/**
 * PAC (Proxy Auto-Config) proxy management.
 * Builds and applies a PAC script that routes virtual host traffic through the
 * CONNECT proxy (127.0.0.1:8442). Re-applies automatically if another extension
 * or system setting overrides the proxy configuration.
 * Depends on: state.js (extensionState, pacConfirmedActive, DEFAULT_CONNECT_PROXY_PORT, DEFAULT_PROXY_PORT)
 * Depends on: logs.js (log, debugLog)
 */

/** Extract unique two-label base domains from virtualHosts array, always including hole.sail */
function getActiveTlds(virtualHosts) {
  const seen = new Set(['hole.sail']);
  for (const v of (virtualHosts || [])) {
    if (v && v.hostname) {
      const parts = v.hostname.split('.');
      if (parts.length >= 3) seen.add(parts.slice(-2).join('.'));
    }
  }
  return Array.from(seen).map(b => '.' + b);
}

/**
 * Build and apply a PAC script routing all virtual host TLDs through the CONNECT proxy.
 * If `tlds` is omitted, derives the active TLD list from `extensionState.virtualHosts`.
 * @param {string[]} [tlds] - Array of TLD suffixes (e.g. `['.hole.sail', '.hs']`).
 */
function applyPAC(tlds) {
  if (!browser.proxy || !browser.proxy.settings) {
    log('applyPAC: SKIPPED - no browser.proxy.settings API');
    return;
  }
  const proxyPort = extensionState.connectProxyPort ?? DEFAULT_CONNECT_PROXY_PORT ?? extensionState.proxyPort ?? DEFAULT_PROXY_PORT;
  const activeTlds = tlds || getActiveTlds(extensionState.virtualHosts);
  log('applyPAC: setting PAC port=', proxyPort, 'tlds=', activeTlds);

  const clauses = activeTlds.map(t =>
    `  if (dnsDomainIs(host, "${t}")) return "PROXY 127.0.0.1:${proxyPort}";`
  ).join('\n');
  const pacData = `function FindProxyForURL(url, host) {\n${clauses}\n  return "DIRECT";\n}`;

  browser.proxy.settings.set(
    { value: { mode: 'pac_script', pacScript: { data: pacData, mandatory: false } }, scope: 'regular' },
    () => {
      if (browser.runtime.lastError) {
        log('applyPAC: ERROR:', browser.runtime.lastError.message);
        pacConfirmedActive = false;
        return;
      }
      browser.proxy.settings.get({}, (details) => {
        if (browser.runtime.lastError) {
          log('applyPAC: get ERROR:', browser.runtime.lastError.message);
          return;
        }
        const mode = details && details.value && details.value.mode;
        const loc = details && details.levelOfControl;
        log('applyPAC: mode=', mode, 'levelOfControl=', loc);
        if (loc === 'controlled_by_this_extension' && mode === 'pac_script') {
          pacConfirmedActive = true;
          log('applyPAC: ACTIVE');
        } else {
          pacConfirmedActive = false;
          log('applyPAC: WARNING not active - mode=', mode, 'loc=', loc);
        }
      });
    }
  );
}

// Re-apply PAC whenever proxy settings change (e.g. another extension or system override)
if (browser.proxy && browser.proxy.settings && browser.proxy.settings.onChange) {
  browser.proxy.settings.onChange.addListener((details) => {
    const loc = details && details.levelOfControl;
    const mode = details && details.value && details.value.mode;
    log('proxy.settings.onChange: levelOfControl=', loc, 'mode=', mode);
    if (loc === 'controlled_by_this_extension' && mode === 'pac_script') {
      pacConfirmedActive = true;
      return;
    }
    pacConfirmedActive = false;
    log('proxy settings changed externally - reapplying PAC');
    applyPAC();
  });
}

/**
 * Clear the PAC proxy setting, reverting to direct connections.
 * Called when the native host disconnects.
 */
function clearProxy() {
  debugLog('clearProxy');
  if (!browser.proxy || !browser.proxy.settings) return;
  browser.proxy.settings.set({ value: { mode: 'direct' }, scope: 'regular' }).catch(() => {});
}

// Log proxy errors for *.hole.sail to help diagnose issues
if (browser.proxy && browser.proxy.onError) {
  browser.proxy.onError.addListener((details) => {
    log('Proxy error:', details.error, 'url=', details.url);
  });
}