import { IncomingMessage, ServerResponse } from "http";

import { getRelativePart } from "./urls";

class ServerResponseWithBodyChunks extends ServerResponse {

bodyChunks: Uint8Array[] = [];

// note: we actually override this, even though it's private in the parent

_send(data: string, encoding: BufferEncoding, callback?: (() => void) | null, byteLength?: number) {

if (typeof encoding === "function") {

callback = encoding;

encoding = "utf-8";

}

const encodedBuffer = new Uint8Array(Buffer.from(data, encoding));

this.bodyChunks.push(encodedBuffer);

callback?.();

}

}

export async function createNodeHttpServerDuplex(options: {

method: string,

originalUrl?: URL,

url: URL,

headers: Headers,

body: Uint8Array,

}): Promise<[IncomingMessage, ServerResponseWithBodyChunks]> {

// See https://github.com/nodejs/node/blob/main/lib/_http_incoming.js

// and https://github.com/nodejs/node/blob/main/lib/_http_common.js (particularly the `parserXyz` functions)

const incomingMessage = new IncomingMessage({

encrypted: options.originalUrl?.protocol === "https:", // trick frameworks into believing this is an HTTPS request

} as any);

incomingMessage.httpVersionMajor = 1;

incomingMessage.httpVersionMinor = 1;

incomingMessage.httpVersion = '1.1';

incomingMessage.method = options.method;

incomingMessage.url = getRelativePart(options.url);

(incomingMessage as any).originalUrl = options.originalUrl && getRelativePart(options.originalUrl); // originalUrl is an extension used by some servers; for example, oidc-provider reads it to construct the paths for the .well-known/openid-configuration

const rawHeaders = [...options.headers.entries()].flat();

(incomingMessage as any)._addHeaderLines(rawHeaders, rawHeaders.length);

incomingMessage.push(Buffer.from(options.body));

incomingMessage.complete = true;

incomingMessage.push(null); // to emit end event, see: https://github.com/nodejs/node/blob/4cf6fabce20eb3050c5b543d249e931ea3d3cad5/lib/_http_common.js#L150

const serverResponse = new ServerResponseWithBodyChunks(incomingMessage);

return [incomingMessage, serverResponse];

}