Push notification permission flow

import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';

enum PushState { granted, askable, blocked }

class PushPermission {
  /// Reads the current state without showing any system dialog.
  static Future<PushState> check() async {
    final s = await Permission.notification.status;
    if (s.isGranted || s.isProvisional) return PushState.granted;
    if (s.isPermanentlyDenied) return PushState.blocked;
    return PushState.askable;
  }

  /// Shows our own explanation first; the system dialog is only spent on a yes.
  static Future<PushState> request(BuildContext context) async {
    final current = await check();
    if (current != PushState.askable || !context.mounted) {
      if (current == PushState.blocked && context.mounted) await _offerSettings(context);
      return current;
    }
    final agree = await showDialog<bool>(
      context: context,
      builder: (c) => AlertDialog(
        icon: const Icon(Icons.notifications_active_outlined),
        title: const Text('Stay up to date'),
        content: const Text('Allow notifications so we can tell you when your ride or order status changes.'),
        actions: [
          TextButton(onPressed: () => Navigator.pop(c, false), child: const Text('Not now')),
          FilledButton(onPressed: () => Navigator.pop(c, true), child: const Text('Allow')),
        ],
      ),
    );
    if (agree != true) return PushState.askable; // keep the system prompt for later
    final result = await Permission.notification.request();
    return result.isGranted || result.isProvisional
        ? PushState.granted
        : (result.isPermanentlyDenied ? PushState.blocked : PushState.askable);
  }

  static Future<void> _offerSettings(BuildContext context) async {
    final open = await showDialog<bool>(
      context: context,
      builder: (c) => AlertDialog(
        title: const Text('Notifications are off'),
        content: const Text('You can turn them on in system settings.'),
        actions: [
          TextButton(onPressed: () => Navigator.pop(c, false), child: const Text('Cancel')),
          FilledButton(onPressed: () => Navigator.pop(c, true), child: const Text('Open settings')),
        ],
      ),
    );
    if (open == true) await openAppSettings();
  }
}