//
//  FetchingServersOperation.swift
//  PrivadoVPN
//
//  Created by Juraldinio on 3/20/21.
//  Copyright © 2021 Privado LLC. All rights reserved.
//

import Foundation

protocol FetchingServersOperationOutput {
    var result: Result<MainInteractorResult, Error>? { get }
}

final class FetchingServersOperation: AsyncOperation {
    
    enum OperationError: Error {
        case cancelled
    }
    
    private(set) var result: Result<MainInteractorResult, Error>? // FetchingServersOperationOutput
    private let interactor: MainInteractorInput
    
    init(interactor: MainInteractorInput) {
        self.interactor = interactor
    }
    
    // MARK: - AsyncOperation
    
    override func main() {
        
        guard !self.isCancelled else {
            self.result = Result.failure(OperationError.cancelled)
            return
        }
        
        self.interactor.fetchServers { [weak self] result in
            
            guard let self = self else { return }
            
            guard !self.isCancelled else {
                self.result = Result.failure(OperationError.cancelled)
                self.state = .finished
                return
            }
            
            self.result = result
            self.state = .finished
        }
        
    }
    
    override func cancel() {
        self.result = Result.failure(OperationError.cancelled)
        super.cancel()
    }
    
}

extension FetchingServersOperation: FetchingServersOperationOutput { }