'use client';

import React, { 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>('light'); // Default to light

  useEffect(() => {
    try {
      const savedTheme = localStorage.getItem('theme') as Theme | null;
      if (savedTheme === 'dark') {
        setTheme('dark');
        document.documentElement.classList.add('dark');
        document.documentElement.setAttribute('data-theme', 'dark');
      } else {
        setTheme('light');
        document.documentElement.classList.remove('dark');
        document.documentElement.setAttribute('data-theme', 'light');
        // If not set, explicitly store the default 'light' preference
        if (!savedTheme) {
          localStorage.setItem('theme', 'light');
        }
      }
    } catch (e) {
      console.error('Failed to read theme preference from localStorage:', e);
    }
  }, []);

  const toggleTheme = () => {
    setTheme((prevTheme) => {
      const nextTheme = prevTheme === 'light' ? 'dark' : 'light';
      try {
        localStorage.setItem('theme', nextTheme);
      } catch (e) {
        console.error('Failed to write theme preference to localStorage:', e);
      }

      if (nextTheme === 'dark') {
        document.documentElement.classList.add('dark');
        document.documentElement.setAttribute('data-theme', 'dark');
      } else {
        document.documentElement.classList.remove('dark');
        document.documentElement.setAttribute('data-theme', 'light');
      }

      return nextTheme;
    });
  };

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

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