//
// Copyright 2022 New Vector Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

import Combine
import SwiftUI

typealias SecureBackupRecoveryKeyScreenViewModelType = StateStoreViewModel<SecureBackupRecoveryKeyScreenViewState, SecureBackupRecoveryKeyScreenViewAction>

class SecureBackupRecoveryKeyScreenViewModel: SecureBackupRecoveryKeyScreenViewModelType, SecureBackupRecoveryKeyScreenViewModelProtocol {
    private let secureBackupController: SecureBackupControllerProtocol
    private let userIndicatorController: UserIndicatorControllerProtocol
    
    private var actionsSubject: PassthroughSubject<SecureBackupRecoveryKeyScreenViewModelAction, Never> = .init()
    var actions: AnyPublisher<SecureBackupRecoveryKeyScreenViewModelAction, Never> {
        actionsSubject.eraseToAnyPublisher()
    }

    init(secureBackupController: SecureBackupControllerProtocol, userIndicatorController: UserIndicatorControllerProtocol) {
        self.secureBackupController = secureBackupController
        self.userIndicatorController = userIndicatorController
        
        super.init(initialViewState: .init(mode: secureBackupController.recoveryKeyState.value.viewMode, bindings: .init()))
        
        secureBackupController.recoveryKeyState
            .receive(on: DispatchQueue.main)
            .sink(receiveValue: { [weak userIndicatorController] state in
                let loadingIndicatorIdentifier = "SecureBackupRecoveryKeyScreenLoading"
                switch state {
                case .settingUp:
                    userIndicatorController?.submitIndicator(.init(id: loadingIndicatorIdentifier, type: .modal, title: L10n.commonLoading, persistent: true))
                default:
                    userIndicatorController?.retractIndicatorWithId(loadingIndicatorIdentifier)
                }
            })
            .store(in: &cancellables)
    }
    
    // MARK: - Public
    
    override func process(viewAction: SecureBackupRecoveryKeyScreenViewAction) {
        MXLog.info("View model: received view action: \(viewAction)")
        
        switch viewAction {
        case .generateKey:
            Task {
                switch await secureBackupController.generateRecoveryKey() {
                case .success(let key):
                    state.recoveryKey = key
                case .failure(let error):
                    MXLog.error("Failed generating recovery key with error: \(error)")
                    state.bindings.alertInfo = .init(id: .init())
                }
            }
        case .copyKey:
            UIPasteboard.general.string = state.recoveryKey
            userIndicatorController.submitIndicator(.init(title: "Copied recovery key"))
            state.doneButtonEnabled = true
        case .keySaved:
            state.doneButtonEnabled = true
        case .confirmKey:
            Task {
                switch await secureBackupController.confirmRecoveryKey(state.bindings.confirmationRecoveryKey) {
                case .success:
                    actionsSubject.send(.done(mode: context.viewState.mode))
                case .failure(let error):
                    MXLog.error("Failed confirming recovery key with error: \(error)")
                    state.bindings.alertInfo = .init(id: .init())
                }
            }
        case .cancel:
            actionsSubject.send(.cancel)
        case .done:
            state.bindings.alertInfo = .init(id: .init(),
                                             title: L10n.screenRecoveryKeySetupConfirmationTitle,
                                             message: L10n.screenRecoveryKeySetupConfirmationDescription,
                                             primaryButton: .init(title: L10n.actionCancel, role: .cancel, action: nil),
                                             secondaryButton: .init(title: L10n.actionContinue, action: { [weak self] in
                                                 guard let self else { return }
                                                 actionsSubject.send(.done(mode: context.viewState.mode))
                                             }))
        }
    }
}

extension SecureBackupRecoveryKeyState {
    var viewMode: SecureBackupRecoveryKeyScreenViewMode {
        switch self {
        case .disabled:
            return .setupRecovery
        case .enabled:
            return .changeRecovery
        case .incomplete:
            return .fixRecovery
        default:
            fatalError("Invalid recovery state")
        }
    }
}