"use client";

import {
  ArrowRightStartOnRectangleIcon,
  CalendarDaysIcon,
  ChartBarIcon,
  BellAlertIcon,
  BoltIcon,
  ChevronRightIcon,
  ChevronUpDownIcon,
  Cog6ToothIcon,
  DevicePhoneMobileIcon,
  FireIcon,
  MoonIcon,
  ScaleIcon,
  ShoppingCartIcon,
  SparklesIcon,
  SunIcon,
  UserIcon,
  UsersIcon,
} from "@heroicons/react/24/outline";
import Link from "next/link";
import { usePathname, useRouter } from "next/navigation";
import { useEffect, useRef, useState } from "react";
import { signOut, useSession } from "@/lib/auth-client";
import { useTheme } from "./theme-provider";

type NavItem = {
  href?: string;
  label: string;
  icon: React.ComponentType<{ className?: string }>;
  disabled?: boolean;
  hint?: string;
};

type NavGroup = {
  label: string;
  items: NavItem[];
};

const navGroups: NavGroup[] = [
  {
    label: "Heute",
    items: [
      { href: "/", label: "Tagesansicht", icon: CalendarDaysIcon },
      { href: "/wochenbudget", label: "Wochenbudget", icon: ChartBarIcon },
      { href: "/statistiken", label: "Statistiken", icon: ChartBarIcon },
      { href: "/erinnerungen", label: "Erinnerungen", icon: BellAlertIcon },
      { href: "/aktivitaeten", label: "Aktivitäten", icon: BoltIcon },
      { href: "/wearables", label: "Wearables", icon: DevicePhoneMobileIcon },
      { href: "/hellfireclub", label: "Hellfireclub", icon: FireIcon },
      { href: "/gewicht", label: "Gewicht", icon: ScaleIcon },
    ],
  },
  {
    label: "Ernährung",
    items: [
      { href: "/planung", label: "Essensplanung", icon: SparklesIcon },
      { href: "/lebensmittel", label: "Lebensmittel", icon: ShoppingCartIcon },
      { href: "/maerkte", label: "Märkte", icon: ShoppingCartIcon },
      { href: "/rezepte", label: "Rezepte", icon: SparklesIcon },
      { href: "/rezepte/pruefung", label: "Rezeptprüfung", icon: SparklesIcon },
      { href: "/einkaufsliste", label: "Einkaufsliste", icon: ShoppingCartIcon },
    ],
  },
  {
    label: "System",
    items: [
      { href: "/benutzer", label: "Benutzer", icon: UsersIcon },
      { href: "/aktivitaetsfeed", label: "Activity Feed", icon: BellAlertIcon },
      { href: "/einstellungen", label: "Einstellungen", icon: Cog6ToothIcon },
      { href: "/einstellungen/punkte", label: "Punktevergabe", icon: ChartBarIcon },
    ],
  },
];

export function Sidebar() {
  const pathname = usePathname();
  const router = useRouter();
  const { data: session } = useSession();
  const { isDark, toggleDark } = useTheme();
  const [menuOpen, setMenuOpen] = useState(false);
  const [collapsedGroups, setCollapsedGroups] = useState<Set<string>>(new Set());
  const menuRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    function handleOutside(e: MouseEvent) {
      if (menuRef.current && !menuRef.current.contains(e.target as Node)) {
        setMenuOpen(false);
      }
    }
    if (menuOpen) document.addEventListener("mousedown", handleOutside);
    return () => document.removeEventListener("mousedown", handleOutside);
  }, [menuOpen]);

  function toggleGroup(label: string) {
    setCollapsedGroups((prev) => {
      const next = new Set(prev);
      if (next.has(label)) next.delete(label);
      else next.add(label);
      return next;
    });
  }

  const isActive = (href: string) => {
    if (href === "/") return pathname === "/";
    return pathname === href || pathname.startsWith(`${href}/`);
  };

  async function handleSignOut() {
    await signOut();
    if (session?.user?.id) {
      localStorage.removeItem(`hellth-theme:${session.user.id}`);
    }
    document.documentElement.classList.remove("dark");
    router.push("/login");
  }

  return (
    <aside className="sticky top-0 hidden h-screen w-64 shrink-0 flex-col border-r border-gray-200 bg-white dark:border-neutral-800 dark:bg-neutral-900 lg:flex">
      <div className="border-b border-gray-100 px-5 py-5 dark:border-neutral-800">
        <div className="flex items-center gap-2">
          <div className="flex h-[36.8px] w-[36.8px] items-center justify-center rounded-lg bg-[#0F766E] text-xs font-bold text-white">
            HH
          </div>
          <div>
            <p className="leading-none text-sm font-semibold text-gray-900 dark:text-neutral-100">Hellth Hub</p>
            <p className="mt-0.5 text-xs text-gray-400">Home-Lab Health</p>
          </div>
        </div>
      </div>

      <nav className="flex-1 space-y-6 overflow-y-auto px-3 py-4">
        {navGroups.map((group) => (
          <div key={group.label}>
            <button
              type="button"
              onClick={() => toggleGroup(group.label)}
              className="mb-1.5 flex w-full items-center justify-between px-2 text-xs font-semibold uppercase tracking-wider text-gray-400 hover:text-gray-600 dark:hover:text-neutral-300"
            >
              {group.label}
              <ChevronRightIcon className={`h-3 w-3 transition-transform ${!collapsedGroups.has(group.label) ? "rotate-90" : ""}`} />
            </button>
            {!collapsedGroups.has(group.label) ? (
              <ul className="space-y-0.5">
                {group.items.map((item) => {
                  if (item.disabled || !item.href) {
                    return (
                      <li key={`${group.label}-${item.label}`}>
                        <span className="group flex cursor-not-allowed items-center gap-2.5 rounded-lg px-2.5 py-2 text-sm font-medium text-gray-300 dark:text-neutral-600">
                          <item.icon className="h-4.5 w-4.5 shrink-0" />
                          <span className="flex-1">{item.label}</span>
                          {item.hint ? <span className="text-[10px] uppercase">{item.hint}</span> : null}
                        </span>
                      </li>
                    );
                  }

                  const active = isActive(item.href);
                  return (
                    <li key={item.href}>
                      <Link
                        href={item.href}
                        className={`group flex items-center gap-2.5 rounded-lg px-2.5 py-2 text-sm font-medium transition-all ${
                          active
                            ? "bg-teal-50 text-[#0F766E] dark:bg-teal-950/40"
                            : "text-gray-600 hover:bg-gray-50 hover:text-gray-900 dark:text-neutral-300 dark:hover:bg-neutral-800 dark:hover:text-neutral-100"
                        }`}
                      >
                        <item.icon className={`h-4.5 w-4.5 shrink-0 ${active ? "text-[#0F766E]" : "text-gray-400 group-hover:text-gray-600"}`} />
                        <span className="flex-1">{item.label}</span>
                        {active ? <ChevronRightIcon className="h-3.5 w-3.5 text-[#0F766E]" /> : null}
                      </Link>
                    </li>
                  );
                })}
              </ul>
            ) : null}
          </div>
        ))}
      </nav>

      <div className="mt-auto border-t border-gray-100 px-3 py-2 dark:border-neutral-800">
        <div ref={menuRef} className="relative">
          {menuOpen ? (
            <div className="absolute bottom-full left-0 right-0 z-50 mb-1 overflow-hidden rounded-xl border border-gray-200 bg-white shadow-lg dark:border-neutral-800 dark:bg-neutral-900">
              <div className="border-b border-gray-100 px-4 py-3 dark:border-neutral-800">
                <p className="truncate text-sm font-semibold text-gray-900 dark:text-neutral-100">
                  {session?.user?.name ?? "Administrator"}
                </p>
                <p className="truncate text-xs text-gray-400">{session?.user?.email ?? ""}</p>
              </div>

              <div className="border-b border-gray-100 px-4 py-2.5 dark:border-neutral-800">
                <div className="flex items-center justify-between">
                  <div className="flex items-center gap-2.5">
                    {isDark ? <SunIcon className="h-4 w-4 text-gray-400" /> : <MoonIcon className="h-4 w-4 text-gray-400" />}
                    <span className="text-sm text-gray-700 dark:text-neutral-300">
                      {isDark ? "Helles Design" : "Dunkles Design"}
                    </span>
                  </div>
                  <button
                    type="button"
                    onClick={toggleDark}
                    className={`relative inline-flex h-5 w-9 shrink-0 cursor-pointer rounded-full border-2 border-transparent transition-colors duration-200 focus:outline-none ${
                      isDark ? "bg-[#0F766E]" : "bg-gray-200"
                    }`}
                    role="switch"
                    aria-checked={isDark}
                    aria-label="Dunkles Design umschalten"
                  >
                    <span
                      className={`pointer-events-none inline-block h-4 w-4 transform rounded-full bg-white shadow ring-0 transition duration-200 ${
                        isDark ? "translate-x-4" : "translate-x-0"
                      }`}
                    />
                  </button>
                </div>
              </div>

              <Link
                href="/einstellungen"
                onClick={() => setMenuOpen(false)}
                className="flex items-center gap-2.5 px-4 py-2.5 text-sm text-gray-700 transition-colors hover:bg-gray-50 dark:text-neutral-300 dark:hover:bg-neutral-800"
              >
                <Cog6ToothIcon className="h-4 w-4 text-gray-400" />
                Einstellungen
              </Link>

              <button
                type="button"
                onClick={handleSignOut}
                className="flex w-full items-center gap-2.5 px-4 py-2.5 text-sm text-gray-700 transition-colors hover:bg-gray-50 dark:text-neutral-300 dark:hover:bg-neutral-800"
              >
                <ArrowRightStartOnRectangleIcon className="h-4 w-4 text-gray-400" />
                Abmelden
              </button>
            </div>
          ) : null}

          <button
            type="button"
            onClick={() => setMenuOpen((v) => !v)}
            className="flex w-full items-center gap-2.5 rounded-lg px-2.5 py-2 hover:bg-gray-50 dark:hover:bg-neutral-800"
          >
            <div className="flex h-7 w-7 shrink-0 items-center justify-center overflow-hidden rounded-full bg-[#0F766E] text-xs font-bold text-white">
              <UserIcon className="h-4 w-4" />
            </div>
            <div className="min-w-0 flex-1 text-left">
              <p className="truncate text-xs font-medium text-gray-900 dark:text-neutral-100">
                {session?.user?.name ?? "Administrator"}
              </p>
              <p className="truncate text-xs text-gray-400">{session?.user?.email ?? ""}</p>
            </div>
            <ChevronUpDownIcon className="h-3.5 w-3.5 shrink-0 text-gray-400" />
          </button>
        </div>
      </div>
    </aside>
  );
}