// Shared shell for the public, login-free legal pages (/privacy, /terms). These must be
// reachable unauthenticated — Google's OAuth consent screen links to them and reviewers
// fetch them directly — so they render outside the authenticated App tree (see main.tsx),
// with no react-query provider: the operator contact is fetched with a bare `send` below.
//
// Both pages exist in Hungarian and English, like the rest of the UI. The prose is a document, not
// a set of UI strings, so each language's body is its own component (see PrivacyPolicy/Terms) and
// `legalBodies.contract.dom.test.tsx` holds the two to the same sections; the chrome around them is i18n.
import { useEffect, useState, type ReactNode } from "react";
import { useTranslation } from "react-i18next";

import { setLanguage, type LangCode } from "../../i18n";
import { formatDate } from "../../lib/format";
import { send } from "../../lib/http";
import LanguageSwitcher from "../ui/LanguageSwitcher";
import { SURFACE } from "../ui/surfaces";

// The day the text last changed materially — bump it with every edit of either body.
const LAST_UPDATED = "2026-10-04";

// Contact shown on the legal pages: the instance operator's configured admin email, from the
// public /auth/config. One shared fetch across the page; null when the operator set none.
let contactPromise: Promise<string | null> | null = null;
function fetchOperatorContact(): Promise<string | null> {
  if (!contactPromise) {
    contactPromise = send("/auth/config")
      .then((r) => (r.ok ? r.json() : null))
      .then((c) => (c?.operator_contact as string | undefined) ?? null)
      .catch(() => null);
  }
  return contactPromise;
}

function useOperatorContact(): string | null {
  const [contact, setContact] = useState<string | null>(null);
  useEffect(() => {
    let alive = true;
    void fetchOperatorContact().then((c) => alive && setContact(c)); // never rejects: null on failure
    return () => {
      alive = false;
    };
  }, []);
  return contact;
}

// The operator's contact rendered as a mailto link, or a neutral fallback phrase when unset.
export function ContactEmail() {
  const { t } = useTranslation();
  const email = useOperatorContact();
  if (!email) return <>{t("legal.operatorFallback")}</>;
  return (
    <a href={`mailto:${email}`} className="text-accent hover:underline">
      {email}
    </a>
  );
}

export function LegalLink({ href, children }: { href: string; children: ReactNode }) {
  return (
    <a href={href} target="_blank" rel="noreferrer" className="text-accent hover:underline">
      {children}
    </a>
  );
}

export default function LegalLayout({ title, children }: { title: string; children: ReactNode }) {
  const { t, i18n } = useTranslation();
  const contact = useOperatorContact();
  // A link to a section (`/privacy#diagnostics`): the browser tries to scroll to the fragment before
  // this lazily loaded page has rendered it, so jump there once the section exists.
  useEffect(() => {
    const id = decodeURIComponent(window.location.hash.slice(1));
    if (id) document.getElementById(id)?.scrollIntoView();
  }, []);
  // The tab names the document, like every page of the app — a bookmark or a tab strip read just
  // "Siftlode" (prod UAT 2026-09-19).
  useEffect(() => {
    document.title = `${title} · Siftlode`;
  }, [title]);
  return (
    <div className="min-h-dvh bg-bg text-fg">
      <div className="mx-auto w-[min(92vw,720px)] py-12">
        <div className="mb-8 flex items-center justify-between gap-4">
          <a href="/" className="inline-block text-2xl font-bold tracking-tight">
            Sift<span className="text-accent">lode</span>
          </a>
          {/* The landing page's own picker, so the public pages switch language one way. */}
          <LanguageSwitcher value={i18n.language as LangCode} onChange={setLanguage} />
        </div>
        <div className={`${SURFACE.panel} p-8`}>
          <h1 className="text-2xl font-semibold">{title}</h1>
          <p className="text-xs text-muted mt-1 mb-6">
            {t("legal.lastUpdated", { date: formatDate(LAST_UPDATED, i18n.language) })}
          </p>
          <div className="space-y-5 text-sm leading-relaxed text-fg/90">{children}</div>
        </div>
        <footer className="mt-6 flex flex-wrap gap-x-4 gap-y-1 text-xs text-muted">
          <a href="/" className="hover:text-fg transition">
            {t("legal.home")}
          </a>
          <a href="/privacy" className="hover:text-fg transition">
            {t("common.privacyPolicy")}
          </a>
          <a href="/terms" className="hover:text-fg transition">
            {t("common.termsOfService")}
          </a>
          {contact && (
            <a href={`mailto:${contact}`} className="hover:text-fg transition">
              {t("legal.contact")}
            </a>
          )}
        </footer>
      </div>
    </div>
  );
}

/** A section heading. `id` is required: it is the anchor a link can point at (Settings →
 *  Diagnosztika links `/privacy#diagnostics`), and what holds the two languages to the same sections. */
export function H2({ id, children }: { id: string; children: ReactNode }) {
  return (
    <h2 id={id} className="text-base font-semibold text-fg pt-2 scroll-mt-6">
      {children}
    </h2>
  );
}