"use client";

import { useEffect, useState } from "react";
import { Sun, Moon } from "lucide-react";

type Theme = "light" | "dark";

export default function ThemeToggle() {
  const [theme, setTheme] = useState<Theme>("dark");
  const [mounted, setMounted] = useState(false);

  useEffect(() => {
    const stored = (localStorage.getItem("theme") as Theme | null) ?? "dark";
    setTheme(stored);
    setMounted(true);
  }, []);

  if (!mounted) return null; // prevents hydration mismatch

  function toggle() {
    const next: Theme = theme === "dark" ? "light" : "dark";
    setTheme(next);
    localStorage.setItem("theme", next);
    document.documentElement.classList.toggle("dark", next === "dark");
  }

  return (
    <button
      type="button"
      onClick={toggle}
      aria-label="Toggle theme"
      className="inline-flex items-center gap-2 rounded-md border border-zinc-700 bg-zinc-900/70 px-3 py-1.5 text-xs font-semibold text-zinc-200 hover:bg-zinc-800 transition-colors
                 dark:border-zinc-700 dark:bg-zinc-900/70 dark:text-zinc-200
                 border-zinc-300 bg-white text-zinc-900 hover:bg-zinc-100 dark:hover:bg-zinc-800"
    >
      {theme === "dark" ? (
        <>
          <Sun className="h-4 w-4" />
          Light
        </>
      ) : (
        <>
          <Moon className="h-4 w-4" />
          Dark
        </>
      )}
    </button>
  );
}