protocol ReverseGeocodingHelper {
    typealias CountryComparisonCompletion = (Bool, [Error]?) -> ()
    func checkIf(location firstLocation:CLLocation, inTheSameCountryAs secondLocation:CLLocation, completion:@escaping CountryComparisonCompletion)
}
class CoreLocationReverseGeocodingHelper : ReverseGeocodingHelper{

//    typealias CountryComparisonCompletion = (Bool, [Error]?) -> ()

    func checkIf(location firstLocation:CLLocation, inTheSameCountryAs secondLocation:CLLocation, completion:@escaping CountryComparisonCompletion){

        //Declare variables that we would use after
        var firstLocationCountry : String?
        var secondLocationCountry : String?
        var errorInFirstLocationReverseGeocodingRequest : Error?
        var errorInSecondLocationReverseGeocodingRequest : Error?

        //Declare the dispatch group
        let dispatchGroup = DispatchGroup()

        //Declare nested function for each of the locations
        func reverseGeocodeFirstLocation(){
            dispatchGroup.enter()
            CLGeocoder().reverseGeocodeLocation(firstLocation) { (placemarks, error) in
                firstLocationCountry = placemarks?.first?.country
                errorInFirstLocationReverseGeocodingRequest = error
                dispatchGroup.leave()
            }
        }
        func reverseGeocodeSecondLocation(){
            dispatchGroup.enter()
            CLGeocoder().reverseGeocodeLocation(secondLocation) { (placemarks, error) in
                secondLocationCountry = placemarks?.first?.country
                errorInFirstLocationReverseGeocodingRequest = error
                dispatchGroup.leave()
            }
        }


        //Do the work in a dispatch group
        //Both functions enter the same dispatch group, so call both
        reverseGeocodeFirstLocation()
        reverseGeocodeSecondLocation()

        let queue:DispatchQueue = DispatchQueue.global(qos: .userInteractive)
        dispatchGroup.notify(queue: queue) {
            //Completion will be called only after both items reverse geocoding finished
            let errors : [Error] = [errorInFirstLocationReverseGeocodingRequest,errorInSecondLocationReverseGeocodingRequest].compactMap{$0} //Map only non nil to the array
            if errors.count > 0{
                completion(false,errors)
            }else{
                print("First locations is in:\(firstLocationCountry!)\n Second locations is in:\(secondLocationCountry!)")
                let bothLocationsInSameCountry : Bool = firstLocationCountry! == secondLocationCountry!
                completion(bothLocationsInSameCountry,nil)
            }
        }

    }
}