NotificationPermission.cs

#if IOS
using Foundation;
using UIKit;
using UserNotifications;
#endif
#if ANDROID
using System.Linq;
using Android;
using Android.App;
using Android.Content.PM;
using Android.OS;
using AndroidX.Core.Content;
using NeuroAccessMaui.Services;
#endif
 
 
namespace NeuroAccessMaui.CustomPermissions
{
    public class NotificationPermission : Permissions.BasePermission
    {
        public override Task<PermissionStatus> CheckStatusAsync()
        {
#if IOS
            return CheckStatusIOSAsync();
#elif ANDROID
            // For Android 13+ (API level 33), notifications are a runtime permission.
            if (Build.VERSION.SdkInt >= BuildVersionCodes.Tiramisu && OperatingSystem.IsAndroidVersionAtLeast(33))
            {
                Android.Content.Context Context = Android.App.Application.Context;
                // Check the POST_NOTIFICATIONS permission
                int Result = (int)ContextCompat.CheckSelfPermission(Context, Manifest.Permission.PostNotifications);
                return Task.FromResult(Result == (int)Permission.Granted ? PermissionStatus.Granted : PermissionStatus.Denied);
            }
            // For earlier versions, notifications are granted by default.
            return Task.FromResult(PermissionStatus.Granted);
#else
            return Task.FromResult(PermissionStatus.Unknown);
#endif
        }
 
#if IOS
        private static async Task<PermissionStatus> CheckStatusIOSAsync()
        {
            // Check the current notification settings on iOS
            UNNotificationSettings Settings = await UNUserNotificationCenter.Current.GetNotificationSettingsAsync();
            return Settings.AuthorizationStatus switch
            {
                UNAuthorizationStatus.Authorized => PermissionStatus.Granted,
                UNAuthorizationStatus.Denied => PermissionStatus.Denied,
                _ => PermissionStatus.Unknown
            };
        }
#endif
 
        public override void EnsureDeclared()
        {
#if ANDROID
            if (!OperatingSystem.IsAndroidVersionAtLeast(33))
                return;
 
            try
            {
                // On Android, check that the POST_NOTIFICATIONS permission is declared in the manifest.
                Android.Content.Context Context = Android.App.Application.Context;
                PackageManager PackageManager = Context.PackageManager ?? throw new Exception();
                string? PackageName = Context.PackageName;
 
                PackageInfo PackageInfo = PackageManager.GetPackageInfo(PackageName ?? string.Empty, PackageInfoFlags.Permissions) ?? throw new Exception();
                IList<string>? DeclaredPermissions = PackageInfo.RequestedPermissions;
                if (DeclaredPermissions is null || !DeclaredPermissions.Contains(Manifest.Permission.PostNotifications))
                {
                    throw new PermissionException($"The Android manifest does not declare the required permission: {Manifest.Permission.PostNotifications}");
                }
            }
            catch (PackageManager.NameNotFoundException)
            {
                ServiceRef.LogService.LogWarning("Unable to verify that the POST_NOTIFICATIONS permission is declared in the manifest.");
                throw new PermissionException("The Android manifest does not declare the required permission: " + Manifest.Permission.PostNotifications);
            }
            catch (Exception)
            {
                // assume declared if there is any weird errors with the PackageManager
                return;
            }
#endif
            // For iOS and other platforms, no manifest declaration is required.
        }
 
        public override async Task<PermissionStatus> RequestAsync()
        {
#if IOS
            // Request notification permission on iOS using UNUserNotificationCenter
            (bool Granted, NSError Error) = await UNUserNotificationCenter.Current.RequestAuthorizationAsync(
                 UNAuthorizationOptions.Alert | UNAuthorizationOptions.Badge | UNAuthorizationOptions.Sound);
 
            if (Granted)
            {
                UIApplication.SharedApplication.InvokeOnMainThread(() =>
                {
                    UIApplication.SharedApplication.RegisterForRemoteNotifications();
                });
            }
            return Granted ? PermissionStatus.Granted : PermissionStatus.Denied;
#elif ANDROID
            if (Build.VERSION.SdkInt >= BuildVersionCodes.Tiramisu && OperatingSystem.IsAndroidVersionAtLeast(33))
            {
                // For Android 13+, request the POST_NOTIFICATIONS permission.
                PermissionStatus Status = await Permissions.RequestAsync<Permissions.PostNotifications>();
                return Status;
            }
            // For earlier versions, notifications are automatically granted.
            return PermissionStatus.Granted;
#else
            return PermissionStatus.Unknown;
#endif
        }
 
        // Optional: Override ShouldShowRationale if you want to provide additional info to the user.
        public override bool ShouldShowRationale() => true;
    }
}