import { ServiceError } from '@bytelyst/errors';

type DependencyKind = 'extraction-service' | 'llm' | 'blob';

function causeMessage(error: unknown): string {
  return error instanceof Error ? error.message : String(error);
}

function dependencyError(
  dependency: DependencyKind,
  statusCode: number,
  message: string,
  code: string,
  error: unknown,
): ServiceError {
  return new ServiceError(statusCode, message, {
    code,
    dependency,
    cause: causeMessage(error),
  });
}

export function mapExtractionFailure(error: unknown): ServiceError {
  return dependencyError(
    'extraction-service',
    502,
    'Extraction service failed',
    'EXTRACTION_SERVICE_FAILURE',
    error,
  );
}

export function mapLlmFailure(error: unknown): ServiceError {
  const message = causeMessage(error).toLowerCase();
  const timedOut = message.includes('timed out') || message.includes('timeout');

  return dependencyError(
    'llm',
    timedOut ? 504 : 502,
    timedOut ? 'LLM request timed out' : 'LLM request failed',
    timedOut ? 'LLM_TIMEOUT' : 'LLM_FAILURE',
    error,
  );
}

export function mapBlobFailure(error: unknown): ServiceError {
  return dependencyError(
    'blob',
    502,
    'Blob service failed',
    'BLOB_SERVICE_FAILURE',
    error,
  );
}