Privado-iOS/iOS/Privado/Sources/Common/AsyncOperation.swift

//
//  AsyncOperation.swift
//  PrivadoVPN
//
//  Created by Juraldinio on 3/8/21.
//  Copyright © 2021 Privado LLC. All rights reserved.
//

import Foundation

open class AsyncOperation: Operation {
    
    enum State: String {
        case ready
        case executing
        case finished
        
        var keyPath: String { return "is\(self.rawValue.capitalized)" }
    }
    
    var state: State = .ready {
        willSet {
            self.willChangeValue(forKey: newValue.keyPath)
            self.willChangeValue(forKey: self.state.keyPath)
        }
        
        didSet {
            self.didChangeValue(forKey: oldValue.keyPath)
            self.didChangeValue(forKey: self.state.keyPath)
        }
    }
    
    // MARK: - Operation
    
    override open var isAsynchronous: Bool { true }
    
    override open var isReady: Bool { super.isReady && self.state == .ready }
    
    override open var isExecuting: Bool { self.state == .executing }
    
    override open var isFinished: Bool { self.state == .finished }
    
    override open func start() {
        
        guard !self.isCancelled else {
            self.state = .finished
            return
        }
        
        self.state = .executing
        
        self.main()
        
    }
    
    override open func cancel() {
        super.cancel()
        self.state = .finished
    }
    
}