public Task<string> GetAlbumLocalIdentifier ()
{
if (albumLocalIdTcs == null || (int)albumLocalIdTcs.Task.Status >= 5) {
albumLocalIdTcs = new TaskCompletionSource<string> ();
} else if ((int)albumLocalIdTcs.Task.Status <= 4) {
return albumLocalIdTcs.Task;
}
PHPhotoLibrary.RequestAuthorization(async status => {
if (status == PHAuthorizationStatus.Authorized) {
if (!string.IsNullOrEmpty(albumLocalIdentifier)) {
albumLocalIdTcs.TrySetResult(albumLocalIdentifier);
} else {
var keychain = new Keychain<TrapAlbum> (new TrapAlbum ());
var values = keychain.GetStoredKeyValues();
var identifier = values.ContainsKey(DataKeys.LocalIdentifier) ? values[DataKeys.LocalIdentifier] : null;
if (identifier != null) {
// ensure the album with that localIdentifier is there
var collection = PHAssetCollection.FetchAssetCollections(new [] { identifier }, null)?.firstObject as PHAssetCollection;
if (collection != null) {
albumLocalIdentifier = identifier;
if (!albumLocalIdTcs.TrySetResult(identifier)) {
var ex = new Exception ("GetAlbumLocalIdentifier Failed");
albumLocalIdTcs.TrySetException(ex);
// Log.Error(ex);
}
} else {
if (!albumLocalIdTcs.TrySetResult(await createAlbumAndSaveLocalIdentifier())) {
var ex = new Exception ("GetAlbumLocalIdentifier Failed");
albumLocalIdTcs.TrySetException(ex);
// Log.Error(ex);
}
}
} else {
if (!albumLocalIdTcs.TrySetResult(await createAlbumAndSaveLocalIdentifier())) {
var ex = new Exception ("GetAlbumLocalIdentifier Failed");
albumLocalIdTcs.TrySetException(ex);
// Log.Error(ex);
}
}
}
} else {
var ex = new Exception ("Unauthorized");
albumLocalIdTcs.TrySetException(ex);
// Log.Error(ex);
}
});
return albumLocalIdTcs.Task;
}