/**
 * @requires SuperMap/Layer/CanvasLayer.js
 * @requires SuperMap/Layer/Grid.js
 * @requires SuperMap/Tile/Image.js
 */

/**
 * Class: SuperMap.Layer.Baidu
 * Baidu服务图层类。
 *     用于显示Baidu的地图，使用<SuperMap.Layer.Baidu>的
 *     构造函数可以创建Baidu图层，更多信息查看：
 *
 *
 *
 * Inherits from:
 *  - <SuperMap.Layer.CanvasLayer>
 */
SuperMap.Layer.Baidu = SuperMap.Class(SuperMap.CanvasLayer, {

    offsetXY:null,

    /**
     * APIProperty: dpi
     * {Float} 屏幕上每英寸包含像素点的个数。
     * 该参数结合图层比例尺可以推算出该比例尺下图层的分辨率.默认为96。
     */
    dpi: 96,

    /**
     * Property: attribution
     * {String} The layer attribution.
     */
    attribution: "Data by <a style='white-space: nowrap' target='_blank' href='http://map.baidu.com/'>Baidu</a>",

    /**
     * Property: zOffset
     * {Number} 图片url中z值偏移量
     */
    zOffset:3,

    /**
     * Constructor: SuperMap.Layer.Baidu
     * 创建Baidu图层
     *
     * Example:
     * (code)
     *
     * var baiduLayer = new SuperMap.Layer.Baidu();
     * (end)
     */
    initialize: function (options) {
        var me = this;
        me.name = "Baidu";
        me.url = "http://online${num}.map.bdimg.com/onlinelabel/?qt=tile&x=${x}&y=${y}&z=${z}&styles=pl&udt=20150815&scaler=1";
//        me.url = "http://shangetu${num}.map.bdimg.com/it/u=x=${x};y=${y};z=${z};v=017;type=web&fm=44&udt=20130712";

/*
        offsetXY = [];
        offsetXY.push({x:-3,y:1});//3
        offsetXY.push({x:-6,y:3});//4
        offsetXY.push({x:-12,y:7});//5
        offsetXY.push({x:-24,y:15});//6
        offsetXY.push({x:-48,y:31});//7
        offsetXY.push({x:-96,y:63});//8
        offsetXY.push({x:-192,y:127});//9
        offsetXY.push({x:-384,y:255});//10
        offsetXY.push({x:-768,y:511});//11
        offsetXY.push({x:-1536,y:1023});//12
        offsetXY.push({x:-3072,y:2047});//13
        offsetXY.push({x:-6144,y:4095});//14
        offsetXY.push({x:-12288,y:8191});//15
        offsetXY.push({x:-24576,y:16383});//16
        offsetXY.push({x:-49152,y:32767});//17
        offsetXY.push({x:-98304,y:65535});//18
        offsetXY.push({x:-196608,y:131071});//19
        */
/*
        var minX = 6291456;
        var minY = 0;
        var maxX= minX + Math.pow(2, 14) * 256 * 5;
        var maxY= minY + Math.pow(2, 14) * 256 * 4;
*/

       // console.log(Math.pow(2, 15) * 256 * 4);    // bounds 3 16  2 4  1 1     19-3=16     0.5  15
        var minX = -33554432;
        var minY = -33554432;
        var maxX= 33554432;
        var maxY= 33554432;


        var res = Math.pow(2,15);
        var resAry= [];
        for (var i = 0; i < 17; i++)    //百度 3-19
        {
            resAry[i] = res;
            res *= 0.5;                 //每次二分之一
        }

        //计算比例尺数组
        var scaAry = [];
        for(var i = 0;i<17;i++)
        {
            scaAry[i] = 0.0254/(96*resAry[i]);   //0.0254 为英寸和米的转换常数 //PPI 每英寸的像素点数
        }

        options = SuperMap.Util.extend({
            maxExtent: new SuperMap.Bounds(
                minX, minY, maxX, maxY
            ),
            tileOrigin:new SuperMap.LonLat(minX, maxY),
            resolutions:resAry
        }, options);

        SuperMap.CanvasLayer.prototype.initialize.apply(me, [me.name, me.url, null, options]);

        me.units = "m";
		//投影从非官方的900913改为3857
        me.projection = "EPSG:3857";
    },

    /**
     * APIMethod: clone
     * 创建当前图层的副本。
     *
     * Parameters:
     * obj - {Object}
     *
     * Returns:
     * {<SuperMap.Layer.Baidu>}  新的图层。
     */
    clone: function (obj) {
        var me = this;
        if (obj == null) {
            obj = new SuperMap.Layer.Baidu(
                me.name, me.url, me.params, me.getOptions());
        }

        obj = SuperMap.CanvasLayer.prototype.clone.apply(me, [obj]);
        obj._timeoutId = null;

        return obj;
    },

    getTileUrl:function(xyz){
        var me = this,
            url = me.url;

        /*
        var x = xyz.x + offsetXY[xyz.z].x;
        var y = offsetXY[xyz.z].y - xyz.y;

        var z = xyz.z + 3;
        var num = Math.abs((xyz.x + xyz.y) % 8);
        num++;
        */

        var zoom = xyz.z + me.zOffset;
        var offsetX = Math.pow(2, zoom-1);

        var offsetY = offsetX - 1;

        var numX = xyz.x - offsetX;

        var numY = -xyz.y + offsetY;

        var num =  Math.abs((xyz.x + xyz.y) % 8)+1;
        url = SuperMap.String.format(url, {
            num: num,
            x: numX,
            y: numY,
            z: zoom
        });
        url = url.replace(/-/g,"M");
        return url;
    },

    CLASS_NAME: 'SuperMap.Layer.Baidu'
});