// ContentView.swift

import SwiftUI
import UIKit

struct ContentView: View {
    @EnvironmentObject private var auth: AuthManager
    @EnvironmentObject private var sync: SyncManager
    @StateObject private var updateChecker = UpdateChecker.shared
    @Environment(\.scenePhase) private var scenePhase

    var body: some View {
        Group {
            if auth.isLoading && !auth.isAuthenticated {
                VStack(spacing: 16) {
                    Image(systemName: "checkmark.seal.fill")
                        .font(.system(size: 64))
                        .foregroundStyle(.blue)
                    ProgressView("Loading…")
                }
            } else if auth.isAuthenticated {
                DashboardView()
            } else {
                LoginView()
            }
        }
        .animation(.easeInOut(duration: 0.3), value: auth.isAuthenticated)
        .task {
            // 1. Restore session first — sets isAuthenticated and loads tokens.
            await AuthManager.shared.restoreSession()
            // 2. Only start network monitoring AFTER auth is resolved.
            //    startMonitoring() fires triggerSync() immediately on connectivity,
            //    so it must not run before tokens are in place.
            SyncManager.shared.startMonitoring()
            // 3. If already online and authenticated, do an initial sync.
            if SyncManager.shared.isOnline && AuthManager.shared.isAuthenticated {
                await SyncManager.shared.triggerSync()
            }
            // 4. Check the App Store for a newer version. Independent of auth —
            //    runs even on the login screen so unauthenticated devices still
            //    get prompted. Throttled internally to once per 24h; silent on
            //    any failure (offline, parse error, etc.) so it never disrupts
            //    normal app use.
            await updateChecker.checkForUpdate()
            // 5. Register device now that auth is fully resolved.
            //    The .onChange(scenePhase == .active) fires BEFORE restoreSession()
            //    completes on first launch, so auth.isAuthenticated is false there
            //    and registration is skipped. This call covers that gap.
            if AuthManager.shared.isAuthenticated {
                await APIClient.shared.registerDevice()
            }
        }
        // Stop the 60s notification poll when the app goes to background and
        // restart it when it returns to the foreground. iOS suspends Tasks
        // automatically in the background anyway, but explicitly managing the
        // poll task here:
        //   • Prevents the Task object from accumulating sleep-resume cycles
        //     that never fired while suspended.
        //   • Triggers an immediate sync+poll when the inspector returns to the
        //     app after being away, rather than waiting up to 60s for the next
        //     scheduled poll tick.
        //   • Makes the lifecycle intent explicit and avoids relying on implicit
        //     iOS suspension behaviour.
        .onChange(of: scenePhase) { _, newPhase in
            switch newPhase {
            case .background:
                SyncManager.shared.suspendPolling()
            case .active:
                SyncManager.shared.resumePolling()
                // Register / update device record on every foreground.
                // Fire-and-forget — auth guard is inside registerDevice().
                if auth.isAuthenticated {
                    Task { await APIClient.shared.registerDevice() }
                }
            default:
                break
            }
        }
        .alert("Update Available", isPresented: $updateChecker.updateAvailable) {
            Button("Update") {
                if let url = updateChecker.appStoreURL {
                    UIApplication.shared.open(url)
                }
            }
            Button("Later", role: .cancel) {
                updateChecker.dismissForNow()
            }
        } message: {
            if let version = updateChecker.latestVersion {
                Text("Version \(version) is available on the App Store. Update now for the latest fixes and features.")
            } else {
                Text("A new version is available on the App Store.")
            }
        }
    }
}