/* ═══════════════════════════════════════════════════════════════
   ADMIN LAYOUT

   Bare on purpose. No PageShell, no announcement banner, no
   footer site map — none of that belongs around a staff tool, and
   /admin should never appear in navConfig.

   Three areas share this chrome: Home, the CMS and the Panel. The
   wordmark names whichever one you're in, and from anywhere but
   Home it's the way back to Home.

   The tab row is drawn everywhere except Home, where the card grid
   is the navigation and drawing both would say the same thing
   twice. Which tabs appear depends on the signed-in user —
   navFor() drops the superadmin-only ones — but that's cosmetics.
   The route guard and the API are what actually say no.
   ═══════════════════════════════════════════════════════════════ */

import { useCallback, useEffect, useMemo, useState } from "react";
import { Link, NavLink, Outlet, useLocation, useNavigate } from "react-router-dom";
import { useAuth } from "../../lib/auth.tsx";
import { AdminTitleContext } from "../../lib/adminTitle.tsx";
import { SITE_VERSION } from "../../lib/version.ts";
import { ROLE_LABELS, isSuper } from "../../lib/roles.ts";
import nguLogo from "../../assets/NGU_Logo.svg";
import {
  ADMIN_HOME,
  AREA_TITLES,
  areaFor,
  matches,
  navFor,
  target,
} from "./adminNav.ts";

export default function AdminLayout() {
  const { user, logout } = useAuth();
  const navigate = useNavigate();
  const { pathname } = useLocation();

  const area = areaFor(pathname);
  const areaTitle = AREA_TITLES[area];
  const isHome = area === "home";

  const nav = useMemo(() => navFor(user), [user]);

  const active = nav.find(
    (item) =>
      matches(pathname, item.to) ||
      (item.children ?? []).some((child) => matches(pathname, child.to)),
  );

  const activeChild = (active?.children ?? []).find((child) =>
    matches(pathname, child.to),
  );

  // What the page below has published about itself — a record
  // name, or null on a list. setDetail is stable so publishing
  // can't loop.
  const [detail, setDetail] = useState<any>(null);
  const stableSet = useCallback((value) => setDetail(value), []);
  const titleContext = useMemo(() => ({ setDetail: stableSet }), [stableSet]);

  useEffect(() => {
    // Sections only exist in the CMS. Home and Panel already say
    // what they are in the area title; "Panel | NGU Admin Panel"
    // would just stutter.
    const section = area === "cms" ? activeChild?.label ?? active?.label : null;
    document.title = [detail, section, areaTitle].filter(Boolean).join(" | ");
  }, [area, areaTitle, active, activeChild, detail]);

  async function handleLogout() {
    await logout();
    navigate("/admin/login", { replace: true });
  }

  const subnav = active?.children ?? [];

  const wordmark = <span className="text-lg font-bold text-[#138ba0]">{areaTitle}</span>;

  return (
    <div className="flex min-h-screen flex-col bg-[#f6fbfc]">
      <header className="border-b border-[#138ba0]/20 bg-white">
        <div className="mx-auto flex max-w-5xl flex-wrap items-center gap-x-8 gap-y-3 px-6 py-4">
          {/* Already home, so nothing to link to. */}
          {isHome ? (
            wordmark
          ) : (
            <Link
              to={ADMIN_HOME}
              className="rounded transition-opacity hover:opacity-70"
              title="Back to the admin home"
            >
              {wordmark}
            </Link>
          )}

          {!isHome && (
            <nav className="flex items-center gap-6 text-sm">
              {nav.map((item) => (
                <div key={item.label} className="flex items-center gap-6">
                  {item.separated && (
                    <span
                      aria-hidden="true"
                      className="h-4 w-px bg-[#4a6b72]/25"
                    />
                  )}
                  <NavLink
                    to={target(item)}
                    className={
                      item === active
                        ? "font-semibold text-[#138ba0]"
                        : "text-[#4a6b72] transition-colors hover:text-[#138ba0]"
                    }
                  >
                    {item.label}
                  </NavLink>
                </div>
              ))}
            </nav>
          )}

          <div className="ml-auto flex items-center gap-4 text-sm text-[#4a6b72]">
            <span>
              {user?.name || user?.email}
            </span>
            <button
              type="button"
              onClick={handleLogout}
              className="rounded-full border border-[#4a6b72]/30 px-4 py-1.5 font-medium transition-colors hover:bg-[#eef9fb] hover:text-[#138ba0]"
            >
              Sign out
            </button>
          </div>
        </div>

        {/* Subnav. Only drawn where there is something to draw, so
            Events and People don't get an empty grey strip. */}
        {subnav.length > 0 && (
          <div className="border-t border-[#138ba0]/10 bg-[#f6fbfc]">
            <div className="mx-auto flex max-w-5xl flex-wrap gap-6 px-6 py-2.5 text-sm">
              {subnav.map((child) => (
                <NavLink
                  key={child.to}
                  to={child.to}
                  className={
                    child === activeChild
                      ? "font-semibold text-[#138ba0]"
                      : "text-[#4a6b72] transition-colors hover:text-[#138ba0]"
                  }
                >
                  {child.label}
                </NavLink>
              ))}
            </div>
          </div>
        )}
      </header>

      {/* flex-1 rather than a fixed height: the footer sits at the
          bottom of a short page and below the content of a long one,
          without ever floating over it. */}
      <main className="mx-auto w-full max-w-5xl flex-1 px-6 py-10">
        <AdminTitleContext.Provider value={titleContext}>
          <Outlet />
        </AdminTitleContext.Provider>
      </main>

      <footer className="border-t border-[#138ba0]/15 bg-white">
        <div className="mx-auto flex max-w-5xl items-center gap-4 px-6 py-3">
          <Link to={ADMIN_HOME} className="transition-opacity hover:opacity-70">
            <img src={nguLogo} alt="NGU" className="h-6 w-auto" />
          </Link>
          <span className="ml-auto font-mono text-xs text-[#4a6b72]/70">
            {SITE_VERSION}
          </span>
        </div>
      </footer>
    </div>
  );
}