NavidromeApp/iOS/App/NavidromePlayerApp.swift

import SwiftUI
import BackgroundTasks

// MARK: - App Delegate (Background Sessions + BGTask Registration)

class AppDelegate: NSObject, UIApplicationDelegate {
    
    static let smartDJTaskId = "com.navidromeplayer.smartdj.refresh"
    static let syncTaskId = "com.navidromeplayer.library.sync"
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil) -> Bool {
        // Register background tasks
        BGTaskScheduler.shared.register(forTaskWithIdentifier: Self.smartDJTaskId, using: nil) { task in
            self.handleSmartDJRefresh(task: task as! BGAppRefreshTask)
        }
        BGTaskScheduler.shared.register(forTaskWithIdentifier: Self.syncTaskId, using: nil) { task in
            self.handleLibrarySync(task: task as! BGProcessingTask)
        }
        return true
    }
    
    /// Return a custom scene configuration so NavidromeSceneDelegate can provide
    /// NavidromeHostingController — giving us UIKit-level preferredStatusBarStyle
    /// control without touching SwiftUI's colorScheme environment.
    func application(
        _ application: UIApplication,
        configurationForConnecting connectingSceneSession: UISceneSession,
        options: UIScene.ConnectionOptions
    ) -> UISceneConfiguration {
        let config = UISceneConfiguration(name: nil, sessionRole: connectingSceneSession.role)
        config.delegateClass = NavidromeSceneDelegate.self
        return config
    }
    
    func application(
        _ application: UIApplication,
        handleEventsForBackgroundURLSession identifier: String,
        completionHandler: @escaping () -> Void
    ) {
        if identifier == "com.navidromeplayer.batchupload" {
            ZipImportManager.shared.setBackgroundCompletionHandler(completionHandler)
            DebugLogger.shared.log("Background session woke app: \(identifier)", category: "Upload")
        }
    }
    
    // MARK: - Smart DJ Background Refresh
    
    private func handleSmartDJRefresh(task: BGAppRefreshTask) {
        Self.scheduleSmartDJRefresh() // re-schedule next run immediately

        let refreshTask = Task {
            // Pre-fetch profiles using the shared singleton — no per-song URLSession leak
            if CompanionSettings.shared.isEnabled,
               CompanionSettings.shared.smartDJEnabled {
                let queue = AudioPlayer.shared.queue
                let idx   = AudioPlayer.shared.queueIndex
                let upcoming = Array(queue.dropFirst(idx + 1).prefix(5))
                let api = CompanionAPIService.shared
                for song in upcoming {
                    guard let path = song.path else { continue }
                    _ = try? await api.fetchProfile(relativePath: path)
                }
            }

            // Await the actual sync — BGTask stays alive until work completes
            await SyncEngine.shared.syncAndWait()
            OptimisticActionQueue.shared.flush()

            task.setTaskCompleted(success: true)
            DebugLogger.shared.log("BGTask SmartDJ refresh completed", category: "Sync", level: .info)
        }

        task.expirationHandler = {
            refreshTask.cancel()
            task.setTaskCompleted(success: false)
            DebugLogger.shared.log("BGTask SmartDJ refresh expired", category: "Sync", level: .warning)
        }
    }
    
    private func handleLibrarySync(task: BGProcessingTask) {
        let syncTask = Task {
            // Await real completion — previously fired setTaskCompleted immediately
            // before any sync work started, causing iOS to kill the process (AUDIT-044)
            await SyncEngine.shared.syncAndWait()
            task.setTaskCompleted(success: true)
            DebugLogger.shared.log("BGTask library sync completed", category: "Sync", level: .info)
        }
        task.expirationHandler = {
            syncTask.cancel()
            task.setTaskCompleted(success: false)
            DebugLogger.shared.log("BGTask library sync expired", category: "Sync", level: .warning)
        }
    }
    
    static func scheduleSmartDJRefresh() {
        let request = BGAppRefreshTaskRequest(identifier: smartDJTaskId)
        request.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60) // 15 min
        try? BGTaskScheduler.shared.submit(request)
    }
    
    static func scheduleLibrarySync() {
        let request = BGProcessingTaskRequest(identifier: syncTaskId)
        request.requiresNetworkConnectivity = true
        request.earliestBeginDate = Date(timeIntervalSinceNow: 60 * 60) // 1 hour
        try? BGTaskScheduler.shared.submit(request)
    }
}

@main
struct NavidromePlayerApp: App {
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

    @StateObject private var serverManager = ServerManager.shared
    @StateObject private var audioPlayer = AudioPlayer.shared
    @StateObject private var offlineManager = OfflineManager.shared

    // Initialize WatchConnectivity so sync works immediately
    private let watchConnectivity = WatchConnectivityManager.shared

    init() {
        // Dismiss keyboard when scrolling any scroll view
        UIScrollView.appearance().keyboardDismissMode = .interactive
    }

    var body: some Scene {
        WindowGroup {
            RootView()
                .environmentObject(serverManager)
                .environmentObject(audioPlayer)
                .environmentObject(offlineManager)
                .tint(Color(red: 1.0, green: 0.176, blue: 0.333))
        }
    }
}

struct RootView: View {
    @EnvironmentObject var serverManager: ServerManager
    
    var body: some View {
        Group {
            if serverManager.servers.isEmpty {
                // No servers configured — show login
                LoginView()
            } else {
                // Servers exist — show main UI immediately (connects in background)
                MainTabView()
            }
        }
        .dismissKeyboardOnTap()
        .task {
            ImageCache.shared.trimDiskCache()
            AudioPreFetcher.shared.cleanOldPrefetches(keeping: AudioPlayer.shared.queue)
            WidgetBridge.shared.start()
            
            if serverManager.activeServer != nil {
                await serverManager.connectToActive()
                
                // Background sync — fills LibraryCache so UI never waits for network
                SyncEngine.shared.syncIfNeeded()
                
                // Flush any pending optimistic actions (star/unstar that failed offline)
                OptimisticActionQueue.shared.flush()
                
                // Bulk-fetch all Smart DJ profiles in one request (~30KB gzipped).
                // Populates SmartDJCache so crossfade/volume data is instant for every song.
                if CompanionSettings.shared.smartDJEnabled {
                    SmartDJCache.shared.loadBulkCache()  // disk → memory (instant)
                    Task.detached(priority: .utility) {
                        do {
                            let api = CompanionAPIService.shared
                            let profiles = try await api.fetchAllProfiles()
                            SmartDJCache.shared.bulkImport(profiles)
                        } catch {
                            DebugLogger.shared.log(
                                "DJ profile bulk fetch failed: \(error.localizedDescription)",
                                category: "SmartDJ"
                            )
                        }
                    }
                }

                // Restore queue from last session if the app was killed by iOS.
                // Only restore if no song is already playing (e.g. from a widget tap).
                // Restoration starts paused at the saved position — user taps Play.
                if AudioPlayer.shared.currentSong == nil,
                   let saved = PlaybackStateStore.shared.load() {
                    let player = AudioPlayer.shared
                    // Load queue without starting playback
                    player.queue      = saved.queue
                    player.queueIndex = saved.index
                    player.currentSong = saved.currentSong
                    player.currentTime = saved.currentTime
                    // Duration will populate when the player item loads
                    DebugLogger.shared.log(
                        "Restored queue: \(saved.queue.count) songs, index \(saved.index), t=\(Int(saved.currentTime))s",
                        category: "Audio", level: .info
                    )
                }
            }
            
            // Connect Companion push client if enabled
            if CompanionSettings.shared.isEnabled {
                CompanionPushClient.shared.connect()
            }
            
            // Schedule background tasks
            AppDelegate.scheduleSmartDJRefresh()
            AppDelegate.scheduleLibrarySync()
        }
    }
}