"use client";

import { useEffect, useState } from "react";

import { cn } from "@/lib/utils";
import { MoonIcon, SunIcon } from "@/components/icons";

const STORAGE_KEY = "freezmo.theme";

export function useTheme() {
  const [theme, setTheme] = useState<"light" | "dark">("light");

  useEffect(() => {
    const stored = window.localStorage.getItem(STORAGE_KEY);
    const isDark = stored
      ? stored === "dark"
      : window.matchMedia("(prefers-color-scheme: dark)").matches;
    setTheme(isDark ? "dark" : "light");
  }, []);

  const apply = (next: "light" | "dark") => {
    setTheme(next);
    document.documentElement.classList.toggle("dark", next === "dark");
    try {
      window.localStorage.setItem(STORAGE_KEY, next);
    } catch {
      /* private mode */
    }
  };

  return { theme, toggle: () => apply(theme === "dark" ? "light" : "dark") };
}

export function ThemeToggle({ className }: { className?: string }) {
  const { theme, toggle } = useTheme();
  const dark = theme === "dark";

  return (
    <button
      type="button"
      onClick={toggle}
      aria-label={dark ? "Switch to light mode" : "Switch to dark mode"}
      title={dark ? "Light mode" : "Dark mode"}
      className={cn(
        "inline-flex size-9 items-center justify-center rounded-full text-[var(--text-muted)] transition hover:bg-[var(--hover)] hover:text-[var(--text)]",
        className,
      )}
    >
      <span aria-hidden>
        {dark ? <SunIcon className="size-5" /> : <MoonIcon className="size-5" />}
      </span>
    </button>
  );
}