"use client";

import { useEffect, useRef } from 'react';
import { useCookieConsentStore } from '../../store/cookieConsentStore';

declare global {
  interface Window {
    dataLayer?: any[];
    gtag?: (...args: any[]) => void;
    fbq?: any;
    _fbq?: any;
    ttq?: any;
  }
}

export default function ScriptManager() {
  const { record, isHydrated } = useCookieConsentStore();
  const consentInitializedRef = useRef(false);
  const gaInjectedRef = useRef(false);
  const metaInjectedRef = useRef(false);
  const tiktokInjectedRef = useRef(false);

  // 1. Initialize Google Consent Mode v2 Defaults
  useEffect(() => {
    if (typeof window === 'undefined' || consentInitializedRef.current) return;
    consentInitializedRef.current = true;

    window.dataLayer = window.dataLayer || [];
    if (!window.gtag) {
      window.gtag = function () {
        window.dataLayer?.push(arguments);
      };
    }

    // Default to 'denied' as required by GDPR/PDPA prior to user choice
    window.gtag('consent', 'default', {
      analytics_storage: 'denied',
      ad_storage: 'denied',
      ad_user_data: 'denied',
      ad_personalization: 'denied',
    });
  }, []);

  // 2. Sync consent updates whenever state changes
  useEffect(() => {
    if (!isHydrated || typeof window === 'undefined') return;

    const { preferences, hasResponded } = record;

    if (window.gtag) {
      window.gtag('consent', 'update', {
        analytics_storage: hasResponded && preferences.analytics ? 'granted' : 'denied',
        ad_storage: hasResponded && preferences.marketing ? 'granted' : 'denied',
        ad_user_data: hasResponded && preferences.marketing ? 'granted' : 'denied',
        ad_personalization: hasResponded && preferences.marketing ? 'granted' : 'denied',
      });
    }

    // Dispatch custom browser event for any other custom tags/scripts
    window.dispatchEvent(
      new CustomEvent('homaroma:consent-change', {
        detail: {
          hasResponded,
          preferences,
        },
      })
    );

    // 3. Inject GA4 dynamically if enabled and configured
    const gaId = process.env.NEXT_PUBLIC_GA_MEASUREMENT_ID;
    if (gaId && hasResponded && preferences.analytics && !gaInjectedRef.current) {
      gaInjectedRef.current = true;
      const script = document.createElement('script');
      script.src = `https://www.googletagmanager.com/gtag/js?id=${gaId}`;
      script.async = true;
      document.head.appendChild(script);

      window.gtag?.('js', new Date());
      window.gtag?.('config', gaId, {
        anonymize_ip: true,
      });
    }

    // 4. Inject Meta Pixel dynamically if enabled and configured
    const metaPixelId = process.env.NEXT_PUBLIC_META_PIXEL_ID;
    if (metaPixelId && hasResponded && preferences.marketing && !metaInjectedRef.current) {
      metaInjectedRef.current = true;
      (function (f: any, b: any, e: any, v: any, n?: any, t?: any, s?: any) {
        if (f.fbq) return;
        n = f.fbq = function () {
          n.callMethod ? n.callMethod.apply(n, arguments) : n.queue.push(arguments);
        };
        if (!f._fbq) f._fbq = n;
        n.push = n;
        n.loaded = true;
        n.version = '2.0';
        n.queue = [];
        t = b.createElement(e);
        t.async = true;
        t.src = v;
        s = b.getElementsByTagName(e)[0];
        s.parentNode.insertBefore(t, s);
      })(window, document, 'script', 'https://connect.facebook.net/en_US/fbevents.js');

      window.fbq('init', metaPixelId);
      window.fbq('track', 'PageView');
    }

    // 5. Inject TikTok Pixel dynamically if enabled and configured
    const tiktokPixelId = process.env.NEXT_PUBLIC_TIKTOK_PIXEL_ID;
    if (tiktokPixelId && hasResponded && preferences.marketing && !tiktokInjectedRef.current) {
      tiktokInjectedRef.current = true;
      (function (w: any, d: any, t: any) {
        w.TiktokAnalyticsObject = t;
        const ttq = (w[t] = w[t] || []);
        ttq.methods = [
          'page',
          'track',
          'identify',
          'instances',
          'debug',
          'on',
          'off',
          'once',
          'ready',
          'alias',
          'group',
          'enableCookie',
          'disableCookie',
        ];
        ttq.setAndDefer = function (t: any, e: any) {
          t[e] = function () {
            t.push([e].concat(Array.prototype.slice.call(arguments, 0)));
          };
        };
        for (let i = 0; i < ttq.methods.length; i++) {
          ttq.setAndDefer(ttq, ttq.methods[i]);
        }
        ttq.instance = function (t: any) {
          const e = ttq._i[t] || [];
          for (let n = 0; n < ttq.methods.length; n++) {
            ttq.setAndDefer(e, ttq.methods[n]);
          }
          return e;
        };
        ttq.load = function (e: any, n: any) {
          const i = 'https://analytics.tiktok.com/i18n/pixel/events.js';
          ttq._i = ttq._i || {};
          ttq._i[e] = [];
          ttq._i[e]._u = i;
          ttq._t = ttq._t || {};
          ttq._t[e] = +new Date();
          ttq._o = ttq._o || {};
          ttq._o[e] = n || {};
          const o = d.createElement('script');
          o.type = 'text/javascript';
          o.async = true;
          o.src = `${i}?sdkid=${e}&lib=${t}`;
          const a = d.getElementsByTagName('script')[0];
          a.parentNode.insertBefore(o, a);
        };
      })(window, document, 'ttq');

      window.ttq?.load(tiktokPixelId);
      window.ttq?.page();
    }
  }, [record, isHydrated]);

  return null;
}