"use client";

import { useEffect, useState } from "react";
import Link from "next/link";
import { Cookie, Settings2, X } from "lucide-react";
import {
  CONSENT_COOKIE_NAME,
  CONSENT_STORAGE_KEY,
  CONSENT_TTL_DAYS,
  CONSENT_VERSION,
  type ConsentState,
} from "@/lib/consent-types";

type Mode = "hidden" | "banner" | "settings";

declare global {
  interface Window {
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    dataLayer?: any[];
    gtag?: (...args: unknown[]) => void;
    openCookieSettings?: () => void;
  }
}

function setCookie(value: string) {
  const expires = new Date();
  expires.setDate(expires.getDate() + CONSENT_TTL_DAYS);
  document.cookie = `${CONSENT_COOKIE_NAME}=${encodeURIComponent(value)}; expires=${expires.toUTCString()}; path=/; SameSite=Lax`;
}

function loadConsent(): ConsentState | null {
  try {
    const raw = localStorage.getItem(CONSENT_STORAGE_KEY);
    if (!raw) return null;
    const parsed = JSON.parse(raw) as ConsentState;
    if (parsed.version !== CONSENT_VERSION) return null;
    return parsed;
  } catch {
    return null;
  }
}

function saveConsent(state: ConsentState) {
  localStorage.setItem(CONSENT_STORAGE_KEY, JSON.stringify(state));
  setCookie(JSON.stringify({ a: state.analytics, m: state.marketing, p: state.preferences }));

  // Google Consent Mode v2 update
  if (typeof window !== "undefined" && window.gtag) {
    window.gtag("consent", "update", {
      ad_storage: state.marketing ? "granted" : "denied",
      ad_user_data: state.marketing ? "granted" : "denied",
      ad_personalization: state.marketing ? "granted" : "denied",
      analytics_storage: state.analytics ? "granted" : "denied",
      functionality_storage: "granted",
      personalization_storage: state.preferences ? "granted" : "denied",
      security_storage: "granted",
    });
  }

  window.dispatchEvent(new CustomEvent("kovak:consent-updated", { detail: state }));
}

export function CookieBanner() {
  const [mode, setMode] = useState<Mode>("hidden");
  const [analytics, setAnalytics] = useState(false);
  const [marketing, setMarketing] = useState(false);
  const [preferences, setPreferences] = useState(false);

  useEffect(() => {
    const existing = loadConsent();
    if (existing) {
      setAnalytics(existing.analytics);
      setMarketing(existing.marketing);
      setPreferences(existing.preferences);
      setMode("hidden");
    } else {
      // Tarayıcı yüklendikten sonra göster, FCP'yi etkilememek için kısa gecikme
      const t = setTimeout(() => setMode("banner"), 800);
      return () => clearTimeout(t);
    }
  }, []);

  useEffect(() => {
    window.openCookieSettings = () => setMode("settings");
    return () => {
      delete window.openCookieSettings;
    };
  }, []);

  const acceptAll = () => {
    saveConsent({
      necessary: true,
      analytics: true,
      marketing: true,
      preferences: true,
      timestamp: Date.now(),
      version: CONSENT_VERSION,
    });
    setAnalytics(true);
    setMarketing(true);
    setPreferences(true);
    setMode("hidden");
  };

  const rejectAll = () => {
    saveConsent({
      necessary: true,
      analytics: false,
      marketing: false,
      preferences: false,
      timestamp: Date.now(),
      version: CONSENT_VERSION,
    });
    setAnalytics(false);
    setMarketing(false);
    setPreferences(false);
    setMode("hidden");
  };

  const saveSelection = () => {
    saveConsent({
      necessary: true,
      analytics,
      marketing,
      preferences,
      timestamp: Date.now(),
      version: CONSENT_VERSION,
    });
    setMode("hidden");
  };

  if (mode === "hidden") return null;

  return (
    <>
      {/* Banner */}
      {mode === "banner" && (
        <div className="fixed inset-x-3 bottom-3 z-50 sm:inset-x-auto sm:bottom-5 sm:left-5 sm:right-5 md:max-w-2xl">
          <div className="rounded-2xl border border-[var(--border)] bg-white p-5 shadow-2xl shadow-[var(--navy)]/15 sm:p-6">
            <div className="flex items-start gap-3">
              <div className="hidden size-10 shrink-0 items-center justify-center rounded-xl bg-[var(--navy-50)] text-[var(--navy)] sm:flex">
                <Cookie className="size-5" />
              </div>
              <div className="flex-1">
                <h3 className="text-sm font-semibold text-[var(--navy)]">
                  Çerez tercihiniz
                </h3>
                <p className="mt-1 text-xs leading-relaxed text-[var(--muted)]">
                  Web sitemizde deneyiminizi geliştirmek, trafiği analiz etmek ve
                  reklam performansını ölçmek için çerezler kullanıyoruz.{" "}
                  <Link
                    href="/cerez-politikasi"
                    className="underline hover:text-[var(--navy)]"
                  >
                    Çerez Politikası
                  </Link>
                </p>

                <div className="mt-4 flex flex-wrap gap-2">
                  <button
                    type="button"
                    onClick={acceptAll}
                    className="rounded-full bg-[var(--navy)] px-4 py-2 text-xs font-medium text-white transition hover:bg-[var(--navy-700)]"
                  >
                    Tümünü kabul et
                  </button>
                  <button
                    type="button"
                    onClick={rejectAll}
                    className="rounded-full border border-[var(--border)] bg-white px-4 py-2 text-xs font-medium text-[var(--navy)] transition hover:bg-[var(--navy-50)]"
                  >
                    Tümünü reddet
                  </button>
                  <button
                    type="button"
                    onClick={() => setMode("settings")}
                    className="inline-flex items-center gap-1.5 rounded-full border border-[var(--border)] bg-white px-4 py-2 text-xs font-medium text-[var(--muted)] transition hover:text-[var(--navy)]"
                  >
                    <Settings2 className="size-3.5" />
                    Ayarları yönet
                  </button>
                </div>
              </div>
            </div>
          </div>
        </div>
      )}

      {/* Settings Modal */}
      {mode === "settings" && (
        <div
          className="fixed inset-0 z-50 flex items-end justify-center bg-black/60 p-4 sm:items-center"
          onClick={() => setMode("banner")}
        >
          <div
            className="w-full max-w-lg rounded-2xl bg-white shadow-2xl"
            onClick={(e) => e.stopPropagation()}
          >
            <div className="flex items-start justify-between border-b border-[var(--border)] p-6">
              <div>
                <h3 className="text-lg font-semibold text-[var(--navy)]">
                  Çerez ayarları
                </h3>
                <p className="mt-1 text-xs text-[var(--muted)]">
                  Hangi çerez türlerine izin verdiğinizi seçin.
                </p>
              </div>
              <button
                type="button"
                aria-label="Kapat"
                onClick={() => setMode("banner")}
                className="rounded-md p-1 text-[var(--muted)] hover:bg-[var(--navy-50)] hover:text-[var(--navy)]"
              >
                <X className="size-5" />
              </button>
            </div>

            <div className="max-h-[60vh] space-y-4 overflow-y-auto p-6">
              <CategoryRow
                title="Zorunlu çerezler"
                description="Site temel işlevleri için gerekli. Oturum, güvenlik, form gönderimi. Devre dışı bırakılamaz."
                checked
                disabled
              />
              <CategoryRow
                title="Analitik çerezler"
                description="Ziyaretçi sayısı, sayfa görüntüleme, trafik kaynağı gibi anonim istatistikler. Google Analytics."
                checked={analytics}
                onChange={setAnalytics}
              />
              <CategoryRow
                title="Reklam çerezleri"
                description="Sizinle ilgili olabilecek reklamların gösterilmesi ve reklam performansının ölçülmesi. Google Ads, Meta Pixel."
                checked={marketing}
                onChange={setMarketing}
              />
              <CategoryRow
                title="Tercih çerezleri"
                description="Dil, bölge, görüntüleme tercihlerinizi hatırlamak için."
                checked={preferences}
                onChange={setPreferences}
              />
            </div>

            <div className="flex flex-wrap items-center justify-end gap-2 border-t border-[var(--border)] bg-[var(--navy-50)]/40 p-4">
              <button
                type="button"
                onClick={rejectAll}
                className="rounded-full border border-[var(--border)] bg-white px-4 py-2 text-xs font-medium text-[var(--muted)] hover:text-[var(--navy)]"
              >
                Tümünü reddet
              </button>
              <button
                type="button"
                onClick={saveSelection}
                className="rounded-full border border-[var(--navy)] bg-white px-4 py-2 text-xs font-medium text-[var(--navy)] hover:bg-[var(--navy-50)]"
              >
                Seçimi kaydet
              </button>
              <button
                type="button"
                onClick={acceptAll}
                className="rounded-full bg-[var(--navy)] px-4 py-2 text-xs font-medium text-white hover:bg-[var(--navy-700)]"
              >
                Tümünü kabul et
              </button>
            </div>
          </div>
        </div>
      )}
    </>
  );
}

function CategoryRow({
  title,
  description,
  checked,
  disabled,
  onChange,
}: {
  title: string;
  description: string;
  checked: boolean;
  disabled?: boolean;
  onChange?: (v: boolean) => void;
}) {
  return (
    <div className="rounded-xl border border-[var(--border)] bg-white p-4">
      <div className="flex items-start justify-between gap-4">
        <div>
          <p className="text-sm font-semibold text-[var(--navy)]">{title}</p>
          <p className="mt-1 text-xs leading-relaxed text-[var(--muted)]">
            {description}
          </p>
        </div>
        <label className="relative inline-flex shrink-0 cursor-pointer items-center">
          <input
            type="checkbox"
            checked={checked}
            disabled={disabled}
            onChange={(e) => onChange?.(e.target.checked)}
            className="peer sr-only"
          />
          <div
            className={`h-6 w-11 rounded-full transition ${
              disabled
                ? "bg-[var(--sky)]/60"
                : "bg-[var(--border)] peer-checked:bg-[var(--navy)]"
            }`}
          />
          <div
            className={`absolute left-0.5 top-0.5 size-5 rounded-full bg-white shadow transition ${
              checked ? "translate-x-5" : ""
            }`}
          />
        </label>
      </div>
    </div>
  );
}