import 'package:flutter/foundation.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:permission_handler/permission_handler.dart';

/// The three things the app asks for, in the order it asks.
enum AppPermission { location, notifications, camera }

extension AppPermissionX on AppPermission {
  Permission get _platform => switch (this) {
    // While-in-use only: clock-in needs to know you are at the venue, and
    // nothing here justifies background tracking.
    AppPermission.location => Permission.locationWhenInUse,
    AppPermission.notifications => Permission.notification,
    AppPermission.camera => Permission.camera,
  };
}

/// Thin wrapper over `permission_handler`.
///
/// Exists so the rest of the app never imports the plugin directly, and so the
/// platforms it has no implementation for — web, desktop — degrade to "granted"
/// instead of throwing. On the web the browser prompts at the point of use
/// anyway, so asking up front is neither possible nor needed.
class PermissionService {
  const PermissionService();

  bool get _supported =>
      !kIsWeb &&
      (defaultTargetPlatform == TargetPlatform.android ||
          defaultTargetPlatform == TargetPlatform.iOS);

  /// Shows the platform dialog. Returns whether the permission ended up
  /// granted — which is not the same as whether the user tapped Allow, since
  /// it may already have been permanently denied.
  Future<bool> request(AppPermission permission) async {
    if (!_supported) return true;
    final status = await permission._platform.request();
    return status.isGranted || status.isLimited;
  }

  Future<bool> isGranted(AppPermission permission) async {
    if (!_supported) return true;
    final status = await permission._platform.status;
    return status.isGranted || status.isLimited;
  }

  /// True once the OS will no longer show a dialog, so the only way back is
  /// the system settings page.
  Future<bool> isPermanentlyDenied(AppPermission permission) async {
    if (!_supported) return false;
    return permission._platform.status.then((s) => s.isPermanentlyDenied);
  }

  Future<void> openSettings() async {
    if (!_supported) return;
    await openAppSettings();
  }
}

final permissionServiceProvider = Provider<PermissionService>(
  (ref) => const PermissionService(),
);