/*
* The original implementation of the GeoExt.WMSLegend only use image/gif as format, we wnat image/png.
* This prototype method does. It is a copy of the original with code inserted various places.
**/


Ext.onReady(function () {

    GeoExt.WMSLegend.prototype.getLegendUrl = function(layerName, layerNames) {
        var rec = this.layerRecord;
        var url;
        var styles = rec && rec.get("styles");
        var layer = rec.getLayer();
        layerNames = layerNames || [layer.params.LAYERS].join(",").split(",");

        var styleNames = layer.params.STYLES &&
                                 [layer.params.STYLES].join(",").split(",");
        var idx = layerNames.indexOf(layerName);
        var styleName = styleNames && styleNames[idx];
        // check if we have a legend URL in the record's
        // "styles" data field
        if (styles && styles.length > 0) {
            if (styleName) {
                Ext.each(styles, function (s) {
                    url = (s.name == styleName && s.legend) && s.legend.href;
                    return !url;
                });
            } else if (this.defaultStyleIsFirst === true && !styleNames &&
                          !layer.params.SLD && !layer.params.SLD_BODY) {
                url = styles[0].legend && styles[0].legend.href;
            }
        }
        if (!url) {
            url = layer.getFullRequestString({
                REQUEST: "GetLegendGraphic",
                WIDTH: null,
                HEIGHT: null,
                EXCEPTIONS: "application/vnd.ogc.se_xml",
                LAYER: layerName,
                LAYERS: null,
                STYLE: (styleName !== '') ? styleName : null,
                STYLES: null,
                SRS: null,
                FORMAT: null
            });
        }
        // add scale parameter - also if we have the url from the record's
        // styles data field and it is actually a GetLegendGraphic request.
        if (this.useScaleParameter === true &&
                    url.toLowerCase().indexOf("request=getlegendgraphic") != -1) {
            var scale = layer.map.getScale();
            url = Ext.urlAppend(url, "SCALE=" + scale);
        }
        var params = this.baseParams || {};
        Ext.applyIf(params, { FORMAT: 'image/png' });
        if (url.indexOf('?') > 0) {
            url = Ext.urlEncode(params, url);
        }

        return url;
    }
});