"use client";

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

type Theme = 'light' | 'dark';

interface ThemeProviderProps {
  children: ReactNode;
  defaultTheme?: Theme;
  storageKey?: string;
}

interface ThemeProviderState {
  theme: Theme;
  setTheme: (theme: Theme) => void;
}

const initialState: ThemeProviderState = {
  theme: 'light', // Default to light if no specific default is provided or found
  setTheme: () => null,
};

const ThemeProviderContext = createContext<ThemeProviderState>(initialState);

export function ThemeProvider({
  children,
  defaultTheme = 'light',
  storageKey = 'anita-deploy-ui-theme', // Specific storage key
}: ThemeProviderProps) {
  const [theme, setTheme] = useState<Theme>(() => {
    if (typeof window !== 'undefined') {
      const storedTheme = localStorage.getItem(storageKey) as Theme | null;
      if (storedTheme && (storedTheme === 'light' || storedTheme === 'dark')) {
        return storedTheme;
      }
      // No valid theme in localStorage, check for system preference if defaultTheme is 'system'
      // For simplicity now, we'll just use the passed defaultTheme or 'light'
      // if (defaultTheme === 'system' && window.matchMedia('(prefers-color-scheme: dark)').matches) {
      //   return 'dark';
      // }
    }
    return defaultTheme === 'dark' ? 'dark' : 'light'; // Ensure a valid theme
  });

  useEffect(() => {
    if (typeof window === 'undefined') return;

    const root = window.document.documentElement;
    root.classList.remove('light', 'dark');
    root.classList.add(theme);
    localStorage.setItem(storageKey, theme);
  }, [theme, storageKey]);

  const value = {
    theme,
    setTheme: (newTheme: Theme) => {
      setTheme(newTheme);
    },
  };

  return (
    <ThemeProviderContext.Provider value={value}>
      {children}
    </ThemeProviderContext.Provider>
  );
}

export const useTheme = () => {
  const context = useContext(ThemeProviderContext);
  if (context === undefined) {
    throw new Error('useTheme must be used within a ThemeProvider');
  }
  return context;
};