//
//  CLLocationExt.swift
//  ExtensionKit
//
//  Created by FFIB on 2017/9/24.
//  Copyright © 2017年 FFIB. All rights reserved.
//

import UIKit
import CoreLocation
let a = 6378245.0
let ee = 0.00669342162296594323
//the world coordinate transformation to mars
extension CLLocation {
    public func transformationWorldCoordinateToMars() -> CLLocationCoordinate2D {
        let lat = coordinate.latitude
        let lon = coordinate.longitude
        if outOfChina() {
            return coordinate
        }
        var dLat = transformLatWithX(x: lon - 105.0, y: lat - 35.0)
        var dLon = transformLonWithY(x: lon - 105.0, y: lat - 35.0)
        let radLat = lat / 180.0 * .pi
        var magic = sin(radLat)
        magic = 1 - ee * magic * magic
        let sqrtMagic = sqrt(magic)
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * .pi)
        dLon = (dLon * 180.0) / (a / sqrtMagic * cos(radLat) * .pi)
        return CLLocationCoordinate2DMake(dLat + coordinate.latitude, dLon + coordinate.longitude)
    }
    
    //judge china
    public func outOfChina() -> Bool {
        guard case 72.005..<137.8347 = coordinate.longitude else{
            return true
        }
        guard case 0.8293..<55.8271 = coordinate.latitude else{
            return true
        }
        return false
    }
    
    public func transformLatWithX(x: Double, y: Double) -> Double {
        var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 *  sqrt(abs(x))
        ret += (20.0 * sin(6.0 * x * .pi) + 20.0 * sin(2.0 * x * .pi)) * 2.0 / 3.0
        ret += (20.0 * sin(y * .pi) + 40.0 * sin(y / 3.0 * .pi)) * 2.0 / 3.0
        ret += (160.0 * sin(y / 12.0 * .pi) + 320.0 * sin(y * .pi / 30.0)) * 2.0 / 3.0
        return ret
    }
    
    public func transformLonWithY(x: Double, y: Double) -> Double {
        var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * sqrt(abs(x))
        ret += (20.0 * sin(6.0 * x * .pi) + 20.0 * sin(2.0 * x * .pi)) * 2.0 / 3.0
        ret += (20.0 * sin(x * .pi) + 40.0 * sin(x / 3.0 * .pi)) * 2.0 / 3.0
        ret += (150.0 * sin(x / 12.0 * .pi) + 300.0 * sin(x / 30.0 * .pi)) * 2.0 / 3.0
        return ret
    }
}