layui.define(['layer'],function (exports) {
    var $ = layui.jquery,
        layer=layui.layer,
        MOD_NAME = "locationX";

    var GPS = {
        PI : 3.14159265358979324,
        x_pi : 3.14159265358979324 * 3000.0 / 180.0,
        delta : function (lat, lon) {
            // Krasovsky 1940
            //
            // a = 6378245.0, 1/f = 298.3
            // b = a * (1 - f)
            // ee = (a^2 - b^2) / a^2;
            var a = 6378245.0; //  a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
            var ee = 0.00669342162296594323; //  ee: 椭球的偏心率。
            var dLat = this.transformLat(lon - 105.0, lat - 35.0);
            var dLon = this.transformLon(lon - 105.0, lat - 35.0);
            var radLat = lat / 180.0 * this.PI;
            var magic = Math.sin(radLat);
            magic = 1 - ee * magic * magic;
            var sqrtMagic = Math.sqrt(magic);
            dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * this.PI);
            dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * this.PI);
            return {'lat': dLat, 'lon': dLon};
        },

        //WGS-84 to GCJ-02
        gcj_encrypt : function (wgsLat, wgsLon) {
            if (this.outOfChina(wgsLat, wgsLon))
                return {'lat': wgsLat, 'lon': wgsLon};

            var d = this.delta(wgsLat, wgsLon);
            return {'lat' : wgsLat + d.lat,'lon' : wgsLon + d.lon};
        },
        //GCJ-02 to WGS-84
        gcj_decrypt : function (gcjLat, gcjLon) {
            if (this.outOfChina(gcjLat, gcjLon))
                return {'lat': gcjLat, 'lon': gcjLon};

            var d = this.delta(gcjLat, gcjLon);
            return {'lat': gcjLat - d.lat, 'lon': gcjLon - d.lon};
        },
        //GCJ-02 to WGS-84 exactly
        gcj_decrypt_exact : function (gcjLat, gcjLon) {
            var initDelta = 0.01;
            var threshold = 0.000000001;
            var dLat = initDelta, dLon = initDelta;
            var mLat = gcjLat - dLat, mLon = gcjLon - dLon;
            var pLat = gcjLat + dLat, pLon = gcjLon + dLon;
            var wgsLat, wgsLon, i = 0;
            while (1) {
                wgsLat = (mLat + pLat) / 2;
                wgsLon = (mLon + pLon) / 2;
                var tmp = this.gcj_encrypt(wgsLat, wgsLon)
                dLat = tmp.lat - gcjLat;
                dLon = tmp.lon - gcjLon;
                if ((Math.abs(dLat) < threshold) && (Math.abs(dLon) < threshold))
                    break;

                if (dLat > 0) pLat = wgsLat; else mLat = wgsLat;
                if (dLon > 0) pLon = wgsLon; else mLon = wgsLon;

                if (++i > 10000) break;
            }
            //console.log(i);
            return {'lat': wgsLat, 'lon': wgsLon};
        },
        //GCJ-02 to BD-09
        bd_encrypt : function (gcjLat, gcjLon) {
            var x = gcjLon, y = gcjLat;
            var z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * this.x_pi);
            var theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * this.x_pi);
            bdLon = z * Math.cos(theta) + 0.0065;
            bdLat = z * Math.sin(theta) + 0.006;
            return {'lat' : bdLat,'lon' : bdLon};
        },
        //BD-09 to GCJ-02
        bd_decrypt : function (bdLat, bdLon) {
            var x = bdLon - 0.0065, y = bdLat - 0.006;
            var z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * this.x_pi);
            var theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * this.x_pi);
            var gcjLon = z * Math.cos(theta);
            var gcjLat = z * Math.sin(theta);
            return {'lat' : gcjLat, 'lon' : gcjLon};
        },
        //
        bd_WGS84:function(bdLat, bdLon){
            var gcj=GPS.bd_decrypt(bdLat, bdLon);
            return GPS.gcj_decrypt(gcj.lat,gcj.lon);
        },
        // 天地图坐标->百度坐标
        WGS84_bd:function(bdLat, bdLon){
            var gcj=GPS.gcj_encrypt(bdLat, bdLon);
            return GPS.bd_encrypt(gcj.lat,gcj.lon);
        },
        //WGS-84 to Web mercator
        //mercatorLat -> y mercatorLon -> x
        mercator_encrypt : function(wgsLat, wgsLon) {
            var x = wgsLon * 20037508.34 / 180.;
            var y = Math.log(Math.tan((90. + wgsLat) * this.PI / 360.)) / (this.PI / 180.);
            y = y * 20037508.34 / 180.;
            return {'lat' : y, 'lon' : x};
            /*
             if ((Math.abs(wgsLon) > 180 || Math.abs(wgsLat) > 90))
             return null;
             var x = 6378137.0 * wgsLon * 0.017453292519943295;
             var a = wgsLat * 0.017453292519943295;
             var y = 3189068.5 * Math.log((1.0 + Math.sin(a)) / (1.0 - Math.sin(a)));
             return {'lat' : y, 'lon' : x};
             //*/
        },
        // Web mercator to WGS-84
        // mercatorLat -> y mercatorLon -> x
        mercator_decrypt : function(mercatorLat, mercatorLon) {
            var x = mercatorLon / 20037508.34 * 180.;
            var y = mercatorLat / 20037508.34 * 180.;
            y = 180 / this.PI * (2 * Math.atan(Math.exp(y * this.PI / 180.)) - this.PI / 2);
            return {'lat' : y, 'lon' : x};
            /*
             if (Math.abs(mercatorLon) < 180 && Math.abs(mercatorLat) < 90)
             return null;
             if ((Math.abs(mercatorLon) > 20037508.3427892) || (Math.abs(mercatorLat) > 20037508.3427892))
             return null;
             var a = mercatorLon / 6378137.0 * 57.295779513082323;
             var x = a - (Math.floor(((a + 180.0) / 360.0)) * 360.0);
             var y = (1.5707963267948966 - (2.0 * Math.atan(Math.exp((-1.0 * mercatorLat) / 6378137.0)))) * 57.295779513082323;
             return {'lat' : y, 'lon' : x};
             //*/
        },
        // two point's distance
        distance : function (latA, lonA, latB, lonB) {
            var earthR = 6371000.;
            var x = Math.cos(latA * this.PI / 180.) * Math.cos(latB * this.PI / 180.) * Math.cos((lonA - lonB) * this.PI / 180);
            var y = Math.sin(latA * this.PI / 180.) * Math.sin(latB * this.PI / 180.);
            var s = x + y;
            if (s > 1) s = 1;
            if (s < -1) s = -1;
            var alpha = Math.acos(s);
            var distance = alpha * earthR;
            return distance;
        },
        outOfChina : function (lat, lon) {
            if (lon < 72.004 || lon > 137.8347)
                return true;
            if (lat < 0.8293 || lat > 55.8271)
                return true;
            return false;
        },
        transformLat : function (x, y) {
            var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
            ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0;
            ret += (20.0 * Math.sin(y * this.PI) + 40.0 * Math.sin(y / 3.0 * this.PI)) * 2.0 / 3.0;
            ret += (160.0 * Math.sin(y / 12.0 * this.PI) + 320 * Math.sin(y * this.PI / 30.0)) * 2.0 / 3.0;
            return ret;
        },
        transformLon : function (x, y) {
            var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
            ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0;
            ret += (20.0 * Math.sin(x * this.PI) + 40.0 * Math.sin(x / 3.0 * this.PI)) * 2.0 / 3.0;
            ret += (150.0 * Math.sin(x / 12.0 * this.PI) + 300.0 * Math.sin(x / 30.0 * this.PI)) * 2.0 / 3.0;
            return ret;
        }
    };

    exports(MOD_NAME,GPS);

})
