background.js

/**
 * deepblur — background
 *
 * Modes (browser.storage.local "imageMode"):
 *   "block" — cancel image-class requests via webRequest
 *   "blur"  — allow requests; content script applies CSS blur
 *   "allow" — full images
 *
 * Default: "block"
 */

const IMAGE_TYPES = ["image", "imageset", "media"];
const STORAGE_KEY = "imageMode";
const DEFAULT_MODE = "block";

let currentMode = DEFAULT_MODE;

browser.storage.local.get(STORAGE_KEY).then((result) => {
  currentMode = result[STORAGE_KEY] || DEFAULT_MODE;
  applyWebRequestRule();
});

browser.storage.onChanged.addListener((changes, area) => {
  if (area === "local" && changes[STORAGE_KEY]) {
    currentMode = changes[STORAGE_KEY].newValue;
    applyWebRequestRule();
    notifyAllTabs();
  }
});

function blockListener(details) {
  return { cancel: true };
}

function applyWebRequestRule() {
  if (browser.webRequest.onBeforeRequest.hasListener(blockListener)) {
    browser.webRequest.onBeforeRequest.removeListener(blockListener);
  }

  if (currentMode === "block") {
    browser.webRequest.onBeforeRequest.addListener(
      blockListener,
      { urls: ["<all_urls>"], types: IMAGE_TYPES },
      ["blocking"]
    );
  }
}

browser.runtime.onMessage.addListener((msg, sender, sendResponse) => {
  if (msg.type === "GET_MODE") {
    sendResponse({ mode: currentMode });
    return true;
  }
  if (msg.type === "SET_MODE") {
    const newMode = msg.mode;
    browser.storage.local.set({ [STORAGE_KEY]: newMode });
    sendResponse({ ok: true });
    return true;
  }
});

function notifyAllTabs() {
  browser.tabs.query({}).then((tabs) => {
    for (const tab of tabs) {
      browser.tabs
        .sendMessage(tab.id, { type: "MODE_CHANGED", mode: currentMode })
        .catch(() => {});
    }
  });
}