBP_PreviewBlockIDPrefix = 'preview-block-';
var TOL_GBP_PreviewLinkClassPrefix = 'a.preview-link-';

function TOL_GBP_callback( data ) {

	for ( var isbn in data ) {
        var janCd = isbn.replace('isbn:', '');
		var elemId = TOL_GBP_PreviewBlockIDPrefix + janCd;
        var linkClass = TOL_GBP_PreviewLinkClassPrefix + janCd;

        if ( data[isbn].embeddable == true ) { 
            $$( linkClass ).each( function(linkElem) { 
                linkElem.href = linkElem.rel + janCd;
            });
	        var btnElem = document.getElementById( elemId );
	        if ( btnElem ) { 
	            btnElem.style.display=''; 
            } 
	    }
    }
}

function TOL_GBP_PreviewButtonControl() {
    var btnList = $$('.googlePreviewBtn');
    var btnListLen = btnList.length;

    var isbnList = [];
    for( var i = 0; i < btnListLen; i++ ) {
        var btnElem = btnList[i];
        var janCd = btnElem.id.replace(TOL_GBP_PreviewBlockIDPrefix, '');
        isbnList.push('isbn:' + janCd);
    }

    if ( isbnList.length > 0 ) {
        var params = '&callback=TOL_GBP_callback&bibkeys=' + isbnList.join(',');
        
        // make JSONP request
        var src = TOL_GBP_GoogleAPIUrl + params;
        var script = document.createElement("script");
        script.setAttribute('type', 'text/javascript');
        script.setAttribute('charset', 'utf-8');
        script.setAttribute('src', src);
        var head = document.getElementsByTagName('head').item(0);
        head.appendChild(script);
    }
}
TOL_GBP_PreviewButtonControl();