components/auth.py

import streamlit as st
import uuid
from datetime import datetime
from sqlalchemy.exc import IntegrityError
from db.connection import get_db
from db.models import User
from components.session_manager import set_auth_cookie, clear_auth_cookie

def render_auth_page():
    """Render the authentication page with login and signup forms"""
    # Check for existing auth cookie first
    if st.session_state.get("authenticated", False):
        st.rerun()
        return
        
    st.title("🧠 TailorED - AI-Powered Educational Content Generator")
    st.info("💡 **Tip**: For the best experience, keep this browser tab open while using TailorED. You may need to log in again if you refresh the page.")
    st.markdown("---")
    
    # Initialize session state for auth
    if "auth_page" not in st.session_state:
        st.session_state.auth_page = "login"
    
    # Toggle between login and signup
    col1, col2 = st.columns(2)
    with col1:
        if st.button("🔐 Login", use_container_width=True, 
                    type="primary" if st.session_state.auth_page == "login" else "secondary"):
            st.session_state.auth_page = "login"
            st.rerun()
    with col2:
        if st.button("📝 Sign Up", use_container_width=True,
                    type="primary" if st.session_state.auth_page == "signup" else "secondary"):
            st.session_state.auth_page = "signup"
            st.rerun()
    
    st.markdown("---")
    
    # Render the appropriate form
    if st.session_state.auth_page == "login":
        render_login_form()
    else:
        render_signup_form()

def render_login_form():
    """Render the login form"""
    st.header("🔐 Login to Your Account")
    
    with st.form("login_form"):
        username = st.text_input("👤 Username", placeholder="Enter your username")
        password = st.text_input("🔒 Password", type="password", placeholder="Enter your password")
        
        if st.form_submit_button("🚀 Login", use_container_width=True, type="primary"):
            if not username or not password:
                st.error("❌ Please fill in all fields")
                return
            
            user = authenticate_user(username, password)
            if user:
                # Successful login
                st.session_state.user_id = str(user.id)
                st.session_state.username = user.username
                st.session_state.fullname = user.fullname
                st.session_state.authenticated = True
                st.session_state.current_page = "generator"
                
                # Set authentication cookie
                set_auth_cookie({
                    "user_id": str(user.id),
                    "username": user.username,
                    "fullname": user.fullname
                })
                
                # Update last login
                update_last_login(user.id)
                
                st.success(f"✅ Welcome back, {user.fullname}!")
                st.rerun()
            else:
                st.error("❌ Invalid username or password")

def render_signup_form():
    """Render the signup form"""
    st.header("📝 Create New Account")
    
    with st.form("signup_form"):
        fullname = st.text_input("👤 Full Name", placeholder="Enter your full name")
        username = st.text_input("👥 Username", placeholder="Choose a username")
        password = st.text_input("🔒 Password", type="password", placeholder="Create a password")
        confirm_password = st.text_input("✅ Confirm Password", type="password", placeholder="Confirm your password")
        
        if st.form_submit_button("🎯 Create Account", use_container_width=True, type="primary"):
            # Validation
            if not all([fullname, username, password, confirm_password]):
                st.error("❌ Please fill in all fields")
                return
            
            if password != confirm_password:
                st.error("❌ Passwords do not match")
                return
            
            if len(password) < 6:
                st.error("❌ Password must be at least 6 characters long")
                return
            
            if len(username) < 3:
                st.error("❌ Username must be at least 3 characters long")
                return
            
            # Check if username exists
            if check_username_exists(username):
                st.error("❌ Username already exists. Please choose another one.")
                return
            
            # Create new user
            user_id = create_user(fullname, username, password)
            if user_id:
                st.session_state.user_id = user_id
                st.session_state.username = username
                st.session_state.fullname = fullname
                st.session_state.authenticated = True
                st.session_state.current_page = "generator"
                
                # Set authentication cookie
                set_auth_cookie({
                    "user_id": user_id,
                    "username": username,
                    "fullname": fullname
                })
                
                st.success(f"✅ Account created successfully! Welcome, {fullname}!")
                st.rerun()
            else:
                st.error("❌ Failed to create account. Please try again.")

def authenticate_user(username, password):
    """Authenticate user with username and password"""
    with next(get_db()) as db:
        try:
            user = db.query(User).filter_by(username=username).first()
            if user and user.check_password(password):
                return user
            return None
        except Exception as e:
            st.error(f"❌ Authentication error: {e}")
            return None

def check_username_exists(username):
    """Check if username already exists"""
    with next(get_db()) as db:
        try:
            user = db.query(User).filter_by(username=username).first()
            return user is not None
        except Exception as e:
            st.error(f"❌ Error checking username: {e}")
            return True  # Return True to prevent creation on error

def create_user(fullname, username, password):
    """Create a new user account"""
    with next(get_db()) as db:
        try:
            user = User()
            user.id = uuid.uuid4()
            user.fullname = fullname.strip()
            user.username = username.strip().lower()
            user.set_password(password)
            user.created_at = datetime.utcnow()
            
            db.add(user)
            db.commit()
            
            print(f"✅ Created new user: {username}")
            return str(user.id)
            
        except IntegrityError:
            db.rollback()
            st.error("❌ Username already exists. Please choose another one.")
            return None
        except Exception as e:
            db.rollback()
            st.error(f"❌ Error creating user: {e}")
            return None

def update_last_login(user_id):
    """Update user's last login timestamp"""
    with next(get_db()) as db:
        try:
            user = db.query(User).filter_by(id=user_id).first()
            if user:
                user.last_login = datetime.utcnow()
                db.commit()
        except Exception as e:
            print(f"⚠️ Error updating last login: {e}")

def logout():
    """Logout user and clear session"""
    clear_auth_cookie()
    
    # Clear all session state
    for key in list(st.session_state.keys()):
        del st.session_state[key]
    
    # Re-initialize with default auth state
    st.session_state.authenticated = False
    st.session_state.current_page = "auth"
    st.rerun()

def require_auth():
    """Check if user is authenticated, redirect to auth if not"""
    if not st.session_state.get("authenticated", False):
        st.session_state.current_page = "auth"
        st.rerun()