import SwiftUI
import APNSwift
import Push
import PushMessageDefinitions
import SFSafeSymbols

struct ContentView: View {
    
    @AppStorage("pushToken")
    var pushToken: PushToken?

    var hasPushToken: Bool {
        pushToken != nil
    }
    
    @AppStorage("authToken")
    var authToken: AuthenticationToken?
    
    @State
    var isConfirmed = false

    @State
    var hasNotificationPermissions: Bool? = nil
    
    @State
    var showDeviceList = false

    @State
    var api: PushClient?

    @AppStorage("server")
    var server: String = ""

    @AppStorage("application")
    var application = ""

    @AppStorage("deviceName")
    var deviceName: String = ""

    @State
    var deviceList: [DeviceRegistration] = []

    var couldBeRegistered: Bool {
        pushToken != nil && authToken != nil
    }

    @AppStorage("pushTitle")
    var pushMessageTitle: String = ""

    @AppStorage("pushBody")
    var pushMessageText: String = ""

    @State
    var includeOwnDeviceInPush = false

    var canSendNotification: Bool {
        isConfirmed && (includeOwnDeviceInPush || deviceList.count > 1)
    }

    func statusView(_ state: Bool?) -> some View {
        let symbol: SFSymbol
        let color: Color
        if let state = state {
            symbol = state ? .checkmarkCircle : .xmarkCircle
            color = state ? .green : .red
        } else {
            symbol = .questionmarkCircle
            color = .gray
        }
        return Image(systemSymbol: symbol)
            .renderingMode(.template)
            .foregroundColor(color)
    }

    func updateNotificationPermissionState() {
        Task {
            let state = await getPushPermissionState()
            DispatchQueue.main.async {
                hasNotificationPermissions = state
            }
        }
    }

    private func getPushPermissionState() async -> Bool? {
        let settings = await UNUserNotificationCenter.current().notificationSettings()
        switch settings.authorizationStatus {
        case .authorized, .provisional, .ephemeral:
            return true
        case .denied:
            return false
        case .notDetermined:
            return nil
        @unknown default:
            return nil
        }
    }
    
    var body: some View {
        NavigationView {
            VStack(spacing: 8) {
                HStack {
                    statusView(hasPushToken)
                    Text("remote-notifications-title")
                }
                HStack {
                    statusView(hasNotificationPermissions)
                    Text("notification-permissions-title")
                }
                HStack {
                    statusView(authToken != nil)
                    Text("push-server-registration-title")
                }
                HStack {
                    statusView(deviceList.count > 1)
                    Text("other-devices-title")
                }
                if pushToken == nil {
                    Text("register-for-remote-notifications-text")
                        .padding()
                        .multilineTextAlignment(.center)
                    Button("register-for-remote-notifications-button", action: registerForRemoteNotifications)
                        .padding()
                } else if hasNotificationPermissions == nil {
                    Button("request-notification-permission-button", action: requestNotificationPermission)
                        .padding()
                } else if hasNotificationPermissions == false {
                    Text("no-notification-permissions-text")
                        .padding()
                        .multilineTextAlignment(.center)
                    Button("no-notification-permissions-button", action: openNotificationSettings)
                        .padding()
                } else if authToken == nil {
                    Text("register-device-text")
                        .padding()
                    TextEntryField("Server url", placeholder: "register-device-server-placeholder", symbol: .network, showClearButton: true, text: $server)
                        .padding(.horizontal, 50)
                        .padding(.top)
                    TextEntryField("Application", placeholder: "register-device-application-placeholder", symbol: .questionmarkApp, showClearButton: true, text: $application)
                        .padding(.horizontal, 50)
                        .padding(.top)
                    TextEntryField("Device name", placeholder: "register-device-name-placeholder", symbol: .iphone, text: $deviceName)
                        .padding(.horizontal, 50)
                        .padding(.top)
                    Button("register-device-button", action: register)
                        .disabled(pushToken == nil || authToken != nil || deviceName.isEmpty)
                        .padding()
                } else {
                    Text("push-message-description")
                        .padding()
                    TextEntryField("Push title", placeholder: "push-message-title-placeholder", symbol: .bubbleLeft, showClearButton: true, text: $pushMessageTitle)
                        .padding(.horizontal, 50)
                        .disabled(!isConfirmed)
                    TextEntryField("Push text", placeholder: "push-message-placeholder", symbol: .textformat, showClearButton: true, text: $pushMessageText)
                        .padding(.horizontal, 50)
                        .disabled(!isConfirmed)
                    Toggle("toggle-include-own-device-text", isOn: $includeOwnDeviceInPush)
                        .padding(.horizontal, 50)
                        .padding(.top)
                    Button("send-notification-button", action: sendPush)
                        .disabled(!canSendNotification)
                        .padding()
                    Button("show-device-list-button", action: showDevices)
                        .disabled(!isConfirmed)
                        .padding()
                }
                Spacer()
            }
            .navigationTitle("FlurSchnaps")
        }
        .sheet(isPresented: $showDeviceList) {
            if let push = pushToken, let auth = authToken, let api = api {
                DeviceList(pushToken: push,
                           authToken: auth,
                           api: api,
                           isPresented: $showDeviceList,
                           devices: deviceList)
            }
        }.onAppear {
            startPeriodicUpdates()
            if server == "" {
                server = "https://christophhagen.de/push"
            }
            if application == "" {
                application = "FlurSchnaps"
            }
            if pushMessageTitle == "" {
                pushMessageTitle = "Flur-Schnaps"
            }
            if pushMessageText == "" {
                pushMessageText = "Du hast 30 Sekunden, um im Flur zu erscheinen"
            }
        }.onDisappear {
            stopPeriodicUpdates()
        }
    }

    @State
    private var timer: Timer?

    private func startPeriodicUpdates() {
        guard timer == nil else {
            return
        }
        timer = Timer.scheduledTimer(withTimeInterval: 5, repeats: true) { _ in
            updateState()
        }
        updateState()
    }

    private func stopPeriodicUpdates() {
        timer?.invalidate()
        timer = nil
    }

    private func updateState() {
        updateNotificationPermissionState()
        if isConfirmed {
            updateDeviceList()
        } else if couldBeRegistered {
            checkPushRegistrationStatus()
        }
    }

    func registerForRemoteNotifications() {
        UIApplication.shared.registerForRemoteNotifications()
    }

    func requestNotificationPermission() {
        let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
        UNUserNotificationCenter.current().requestAuthorization(
            options: authOptions,
            completionHandler: {_, _ in
                updateNotificationPermissionState()
            })
    }

    func openNotificationSettings() {
        if let appSettings = URL(string: UIApplication.openSettingsURLString), UIApplication.shared.canOpenURL(appSettings) {
            UIApplication.shared.open(appSettings)
        }
    }

    func register() {
        guard let token = pushToken else {
            print("No token to register")
            return
        }
        guard let url = URL(string: server) else {
            return
        }
        let api = PushClient(server: url, application: application)
        self.api = api
        let name = deviceName
        Task {
            print("Registering...")
            guard let auth = await api.register(token: token, name: name) else {
                DispatchQueue.main.async {
                    authToken = nil
                    isConfirmed = false
                }
                return
            }
            print("Registered")
            DispatchQueue.main.async {
                authToken = auth
                isConfirmed = false
                updateDeviceList()
            }
        }
    }
    
    func checkPushRegistrationStatus() {
        guard let token = pushToken,
              let authToken = authToken,
              let api = api else {
            return
        }
        Task {
            let confirmed = await api.isConfirmed(token: token, authentication: authToken)
            if !confirmed {
                print(token.base64EncodedString())
                print(authToken.base64EncodedString())
            }
            DispatchQueue.main.async {
                isConfirmed = confirmed
            }
        }
    }

    func updateDeviceList() {
        guard let authToken = authToken,
              let pushToken = pushToken,
              let api = api else {
            return
        }
        Task {
            let devices = await api.getDeviceList(pushToken: pushToken, authToken: authToken)
            DispatchQueue.main.async {
                self.deviceList = devices ?? []
            }
        }
    }
    
    func showDevices() {
        showDeviceList = true
    }
    
    func sendPush() {
        guard let authToken = authToken,
              let pushToken = pushToken,
              let api = api else {
            return
        }

        var recipients = deviceList.map { $0.pushToken }
        guard recipients.count > 0 else {
            return
        }
        if !includeOwnDeviceInPush {
            recipients = recipients.filter { $0 != pushToken }
        }
        let body = pushMessageText
        let alert = APNSwiftAlert(
            title: pushMessageTitle,
            body: body)
        let payload = APNSwiftPayload(
            alert: alert,
            sound: .normal("default"))
        let content = PushMessage(
            recipients: recipients,
            payload: payload,
            pushType: .alert)
        let sender = DeviceAuthentication(
            pushToken: pushToken,
            authentication: authToken)
        let message = AuthenticatedPushMessage(
            sender: sender,
            message: content)
        Task {
            let sent = await api.send(push: message)
            print("Sent push message: \(sent)")
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
            .previewDevice("iPhone 8")
    }
}