/**
 * Created by bingqx on 2016/12/25.
 */
'use strict';

const {Cartesian3, Cartographic, WebMercatorProjection, SceneTransforms, CesiumMath} = require('cesium');


/**
 * 坐标转换类
 * @param {Object} viewer 地球容器
 * @constructor
 */
function CoorTrans(viewer) {
    this._viewer = viewer;
    this._wmp = new WebMercatorProjection();
}

/**
 * 屏幕坐标转世界坐标
 * @param {Number} [screenX] 屏幕坐标x
 * @param {Number} [screenY] 屏幕坐标y
 * @returns {Cartesian3} 世界坐标
 */
CoorTrans.prototype.fromScreenToCartesian3 = function (screenX, screenY) {
    let pick = new Cartesian2(screenX, screenY);
    if (this._viewer.scene.mode === 3) {
        return this._viewer.scene.globe.pick(this._viewer.camera.getPickRay(pick), this._viewer.scene);
    } else {
        return this._viewer.camera.pickEllipsoid(pick, this._viewer.scene.globe.ellipsoid);
    }
};

/**
 * 世界坐标转地理坐标（弧度）
 * @param {Cartesian3} [cartesian] 世界坐标
 * @returns {Cartographic} 地理坐标（弧度）
 */
CoorTrans.prototype.fromCartesian3ToCartographic = function (cartesian) {
    return this._viewer.scene.globe.ellipsoid.cartesianToCartographic(cartesian);
};

/**
 * 世界坐标转屏幕坐标
 * @param {Cartesian3} [cartesian] 世界坐标
 * @returns {Cartesian2} 屏幕坐标
 */
CoorTrans.prototype.fromCartesian3ToScreen = function (cartesian) {
    return SceneTransforms.wgs84ToWindowCoordinates(this._viewer.scene, cartesian);
};

/**
 * 世界坐标转经纬度坐标
 * @param {Cartesian3} cartesian  世界坐标
 * @returns {Object} 经纬度坐标
 */
CoorTrans.prototype.fromCartesian3ToDegree = function (cartesian) {
    let cartographic = this.fromCartesian3ToCartographic(cartesian);
    return this.fromCartographicToDegree(cartographic)
};

/**
 * 地理坐标（弧度）转经纬度坐标
 * @param {Cartographic} [cartographic] 地理坐标（弧度）
 * @returns {Object} 经纬度坐标
 */
CoorTrans.prototype.fromCartographicToDegree = function (cartographic) {
    return {
        "lon": CesiumMath.toDegrees(cartographic.longitude),
        "lat": CesiumMath.toDegrees(cartographic.latitude),
        "height": cartographic.height
    }
};

/**
 * 地理坐标（弧度）转世界坐标
 * @param {Cartographic} [cartographic] 地理坐标（弧度）
 * @returns {Cartesian3} 世界坐标
 */
CoorTrans.prototype.fromCartographicToCartesian3 = function (cartographic) {
    return this._viewer.scene.globe.ellipsoid.cartographicToCartesian(cartographic);
};

/**
 * 经纬度坐标转地理坐标（弧度）
 * @param {Object} [degrees] 经纬度坐标
 * @returns {Cartographic} 地理坐标（弧度）
 */
CoorTrans.prototype.fromDegreesToCartographic = function (degrees) {
    return Cartographic.fromDegrees(degrees.lon, degrees.lat, degrees.height);
};

/**
 * 经纬度转世界坐标
 * @param {Object} [degrees] 经纬度坐标
 * @returns {Cartesian3} 世界坐标
 */
CoorTrans.prototype.fromDegreesToCartesian3 = function (degrees) {
    return Cartesian3.fromDegrees(degrees.lon, degrees.lat, degrees.height);
};

/**
 * WGS84坐标转墨卡托
 * @param {Cartographic} cartographic 经纬度（弧度）
 * @returns {Cartesian3} 墨卡托坐标，单位米
 */
CoorTrans.prototype.fromWGS84ToMercator = function (cartographic) {
    return this._wmp.project(cartographic);
};

/**
 * 墨卡托坐标转WGS84
 * @param {Cartesian3} cartesian 墨卡托坐标，单位米，例如new Cartesian3(x,y,0)
 * @returns {Cartographic} 经纬度（弧度）
 */
CoorTrans.prototype.fromMercatorToWGS84 = function (cartesian) {
    return this._wmp.unproject(cartesian)
};

module.exports = {
    CoorTrans: CoorTrans
};