//
//  ConnectionPanelPresenter.swift
//  PrivadoVPN
//
//  Created by Juraldinio on 1/31/21.
//  Copyright © 2021 Privado LLC. All rights reserved.
//

import Foundation

enum ConnectionPanelState: Equatable {
    case undefined
    case connecting
    case connected(ip: String, secured: Bool)
    case disconnecting
    case disconnected(ip: String, city: String, country: String)
    case reconnecting
}

protocol ConnectionPanelOutput: AnyObject {
    var updateEmitter: Emitter<Void> { get }
    
    func connectServer()
    func disconnectServer()
    func update(for panel: ConnectionPanelInput)
    
    func navigate(to route: Route)
}

protocol ConnectionPanelInput {
    func update(state: ConnectionPanelState)
}

final class ConnectionPanelPresenter {
    
    private enum Constants {
        
        enum LocalizedString {
            static let connecting = "connection.status.connecting"
            static let connected = "connection.status.connected"
            static let disconnecting = "connection.status.disconnecting"
            static let disconnected = "connection.status.disconnected"
            static let reconnecting = "connection.status.reconnecting"
        }
    }
    
    private weak var output: ConnectionPanelOutput?
    weak var viewInput: ConnectionPanelViewInput?
    
    private var state: ConnectionPanelState = .undefined
    
    // MARK: - Init
    
    init(output: ConnectionPanelOutput?) {
        self.output = output
        
        self.output?.updateEmitter.addReaction { [weak self] _ -> ShouldContinueReceiveNotifications in
            guard let self = self else { return false }
            self.output?.update(for: self)
            return true
        }
    }
    
}

// MARK: - ConnectionPanelInput

extension ConnectionPanelPresenter: ConnectionPanelInput {
    
    func update(state: ConnectionPanelState) {
        
        self.state = state
        
        guard let viewInput = self.viewInput else { return }
        
        switch state {
        case .undefined:
            viewInput.hide()
        case .connecting:
            viewInput.interactionEnabled(false)
            viewInput.progress(status: NSLocalizedString(Constants.LocalizedString.connecting, comment: ""), type: .connecting)
        case .disconnecting:
            viewInput.interactionEnabled(false)
            viewInput.progress(status: NSLocalizedString(Constants.LocalizedString.disconnecting, comment: ""), type: .disconnecting)
        case let .connected(ip: ip, secured: secured):
            viewInput.location(connected: true,
                               ip: "IP \(ip)",
                               city: "",
                               secured: secured,
                               status: NSLocalizedString(Constants.LocalizedString.connected, comment: ""))
            viewInput.interactionEnabled(true)
            self.output?.navigate(to: .show)
        case let .disconnected(ip: ip, city: city, country: country):
            viewInput.location(connected: false,
                               ip: "IP \(ip)",
                               city: city.isEmpty ? country : "\(city), \(CountryResolver.code(from: country))",
                               secured: false,
                               status: NSLocalizedString(Constants.LocalizedString.disconnected, comment: ""))
            viewInput.interactionEnabled(true)
        case .reconnecting:
            viewInput.interactionEnabled(false)
            viewInput.progress(status: NSLocalizedString(Constants.LocalizedString.reconnecting, comment: ""), type: .reconnecting)
        }
    }
}

// MARK: - ConnectionPanelViewOutput

extension ConnectionPanelPresenter: ConnectionPanelViewOutput {
    
    func viewIsReady() {
        self.output?.update(for: self)
    }
    
    func viewWillDisappear() { }
    
    func viewConnectButtonClicked() {
        switch self.state {
        case .connected:
            self.output?.disconnectServer()
        case .disconnected:
            self.output?.connectServer()
        default: break
        }
    }
}