module.exports = {
  injectHead({ pluginConfig, pageType }) {
    const trackingId = pluginConfig.tracking_id;
    if (!trackingId) return '';

    // 1. Never inject analytics on administrative moderation pages
    if (pageType === 'admin') {
      return '';
    }

    // 2. Do not inject in development, staging, or testing modes (unless explicitly enabled)
    const isProd = process.env.NODE_ENV === 'production' && process.env.APP_ENV !== 'staging';
    if (!isProd && !pluginConfig.enable_in_dev) {
      return '';
    }

    return `
    <!-- Google Analytics (GA4 via Plugin) -->
    <script async src="https://www.googletagmanager.com/gtag/js?id=${trackingId}"></script>
    <script>
      (function() {
        // 3. Client-side domain safeguard: only track on production pengzhan.dev domains
        var host = window.location.hostname;
        if (host !== 'pengzhan.dev' && !host.endsWith('.pengzhan.dev')) {
          window['ga-disable-${trackingId}'] = true;
          window.dataLayer = window.dataLayer || [];
          window.gtag = function(){};
          return;
        }
        window.dataLayer = window.dataLayer || [];
        function gtag(){dataLayer.push(arguments);}
        window.gtag = gtag;
        gtag('js', new Date());
        gtag('config', '${trackingId}');
      })();
    </script>
    `;
  }
};