/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

export const newtabFileHeader = () => {
  let licenseString = [
    "/* This Source Code Form is subject to the terms of the Mozilla Public",
    " * License, v. 2.0. If a copy of the MPL was not distributed with this",
    " * file, You can obtain one at http://mozilla.org/MPL/2.0/. */",
  ].join("\n");

  let commentString = [
    "/* DO NOT EDIT this file directly, instead modify the relevant *.nova.tokens.json file",
    " * and run `mach buildtokens` to see your changes. */",
  ].join("\n");

  let backwardCompatString = [
    "/*",
    " * @backward-compat { version 155 }",
    " * Nova design token overrides are gated on the `browser.design-tokens.nova` pref in",
    " * tokens-shared.css, which is NOT enabled when HNT ships its Nova experience (gated",
    " * on `browser.newtabpage.activity-stream.nova.enabled`). Since the newtab extension",
    " * can train-hop, it cannot rely on toolkit CSS behind a pref gate. This file provides",
    " * those token values directly so nova/activity-stream.css is self-contained.",
    " * Remove this file when `browser.nova.enabled` unifies both prefs and reaches Release.",
    " */",
  ].join("\n");

  let header =
    licenseString +
    "\n\n" +
    commentString +
    "\n\n" +
    backwardCompatString +
    "\n\n";

  return header;
};