export default {
    cartesianToLnglat:(cartesian)=>{
      //  //笛卡尔空间坐标转WGS84弧度.
      //  const ellipsoid84 = Cesium.Ellipsoid.wgs84;
      //  const cartographicPosition = ellipsoid84.cartesianToCartographic(cartesian);
      const cartographicPosition = Cesium.Cartographic.fromCartesian(cartesian);
  
      return [
        Cesium.Math.toDegrees(cartographicPosition.longitude),
        Cesium.Math.toDegrees(cartographicPosition.latitude),
      ]
    },
    getCenterByPositions:(cartesianArr)=>{
        let points = [];
        cartesianArr.forEach(cartesianCoor=>{
            let cartesian = new Cesium.Cartesian3(cartesianCoor.x, cartesianCoor.y, cartesianCoor.z)
            points.push(cUtil.cartesianToLnglat(cartesian))
        })
        var features = turf.points(points);
        let center = turf.center(features);
        return center.geometry.coordinates;
    },
    /**
     * 全局唯一标识符（GUID，Globally Unique Identifier）也称作 UUID(Universally Unique IDentifier) 。
     * 可以指定长度
     * @param len
     * @param radix
     * @returns {string}
     */
    uuid:function(len, radix) {
        var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');
        var uuid = [], i;
        radix = radix || chars.length;
        if (len) {
            // Compact form
            for (i = 0; i < len; i++) uuid[i] = chars[0 | Math.random()*radix];
        } else {
            // rfc4122, version 4 form
            var r;
            // rfc4122 requires these characters
            uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';
            uuid[14] = '4';
            // Fill in random data.  At i==19 set the high bits of clock sequence as
            // per rfc4122, sec. 4.1.5
            for (i = 0; i < 36; i++) {
                if (!uuid[i]) {
                    r = 0 | Math.random() * 16;
                    uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r];
                }
            }
        }
        return uuid.join('');
    },
    focus:(data,angle=-45,h=200)=>{
        const length = (Math.PI * Cesium.Ellipsoid.WGS84.minimumRadius) / 180;
        let dist = h/Math.tan( Math.abs(angle) * Math.PI/180)/length;
        viewer.camera.flyTo({
            destination : Cesium.Cartesian3.fromDegrees(data.lng, data.lat-dist, 200.0),
            orientation: {
                heading: 0.0,
                pitch: Cesium.Math.toRadians(angle),
                roll: 0.0,
            },
        });
    },
  }
// 对Date的扩展，将 Date 转化为指定格式的String
// 月(M)、日(d)、小时(h)、分(m)、秒(s)、季度(q) 可以用 1-2 个占位符，
// 年(y)可以用 1-4 个占位符，毫秒(S)只能用 1 个占位符(是 1-3 位的数字)
// 例子：
// (new Date()).Format("yyyy-MM-dd hh:mm:ss.S") ==> 2006-07-02 08:09:04.423
// (new Date()).Format("yyyy-M-d h:m:s.S")      ==> 2006-7-2 8:9:4.18
Date.prototype.Format = function (fmt) { //author: meizz
    var o = {
        "M+": this.getMonth() + 1, //月份
        "d+": this.getDate(), //日
        "h+": this.getHours(), //小时
        "m+": this.getMinutes(), //分
        "s+": this.getSeconds(), //秒
        "q+": Math.floor((this.getMonth() + 3) / 3), //季度
        "S": this.getMilliseconds() //毫秒
    };
    if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
    for (var k in o)
        if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
    return fmt;
}