ContentView.swift

//
//  ContentView.swift
//  RChat
//
//  Created by Andrew Morgan on 23/11/2020.
//

import SwiftUI
import UserNotifications
import RealmSwift

struct ContentView: View {
    @EnvironmentObject var state: AppState

    @AppStorage("shouldRemindOnlineUser") var shouldRemindOnlineUser = false
    @AppStorage("onlineUserReminderHours") var onlineUserReminderHours = 8.0

    @State private var showingProfileView = false

    var body: some View {
        NavigationView {
            ZStack {
                VStack {
                    if state.loggedIn {
                        if (state.user != nil) && !state.user!.isProfileSet || showingProfileView {
                            SetProfileView(isPresented: $showingProfileView)
                                .environment(\.realmConfiguration, app.currentUser!.configuration(partitionValue: "user=\(state.user?._id ?? "")"))
                        } else {
                            ConversationListView()
                                .environment(\.realmConfiguration, app.currentUser!.configuration(partitionValue: "user=\(state.user?._id ?? "")"))
                            .navigationBarTitle("Chats", displayMode: .inline)
                            .navigationBarItems(
                                trailing: state.loggedIn && !state.shouldIndicateActivity ? UserAvatarView(
                                    photo: state.user?.userPreferences?.avatarImage,
                                    online: true) { showingProfileView.toggle() } : nil
                            )
                        }
                    } else {
                        LoginView()
                    }
                    Spacer()
                    if let error = state.error {
                        Text("Error: \(error)")
                            .foregroundColor(Color.red)
                    }
                }
                if state.busyCount > 0 {
                    OpaqueProgressView("Working With Realm")
                }
            }
        }
        .currentDeviceNavigationViewStyle(alwaysStacked: !state.loggedIn)
        .onReceive(NotificationCenter.default.publisher(for: UIApplication.willResignActiveNotification)) { _ in
            if let user = state.user {
                if user.presenceState == .onLine && shouldRemindOnlineUser {
                    addNotification(timeInHours: Int(onlineUserReminderHours))
                }
            }
        }
        .onReceive(NotificationCenter.default.publisher(for: UIApplication.willEnterForegroundNotification)) { _ in
            clearNotifications()
        }
    }
    
    func addNotification(timeInHours: Int) {
        let center = UNUserNotificationCenter.current()

        let addRequest = {
            let content = UNMutableNotificationContent()
            content.title = "Still logged in"
            content.subtitle = "You've been offline in the background for " +
                "\(onlineUserReminderHours) \(onlineUserReminderHours == 1 ? "hour" : "hours")"
            content.sound = UNNotificationSound.default

            let trigger = UNTimeIntervalNotificationTrigger(
                timeInterval: onlineUserReminderHours * 3600,
                repeats: false)
            let request = UNNotificationRequest(identifier: UUID().uuidString,
                                                content: content,
                                                trigger: trigger)
            center.add(request)
        }

        center.getNotificationSettings { settings in
            if settings.authorizationStatus == .authorized {
                addRequest()
            } else {
                center.requestAuthorization(options: [.alert, .badge, .sound]) { success, _ in
                    if success {
                        addRequest()
                    }
                }
            }
        }
    }

    func clearNotifications() {
        let center = UNUserNotificationCenter.current()
        center.removeAllDeliveredNotifications()
        center.removeAllPendingNotificationRequests()
    }
}

extension View {
    public func currentDeviceNavigationViewStyle(alwaysStacked: Bool) -> AnyView {
        if UIDevice.current.userInterfaceIdiom == .pad && !alwaysStacked {
            return AnyView(self.navigationViewStyle(DefaultNavigationViewStyle()))
        } else {
            return AnyView(self.navigationViewStyle(StackNavigationViewStyle()))
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        AppearancePreviews(
            Group {
                ContentView()
                    .environmentObject(AppState())
                Landscape(ContentView()
                    .environmentObject(AppState()))
            }
        )
    }
}