//
//  SwiftUIView.swift
//  Nextcloud
//
//  Created by Milen on 21.05.24.
//  Copyright © 2024 Marino Faggiana. All rights reserved.
//
//  Author Marino Faggiana <marino.faggiana@nextcloud.com>
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

import NextcloudKit
import SwiftUI

struct NCLoginPoll: View {
    let loginFlowV2Token: String
    let loginFlowV2Endpoint: String
    let loginFlowV2Login: String

    var cancelButtonDisabled = false

    @ObservedObject private var loginManager = LoginManager()
    @Environment(\.dismiss) private var dismiss

    var body: some View {
        VStack {
            Text(NSLocalizedString("_poll_desc_", comment: ""))
                .multilineTextAlignment(.center)
                .foregroundStyle(.white)
                .padding()

            ProgressView()
                .scaleEffect(1.5)
                .tint(.white)
                .padding()

            HStack {
                Button(NSLocalizedString("_cancel_", comment: "")) {
                    dismiss()
                }
                .disabled(loginManager.isLoading || cancelButtonDisabled)
                .buttonStyle(.bordered)
                .tint(.white)

                Button(NSLocalizedString("_retry_", comment: "")) {
                    loginManager.openLoginInBrowser()
                }
                .buttonStyle(.borderedProminent)
                .foregroundStyle(Color(NCBrandColor.shared.customer))
                .tint(.white)
            }
            .padding()
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .onChange(of: loginManager.pollFinished) { value in
            if value {
                let window = UIApplication.shared.firstWindow
                if let controller = window?.rootViewController as? NCMainTabBarController {
                    controller.account = loginManager.account
                    controller.dismiss(animated: true, completion: nil)
                } else {
                    if let controller = UIStoryboard(name: "Main", bundle: nil).instantiateInitialViewController() as? NCMainTabBarController {
                        controller.account = loginManager.account
                        controller.modalPresentationStyle = .fullScreen
                        controller.view.alpha = 0

                        window?.rootViewController = controller
                        window?.makeKeyAndVisible()

                        if let scene = window?.windowScene {
                            SceneManager.shared.register(scene: scene, withRootViewController: controller)
                        }

                        UIView.animate(withDuration: 0.5) {
                            controller.view.alpha = 1
                        }
                    }
                }
            }
        }
        .background(Color(NCBrandColor.shared.customer))
        .onAppear {
            loginManager.configure(loginFlowV2Token: loginFlowV2Token, loginFlowV2Endpoint: loginFlowV2Endpoint, loginFlowV2Login: loginFlowV2Login)

            if !isRunningForPreviews {
                loginManager.openLoginInBrowser()
            }
        }
        .onDisappear {
            loginManager.onDisappear()
        }
        .interactiveDismissDisabled()
    }
}

#Preview {
    NCLoginPoll(loginFlowV2Token: "", loginFlowV2Endpoint: "", loginFlowV2Login: "")
}

private class LoginManager: ObservableObject {
    var loginFlowV2Token = ""
    var loginFlowV2Endpoint = ""
    var loginFlowV2Login = ""

    @Published var pollFinished = false
    @Published var isLoading = false
    @Published var account = ""

    var timer: DispatchSourceTimer?

    func configure(loginFlowV2Token: String, loginFlowV2Endpoint: String, loginFlowV2Login: String) {
        self.loginFlowV2Token = loginFlowV2Token
        self.loginFlowV2Endpoint = loginFlowV2Endpoint
        self.loginFlowV2Login = loginFlowV2Login

        poll()
    }

    func poll() {
        let queue = DispatchQueue.global(qos: .background)
        timer = DispatchSource.makeTimerSource(queue: queue)

        guard let timer = timer else { return }

        timer.schedule(deadline: .now(), repeating: .seconds(1), leeway: .seconds(1))
        timer.setEventHandler(handler: {
            DispatchQueue.main.async {
                let controller = UIApplication.shared.firstWindow?.rootViewController as? NCMainTabBarController
                NextcloudKit.shared.getLoginFlowV2Poll(token: self.loginFlowV2Token, endpoint: self.loginFlowV2Endpoint) { server, loginName, appPassword, _, error in
                    if error == .success, let urlBase = server, let user = loginName, let appPassword {
                        self.isLoading = true
                        NCAccount().createAccount(urlBase: urlBase, user: user, password: appPassword, controller: controller) { account, error in
                            if error == .success {
                                self.account = account
                                self.pollFinished = true
                            }
                        }
                    }
                }
            }
        })

        timer.resume()
    }

    func onDisappear() {
        timer?.cancel()
    }

    func openLoginInBrowser() {
        UIApplication.shared.open(URL(string: loginFlowV2Login)!)
    }
}