app/api/v1/endpoints/auth.py

"""
Authentication endpoints for token management
"""
from fastapi import APIRouter, HTTPException, Depends, Request
from fastapi.security import HTTPBearer
from datetime import datetime, timedelta
from typing import Dict, Any
import jwt
import os
import uuid
import logging
from ..schemas.auth_schemas import TokenRequest, TokenResponse, UserRegistrationRequest, UserResponse
from ....core.config import settings
from ....core.auth import authenticate_request, require_current_user
from ....services.database import (
    get_user_by_username, 
    get_user_by_email, 
    create_user, 
    verify_password, 
    update_last_login,
    create_user_session,
    get_user_session,
    revoke_user_session
)
from ....services.auth_logger import AuthEventLogger, get_client_info

# Setup logger for authentication events
logger = logging.getLogger(__name__)

router = APIRouter()
security = HTTPBearer(auto_error=False)

@router.post("/auth/token", response_model=TokenResponse)
async def get_access_token(credentials: TokenRequest, request: Request):
    """
    Exchange user credentials for a temporary access token
    This endpoint allows users to authenticate and receive a JWT token
    """
    # Extract client information for logging
    client_ip, user_agent = get_client_info(request)
    
    # Validate user credentials against your Supabase database
    user = await validate_user_credentials(credentials.model_dump())
    if not user:
        # Log failed login attempt
        AuthEventLogger.log_login_attempt(
            username=credentials.username,
            client_ip=client_ip,
            user_agent=user_agent,
            success=False,
            failure_reason="Invalid credentials"
        )
        raise HTTPException(status_code=401, detail="Invalid credentials")
    
    # Update last login timestamp
    await update_last_login(user["id"])
    
    # Generate unique JTI (JWT ID) for session tracking
    jti = str(uuid.uuid4())
    expires_at = datetime.utcnow() + timedelta(hours=24)
    
    # Create session in database
    await create_user_session(user["id"], jti, expires_at)
    
    # Generate a temporary JWT token with minimal payload
    payload = {
        "sub": credentials.username,  # Subject (username) - needed for user lookup
        "jti": jti,                   # JWT ID for session tracking
        "exp": expires_at,            # Expiration time
        "iat": datetime.utcnow(),     # Issued at time
        "type": "access_token"        # Token type
        # Note: user_id removed - will be looked up from database using username
    }
    
    secret_key = os.getenv("SECRET_KEY", "your-secret-key-change-this")
    token = jwt.encode(payload, secret_key, algorithm="HS256")
    
    # Log successful login
    AuthEventLogger.log_login_attempt(
        username=credentials.username,
        client_ip=client_ip,
        user_agent=user_agent,
        success=True,
        user_id=user["id"]
    )
    
    return TokenResponse(
        access_token=token,
        token_type="bearer",
        expires_in=86400  # 24 hours
    )

@router.post("/auth/refresh")
async def refresh_access_token(refresh_token: str, request: Request):
    """
    Refresh an expired access token
    """
    # Extract client information for logging
    client_ip, user_agent = get_client_info(request)
    
    try:
        secret_key = os.getenv("SECRET_KEY", "your-secret-key-change-this")
        payload = jwt.decode(refresh_token, secret_key, algorithms=["HS256"])
        
        if payload.get("type") != "refresh_token":
            AuthEventLogger.log_token_refresh(
                username=payload.get("sub", "unknown"),
                client_ip=client_ip,
                user_agent=user_agent,
                success=False,
                failure_reason="Invalid token type"
            )
            raise HTTPException(status_code=401, detail="Invalid token type")
        
        # Generate new access token
        new_payload = {
            "sub": payload["sub"],
            "exp": datetime.utcnow() + timedelta(hours=24),
            "iat": datetime.utcnow(),
            "type": "access_token"
        }
        
        new_token = jwt.encode(new_payload, secret_key, algorithm="HS256")
        
        AuthEventLogger.log_token_refresh(
            username=payload["sub"],
            client_ip=client_ip,
            user_agent=user_agent,
            success=True
        )
        
        return TokenResponse(
            access_token=new_token,
            token_type="bearer",
            expires_in=86400
        )
        
    except jwt.InvalidTokenError as e:
        AuthEventLogger.log_token_refresh(
            username="unknown",
            client_ip=client_ip,
            user_agent=user_agent,
            success=False,
            failure_reason=f"Invalid refresh token: {str(e)}"
        )
        raise HTTPException(status_code=401, detail="Invalid refresh token")

@router.post("/auth/register", response_model=UserResponse)
async def register_user(user_data: UserRegistrationRequest, request: Request):
    """
    Register a new user account
    """
    # Extract client information for logging
    client_ip, user_agent = get_client_info(request)
    
    # Check if username already exists
    existing_user = await get_user_by_username(user_data.username)
    if existing_user:
        AuthEventLogger.log_registration_attempt(
            username=user_data.username,
            email=user_data.email,
            client_ip=client_ip,
            user_agent=user_agent,
            success=False,
            failure_reason="Username already exists"
        )
        raise HTTPException(status_code=400, detail="Username already exists")
    
    # Check if email already exists
    existing_email = await get_user_by_email(user_data.email)
    if existing_email:
        AuthEventLogger.log_registration_attempt(
            username=user_data.username,
            email=user_data.email,
            client_ip=client_ip,
            user_agent=user_agent,
            success=False,
            failure_reason="Email already registered"
        )
        raise HTTPException(status_code=400, detail="Email already registered")
    
    # Create new user
    new_user = await create_user(user_data.username, user_data.email, user_data.password)
    if not new_user:
        AuthEventLogger.log_registration_attempt(
            username=user_data.username,
            email=user_data.email,
            client_ip=client_ip,
            user_agent=user_agent,
            success=False,
            failure_reason="Database error - failed to create user"
        )
        raise HTTPException(status_code=500, detail="Failed to create user")
    
    AuthEventLogger.log_registration_attempt(
        username=user_data.username,
        email=user_data.email,
        client_ip=client_ip,
        user_agent=user_agent,
        success=True,
        user_id=new_user["id"]
    )
    
    return UserResponse(**new_user)

@router.post("/auth/logout")
async def logout_user(request: Request, token: str = Depends(security)):
    """
    Logout user by revoking their session
    """
    # Extract client information for logging
    client_ip, user_agent = get_client_info(request)
    
    if not token:
        AuthEventLogger.log_logout(
            username="unknown",
            client_ip=client_ip,
            user_agent=user_agent,
            success=False,
            failure_reason="No token provided"
        )
        raise HTTPException(status_code=401, detail="No token provided")
    
    try:
        secret_key = os.getenv("SECRET_KEY", "your-secret-key-change-this")
        payload = jwt.decode(token.credentials, secret_key, algorithms=["HS256"])
        jti = payload.get("jti")
        username = payload.get("sub")
        
        if jti:
            await revoke_user_session(jti)
            AuthEventLogger.log_logout(
                username=username,
                client_ip=client_ip,
                user_agent=user_agent,
                success=True
            )
            return {"message": "Successfully logged out"}
        else:
            AuthEventLogger.log_logout(
                username=username,
                client_ip=client_ip,
                user_agent=user_agent,
                success=False,
                failure_reason="Invalid token format - missing JTI"
            )
            raise HTTPException(status_code=400, detail="Invalid token format")
            
    except jwt.InvalidTokenError as e:
        AuthEventLogger.log_logout(
            username="unknown",
            client_ip=client_ip,
            user_agent=user_agent,
            success=False,
            failure_reason=f"Invalid token: {str(e)}"
        )
        raise HTTPException(status_code=401, detail="Invalid token")

@router.get("/auth/me", response_model=UserResponse)
async def get_current_user_info(current_user: Dict[str, Any] = Depends(require_current_user)):
    """
    Get current authenticated user information
    Requires valid JWT token authentication
    """
    return UserResponse(**current_user)

async def validate_user_credentials(credentials: Dict[str, Any]) -> Dict[str, Any] | None:
    """
    Validate user credentials against your Supabase database
    Returns user data if valid, None if invalid
    """
    username = credentials.get("username")
    password = credentials.get("password")
    
    if not username or not password:
        AuthEventLogger.log_credential_validation(
            username=username or "unknown",
            success=False,
            failure_reason="Missing username or password"
        )
        return None
    
    # Get user from database
    user = await get_user_by_username(username)
    if not user:
        AuthEventLogger.log_credential_validation(
            username=username,
            success=False,
            failure_reason="User not found in database"
        )
        return None
    
    # Verify password
    if not await verify_password(password, user["password_hash"]):
        AuthEventLogger.log_credential_validation(
            username=username,
            success=False,
            failure_reason="Invalid password"
        )
        return None
    
    AuthEventLogger.log_credential_validation(
        username=username,
        success=True
    )
    return user