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

type Theme = "light" | "dark";
type Ctx = { theme: Theme; toggle: () => void };
const ThemeContext = createContext<Ctx>({ theme: "light", toggle: () => {} });

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

  useEffect(() => {
    const saved = (typeof window !== "undefined" && localStorage.getItem("ppc-theme")) as Theme | null;
    if (saved) setTheme(saved);
  }, []);

  useEffect(() => {
    const root = document.documentElement;
    root.classList.toggle("dark", theme === "dark");
    localStorage.setItem("ppc-theme", theme);
  }, [theme]);

  return (
    <ThemeContext.Provider value={{ theme, toggle: () => setTheme((t) => (t === "dark" ? "light" : "dark")) }}>
      {children}
    </ThemeContext.Provider>
  );
}

export const useTheme = () => useContext(ThemeContext);