/*
  Copyright 2019 Google LLC

  Use of this source code is governed by an MIT-style
  license that can be found in the LICENSE file or at
  https://opensource.org/licenses/MIT.
*/

import {canConstructResponseFromBodyStream} from './_private/canConstructResponseFromBodyStream.js';
import './_version.js';


/**
 * Allows developers to copy a response and modify its `headers`, `status`,
 * or `statusText` values (the values settable via a
 * [`ResponseInit`]{@link https://developer.mozilla.org/en-US/docs/Web/API/Response/Response#Syntax}
 * object in the constructor).
 * To modify these values, pass a function as the second argument. That
 * function will be invoked with a single object with the response properties
 * `{headers, status, statusText}`. The return value of this function will
 * be used as the `ResponseInit` for the new `Response`. To change the values
 * either modify the passed parameter(s) and return it, or return a totally
 * new object.
 *
 * @param {Response} response
 * @param {Function} modifier
 * @memberof module:workbox-core
 */
async function copyResponse(
  response: Response,
  modifier?: (responseInit: ResponseInit) => ResponseInit
) {
  const clonedResponse = response.clone();

  // Create a fresh `ResponseInit` object by cloning the headers.
  const responseInit: ResponseInit = {
    headers: new Headers(clonedResponse.headers),
    status: clonedResponse.status,
    statusText: clonedResponse.statusText,
  }

  // Apply any user modifications.
  const modifiedResponseInit = modifier ? modifier(responseInit) : responseInit;

  // Create the new response from the body stream and `ResponseInit`
  // modifications. Note: not all browsers support the Response.body stream,
  // so fall back to reading the entire body into memory as a blob.
  const body = canConstructResponseFromBodyStream() ?
      clonedResponse.body : await clonedResponse.blob();

  return new Response(body, modifiedResponseInit);
}

export {copyResponse}