import 'package:freezed_annotation/freezed_annotation.dart';

part 'api_exception.freezed.dart';

/// Typed errors thrown by [NodeMasterApiClient]/repositories. Riverpod's
/// `AsyncValue` (via `FutureProvider`/`AsyncNotifier`) already catches
/// thrown exceptions into `AsyncValue.error`, so this is the result-type
/// boundary — no separate `Result<T, E>` wrapper is layered on top.
@freezed
sealed class ApiException with _$ApiException implements Exception {
  /// DNS/connection failure — couldn't reach the host at all.
  const factory ApiException.network(String message) = ApiNetworkException;

  /// Connect/send/receive timeout.
  const factory ApiException.timeout() = ApiTimeoutException;

  /// The server responded with a 4xx/5xx and (usually) a `{"error": msg}`
  /// body.
  const factory ApiException.server(int statusCode, String message) = ApiServerException;

  /// The response body wasn't the JSON shape a model expected.
  const factory ApiException.parse(String message) = ApiParseException;

  /// Request was cancelled (e.g. the active connection changed mid-flight).
  const factory ApiException.cancelled() = ApiCancelledException;

  /// Anything else.
  const factory ApiException.unknown(String message) = ApiUnknownException;
}

extension ApiExceptionUserMessage on ApiException {
  /// Short, user-facing copy — screens can use this directly or switch on
  /// the exception type themselves for more specific handling.
  String get userMessage => switch (this) {
    ApiNetworkException() => "Can't reach this node — check the URL and that it's reachable.",
    ApiTimeoutException() => 'The node took too long to respond.',
    ApiServerException(:final statusCode, :final message) => statusCode == 404
        ? 'Not found.'
        : 'Server error ($statusCode): $message',
    ApiParseException() => 'Received an unexpected response from the node.',
    ApiCancelledException() => 'Cancelled.',
    ApiUnknownException(:final message) => message,
  };
}