background.js

// background.js — HeaderForge service worker

const RULE_ID_BASE = 1000;

// ── Storage helpers ────────────────────────────────────────────────────────────

async function getData() {
  return new Promise(resolve => {
    chrome.storage.local.get(['sites', 'activeProfiles'], result => {
      resolve({
        sites: result.sites || {},          // { hostname: { profiles: [{name, headers:[{name,value}]}], enabled } }
        activeProfiles: result.activeProfiles || {}  // { hostname: profileName }
      });
    });
  });
}

async function saveData(data) {
  return new Promise(resolve => chrome.storage.local.set(data, resolve));
}

// ── Rule builder ───────────────────────────────────────────────────────────────

function buildRules(sites, activeProfiles) {
  const rules = [];
  let ruleId = RULE_ID_BASE;

  for (const [hostname, siteData] of Object.entries(sites)) {
    if (!siteData.enabled) continue;

    const profileName = activeProfiles[hostname];
    if (!profileName) continue;

    const profile = (siteData.profiles || []).find(p => p.name === profileName);
    if (!profile || !profile.headers?.length) continue;

    const requestHeaders = profile.headers
      .filter(h => h.name && h.value)
      .map(h => ({ header: h.name, operation: 'set', value: h.value }));

    if (!requestHeaders.length) continue;

    // Match the hostname and all subdomains / paths
    const urlFilter = `||${hostname}^`;

    rules.push({
      id: ruleId++,
      priority: 1,
      action: { type: 'modifyHeaders', requestHeaders },
      condition: {
        urlFilter,
        resourceTypes: [
          'main_frame','sub_frame','xmlhttprequest','script',
          'stylesheet','image','font','other'
        ]
      }
    });
  }

  return rules;
}

// ── Apply rules ────────────────────────────────────────────────────────────────

async function applyRules() {
  const { sites, activeProfiles } = await getData();
  const newRules = buildRules(sites, activeProfiles);

  // Remove all existing dynamic rules first
  const existing = await chrome.declarativeNetRequest.getDynamicRules();
  const removeIds = existing.map(r => r.id);

  await chrome.declarativeNetRequest.updateDynamicRules({
    removeRuleIds: removeIds,
    addRules: newRules
  });

  console.log(`[HeaderForge] Applied ${newRules.length} rule(s).`);
}

// ── Message handler (from popup) ───────────────────────────────────────────────

chrome.runtime.onMessage.addListener((msg, _sender, sendResponse) => {
  (async () => {
    const { sites, activeProfiles } = await getData();

    switch (msg.type) {

      case 'GET_DATA':
        sendResponse({ sites, activeProfiles });
        break;

      case 'SAVE_SITE': {
        // msg.hostname, msg.siteData
        sites[msg.hostname] = msg.siteData;
        await saveData({ sites, activeProfiles });
        await applyRules();
        sendResponse({ ok: true });
        break;
      }

      case 'DELETE_SITE': {
        delete sites[msg.hostname];
        delete activeProfiles[msg.hostname];
        await saveData({ sites, activeProfiles });
        await applyRules();
        sendResponse({ ok: true });
        break;
      }

      case 'SET_ACTIVE_PROFILE': {
        // msg.hostname, msg.profileName (null = none)
        if (msg.profileName) {
          activeProfiles[msg.hostname] = msg.profileName;
        } else {
          delete activeProfiles[msg.hostname];
        }
        await saveData({ sites, activeProfiles });
        await applyRules();
        sendResponse({ ok: true });
        break;
      }

      case 'TOGGLE_SITE': {
        if (sites[msg.hostname]) {
          sites[msg.hostname].enabled = msg.enabled;
          await saveData({ sites, activeProfiles });
          await applyRules();
        }
        sendResponse({ ok: true });
        break;
      }

      case 'APPLY_RULES':
        await applyRules();
        sendResponse({ ok: true });
        break;

      default:
        sendResponse({ error: 'Unknown message type' });
    }
  })();
  return true; // keep channel open for async
});

// Re-apply on startup
chrome.runtime.onStartup.addListener(applyRules);
chrome.runtime.onInstalled.addListener(applyRules);