background.js

/**
 * SatyaCheck — Background Service Worker
 * सत्य की जाँच | India's AI Fake News Detector
 *
 * Runs as a Manifest V3 background service worker.
 * Responsibilities:
 *   1. Badge management — shows ✓/! icon on suspicious pages
 *   2. Tab tracking — remembers analysis results per tab
 *   3. Context menu — right-click "Check with SatyaCheck"
 *   4. Backend health check on startup
 *   5. Extension install/update handler
 *
 * File: dist/background.js
 */

'use strict';

// ─── Configuration ─────────────────────────────────────────────────────────────
const BACKEND_URL = 'http://localhost:8000';
const VERSION = '2.1.0';

// ─── Tab Result Store ──────────────────────────────────────────────────────────
// Stores the last analysis result for each tab (by tab ID)
const tabResults = new Map();

// ─── Install / Update Handler ──────────────────────────────────────────────────
chrome.runtime.onInstalled.addListener((details) => {
  if (details.reason === 'install') {
    console.log(`[SatyaCheck] v${VERSION} installed — सत्य की जाँच`);

    // Set default settings on install
    chrome.storage.sync.set({
      autoScan: false,
      alertOnFake: true,
      checkImages: true,
      checkSources: true,
      sensitivity: 'strict',
      language: 'english',
      backendUrl: BACKEND_URL,
      installedAt: new Date().toISOString(),
    });

    // Open welcome/setup tab
    chrome.tabs.create({
      url: chrome.runtime.getURL('index.html'),
    });
  }

  if (details.reason === 'update') {
    console.log(`[SatyaCheck] Updated to v${VERSION}`);
  }

  // Create right-click context menu
  chrome.contextMenus.create({
    id: 'satyacheck-check',
    title: '🔍 Check with SatyaCheck',
    contexts: ['page', 'selection'],
  });
});


// ─── Context Menu Handler ─────────────────────────────────────────────────────
chrome.contextMenus.onClicked.addListener((info, tab) => {
  if (info.menuItemId === 'satyacheck-check') {
    // Open the popup (can't programmatically open popup in MV3, so open in new tab)
    chrome.tabs.create({
      url: chrome.runtime.getURL('index.html') + '?tab=' + tab.id,
    });
  }
});


// ─── Message Handler ─────────────────────────────────────────────────────────
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {

  // Store analysis result for a tab
  if (message.action === 'storeResult') {
    const tabId = sender.tab?.id || message.tabId;
    if (tabId) {
      tabResults.set(tabId, {
        result: message.result,
        timestamp: Date.now(),
      });
      // Update badge
      updateBadge(tabId, message.result?.layer4?.overallRisk || message.result?.layer4?.overall_risk);
    }
    sendResponse({ success: true });
    return true;
  }

  // Get stored result for a tab
  if (message.action === 'getResult') {
    const tabId = message.tabId;
    const stored = tabResults.get(tabId);
    sendResponse({ result: stored?.result || null });
    return true;
  }

  // Page info from content script
  if (message.action === 'pageInfo') {
    const tabId = sender.tab?.id;
    if (tabId && message.isArticle) {
      // Show a subtle badge indicating the page can be checked
      chrome.action.setBadgeText({ text: '?', tabId });
      chrome.action.setBadgeBackgroundColor({ color: '#64748b', tabId });
      chrome.action.setBadgeTextColor({ color: '#ffffff', tabId });
    }
    return true;
  }

  // Backend health check
  if (message.action === 'checkBackend') {
    checkBackendHealth()
      .then(status => sendResponse({ status }))
      .catch(() => sendResponse({ status: 'offline' }));
    return true; // async
  }

  // Clear badge for tab
  if (message.action === 'clearBadge') {
    const tabId = sender.tab?.id || message.tabId;
    if (tabId) {
      chrome.action.setBadgeText({ text: '', tabId });
    }
    sendResponse({ success: true });
    return true;
  }
});


// ─── Tab Close Handler ─────────────────────────────────────────────────────────
chrome.tabs.onRemoved.addListener((tabId) => {
  tabResults.delete(tabId);
});


// ─── Badge Management ──────────────────────────────────────────────────────────

/**
 * Update the extension icon badge based on analysis result.
 * @param {number} tabId
 * @param {string} riskLevel - TRUSTWORTHY / BE CAREFUL / MISLEADING / FAKE NEWS
 */
function updateBadge(tabId, riskLevel) {
  if (!tabId || !riskLevel) return;

  const badgeConfig = {
    'TRUSTWORTHY': { text: '✓', color: '#10b981' },   // Green
    'BE CAREFUL':  { text: '!',  color: '#f59e0b' },   // Amber
    'MISLEADING':  { text: '!!', color: '#f97316' },   // Orange
    'FAKE NEWS':   { text: '✕',  color: '#ef4444' },   // Red
  };

  const config = badgeConfig[riskLevel] || { text: '?', color: '#64748b' };

  chrome.action.setBadgeText({ text: config.text, tabId });
  chrome.action.setBadgeBackgroundColor({ color: config.color, tabId });
  chrome.action.setBadgeTextColor({ color: '#ffffff', tabId });
}


// ─── Backend Health Check ─────────────────────────────────────────────────────

/**
 * Check if the SatyaCheck backend is running and reachable.
 * @returns {Promise<string>} 'online' | 'offline' | 'error'
 */
async function checkBackendHealth() {
  try {
    const settings = await chrome.storage.sync.get(['backendUrl']);
    const url = settings.backendUrl || BACKEND_URL;

    const response = await fetch(`${url}/health/ping`, {
      method: 'GET',
      signal: AbortSignal.timeout(5000), // 5 second timeout
    });

    if (response.ok) {
      return 'online';
    }
    return 'error';
  } catch (error) {
    console.warn('[SatyaCheck] Backend unreachable:', error.message);
    return 'offline';
  }
}


// ─── Startup Health Check ─────────────────────────────────────────────────────
// Check backend health when service worker starts
checkBackendHealth().then(status => {
  console.log(`[SatyaCheck] Backend status on startup: ${status}`);
}).catch(() => {});