import type { BunFile } from 'bun';
import { fetchWithRetry, defaultRequestInit } from './fetch-retry';

import { TextLineStream } from './text-line-transform-stream';
import { PolyfillTextDecoderStream } from './text-decoder-stream';
function createTextLineStreamFromStreamSource(stream: ReadableStream<Uint8Array>) {
  return stream
    .pipeThrough(new PolyfillTextDecoderStream())
    .pipeThrough(new TextLineStream());
}

// const decoder = new TextDecoder('utf-8');
// async function *createTextLineAsyncGeneratorFromStreamSource(stream: ReadableStream<Uint8Array>): AsyncGenerator<string> {
//   let buf = '';

//   for await (const chunk of stream) {
//     const chunkStr = decoder.decode(chunk).replaceAll('\r\n', '\n');
//     for (let i = 0, len = chunkStr.length; i < len; i++) {
//       const char = chunkStr[i];
//       if (char === '\n') {
//         yield buf;
//         buf = '';
//       } else {
//         buf += char;
//       }
//     }
//   }

//   if (buf) {
//     yield buf;
//   }
// }

export function readFileByLine(file: string | URL | BunFile) {
  if (typeof file === 'string') {
    file = Bun.file(file);
  } else if (!('writer' in file)) {
    file = Bun.file(file);
  }

  return createTextLineStreamFromStreamSource(file.stream());
}

export function createReadlineInterfaceFromResponse(resp: Response) {
  if (!resp.body) {
    throw new Error('Failed to fetch remote text');
  }
  if (resp.bodyUsed) {
    throw new Error('Body has already been consumed.');
  }

  return createTextLineStreamFromStreamSource(resp.body);
}

export function fetchRemoteTextByLine(url: string | URL) {
  return fetchWithRetry(url, defaultRequestInit).then(res => createReadlineInterfaceFromResponse(res));
}