"use client";

import { useEffect, useState } from "react";
import { usePathname } from "next/navigation";
import { getConsent, hasCurrentConsentDecision, setAnalyticsConfig, setConsent, track } from "@/lib/analytics/client";

type CategoryText = { label: string; description: string };

type AnalyticsProps = {
  consentVersion: string;
  preferencesEnabled: boolean;
  statisticsEnabled: boolean;
  necessary: CategoryText;
  preferences: CategoryText;
  statistics: CategoryText;
};

const buttonBase =
  "inline-flex items-center justify-center rounded-full px-6 py-3 text-sm font-medium tracking-wide transition-colors duration-300 focus-visible:outline-2 focus-visible:outline-offset-4";

/**
 * Mounted once in app/(frontend)/layout.tsx. Combines two independent jobs:
 * (1) the cookie-consent banner, and (2) automatic page_view tracking on
 * every client-side route change. Both only ever act through track()/
 * setAnalyticsConfig() from lib/analytics/client.ts - no network call is
 * possible from this component before a visitor has actually consented.
 */
export function Analytics({ consentVersion, preferencesEnabled, statisticsEnabled, necessary, preferences, statistics }: AnalyticsProps) {
  // Plain assignment during render (not an effect): must be set before the
  // page_view effect below ever fires, on every render including the first.
  setAnalyticsConfig({ statisticsEnabled, consentVersion });

  const pathname = usePathname();
  const [showBanner, setShowBanner] = useState(false);
  const [expanded, setExpanded] = useState(false);
  const [prefChoice, setPrefChoice] = useState(false);
  const [statChoice, setStatChoice] = useState(false);

  useEffect(() => {
    if (!hasCurrentConsentDecision()) {
      // eslint-disable-next-line react-hooks/set-state-in-effect
      setShowBanner(true);
      const existing = getConsent();
      setPrefChoice(existing?.preferences ?? false);
      setStatChoice(existing?.statistics ?? false);
    }
  }, [consentVersion]);

  useEffect(() => {
    track("page_view", { path: pathname });
  }, [pathname]);

  function acceptAll() {
    setConsent({ preferences: preferencesEnabled, statistics: statisticsEnabled }, consentVersion);
    setShowBanner(false);
  }

  function acceptNecessaryOnly() {
    setConsent({ preferences: false, statistics: false }, consentVersion);
    setShowBanner(false);
  }

  function saveSelection() {
    setConsent({ preferences: preferencesEnabled && prefChoice, statistics: statisticsEnabled && statChoice }, consentVersion);
    setShowBanner(false);
  }

  if (!showBanner) return null;

  return (
    <div
      role="dialog"
      aria-modal="false"
      aria-label="Cookie-Einstellungen"
      className="fixed inset-x-0 bottom-0 z-[90] border-t border-anouma-taupe/30 bg-anouma-cream-light px-6 py-6 shadow-[0_-4px_24px_rgba(0,0,0,0.08)] sm:px-8"
    >
      <div className="mx-auto flex max-w-4xl flex-col gap-4">
        <div>
          <h2 className="font-serif text-xl font-medium text-anouma-plum">Cookie-Einstellungen</h2>
          <p className="mt-2 text-sm leading-relaxed text-anouma-plum/90">
            Wir nutzen Cookies, um die Website technisch bereitzustellen{statisticsEnabled ? " und, mit deiner Zustimmung, datensparsame Statistiken zu erheben" : ""}. Du
            kannst deine Auswahl jederzeit ändern.
          </p>
        </div>

        {expanded && (
          <div className="grid gap-3 rounded-2xl border border-anouma-taupe/30 bg-white/60 p-4 sm:grid-cols-3">
            <label className="flex items-start gap-2 text-sm text-anouma-plum opacity-70">
              <input type="checkbox" checked disabled className="mt-1" />
              <span>
                <strong className="block">{necessary.label}</strong>
                {necessary.description}
              </span>
            </label>

            {preferencesEnabled && (
              <label className="flex items-start gap-2 text-sm text-anouma-plum">
                <input
                  type="checkbox"
                  checked={prefChoice}
                  onChange={(e) => setPrefChoice(e.target.checked)}
                  className="mt-1"
                />
                <span>
                  <strong className="block">{preferences.label}</strong>
                  {preferences.description}
                </span>
              </label>
            )}

            {statisticsEnabled && (
              <label className="flex items-start gap-2 text-sm text-anouma-plum">
                <input
                  type="checkbox"
                  checked={statChoice}
                  onChange={(e) => setStatChoice(e.target.checked)}
                  className="mt-1"
                />
                <span>
                  <strong className="block">{statistics.label}</strong>
                  {statistics.description}
                </span>
              </label>
            )}
          </div>
        )}

        <div className="flex flex-wrap items-center gap-3">
          <button type="button" onClick={acceptAll} className={`${buttonBase} bg-anouma-mauve-dark text-white hover:bg-anouma-plum`}>
            Alle akzeptieren
          </button>
          <button
            type="button"
            onClick={acceptNecessaryOnly}
            className={`${buttonBase} border border-anouma-mauve-dark/40 text-anouma-plum hover:bg-anouma-mauve-dark hover:text-white`}
          >
            Nur notwendige
          </button>
          {!expanded && (
            <button type="button" onClick={() => setExpanded(true)} className="text-sm text-anouma-plum underline underline-offset-4">
              Einstellungen anpassen
            </button>
          )}
          {expanded && (
            <button type="button" onClick={saveSelection} className={`${buttonBase} border border-anouma-mauve-dark/40 text-anouma-plum hover:bg-anouma-mauve-dark hover:text-white`}>
              Auswahl speichern
            </button>
          )}
        </div>
      </div>
    </div>
  );
}