/*
Copyright 2019-2024 New Vector Ltd.

SPDX-License-Identifier: AGPL-3.0-only
Please see LICENSE in the repository root for full details.
 */

import UIKit

@objcMembers
final class KeyBackupSetupCoordinator: KeyBackupSetupCoordinatorType {
    
    // MARK: - Properties
    
    // MARK: Private
    
    private let navigationRouter: NavigationRouterType
    private let session: MXSession
    private let isStartedFromSignOut: Bool
    
    // MARK: Public
    
    var childCoordinators: [Coordinator] = []
    
    weak var delegate: KeyBackupSetupCoordinatorDelegate?
    
    // MARK: - Setup
    
    init(session: MXSession, isStartedFromSignOut: Bool) {
        self.navigationRouter = NavigationRouter(navigationController: RiotNavigationController())
        self.session = session
        self.isStartedFromSignOut = isStartedFromSignOut
    }    
    
    // MARK: - Public methods
    
    func start() {
        if self.session.crypto.recoveryService.hasRecovery() {
            showUnlockSecureBackup()
        } else {
            showSetupIntro()
        }
    }
    
    func toPresentable() -> UIViewController {
        return self.navigationRouter.toPresentable()
    }
    
    // MARK: - Private methods
    
    private func showSetupIntro() {
        // Set key backup setup intro as root controller
        let keyBackupSetupIntroViewController = self.createSetupIntroViewController()
        keyBackupSetupIntroViewController.delegate = self
        self.navigationRouter.setRootModule(keyBackupSetupIntroViewController)
    }
    
    private func createSetupIntroViewController() -> KeyBackupSetupIntroViewController {
        
        let backupState = self.session.crypto?.backup?.state ?? MXKeyBackupStateUnknown
        let isABackupAlreadyExists: Bool
        
        switch backupState {
        case MXKeyBackupStateUnknown, MXKeyBackupStateDisabled, MXKeyBackupStateCheckingBackUpOnHomeserver:
            isABackupAlreadyExists = false
        default:
            isABackupAlreadyExists = true
        }
        
        let encryptionKeysExportPresenter: EncryptionKeysExportPresenter?
        
        if self.isStartedFromSignOut {
            encryptionKeysExportPresenter = EncryptionKeysExportPresenter(session: self.session)
        } else {
            encryptionKeysExportPresenter = nil
        }
        
        return KeyBackupSetupIntroViewController.instantiate(isABackupAlreadyExists: isABackupAlreadyExists, encryptionKeysExportPresenter: encryptionKeysExportPresenter)
    }
    
    private func showUnlockSecureBackup() {
        let recoveryGoal: SecretsRecoveryGoal = .unlockSecureBackup { (privateKey, completion) in
            self.createKeyBackupUsingSecureBackup(privateKey: privateKey, completion: completion)
        }
        
        let coordinator = SecretsRecoveryCoordinator(session: self.session, recoveryMode: .passphraseOrKey, recoveryGoal: recoveryGoal, navigationRouter: self.navigationRouter, cancellable: true)
        coordinator.delegate = self
        coordinator.start()
        self.add(childCoordinator: coordinator)
    }
    
    private func showSetupPassphrase(animated: Bool) {
        guard let keyBackup = self.session.crypto?.backup else {
            MXLog.failure("[KeyBackupSetupCoordinator] Cannot setup backups without backup module")
            return
        }
        
        let keyBackupSetupPassphraseCoordinator = KeyBackupSetupPassphraseCoordinator(keyBackup: keyBackup)
        keyBackupSetupPassphraseCoordinator.delegate = self
        keyBackupSetupPassphraseCoordinator.start()
        
        self.add(childCoordinator: keyBackupSetupPassphraseCoordinator)
        self.navigationRouter.push(keyBackupSetupPassphraseCoordinator, animated: animated) { [weak self] in
            self?.remove(childCoordinator: keyBackupSetupPassphraseCoordinator)
        }
    }
    
    private func showSetupRecoveryKeySuccess(with recoveryKey: String, animated: Bool) {

        let viewController = KeyBackupSetupSuccessFromRecoveryKeyViewController.instantiate(with: recoveryKey)
        viewController.delegate = self
        self.navigationRouter.push(viewController, animated: animated, popCompletion: nil)
    }
    
    private func showSetupPassphraseSuccess(with recoveryKey: String, animated: Bool) {
        
        let viewController = KeyBackupSetupSuccessFromPassphraseViewController.instantiate(with: recoveryKey)
        viewController.delegate = self
        self.navigationRouter.push(viewController, animated: animated, popCompletion: nil)
    }
    
    private func showSetupWithSecureBackupSuccess(animated: Bool) {
        let viewController = KeyBackupSetupSuccessFromSecureBackupViewController.instantiate()
        viewController.delegate = self
        self.navigationRouter.push(viewController, animated: animated, popCompletion: nil)
    }
    
    private func createKeyBackupUsingSecureBackup(privateKey: Data, completion: @escaping (Result<Void, Error>) -> Void) {
        guard let keyBackup = session.crypto?.backup, let recoveryService = session.crypto?.recoveryService else {
            return
        }
        
        keyBackup.prepareKeyBackupVersion(withPassword: nil, algorithm: nil, success: { megolmBackupCreationInfo in
            keyBackup.createKeyBackupVersion(megolmBackupCreationInfo, success: { _ in
                recoveryService.updateRecovery(forSecrets: [MXSecretId.keyBackup.takeUnretainedValue() as String], withPrivateKey: privateKey) {
                    completion(.success(Void()))
                } failure: { error in
                    completion(.failure(error))
                }
                
            }, failure: { error in
                completion(.failure(error))
            })
        }, failure: { error in
            completion(.failure(error))
        })
    }
}

// MARK: - KeyBackupSetupIntroViewControllerDelegate
extension KeyBackupSetupCoordinator: KeyBackupSetupIntroViewControllerDelegate {
    
    func keyBackupSetupIntroViewControllerDidTapSetupAction(_ keyBackupSetupIntroViewController: KeyBackupSetupIntroViewController) {
        self.showSetupPassphrase(animated: true)
    }
    
    func keyBackupSetupIntroViewControllerDidCancel(_ keyBackupSetupIntroViewController: KeyBackupSetupIntroViewController) {
        self.delegate?.keyBackupSetupCoordinatorDidCancel(self)
    }
}

// MARK: - KeyRecoveryPassphraseCoordinatorDelegate
extension KeyBackupSetupCoordinator: KeyBackupSetupPassphraseCoordinatorDelegate {
    func keyBackupSetupPassphraseCoordinator(_ keyBackupSetupPassphraseCoordinator: KeyBackupSetupPassphraseCoordinatorType, didCreateBackupFromPassphraseWithResultingRecoveryKey recoveryKey: String) {
        self.showSetupPassphraseSuccess(with: recoveryKey, animated: true)
    }
    
    func keyBackupSetupPassphraseCoordinator(_ keyBackupSetupPassphraseCoordinator: KeyBackupSetupPassphraseCoordinatorType, didCreateBackupFromRecoveryKey recoveryKey: String) {
        self.showSetupRecoveryKeySuccess(with: recoveryKey, animated: true)
    }
    
    func keyBackupSetupPassphraseCoordinatorDidCancel(_ keyBackupSetupPassphraseCoordinator: KeyBackupSetupPassphraseCoordinatorType) {
        self.delegate?.keyBackupSetupCoordinatorDidCancel(self)
    }
}

// MARK: - SecretsRecoveryCoordinatorDelegate
extension KeyBackupSetupCoordinator: SecretsRecoveryCoordinatorDelegate {
    func secretsRecoveryCoordinatorDidRecover(_ coordinator: SecretsRecoveryCoordinatorType) {
        self.showSetupWithSecureBackupSuccess(animated: true)
    }
    
    func secretsRecoveryCoordinatorDidCancel(_ coordinator: SecretsRecoveryCoordinatorType) {
        self.delegate?.keyBackupSetupCoordinatorDidCancel(self)
    }
}

// MARK: - KeyBackupSetupSuccessFromPassphraseViewControllerDelegate
extension KeyBackupSetupCoordinator: KeyBackupSetupSuccessFromPassphraseViewControllerDelegate {
    func keyBackupSetupSuccessFromPassphraseViewControllerDidTapDoneAction(_ viewController: KeyBackupSetupSuccessFromPassphraseViewController) {
        self.delegate?.keyBackupSetupCoordinatorDidSetupRecoveryKey(self)
    }
}

// MARK: - KeyBackupSetupSuccessFromRecoveryKeyViewControllerDelegate
extension KeyBackupSetupCoordinator: KeyBackupSetupSuccessFromRecoveryKeyViewControllerDelegate {
    func keyBackupSetupSuccessFromRecoveryKeyViewControllerDidTapDoneAction(_ viewController: KeyBackupSetupSuccessFromRecoveryKeyViewController) {
        self.delegate?.keyBackupSetupCoordinatorDidSetupRecoveryKey(self)
    }
}

// MARK: - KeyBackupSetupSuccessFromSecureBackupViewControllerDelegate
extension KeyBackupSetupCoordinator: KeyBackupSetupSuccessFromSecureBackupViewControllerDelegate {
    func keyBackupSetupSuccessFromSecureBackupViewControllerDidTapDoneAction(_ viewController: KeyBackupSetupSuccessFromSecureBackupViewController) {
        self.delegate?.keyBackupSetupCoordinatorDidSetupRecoveryKey(self)
    }
}