import Flutter
import UIKit
import AVFoundation
import AVKit

@main
@objc class AppDelegate: FlutterAppDelegate, FlutterImplicitEngineDelegate, FlutterStreamHandler {
  private let castingMethodChannelName = "kryz_go_flutter/casting/methods"
  private let castingEventChannelName = "kryz_go_flutter/casting/events"
  private let playbackMethodChannelName = "kryz_go_flutter/playback/methods"

  private var castingEventSink: FlutterEventSink?
  private var castingStatus: [String: Any] = [
    "status": "idle",
    "platform": "ios"
  ]
  private var playbackMethodChannel: FlutterMethodChannel?

  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    // Ensure iOS uses the playback category so lock screen / Control Center
    // media controls remain available during background audio.
    do {
      try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default, options: [.allowAirPlay])
      try AVAudioSession.sharedInstance().setActive(true)
    } catch {
      NSLog("Failed to configure AVAudioSession: \(error)")
    }

    NotificationCenter.default.addObserver(
      self,
      selector: #selector(handleAudioRouteChange),
      name: AVAudioSession.routeChangeNotification,
      object: nil
    )

    updateCastingStatusForCurrentRoute()

    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }

  func didInitializeImplicitFlutterEngine(_ engineBridge: FlutterImplicitEngineBridge) {
    GeneratedPluginRegistrant.register(with: engineBridge.pluginRegistry)

    guard let registrar = engineBridge.pluginRegistry.registrar(forPlugin: "CastingBridge") else {
      return
    }

    let methodChannel = FlutterMethodChannel(
      name: castingMethodChannelName,
      binaryMessenger: registrar.messenger()
    )
    let eventChannel = FlutterEventChannel(
      name: castingEventChannelName,
      binaryMessenger: registrar.messenger()
    )

    eventChannel.setStreamHandler(self)

    methodChannel.setMethodCallHandler { [weak self] call, result in
      self?.handleCastingMethod(call: call, result: result)
    }

    playbackMethodChannel = FlutterMethodChannel(
      name: playbackMethodChannelName,
      binaryMessenger: registrar.messenger()
    )
  }

  /// Invoke play on the Flutter audio engine. Called by CarPlaySceneDelegate.
  func invokePlay() {
    playbackMethodChannel?.invokeMethod("play", arguments: nil)
  }

  /// Invoke stop on the Flutter audio engine. Called by CarPlaySceneDelegate.
  func invokeStop() {
    playbackMethodChannel?.invokeMethod("stop", arguments: nil)
  }

  @objc private func handleAudioRouteChange() {
    updateCastingStatusForCurrentRoute()
  }

  private func handleCastingMethod(call: FlutterMethodCall, result: @escaping FlutterResult) {
    switch call.method {
    case "getStatus":
      updateCastingStatusForCurrentRoute()
      result(castingStatus)
    case "showDevicePicker":
      showAirPlayPicker()
      result(nil)
    case "startCastingLiveStream":
      // AirPlay route selection controls where iOS outputs audio. No explicit load call needed.
      result(nil)
    case "disconnect":
      // iOS does not expose direct route disconnect. Users select route via picker.
      showAirPlayPicker()
      result(nil)
    default:
      result(FlutterMethodNotImplemented)
    }
  }

  private func showAirPlayPicker() {
    DispatchQueue.main.async {
      guard let rootViewController = self.activeRootViewController() else {
        self.emitCastingEvent(status: "error", message: "Unable to open AirPlay picker")
        return
      }

      let routePickerView = AVRoutePickerView(frame: CGRect(x: 0, y: 0, width: 1, height: 1))
      routePickerView.alpha = 0.01
      rootViewController.view.addSubview(routePickerView)

      for subview in routePickerView.subviews {
        if let button = subview as? UIButton {
          button.sendActions(for: .touchUpInside)
          break
        }
      }

      DispatchQueue.main.asyncAfter(deadline: .now() + 0.25) {
        routePickerView.removeFromSuperview()
      }
    }
  }

  private func activeRootViewController() -> UIViewController? {
    let activeScene = UIApplication.shared.connectedScenes
      .first { $0.activationState == .foregroundActive } as? UIWindowScene
    let keyWindow = activeScene?.windows.first { $0.isKeyWindow }
    return keyWindow?.rootViewController
  }

  private func updateCastingStatusForCurrentRoute() {
    let currentOutputs = AVAudioSession.sharedInstance().currentRoute.outputs
    if let airPlayOutput = currentOutputs.first(where: { $0.portType == .airPlay }) {
      castingStatus = [
        "status": "connected",
        "platform": "ios",
        "deviceName": airPlayOutput.portName
      ]
    } else {
      castingStatus = [
        "status": "idle",
        "platform": "ios"
      ]
    }

    castingEventSink?(castingStatus)
  }

  private func emitCastingEvent(status: String, message: String) {
    let event: [String: Any] = [
      "status": status,
      "platform": "ios",
      "message": message
    ]

    castingStatus = event
    castingEventSink?(event)
  }

  func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
    castingEventSink = events
    events(castingStatus)
    return nil
  }

  func onCancel(withArguments arguments: Any?) -> FlutterError? {
    castingEventSink = nil
    return nil
  }

  deinit {
    NotificationCenter.default.removeObserver(self)
  }
}