Files
nearby_service/lib/src/base/nearby_message_content_base.dart
T

100 lines
3.4 KiB
Dart

import 'package:nearby_service/nearby_service.dart';
import 'package:nearby_service/src/utils/random.dart';
///
/// Abstraction for the message content.
/// The [NearbyMessageContentType] is used to
/// determine, what type of content is it.
///
abstract base class NearbyMessageContent {
const NearbyMessageContent({required this.id});
NearbyMessageContent.create()
: id = RandomUtils.instance.nextInt(1000000, 9999999).toString();
///
/// Contains the conditional logic of creating [NearbyMessageFilesRequest],
/// [NearbyMessageFilesResponse] or [NearbyMessageTextRequest]
/// by `type` field of [json].
///
static C fromJson<C extends NearbyMessageContent>(
Map<String, dynamic>? json,
) {
try {
final type = NearbyMessageContentType.values.firstWhere(
(e) => e.name == json?['type'],
);
if (type.isTextRequest) {
return NearbyMessageTextRequest.fromJson(json) as C;
} else if (type.isTextResponse) {
return NearbyMessageTextResponse.fromJson(json) as C;
} else if (type.isFilesRequest) {
return NearbyMessageFilesRequest.fromJson(json) as C;
} else if (type.isFilesResponse) {
return NearbyMessageFilesResponse.fromJson(json) as C;
} else {
throw NearbyServiceException.unsupportedDecoding(json);
}
} catch (e) {
throw NearbyServiceException(e);
}
}
final String id;
NearbyMessageContentType get _type {
final type = byType(
onTextRequest: (_) => NearbyMessageContentType.textRequest,
onTextResponse: (_) => NearbyMessageContentType.textResponse,
onFilesRequest: (_) => NearbyMessageContentType.filesRequest,
onFilesResponse: (_) => NearbyMessageContentType.filesResponse,
);
if (type != null) {
return type;
}
throw NearbyServiceException(
'Unknown type on NearbyMessageContent - $runtimeType',
);
}
///
/// Check for the content if it is valid for sending or receiving.
///
bool get isValid => id.isNotEmpty;
///
/// * The [onTextRequest] callback returns this instance of [NearbyMessageContent],
/// cast as [NearbyMessageTextRequest] if is a text.
///
/// * The [onFilesRequest] callback returns this instance of [NearbyMessageContent],
/// cast as [NearbyMessageFilesRequest] if is a files pack request.
///
/// * The [onFilesResponse] callback returns this instance of [NearbyMessageContent],
/// cast as [NearbyMessageFilesResponse] if is a files pack response.
///
T? byType<T>({
T Function(NearbyMessageTextRequest)? onTextRequest,
T Function(NearbyMessageTextResponse)? onTextResponse,
T Function(NearbyMessageFilesRequest)? onFilesRequest,
T Function(NearbyMessageFilesResponse)? onFilesResponse,
}) {
if (this is NearbyMessageTextRequest && onTextRequest != null) {
return onTextRequest(this as NearbyMessageTextRequest);
} else if (this is NearbyMessageTextResponse && onTextResponse != null) {
return onTextResponse(this as NearbyMessageTextResponse);
} else if (this is NearbyMessageFilesRequest && onFilesRequest != null) {
return onFilesRequest(this as NearbyMessageFilesRequest);
} else if (this is NearbyMessageFilesResponse && onFilesResponse != null) {
return onFilesResponse(this as NearbyMessageFilesResponse);
}
return null;
}
///
/// Gets [Map] from [NearbyMessageContent]
///
Map<String, dynamic> toJson() {
return {'type': _type.name, 'id': id};
}
}