import 'package:relationship_saver/core/network/backend_exception.dart';
import 'package:relationship_saver/integrations/backend/models/backend_models.dart';

/// Validation rules for outgoing sync envelopes.
class SyncEnvelopeValidator {
  SyncEnvelopeValidator._();

  /// Validates a list of changes before a push call.
  static void validateAll(List<ChangeEnvelope> changes) {
    for (final ChangeEnvelope change in changes) {
      validate(change);
    }
  }

  /// Validates one change envelope.
  static void validate(ChangeEnvelope change) {
    if (change.schemaVersion <= 0) {
      throw ValidationException(
        'schemaVersion must be > 0 for ${change.clientMutationId}',
      );
    }

    if (change.op == ChangeOperation.delete && change.payload != null) {
      throw ValidationException(
        'payload must be null for delete operation (${change.clientMutationId})',
      );
    }

    if (change.op == ChangeOperation.upsert && change.payload == null) {
      throw ValidationException(
        'payload is required for upsert operation (${change.clientMutationId})',
      );
    }
  }
}