// ==UserScript==
// @name DarkReader
// @version 0.0.7
// @match *://*/*
// @downloadURL https://gist.github.com/evanreichard/f983ca26836d4af6ca0f6fb602b9dcaf/raw/darkreader.user.js
// @require https://unpkg.com/darkreader@4.9.46/darkreader.js
// @grant GM.xmlhttpRequest
// @grant GM.registerMenuCommand
// @grant GM.unregisterMenuCommand
// @grant GM_getValue
// @grant GM_setValue
// @inject-into content
// @noframes
// @run-at document-start
// ==/UserScript==

/* globals DarkReader */

let options = {
  brightness: 70,
  contrast: 110,
  sepia: 50,
};

let prefersDark =
  window.matchMedia &&
  window.matchMedia("(prefers-color-scheme: dark)").matches;

function toggleHost() {
  let disabledHosts = GM_getValue("disabledHosts", []);
  let isDisabled = disabledHosts.includes(window.location.hostname);

  if (isDisabled) {
    disabledHosts = disabledHosts.filter(
      (item) => item !== window.location.hostname,
    );
  } else {
    disabledHosts.push(window.location.hostname);
  }

  GM_setValue("disabledHosts", disabledHosts);
  applySettings();
}

function toggleSystem() {
  let useSystem = GM_getValue("useSystem", true);
  GM_setValue("useSystem", !useSystem);
  applySettings();
}

/**
 * This is necessary for CORS related requests. GM.xmlhttpRequest
 * bypasses that restriction.
 **/
async function extensionFetch(url) {
  let responseData = await new Promise((resolve, reject) => {
    GM.xmlhttpRequest({
      url,
      responseType: "blob",
      onerror: reject,
      onload: resolve,
    });
  });

  return new Response(responseData.response);
}

DarkReader.setFetchMethod(extensionFetch);

function applySettings() {
  GM.unregisterMenuCommand("System Mode - Enable");
  GM.unregisterMenuCommand("System Mode - Disable");
  GM.unregisterMenuCommand("DarkReader - Disable");
  GM.unregisterMenuCommand("DarkReader - Enable");

  let disabledHosts = GM_getValue("disabledHosts", []);
  let useSystem = GM_getValue("useSystem", true);

  if (useSystem) {
    GM.registerMenuCommand("System Mode - Disable", toggleSystem);
  } else {
    GM.registerMenuCommand("System Mode - Enable", toggleSystem);
  }

  let isDisabled = disabledHosts.includes(window.location.hostname);
  if (isDisabled) {
    GM.registerMenuCommand("DarkReader - Enable", toggleHost);
  } else {
    GM.registerMenuCommand("DarkReader - Disable", toggleHost);
  }

  if (useSystem && prefersDark && !isDisabled)
    return DarkReader.enable(options);
  if (!useSystem && !isDisabled) return DarkReader.enable(options);

  DarkReader.disable();
}

// System Change
window
  .matchMedia("(prefers-color-scheme: dark)")
  .addEventListener("change", (event) => {
    prefersDark = event.matches;
    applySettings();
  });

// Initial Load
applySettings();