school-attendance/ios/Runner/ProximityMonitorPlugin.swift

// 🛡️ iOS 근접센서로 "주머니 감시"를 흉내내기 위한 네이티브 플러그인.
// UIDevice의 근접센서를 켜면 통화 중처럼 화면이 자동으로 꺼지고 켜지는데,
// 그 상태 변화(가까움/멀어짐)를 Dart 쪽 EventChannel로 그대로 흘려보낸다.
import Flutter
import UIKit

class ProximityMonitorPlugin: NSObject, FlutterPlugin, FlutterStreamHandler {
  private var eventSink: FlutterEventSink?

  static func register(with registrar: FlutterPluginRegistrar) {
    let instance = ProximityMonitorPlugin()

    let methodChannel = FlutterMethodChannel(
      name: "proximity_monitor",
      binaryMessenger: registrar.messenger()
    )
    methodChannel.setMethodCallHandler(instance.handle)

    let eventChannel = FlutterEventChannel(
      name: "proximity_monitor/events",
      binaryMessenger: registrar.messenger()
    )
    eventChannel.setStreamHandler(instance)
  }

  func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    switch call.method {
    case "start":
      UIDevice.current.isProximityMonitoringEnabled = true
      result(nil)
    case "stop":
      UIDevice.current.isProximityMonitoringEnabled = false
      result(nil)
    default:
      result(FlutterMethodNotImplemented)
    }
  }

  func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
    eventSink = events
    NotificationCenter.default.addObserver(
      self,
      selector: #selector(proximityStateChanged),
      name: UIDevice.proximityStateDidChangeNotification,
      object: nil
    )
    return nil
  }

  func onCancel(withArguments arguments: Any?) -> FlutterError? {
    NotificationCenter.default.removeObserver(
      self,
      name: UIDevice.proximityStateDidChangeNotification,
      object: nil
    )
    eventSink = nil
    return nil
  }

  @objc private func proximityStateChanged() {
    eventSink?(UIDevice.current.proximityState)
  }
}