"use client";

// =============================================================================
//  CookieBanner
// =============================================================================
//
//  A small, non-blocking cookie / consent banner shown on first visit.
//  Two buttons:  ACK (accept)  /  RST (reject) — network-engineer humour.
//
//  Behaviour:
//   - On first load, if no consent decision is stored, the banner appears.
//   - "ACK" stores `novarix-cookie-consent = "ack"` in localStorage and the
//     banner closes. The site then behaves as before (intro animation
//     remembers it has played using sessionStorage).
//   - "RST" stores `novarix-cookie-consent = "rst"` in localStorage and the
//     banner closes. We also clear the intro-seen flag so we don't keep any
//     non-consent storage around.
//   - The footer "Cookie preferences" link dispatches a window event that
//     re-opens this banner so users can change their mind.
//
//  All visible text comes from `/content.ts` -> site.cookies.
// =============================================================================

import Link from "next/link";
import { useEffect, useState } from "react";
import { site } from "@/content";

const CONSENT_KEY = "novarix-cookie-consent";
const INTRO_SEEN_KEY = "novarix-intro-seen";
const REOPEN_EVENT = "novarix:open-cookie-banner";
const INTRO_EVENT = "novarix:start-intro";

type Consent = "unknown" | "ack" | "rst";

export default function CookieBanner() {
  // Start from the pre-hydration decision made in layout.tsx so the banner
  // can appear immediately on first visit without waiting for a delayed effect.
  const [visible, setVisible] = useState(() => {
    if (typeof document === "undefined") return false;
    return document.documentElement.dataset.showCookieBanner === "1";
  });

  // Read the stored consent on mount and decide whether to show the banner.
  useEffect(() => {
    try {
      const stored = window.localStorage.getItem(CONSENT_KEY) as Consent | null;
      if (stored !== "ack" && stored !== "rst") {
        document.documentElement.dataset.showCookieBanner = "1";
        // eslint-disable-next-line react-hooks/set-state-in-effect
        setVisible(true);
      } else {
        document.documentElement.dataset.showCookieBanner = "0";
      }
    } catch {
      // localStorage unavailable (private mode, blocked, etc.) — show the
      // banner so the user is still told. Sync-once-on-mount is a legitimate
      // use of setState in an effect.
      // eslint-disable-next-line react-hooks/set-state-in-effect
      document.documentElement.dataset.showCookieBanner = "1";
      setVisible(true);
    }
  }, []);

  // Listen for the "re-open" event from the footer "Cookie preferences" link.
  useEffect(() => {
    const handler = () => setVisible(true);
    window.addEventListener(REOPEN_EVENT, handler);
    return () => window.removeEventListener(REOPEN_EVENT, handler);
  }, []);

  function decide(choice: "ack" | "rst") {
    try {
      window.localStorage.setItem(CONSENT_KEY, choice);
      if (choice === "rst") {
        // Honour the rejection by clearing any non-consent storage.
        window.sessionStorage.removeItem(INTRO_SEEN_KEY);
      } else {
        window.dispatchEvent(new Event(INTRO_EVENT));
      }
    } catch {
      /* storage unavailable — nothing to do */
    }
    document.documentElement.dataset.showCookieBanner = "0";
    setVisible(false);
  }

  if (!visible) return null;

  return (
    <div
      role="dialog"
      aria-live="polite"
      aria-label="Cookie consent"
      className="fixed inset-x-0 bottom-0 z-[2500] flex justify-center p-3 sm:p-5"
    >
      <div className="pointer-events-auto w-full max-w-3xl rounded-2xl border border-[var(--border-strong)] bg-[var(--surface-strong)] p-4 shadow-[0_24px_60px_-20px_oklch(0_0_0/0.45)] backdrop-blur-xl sm:p-5">
        <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between sm:gap-6">
          {/* Message + policy link */}
          <p className="text-sm leading-relaxed text-[var(--text)]">
            {site.cookies.message}{" "}
            <Link
              href={site.cookies.policyHref}
              className="font-medium text-[var(--accent)] underline-offset-4 hover:underline"
            >
              {site.cookies.policyLabel} →
            </Link>
          </p>

          {/* Buttons */}
          <div className="flex flex-shrink-0 gap-2">
            <button
              type="button"
              onClick={() => decide("rst")}
              aria-label={site.cookies.reject.ariaLabel}
              title={site.cookies.reject.tooltip}
              className="group inline-flex h-11 min-w-[5.5rem] flex-col items-center justify-center rounded-xl border border-[var(--border-strong)] bg-transparent px-4 font-mono text-sm font-semibold text-[var(--text)] transition-all hover:-translate-y-0.5 hover:border-[var(--text)]"
            >
              <span className="leading-none">{site.cookies.reject.label}</span>
              <span className="mt-0.5 text-[0.65rem] font-normal tracking-wide text-[var(--text-soft)] uppercase">
                {site.cookies.reject.subtitle}
              </span>
            </button>
            <button
              type="button"
              onClick={() => decide("ack")}
              aria-label={site.cookies.accept.ariaLabel}
              title={site.cookies.accept.tooltip}
              className="group inline-flex h-11 min-w-[5.5rem] flex-col items-center justify-center rounded-xl bg-[var(--button-bg)] px-4 font-mono text-sm font-semibold text-[var(--button-fg)] shadow-sm transition-all hover:-translate-y-0.5 hover:bg-[var(--button-hover)] hover:shadow-md"
            >
              <span className="leading-none">{site.cookies.accept.label}</span>
              <span className="mt-0.5 text-[0.65rem] font-normal tracking-wide opacity-70 uppercase">
                {site.cookies.accept.subtitle}
              </span>
            </button>
          </div>
        </div>
      </div>
    </div>
  );
}

// Helper used by the footer "Cookie preferences" link to re-open the banner.
export function openCookieBanner() {
  window.dispatchEvent(new Event(REOPEN_EVENT));
}