feat: add arch

lib/core/utils/app_exceptions.dart

@@ -0,0 +1,21 @@
+class AppException implements Exception {
+  final String message;
+  final String prefix;
+
+  AppException([this.message = 'An unknown error occurred.', this.prefix = '']);
+
+  @override
+  String toString() {
+    return '$prefix$message';
+  }
+}
+
+class FetchDataException extends AppException {
+  FetchDataException([String? message])
+    : super(message ?? 'Error During Communication: ', 'Network Error');
+}
+
+class AuthenticationException extends AppException {
+  AuthenticationException([String? message])
+    : super(message ?? 'Authentication Failed.', 'Auth Error');
+}

lib/core/utils/result.dart

@@ -0,0 +1,31 @@
+sealed class Result<T> {
+  const Result();
+
+  /// Creates a successful [Result], completed with the specified [value].
+  const factory Result.ok(T value) = Ok._;
+
+  /// Creates an error [Result], completed with the specified [error].
+  const factory Result.error(Exception error) = Error._;
+}
+
+/// Subclass of Result for values
+final class Ok<T> extends Result<T> {
+  const Ok._(this.value);
+
+  /// Returned value in result
+  final T value;
+
+  @override
+  String toString() => 'Result<$T>.ok($value)';
+}
+
+/// Subclass of Result for errors
+final class Error<T> extends Result<T> {
+  const Error._(this.error);
+
+  /// Returned error in result
+  final Exception error;
+
+  @override
+  String toString() => 'Result<$T>.error($error)';
+}