"use client";
import { Analytics } from "@vercel/analytics/next";
import type { BeforeSendEvent } from "@vercel/analytics";
import * as CookieConsent from 'vanilla-cookieconsent';
import 'vanilla-cookieconsent/dist/cookieconsent.css';
import { useEffect } from "react";

// Re-checked on every single event, so it stays correct for the rest of the
// session regardless of the <Analytics> component's own mount state.
// Module-level (not created inside the component) so its reference is
// stable across renders and Analytics doesn't re-register it needlessly.
function gateByConsent(event: BeforeSendEvent) {
    return CookieConsent.acceptedCategory('analytics') ? event : null;
}

export default function CookieBanner() {

    useEffect(() => {
        document.documentElement.classList.add('cc--elegant-black');

        CookieConsent.run({
            guiOptions: {
                consentModal: { layout: 'box', position: 'bottom right' },
                preferencesModal: {layout: 'box'},
            },
            categories: {
                analytics: {}
            },
            language: {
                default: 'de',
                translations: {
                    de: {
                        consentModal: {
                            title: 'Wir nutzen Cookies',
                            description:
                                'Diese Webseite nutzt optionale Cookies für Statistik und Marketing. Mehr dazu in unserer <a href="/datenschutz" target="_blank" rel="noopener">Datenschutzerklärung</a>.',
                            acceptAllBtn: 'Alle akzeptieren',
                            acceptNecessaryBtn: 'Nur notwendige',
                            showPreferencesBtn: 'Einstellungen verwalten',
                        },
                        preferencesModal: {
                            title: 'Cookie-Einstellungen',
                            acceptAllBtn: 'Alle akzeptieren',
                            acceptNecessaryBtn: 'Nur notwendige',
                            savePreferencesBtn: 'Auswahl speichern',
                            sections: [
                                { title: "Statistik", linkedCategory: 'analytics' }
                            ],
                        },
                    },
                },
            },
        })
    }, []);

    return (
        <>
            {/*
             * Always mounted, regardless of consent: @vercel/analytics injects
             * its script into <head> on mount and never removes it on unmount
             * (v2.0.1 has no cleanup), so a script that already loaded would
             * keep tracking after consent is withdrawn if we unmounted this.
             * Gating happens per-event in beforeSend instead, which is
             * re-checked live on every event and therefore stays effective
             * for the rest of the session, including after withdrawal.
             */}
            <Analytics beforeSend={gateByConsent} />
        </>
    )
}