import { test } from "bun:test";
import { once } from "events";
import { request } from "http";
import { AddressInfo, Server } from "net";

const fixture = "node-http-transfer-encoding-fixture.ts";
test(`should not duplicate transfer-encoding header`, async () => {
  const { resolve, promise } = Promise.withResolvers();
  const tcpServer = new Server();
  tcpServer.listen(0, "127.0.0.1");

  await once(tcpServer, "listening");

  tcpServer.on("connection", async socket => {
    const requestHeader = await once(socket, "data").then(data => data.toString());
    queueMicrotask(() => {
      socket.write("HTTP/1.1 200 OK\r\nConnection: close\r\nContent-Length: 0\r\n\r\n");
      socket.end(resolve);
    });

    const httpHeadersArray = requestHeader
      .split("\r\n")
      .slice(1) // Skip the first line (HTTP method line)
      .map(line => line.trim())
      .filter((_, index, arr) => index < arr.indexOf(""))
      .reduce(
        (headers, line) => {
          const [key, value] = line.split(/\s*:\s*/);
          return [...headers, { [key.toLowerCase()]: value }];
        },
        [] as { [key: string]: string }[],
      );
    const transferEncodingHeaders = httpHeadersArray.filter(header => header["transfer-encoding"]);
    if (transferEncodingHeaders.length > 1) {
      throw new Error(`Duplicate 'transfer-encoding' header found: ${JSON.stringify(transferEncodingHeaders)}`);
    }
  });

  const serverAddress = tcpServer.address() as AddressInfo;
  const chunkedRequest = request({
    host: "localhost",
    port: serverAddress.port,
    path: "/",
    method: "PUT",
    agent: false,
    headers: {
      "transfer-encoding": "chunked",
    },
  });

  // Requires multiple chunks to trigger streaming behavior
  chunkedRequest.write("Hello, World!");
  chunkedRequest.end("Goodbye, World!");

  return promise;
});