"use client";

import React, { createContext, useContext, useEffect, useState } from "react";

type Theme = "light" | "dark";

const ThemeContext = createContext<{
  theme: Theme;
  setTheme: (theme: Theme) => void;
  toggleTheme: () => void;
} | null>(null);

const STORAGE_KEY = "techwix-theme";

export function ThemeProvider({ children }: { children: React.ReactNode }) {
  const [theme, setThemeState] = useState<Theme>("light");
  const [mounted, setMounted] = useState(false);

  useEffect(() => {
    const isDark = document.documentElement.classList.contains("dark");
    setThemeState(isDark ? "dark" : "light");
    setMounted(true);
  }, []);

  const setTheme = (next: Theme) => {
    setThemeState(next);
    localStorage.setItem(STORAGE_KEY, next);
    document.documentElement.classList.toggle("dark", next === "dark");
  };

  const toggleTheme = () => {
    setTheme(theme === "dark" ? "light" : "dark");
  };

  return (
    <ThemeContext.Provider value={{ theme, setTheme, toggleTheme }}>
      {children}
    </ThemeContext.Provider>
  );
}

export function useTheme() {
  const ctx = useContext(ThemeContext);
  if (!ctx) throw new Error("useTheme must be used within ThemeProvider");
  return ctx;
}