src/components/ThemeProvider.tsx

"use client";

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

type Theme = "light" | "dark";

interface ThemeContextType {
    theme: Theme;
    toggleTheme: () => void;
}

const ThemeContext = createContext<ThemeContextType | undefined>(undefined);

export function ThemeProvider({ children }: { children: React.ReactNode }) {
    const [theme, setTheme] = useState<Theme>("dark");

    useEffect(() => {
        const saved = localStorage.getItem("theme") as Theme | null;
        if (saved) {
            setTheme(saved);
            document.documentElement.classList.toggle("dark", saved === "dark");
        }
    }, []);

    const toggleTheme = () => {
        const newTheme = theme === "dark" ? "light" : "dark";
        setTheme(newTheme);
        localStorage.setItem("theme", newTheme);
        document.documentElement.classList.toggle("dark", newTheme === "dark");
    };

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

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