llama-swap/ui/src/contexts/ThemeProvider.tsx

import { createContext, useContext, useEffect, type ReactNode } from "react";
import { usePersistentState } from "../hooks/usePersistentState";

type ThemeContextType = {
  isDarkMode: boolean;
  toggleTheme: () => void;
};

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

type ThemeProviderProps = {
  children: ReactNode;
};

export function ThemeProvider({ children }: ThemeProviderProps) {
  const [isDarkMode, setIsDarkMode] = usePersistentState<boolean>("theme", false);

  useEffect(() => {
    document.documentElement.setAttribute("data-theme", isDarkMode ? "dark" : "light");
  }, [isDarkMode]);

  const toggleTheme = () => setIsDarkMode((prev) => !prev);

  return <ThemeContext.Provider value={{ isDarkMode, toggleTheme }}>{children}</ThemeContext.Provider>;
}

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