import Cocoa
import FlutterMacOS

@main
class AppDelegate: FlutterAppDelegate {
  private let winampChannelName = "winamp"

  override func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
    return true
  }

  override func applicationSupportsSecureRestorableState(_ app: NSApplication) -> Bool {
    return true
  }

  override func applicationWillFinishLaunching(_ notification: Notification) {
    super.applicationWillFinishLaunching(notification)
    // Register the channel handler eagerly so Dart's startup menu-state sync
    // is not dropped. `applicationDidFinishLaunching` is never delivered in
    // this Flutter version, so this is the earliest reliable point. The
    // FlutterViewController is already attached here, but poll briefly as a
    // fallback for other Flutter versions where it may not be yet.
    registerWinampChannelWhenReady()
  }

  private func registerWinampChannelWhenReady() {
    guard winampChannel != nil else {
      DispatchQueue.main.asyncAfter(deadline: .now() + 0.05) { [weak self] in
        self?.registerWinampChannelWhenReady()
      }
      return
    }
  }

  private var flutterController: FlutterViewController? {
    return mainFlutterWindow?.contentViewController as? FlutterViewController
  }

  /// Lazily-created channel back to Dart. The handler is registered once so
  /// Dart can report state (always-on-top, EQ/PL open, UI scale) to update
  /// the matching menu checkmarks.
  private var winampChannel: FlutterMethodChannel? {
    if _winampChannel == nil, let controller = flutterController {
      let channel = FlutterMethodChannel(
        name: winampChannelName,
        binaryMessenger: controller.engine.binaryMessenger
      )
      channel.setMethodCallHandler(handleMethodCall)
      _winampChannel = channel
    }
    return _winampChannel
  }

  private var _winampChannel: FlutterMethodChannel?

  /// Custom cursors registered by the Dart side, keyed by skin cursor name.
  private var cursors: [String: NSCursor] = [:]

  private func handleMethodCall(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    switch call.method {
    case "setAlwaysOnTop":
      if let args = call.arguments as? [String: Any],
        let on = args["isAlwaysOnTop"] as? Bool {
        setMenuItemState(id: "win-always-on-top", title: "Always on Top", on: on)
      }
      result(nil)
    case "setWindowShade":
      if let args = call.arguments as? [String: Any], let on = args["on"] as? Bool {
        setMenuItemState(id: "win-window-shade", title: "Window Shade", on: on)
      }
      result(nil)
    case "setEqOpen":
      if let args = call.arguments as? [String: Any], let open = args["open"] as? Bool {
        setMenuItemState(id: "win-equalizer", title: "Equalizer", on: open)
      }
      result(nil)
    case "setPlOpen":
      if let args = call.arguments as? [String: Any], let open = args["open"] as? Bool {
        setMenuItemState(id: "win-playlist", title: "Playlist", on: open)
      }
      result(nil)
    case "setUiScale":
      if let args = call.arguments as? [String: Any], let scale = args["scale"] as? Double {
        setUiScaleMenuState(scale)
      }
      result(nil)
    case "registerCursor":
      if let args = call.arguments as? [String: Any],
        let name = args["name"] as? String,
        let pngData = (args["png"] as? FlutterStandardTypedData)?.data,
        let image = NSImage(data: pngData) {
        let hotX = args["hotspotX"] as? Int ?? 0
        let hotY = args["hotspotY"] as? Int ?? 0
        cursors[name] = NSCursor(image: image, hotSpot: NSPoint(x: hotX, y: hotY))
      }
      result(nil)
    case "setCursor":
      if let args = call.arguments as? [String: Any], let name = args["name"] as? String {
        if let cursor = cursors[name] {
          cursor.set()
        } else {
          NSCursor.arrow.set()
        }
      }
      result(nil)
    default:
      result(FlutterMethodNotImplemented)
    }
  }

  private func setMenuItemState(id: String, title: String, on: Bool) {
    menuItem(id: id, title: title)?.state = on ? .on : .off
  }

  private func setUiScaleMenuState(_ scale: Double) {
    let targetId: String
    let targetTitle: String
    if scale == 1.0 {
      targetId = "win-ui-scale-1x"
      targetTitle = "1.0x"
    } else if scale == 2.0 {
      targetId = "win-ui-scale-2x"
      targetTitle = "2.0x"
    } else {
      targetId = "win-ui-scale-3x"
      targetTitle = "3.0x"
    }
    for (id, title) in [
      ("win-ui-scale-1x", "1.0x"),
      ("win-ui-scale-2x", "2.0x"),
      ("win-ui-scale-3x", "3.0x"),
    ] {
      setMenuItemState(id: id, title: title, on: id == targetId && title == targetTitle)
    }
  }

  private func menuItem(id: String, title: String) -> NSMenuItem? {
    guard let menu = NSApplication.shared.mainMenu else { return nil }
    return findMenuItem(id: id, title: title, in: menu)
  }

  private func findMenuItem(id: String, title: String, in menu: NSMenu) -> NSMenuItem? {
    for item in menu.items {
      if item.identifier?.rawValue == id || item.title == title {
        return item
      }
      if let submenu = item.submenu,
        let found = findMenuItem(id: id, title: title, in: submenu) {
        return found
      }
    }
    return nil
  }

  private func send(_ method: String, _ arguments: Any? = nil) {
    winampChannel?.invokeMethod(method, arguments: arguments)
  }

  @IBAction func toggleAlwaysOnTop(_ sender: NSMenuItem) {
    send("toggleAlwaysOnTop")
  }

  @IBAction func toggleWindowShade(_ sender: NSMenuItem) {
    send("toggleWindowShade")
  }

  @IBAction func toggleEqualizer(_ sender: NSMenuItem) {
    send("toggleEq")
  }

  @IBAction func togglePlaylist(_ sender: NSMenuItem) {
    send("togglePlaylist")
  }

  @IBAction func setUIScale1x(_ sender: NSMenuItem) {
    send("setUIScale", ["scale": 1.0])
  }

  @IBAction func setUIScale2x(_ sender: NSMenuItem) {
    send("setUIScale", ["scale": 2.0])
  }

  @IBAction func setUIScale3x(_ sender: NSMenuItem) {
    send("setUIScale", ["scale": 3.0])
  }

  @IBAction func importSkin(_ sender: NSMenuItem) {
    send("importSkin")
  }
}