/// <reference no-default-lib="true" />
/// <reference lib="esnext" />
/// <reference lib="dom" />
/// <reference lib="dom.iterable" />
import "https://raw.githubusercontent.com/DefinitelyTyped/DefinitelyTyped/3b80d99d9f86950c913035044105257b9fd6f3a9/types/tampermonkey/index.d.ts";

const parseHeaders = (rawHeaders: string) =>
 new Headers(
    rawHeaders
      // Replace instances of \r\n and \n followed by at least one space or horizontal tab with a space
      // https://tools.ietf.org/html/rfc7230#section-3.2
      .replace(/\r?\n[\t ]+/g, " ")
      .split(/\r\n|\r|\n/)
      .flatMap((header) => {
        const [key, value] = header.split(":").map((text) => text.trim());
        if (!key) return [];
        return [[key, value]] as [string, string][];
      })
  );

/** CORSを突破してfetchする
 *
 * interfaceは`fetch`と同一
 */
export const GM_fetch = (input: RequestInfo | URL, init?: RequestInit): Promise<Response> =>
  new Promise((resolve, reject) => {
    const request = new Request(input, init);
    
    const headers = Object.fromEntries(request.headers.entries());
    if (init?.referrer) {
      headers.Referer = init.referrer;
    }

    if (request.signal?.aborted) {
      reject(new DOMException("Aborted", "AbortError"));
      return;
    }
    const { abort } = GM_xmlhttpRequest({
      // @ts-ignore 多分変な文字列は入ってこないはず
      method: request.method,
      url: request.url,
      headers,
      // await request.text() でも同じことができるが、二度手間なのでinitから直接取り出す
      ...(init?.body ? ({ data: init.body }) : ({})),
      anonymous: request.credentials === "omit",
      // @ts-ignore streamも指定可能
      responseType: "stream",
      onerror: () => {
        reject(new TypeError("Network request failed"));
      },
      ontimeout: () => {
        reject(new TypeError("Network request timeout"));
      },
      onabort: () => {
        reject(new DOMException("Aborted", "AbortError"));
      },
      // fetchはHEADERS_RECEIVEDの段階でresolveするので、それにあわせる
      // https://ja.javascript.info/fetch
      onreadystatechange: (res) => {
        switch (res.readyState) {
          case 2: {
            const response = new Response(res.response, {
              status: res.status,
              statusText: res.statusText,
              headers: parseHeaders(res.responseHeaders),
            });
            // urlはconstructor経由で設定できない
            Object.defineProperty(response, "url", { value: res.finalUrl });
            resolve(response);
            break;
          }
          case 4:
            request.signal?.removeEventListener?.("abort", abort);
            break;
          default:
            break;
        }
      },
    });
    
    request.signal?.addEventListener?.("abort", abort);
  });