import type { ServerResponse } from 'node:http';
import { StreamData } from './stream-data';

/**
 * A utility class for streaming text responses.
 */
export class StreamingTextResponse extends Response {
  constructor(res: ReadableStream, init?: ResponseInit, data?: StreamData) {
    let processedStream = res;

    if (data) {
      processedStream = res.pipeThrough(data.stream);
    }

    super(processedStream as any, {
      ...init,
      status: 200,
      headers: {
        'Content-Type': 'text/plain; charset=utf-8',
        ...init?.headers,
      },
    });
  }
}

/**
 * A utility function to stream a ReadableStream to a Node.js response-like object.
 */
export function streamToResponse(
  res: ReadableStream,
  response: ServerResponse,
  init?: { headers?: Record<string, string>; status?: number },
) {
  response.writeHead(init?.status || 200, {
    'Content-Type': 'text/plain; charset=utf-8',
    ...init?.headers,
  });

  const reader = res.getReader();
  function read() {
    reader.read().then(({ done, value }: { done: boolean; value?: any }) => {
      if (done) {
        response.end();
        return;
      }
      response.write(value);
      read();
    });
  }
  read();
}