frontend/src/hooks/useThemeMode.js

import { useState, useEffect } from 'react';

export const useThemeMode = () => {
  // Get system preference
  const getSystemPreference = () => {
    return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
  };

  // Initialize theme mode from system preference
  const [mode, setMode] = useState(getSystemPreference);

  // Listen to system preference changes
  useEffect(() => {
    const mediaQuery = window.matchMedia('(prefers-color-scheme: dark)');
    const handleChange = (e) => {
      setMode(e.matches ? 'dark' : 'light');
    };
 
    mediaQuery.addEventListener('change', handleChange);
    return () => mediaQuery.removeEventListener('change', handleChange);
  }, []);

  const toggleTheme = () => {
    setMode((prevMode) => (prevMode === 'light' ? 'dark' : 'light'));
  };

  return { mode, toggleTheme };
};