/* Copyright (c) 2006 MetaCarta, Inc., published under a modified BSD license.
 * See http://svn.openlayers.org/trunk/openlayers/repository-license.txt 
 * for the full text of the license. */


/**
 * @requires OpenLayers/Layer/EventPane.js
 * @requires OpenLayers/Layer/FixedZoomLevels.js
 * 
 * Class: OpenLayers.Layer.Yahoo
 * 
 * Inherits:
 *  - <OpenLayers.Layer.EventPane>
 *  - <OpenLayers.Layer.FixedZoomLevels>v
 */
OpenLayers.Layer.Yahoo = OpenLayers.Class(
  OpenLayers.Layer.EventPane, OpenLayers.Layer.FixedZoomLevels, {
    
    /** 
     * Constant: MIN_ZOOM_LEVEL
     * {Integer} 0 
     */
    MIN_ZOOM_LEVEL: 0,
    
    /** 
     * Constant: MAX_ZOOM_LEVEL
     * {Integer} 15
     */
    MAX_ZOOM_LEVEL: 15,

    /** 
     * Constant: RESOLUTIONS
     * {Array(Float)} Hardcode these resolutions so that they are more closely
     *                tied with the standard wms projection
     */
    RESOLUTIONS: [1.40625,0.703125,0.3515625,0.17578125,0.087890625,0.0439453125,0.02197265625,0.010986328125,0.0054931640625,0.00274658203125,0.001373291015625,0.0006866455078125,0.00034332275390625,0.000171661376953125,0.0000858306884765625,0.00004291534423828125],

    /**
     * APIProperty: type
     * {YahooMapType}
     */
    type: null,

    /** 
     * Constructor: OpenLayers.Layer.Yahoo
     * 
     * Parameters:
     * name - {String}
     * options - {Object}
     */
    initialize: function(name, options) {
        OpenLayers.Layer.EventPane.prototype.initialize.apply(this, arguments);
        OpenLayers.Layer.FixedZoomLevels.prototype.initialize.apply(this, 
                                                                    arguments);
    },
    
    /**
     * Method: loadMapObject
     */
    loadMapObject:function() {
        try { //do not crash! 
            var size = this.getMapObjectSizeFromOLSize(this.map.getSize());
            this.mapObject = new YMap(this.div, this.type, size);
            this.mapObject.disableKeyControls();
        } catch(e) {}
    },

    /**
     * Method: onMapResize
     * 
     */
    onMapResize: function() {
        try {
            var size = this.getMapObjectSizeFromOLSize(this.map.getSize());
            this.mapObject.resizeTo(size);
        } catch(e) {}     
    },    
    
    
    /** 
     * APIMethod: setMap
     * Overridden from EventPane because we need to remove this yahoo event
     *     pane which prohibits our drag and drop, and we can only do this 
     *     once the map has been loaded and centered.
     * 
     * Parameters:
     * map - {<OpenLayers.Map>}
     */
    setMap: function(map) {
        OpenLayers.Layer.EventPane.prototype.setMap.apply(this, arguments);

        this.map.events.register("moveend", this, this.fixYahooEventPane);
    },

    /** 
     * Method: fixYahooEventPane
     * The map has been centered, so the mysterious yahoo eventpane has been
     *     added. we remove it so that it doesnt mess with *our* event pane.
     */
    fixYahooEventPane: function() {
        var yahooEventPane = OpenLayers.Util.getElement("ygddfdiv");
        if (yahooEventPane != null) {
            if (yahooEventPane.parentNode != null)
                yahooEventPane.parentNode.removeChild(yahooEventPane);

            this.map.events.unregister("moveend", this, 
                                       this.fixYahooEventPane);
        }
    },

    /** 
     * APIMethod: getWarningHTML
     * 
     * Return: 
     * {String} String with information on why layer is broken, how to get
     *          it working.
     */
    getWarningHTML:function() {

        var html = "";
        html += "The Yahoo Layer was unable to load correctly.<br>";
        html += "<br>";
        html += "To get rid of this message, select a new BaseLayer "
        html += "in the layer switcher in the upper-right corner.<br>";
        html += "<br>";
        html += "Most likely, this is because the Yahoo library";
        html += " script was either not correctly included.<br>";
        html += "<br>";
        html += "Developers: For help getting this working correctly, ";
        html += "<a href='http://trac.openlayers.org/wiki/Yahoo' "
        html +=  "target='_blank'>";
        html +=     "click here";
        html += "</a>";

        return html;
    },

  /********************************************************/
  /*                                                      */
  /*             Translation Functions                    */
  /*                                                      */
  /*    The following functions translate GMaps and OL    */ 
  /*     formats for Pixel, LonLat, Bounds, and Zoom      */
  /*                                                      */
  /********************************************************/


  //
  // TRANSLATION: MapObject Zoom <-> OpenLayers Zoom
  //
  
    /**
     * APIMethod: getOLZoomFromMapObjectZoom
     * 
     * Parameters:
     * gZoom - {Integer}
     * 
     * Return:
     * {Integer} An OpenLayers Zoom level, translated from the passed in gZoom
     *           Returns null if null value is passed in.
     */
    getOLZoomFromMapObjectZoom: function(moZoom) {
        var zoom = null;
        if (moZoom != null) {
            zoom = OpenLayers.Layer.FixedZoomLevels.prototype.getOLZoomFromMapObjectZoom.apply(this, [moZoom]);
            zoom = 18 - zoom;
        }
        return zoom;
    },
    
    /**
     * APIMethod: getMapObjectZoomFromOLZoom
     * 
     * Parameters:
     * olZoom - {Integer}
     * 
     * Return:
     * {Integer} A MapObject level, translated from the passed in olZoom
     *           Returns null if null value is passed in
     */
    getMapObjectZoomFromOLZoom: function(olZoom) {
        var zoom = null; 
        if (olZoom != null) {
            zoom = OpenLayers.Layer.FixedZoomLevels.prototype.getMapObjectZoomFromOLZoom.apply(this, [olZoom]);
            zoom = 18 - zoom;
        }
        return zoom;
    },

    /************************************
     *                                  *
     *   MapObject Interface Controls   *
     *                                  *
     ************************************/


  // Get&Set Center, Zoom

    /** 
     * APIMethod: setMapObjectCenter
     * Set the mapObject to the specified center and zoom
     * 
     * Parameters:
     * center - {Object} MapObject LonLat format
     * zoom - {int} MapObject zoom format
     */
    setMapObjectCenter: function(center, zoom) {
        this.mapObject.drawZoomAndCenter(center, zoom); 
    },
   
    /**
     * APIMethod: getMapObjectCenter
     * 
     * Return: 
     * {Object} The mapObject's current center in Map Object format
     */
    getMapObjectCenter: function() {
        return this.mapObject.getCenterLatLon();
    },

    /** 
     * APIMethod: getMapObjectZoom
     * 
     * Return:
     * {Integer} The mapObject's current zoom, in Map Object format
     */
    getMapObjectZoom: function() {
        return this.mapObject.getZoomLevel();
    },


  // LonLat - Pixel Translation
  
    /**
     * APIMethod: getMapObjectLonLatFromMapObjectPixel
     * 
     * Parameters:
     * moPixel - {Object} MapObject Pixel format
     * 
     * Return:
     * {Object} MapObject LonLat translated from MapObject Pixel
     */
    getMapObjectLonLatFromMapObjectPixel: function(moPixel) {
        return this.mapObject.convertXYLatLon(moPixel);
    },

    /**
     * APIMethod: getMapObjectPixelFromMapObjectLonLat
     * 
     * Parameters:
     * moLonLat - {Object} MapObject LonLat format
     * 
     * Return:
     * {Object} MapObject Pixel transtlated from MapObject LonLat
     */
    getMapObjectPixelFromMapObjectLonLat: function(moLonLat) {
        return this.mapObject.convertLatLonXY(moLonLat);
    },


    /************************************
     *                                  *
     *       MapObject Primitives       *
     *                                  *
     ************************************/


  // LonLat
    
    /**
     * APIMethod: getLongitudeFromMapObjectLonLat
     * 
     * Parameters:
     * moLonLat - {Object} MapObject LonLat format
     * 
     * Return:
     * {Float} Longitude of the given MapObject LonLat
     */
    getLongitudeFromMapObjectLonLat: function(moLonLat) {
        return moLonLat.Lon;
    },

    /**
     * APIMethod: getLatitudeFromMapObjectLonLat
     * 
     * Parameters:
     * moLonLat - {Object} MapObject LonLat format
     * 
     * Return:
     * {Float} Latitude of the given MapObject LonLat
     */
    getLatitudeFromMapObjectLonLat: function(moLonLat) {
        return moLonLat.Lat;
    },

    /**
     * APIMethod: getMapObjectLonLatFromLonLat
     * 
     * Parameters:
     * lon - {Float}
     * lat - {Float}
     * 
     * Return:
     * {Object} MapObject LonLat built from lon and lat params
     */
    getMapObjectLonLatFromLonLat: function(lon, lat) {
        return new YGeoPoint(lat, lon);
    },

  // Pixel
    
    /**
     * APIMethod: getXFromMapObjectPixel
     * 
     * Parameters:
     * moPixel - {Object} MapObject Pixel format
     * 
     * Return:
     * {Integer} X value of the MapObject Pixel
     */
    getXFromMapObjectPixel: function(moPixel) {
        return moPixel.x;
    },

    /**
     * APIMethod: getYFromMapObjectPixel
     * 
     * Parameters:
     * moPixel - {Object} MapObject Pixel format
     * 
     * Return:
     * {Integer} Y value of the MapObject Pixel
     */
    getYFromMapObjectPixel: function(moPixel) {
        return moPixel.y;
    },

    /**
     * APIMethod: getMapObjectPixelFromXY
     * 
     * Parameters:
     * x - {Integer}
     * y - {Integer}
     * 
     * Return:
     * {Object} MapObject Pixel from x and y parameters
     */
    getMapObjectPixelFromXY: function(x, y) {
        return new YCoordPoint(x, y);
    },
    
  // Size
  
    /**
     * APIMethod: getMapObjectSizeFromOLSize
     * 
     * Parameters:
     * olSize - {<OpenLayers.Size>}
     * 
     * Return:
     * {Object} MapObject Size from olSize parameter
     */
    getMapObjectSizeFromOLSize: function(olSize) {
        return new YSize(olSize.w, olSize.h);
    },
    
    CLASS_NAME: "OpenLayers.Layer.Yahoo"
});