"use client";

import { useState, useEffect } from "react";
import { Link, useLocale, usePathname, useRouter, useTranslation } from "@/i18n/navigation";
import AuthModal from "./AuthModal";
import ThemeToggle from "./ThemeToggle";

const navLinks = [
  { labelKey: "roadmap" as const, href: "#roadmap" },
  { labelKey: "tools" as const, href: "#tools" },
  { labelKey: "community" as const, href: "#community" },
];

function getStoredUser(): string | null {
  if (typeof window === "undefined") return null;
  try {
    const raw = localStorage.getItem("pb_user");
    if (!raw) return null;
    const user = JSON.parse(raw);
    return user?.email ?? null;
  } catch {
    return null;
  }
}

export default function Header() {
  const { t } = useTranslation("common");
  const { t: tNav } = useTranslation("nav");
  const locale = useLocale();
  const pathname = usePathname();
  const router = useRouter();
  const [mobileOpen, setMobileOpen] = useState(false);
  const [scrolled, setScrolled] = useState(false);
  const [authOpen, setAuthOpen] = useState(false);
  const [userEmail, setUserEmail] = useState<string | null>(null);

  useEffect(() => {
    setUserEmail(getStoredUser());
  }, []);

  const handleLogout = () => {
    localStorage.removeItem("pb_token");
    localStorage.removeItem("pb_user");
    setUserEmail(null);
  };

  return (
    <header
      className={`fixed top-0 left-0 right-0 z-50 transition-all duration-300 ${
        scrolled
          ? "bg-white/80 backdrop-blur-lg shadow-sm dark:bg-slate-900/80 dark:shadow-slate-950/50"
          : "bg-transparent"
      }`}
    >
      <div className="mx-auto max-w-7xl px-4 sm:px-6 lg:px-8">
        <div className="flex h-16 items-center justify-between">
          <Link href="/" className="flex items-center gap-2 text-lg font-bold text-slate-900 dark:text-slate-100">
            <span className="text-2xl">🌍</span>
            <span className="hidden sm:inline">{t("siteName")}</span>
            <span className="sm:hidden">{t("siteNameShort")}</span>
          </Link>

          <nav className="hidden items-center gap-1 md:flex">
            {navLinks.map((link) => (
              <a
                key={link.href}
                href={link.href}
                className="rounded-lg px-3 py-2 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-100 hover:text-slate-900 dark:text-slate-400 dark:hover:bg-slate-800 dark:hover:text-slate-100"
              >
                {tNav(link.labelKey)}
              </a>
            ))}
            <button
              type="button"
              onClick={() => router.replace(pathname, { locale: locale === "zh" ? "en" : "zh" })}
              className="rounded-lg px-3 py-2 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-100 hover:text-slate-900 dark:text-slate-400 dark:hover:bg-slate-800 dark:hover:text-slate-100"
            >
              {locale === "zh" ? "EN" : "中文"}
            </button>
          </nav>

          <div className="flex items-center gap-3">
            {userEmail ? (
              <div className="flex items-center gap-2">
                <span className="hidden max-w-[120px] truncate text-sm text-slate-600 dark:text-slate-400 sm:inline">
                  {userEmail}
                </span>
                <button
                  onClick={handleLogout}
                  className="rounded-full border border-slate-200 px-4 py-2 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-50 dark:border-slate-700 dark:text-slate-400 dark:hover:bg-slate-800"
                >
                  {t("logout")}
                </button>
              </div>
            ) : (
              <button
                onClick={() => setAuthOpen(true)}
                className="hidden rounded-full border border-slate-200 px-4 py-2 text-sm font-medium text-slate-600 transition-colors hover:bg-slate-50 dark:border-slate-700 dark:text-slate-400 dark:hover:bg-slate-800 sm:inline-flex"
              >
                {t("loginRegister")}
              </button>
            )}
            <ThemeToggle />
            <a
              href="#roadmap"
              className="hidden rounded-full bg-sky-500 px-4 py-2 text-sm font-medium text-white transition-colors hover:bg-sky-600 dark:bg-sky-600 dark:hover:bg-sky-500 sm:inline-flex"
            >
              {t("explore")}
            </a>

            <button
              onClick={() => setMobileOpen(!mobileOpen)}
              className="inline-flex items-center justify-center rounded-lg p-2 text-slate-600 transition-colors hover:bg-slate-100 dark:text-slate-400 dark:hover:bg-slate-800 md:hidden"
              aria-label={t("toggleMenu")}
            >
              {mobileOpen ? (
                <svg className="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor">
                  <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M6 18L18 6M6 6l12 12" />
                </svg>
              ) : (
                <svg className="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor">
                  <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M4 6h16M4 12h16M4 18h16" />
                </svg>
              )}
            </button>
          </div>
        </div>
      </div>

      {mobileOpen && (
        <div className="border-t border-slate-100 bg-white/95 backdrop-blur-lg dark:border-slate-800 dark:bg-slate-900/95 md:hidden">
          <nav className="mx-auto max-w-7xl space-y-1 px-4 py-3">
            {navLinks.map((link) => (
              <a
                key={link.href}
                href={link.href}
                onClick={() => setMobileOpen(false)}
                className="block rounded-lg px-3 py-2.5 text-base font-medium text-slate-600 transition-colors hover:bg-slate-100 hover:text-slate-900 dark:text-slate-400 dark:hover:bg-slate-800 dark:hover:text-slate-100"
              >
                {tNav(link.labelKey)}
              </a>
            ))}
            <button
              type="button"
              onClick={() => {
                setMobileOpen(false);
                router.replace(pathname, { locale: locale === "zh" ? "en" : "zh" });
              }}
              className="block w-full rounded-lg px-3 py-2.5 text-left text-base font-medium text-slate-600 transition-colors hover:bg-slate-100 hover:text-slate-900 dark:text-slate-400 dark:hover:bg-slate-800 dark:hover:text-slate-100"
            >
              {locale === "zh" ? "EN" : "中文"}
            </button>
            {userEmail ? (
              <div className="mt-2 flex items-center justify-between rounded-lg border border-slate-100 bg-slate-50 px-4 py-2.5 dark:border-slate-700 dark:bg-slate-800">
                <span className="truncate text-sm text-slate-600">{userEmail}</span>
                <button
                  onClick={() => {
                    handleLogout();
                    setMobileOpen(false);
                  }}
                  className="text-sm font-medium text-sky-500"
                >
                  {t("logout")}
                </button>
              </div>
            ) : (
              <button
                onClick={() => {
                  setMobileOpen(false);
                  setAuthOpen(true);
                }}
                className="mt-2 block w-full rounded-full border border-slate-200 px-4 py-2.5 text-center text-base font-medium text-slate-600 dark:border-slate-700 dark:text-slate-400"
              >
                {t("loginRegister")}
              </button>
            )}
            <a
              href="#roadmap"
              onClick={() => setMobileOpen(false)}
              className="mt-2 block rounded-full bg-sky-500 px-4 py-2.5 text-center text-base font-medium text-white transition-colors hover:bg-sky-600 dark:bg-sky-600 dark:hover:bg-sky-500"
            >
              {t("explore")}
            </a>
          </nav>
        </div>
      )}

      <AuthModal
        isOpen={authOpen}
        onClose={() => setAuthOpen(false)}
        onSuccess={(email) => setUserEmail(email)}
      />
    </header>
  );
}