/**
 * Namespace: Util.OSM
 */
OpenLayers.Util.OSM = {};

/**
 * Constant: MISSING_TILE_URL
 * {String} URL of image to display for missing tiles
 */
OpenLayers.Util.OSM.MISSING_TILE_URL = "/img/404.png";

/**
 * Property: originalOnImageLoadError
 * {Function} Original onImageLoadError function.
 */
OpenLayers.Util.OSM.originalOnImageLoadError = OpenLayers.Util.onImageLoadError;

/**
 * Function: onImageLoadError
 */
OpenLayers.Util.onImageLoadError = function() {
    if (this.src.match(/^http:\/\/[abc]\.[a-z]+\.ika-netzwerke\.de\//)) {
        this.src = OpenLayers.Util.OSM.MISSING_TILE_URL;
    } else if (this.src.match(/^http:\/\/[def]\.bl12\.ika-netzwerke\.de\//)) {
        // do nothing - this layer is transparent
    } else {
        OpenLayers.Util.OSM.originalOnImageLoadError;
    }
};

/**
 * Class: OpenLayers.Layer.OSM.Mapnik
 *
 * Inherits from:
 *  - <OpenLayers.Layer.OSM>
 */
OpenLayers.Layer.OSM.Mapnik = OpenLayers.Class(OpenLayers.Layer.OSM, {
    /**
     * Constructor: OpenLayers.Layer.OSM.Mapnik
     *
     * Parameters:
     * name - {String}
     * options - {Object} Hashtable of extra options to tag onto the layer
     */
    initialize: function(name, options) {
        var url = [
            "http://tile-1.bl12.ika-netzwerke.de/tiles/mapnik-std/${z}/${x}/${y}.png"
            
        ];
        options = OpenLayers.Util.extend({ numZoomLevels: 19 }, options);
        var newArguments = [name, url, options];
        OpenLayers.Layer.OSM.prototype.initialize.apply(this, newArguments);
    },

    CLASS_NAME: "OpenLayers.Layer.OSM.Mapnik"
});