frontend/src/components/layout/theme-toggle.tsx

"use client";

import { Moon, Sun } from "lucide-react";
import { useTheme } from "next-themes";
import { useEffect, useState } from "react";
import { Button } from "@/components/ui/button";

export function ThemeToggle() {
  const { theme, setTheme, resolvedTheme } = useTheme();
  const [mounted, setMounted] = useState(false);
  useEffect(() => setMounted(true), []);

  const current = mounted ? (resolvedTheme ?? theme) : "dark";
  const next = current === "dark" ? "light" : "dark";

  return (
    <Button
      variant="outline"
      size="icon"
      onClick={() => setTheme(next)}
      aria-label="Toggle theme"
    >
      {current === "dark" ? (
        <Sun className="h-4 w-4" />
      ) : (
        <Moon className="h-4 w-4" />
      )}
    </Button>
  );
}