import React, { createContext, useContext, useEffect, useState } from 'react';
import { User, Session } from '@supabase/supabase-js';
import { supabase, isSupabaseConfigured } from '@/lib/supabase';
import { UserProfile } from '@/lib/database.types';
import { aethexToast } from '@/lib/aethex-toast';
import { DemoStorageService } from '@/lib/demo-storage';
import { aethexUserService, type AethexUserProfile } from '@/lib/aethex-database-adapter';

interface AuthContextType {
  user: User | null;
  profile: AethexUserProfile | null;
  session: Session | null;
  loading: boolean;
  signIn: (email: string, password: string) => Promise<void>;
  signUp: (email: string, password: string, userData?: Partial<AethexUserProfile>) => Promise<void>;
  signInWithOAuth: (provider: 'github' | 'google') => Promise<void>;
  signOut: () => Promise<void>;
  updateProfile: (updates: Partial<AethexUserProfile>) => Promise<void>;
}

const AuthContext = createContext<AuthContextType | undefined>(undefined);

export const useAuth = () => {
  const context = useContext(AuthContext);
  if (context === undefined) {
    throw new Error('useAuth must be used within an AuthProvider');
  }
  return context;
};

export const AuthProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
  const [user, setUser] = useState<User | null>(null);
  const [profile, setProfile] = useState<AethexUserProfile | null>(null);
  const [session, setSession] = useState<Session | null>(null);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    // Check if Supabase is configured
    if (!isSupabaseConfigured) {
      console.warn('Supabase is not configured. Please set up your environment variables.');
      setLoading(false);
      return;
    }

    // Get initial session
    supabase.auth.getSession().then(({ data: { session } }) => {
      setSession(session);
      setUser(session?.user ?? null);
      if (session?.user) {
        fetchUserProfile(session.user.id);
      }
      setLoading(false);
    }).catch((error) => {
      console.error('Error getting session:', error);
      setLoading(false);
    });

    // Listen for auth changes
    const {
      data: { subscription },
    } = supabase.auth.onAuthStateChange(async (event, session) => {
      setSession(session);
      setUser(session?.user ?? null);

      if (session?.user) {
        const profile = await fetchUserProfile(session.user.id);

        // Create profile for new OAuth users
        if (!profile && session.user.app_metadata?.provider) {
          try {
            await aethexUserService.createInitialProfile(session.user.id, {
              username: session.user.user_metadata?.user_name ||
                       session.user.user_metadata?.preferred_username ||
                       session.user.email?.split('@')[0] ||
                       `user_${Date.now()}`,
              full_name: session.user.user_metadata?.full_name ||
                        session.user.user_metadata?.name ||
                        session.user.email?.split('@')[0],
              email: session.user.email,
              avatar_url: session.user.user_metadata?.avatar_url,
              user_type: 'community_member', // Default for OAuth users
              experience_level: 'beginner',
            });

            // Fetch the newly created profile
            await fetchUserProfile(session.user.id);

            // Award onboarding achievement for OAuth users
            await aethexAchievementService.checkAndAwardOnboardingAchievement(session.user.id);
          } catch (error) {
            console.error('Error creating OAuth user profile:', error);
          }
        }
      } else {
        setProfile(null);
      }
      setLoading(false);

      // Show toast notifications for auth events
      if (event === 'SIGNED_IN') {
        aethexToast.success({
          title: 'Welcome back!',
          description: 'Successfully signed in to AeThex OS'
        });
      } else if (event === 'SIGNED_OUT') {
        aethexToast.info({
          title: 'Signed out',
          description: 'Come back soon!'
        });
      }
    });

    return () => subscription.unsubscribe();
  }, []);

  const fetchUserProfile = async (userId: string) => {
    if (!isSupabaseConfigured) {
      // Initialize demo data and get profile
      DemoStorageService.initializeDemoData();
      const demoProfile = DemoStorageService.getUserProfile();
      setProfile(demoProfile as AethexUserProfile);
      return;
    }

    try {
      const userProfile = await aethexUserService.getCurrentUser();
      setProfile(userProfile);
    } catch (error) {
      console.error('Error fetching user profile:', error);
    }
  };

  const signIn = async (email: string, password: string) => {
    if (!isSupabaseConfigured) {
      aethexToast.warning({
        title: 'Demo Mode',
        description: 'Supabase not configured. This is a demo - please set up your Supabase project.'
      });
      // Simulate successful login for demo
      setTimeout(() => {
        setUser({ id: 'demo-user', email } as User);
        setSession({ user: { id: 'demo-user', email } } as Session);
      }, 500);
      return;
    }

    try {
      const { error } = await supabase.auth.signInWithPassword({
        email,
        password,
      });

      if (error) throw error;
    } catch (error: any) {
      aethexToast.error({
        title: 'Sign in failed',
        description: error.message
      });
      throw error;
    }
  };

  const signUp = async (email: string, password: string, userData?: Partial<AethexUserProfile>) => {
    if (!isSupabaseConfigured) {
      aethexToast.warning({
        title: 'Demo Mode',
        description: 'Supabase not configured. This is a demo - please set up your Supabase project.'
      });
      return;
    }

    try {
      const { data, error } = await supabase.auth.signUp({
        email,
        password,
      });

      if (error) throw error;

      if (data.user && userData) {
        // Create user profile using AeThex adapter
        await aethexUserService.createInitialProfile(data.user.id, {
          ...userData,
          email,
        });

        aethexToast.success({
          title: 'Account created!',
          description: 'Please check your email to verify your account'
        });
      }
    } catch (error: any) {
      aethexToast.error({
        title: 'Sign up failed',
        description: error.message
      });
      throw error;
    }
  };

  const signInWithOAuth = async (provider: 'github' | 'google') => {
    if (!isSupabaseConfigured) {
      aethexToast.warning({
        title: 'Demo Mode',
        description: 'OAuth login requires Supabase to be configured. Currently in demo mode.'
      });
      return;
    }

    try {
      const { data, error } = await supabase.auth.signInWithOAuth({
        provider,
        options: {
          redirectTo: `${window.location.origin}/dashboard`,
        },
      });

      if (error) throw error;

      aethexToast.success({
        title: 'Redirecting...',
        description: `Signing in with ${provider}`
      });
    } catch (error: any) {
      aethexToast.error({
        title: `${provider} sign in failed`,
        description: error.message
      });
      throw error;
    }
  };

  const signOut = async () => {
    if (!isSupabaseConfigured) {
      setUser(null);
      setSession(null);
      setProfile(null);
      aethexToast.info({
        title: 'Signed out',
        description: 'Demo session ended'
      });
      return;
    }

    try {
      const { error } = await supabase.auth.signOut();
      if (error) throw error;
    } catch (error: any) {
      aethexToast.error({
        title: 'Sign out failed',
        description: error.message
      });
      throw error;
    }
  };

  const updateProfile = async (updates: Partial<AethexUserProfile>) => {
    if (!user) throw new Error('No user logged in');

    if (!isSupabaseConfigured) {
      // Use demo storage
      const updatedProfile = DemoStorageService.updateUserProfile(updates as any);
      setProfile(updatedProfile as AethexUserProfile);
      aethexToast.success({
        title: 'Profile updated',
        description: 'Your profile has been updated successfully'
      });
      return;
    }

    try {
      const updatedProfile = await aethexUserService.updateProfile(user.id, updates);
      setProfile(updatedProfile);
      aethexToast.success({
        title: 'Profile updated',
        description: 'Your profile has been updated successfully'
      });
    } catch (error: any) {
      aethexToast.error({
        title: 'Update failed',
        description: error.message
      });
      throw error;
    }
  };

  const value = {
    user,
    profile,
    session,
    loading,
    signIn,
    signUp,
    signInWithOAuth,
    signOut,
    updateProfile,
  };

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