dark mode safari

safari_dark_mode.js

/**
 * background.js — Smart Dark Mode Extension
 * 
 * Responsibilities:
 *  - Icon state management
 *  - Forwarding toggle messages to active tab
 *  - Re-injecting content script into existing tabs on install/update
 *  - Responding to tab URL changes (re-trigger smart detection per page)
 */

// ─────────────────────────────────────────────────────────────────────────────
// ICON UPDATE
// ─────────────────────────────────────────────────────────────────────────────

function updateIcon(enabled, tabId) {
  const folder = enabled ? 'enabled' : 'disabled';
  const iconSpec = {
    path: {
      "16":  `icons/${folder}/icon16.png`,
      "48":  `icons/${folder}/icon48.png`,
      "128": `icons/${folder}/icon128.png`,
    }
  };
  if (tabId) iconSpec.tabId = tabId;
  chrome.action.setIcon(iconSpec);
}

// ─────────────────────────────────────────────────────────────────────────────
// INSTALL / UPDATE — inject into all existing tabs so reload isn't required
// ─────────────────────────────────────────────────────────────────────────────

chrome.runtime.onInstalled.addListener(async (details) => {
  // Set defaults only on fresh install (not on update, to preserve user prefs)
  if (details.reason === 'install') {
    await chrome.storage.local.set({ enabled: true, smartDetection: true });
  }

  // Re-inject content script into all open, scriptable tabs
  const tabs = await chrome.tabs.query({});
  for (const tab of tabs) {
    if (!tab.url || tab.url.startsWith('chrome://') || tab.url.startsWith('chrome-extension://')) continue;
    try {
      await chrome.scripting.executeScript({
        target: { tabId: tab.id },
        files: ['content.js'],
      });
    } catch (_) {
      // Tab may not allow script injection (e.g. PDF, devtools) — silently skip
    }
  }

  // Sync icon with current state
  const result = await chrome.storage.local.get(['enabled']);
  updateIcon(result.enabled !== false);
});

// ─────────────────────────────────────────────────────────────────────────────
// STARTUP — sync icon
// ─────────────────────────────────────────────────────────────────────────────

chrome.runtime.onStartup.addListener(async () => {
  const result = await chrome.storage.local.get(['enabled']);
  updateIcon(result.enabled !== false);
});

// Also sync immediately at service-worker boot
chrome.storage.local.get(['enabled'], (result) => {
  updateIcon(result.enabled !== false);
});

// ─────────────────────────────────────────────────────────────────────────────
// MESSAGES FROM POPUP
// ─────────────────────────────────────────────────────────────────────────────

chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {

  // Popup asking to update the icon
  if (message.action === 'updateIcon') {
    updateIcon(message.enabled, message.tabId || null);
    sendResponse({ ok: true });
    return true;
  }

  // Popup toggled the switch — forward to the active tab's content script
  if (message.action === 'toggle' || message.action === 'refresh' ||
      message.action === 'enable' || message.action === 'disable') {
    chrome.tabs.query({ active: true, currentWindow: true }, (tabs) => {
      if (tabs[0]) {
        chrome.tabs.sendMessage(tabs[0].id, message, () => {
          // Suppress "no receiving end" errors for pages without content script
          if (chrome.runtime.lastError) {}
        });
      }
    });
    sendResponse({ ok: true });
    return true;
  }

  // Popup asking for current state
  if (message.action === 'getState') {
    chrome.storage.local.get(['enabled', 'smartDetection'], (result) => {
      sendResponse({
        enabled:        result.enabled !== false,
        smartDetection: result.smartDetection !== false,
      });
    });
    return true; // keep channel open for async sendResponse
  }
});

// ─────────────────────────────────────────────────────────────────────────────
// TAB EVENTS — re-trigger content script on navigation (SPA & full loads)
// ─────────────────────────────────────────────────────────────────────────────

// When a tab finishes loading, tell its content script to re-evaluate
chrome.tabs.onUpdated.addListener((tabId, changeInfo) => {
  if (changeInfo.status !== 'complete') return;
  chrome.storage.local.get(['enabled'], (result) => {
    if (result.enabled === false) return;
    chrome.tabs.sendMessage(tabId, { action: 'refresh' }, () => {
      if (chrome.runtime.lastError) {} // content script not injected yet — fine
    });
  });
});

// Keep icon in sync when user switches tabs
chrome.tabs.onActivated.addListener(async ({ tabId }) => {
  const result = await chrome.storage.local.get(['enabled']);
  updateIcon(result.enabled !== false, tabId);
});