//
//  FirebasePushTokenService.swift
//  Malinka
//
//  Created by Nut.Tech on 21.02.2023.
//  Copyright © 2023 NUT.Tech. All rights reserved.
//

import Firebase
import FirebaseMessaging
import Combine
import WalletFoundation

final class FirebasePushTokenService: NSObject, ObservableObject, MessagingDelegate {
    
    private enum Constants {
        static let tokenLifetimeKey = "Firebase.service.pushToken.lifetime"
        static let tokenUpdateQueue = "Firebase.service.pushToken.queue.update"
    }
    
    @Published private (set) var token: String?
    private let firebaseTokenLifetime: ApplicationEnvironmentRecord.FirebaseLifetime
    private let tokenQueue = DispatchQueue(label: Constants.tokenUpdateQueue, qos: .background)
    
    init(tokenLifetime: ApplicationEnvironmentRecord.FirebaseLifetime) {
        self.firebaseTokenLifetime = tokenLifetime
        super.init()
        FirebaseApp.configure()
        Messaging.messaging().delegate = self
        self.updateTokenIfNeeded()
    }
    
    func updateAPNS(token: Data) {
        Messaging.messaging().apnsToken = token
    }
    
    private func updateTokenIfNeeded() {
        Task {
            let lastUpdate = UserDefaults.standard.value(forKey: Constants.tokenLifetimeKey) as? Date
            if !lastUpdate.isExist {
                await self.updateFirebaseToken()
                return
            }
            guard let lastUpdate, 
                    Date().timeIntervalSince(lastUpdate) >= Double(self.firebaseTokenLifetime.rawValue) else { return }
            await self.updateFirebaseToken()
        }
    }
    
    private func updateFirebaseToken() async {
        let error = await withCheckedContinuation { (continuation: CheckedContinuation<Error?, Never>) in
            Messaging.messaging().deleteToken { error in
                continuation.resume(returning: error)
            }
        }
        guard !error.isExist else { return }
        let token = try? await withCheckedThrowingContinuation { (continuation: CheckedContinuation<String?, Error>) in
            Messaging.messaging().token { token, error in
                if let error {
                    continuation.resume(throwing: error)
                } else {
                    continuation.resume(returning: token)
                }
            }
        }
        
        guard token.isExist else { return }
        UserDefaults.standard.set(Date(), forKey: Constants.tokenLifetimeKey)
    }
    
    // MARK: - MessagingDelegate
    
    func messaging(_ messaging: Messaging, didReceiveRegistrationToken fcmToken: String?) {
        self.token = fcmToken
    }
}