import { type TransformOptions } from 'stream';
import { SmartDuplex } from './smartstream.classes.smartduplex.js';

export interface AsyncTransformFunction<TInput, TOutput> {
  (chunkArg: TInput): Promise<TOutput>;
}

export function createTransformFunction<TInput, TOutput>(
  asyncFunction: AsyncTransformFunction<TInput, TOutput>,
  options?: TransformOptions
): SmartDuplex {
  const smartDuplexStream = new SmartDuplex({
    ...options,
    writeFunction: async (chunkArg, toolsArg) => {
      const result = await asyncFunction(chunkArg);
      return result;
    }
  });

  return smartDuplexStream;
}

export const createPassThrough = () => {
  return new SmartDuplex({
    objectMode: true,
    writeFunction: async (chunkArg, toolsArg) => {
      return chunkArg;
    }
  })
}