# app/services/auth_service.py
"""
Authentication service for user registration and login.

This module provides classes and functions for:
- User registration with validation
- User authentication and JWT token generation
- Password management and security
"""

import logging
from datetime import UTC
from typing import Any

from sqlalchemy.orm import Session

from app.exceptions import (
    InvalidCredentialsException,
    UserAlreadyExistsException,
    UserNotActiveException,
    ValidationException,
)
from middleware.auth import AuthManager
from models.database.user import User
from models.schema.auth import UserLogin, UserRegister

logger = logging.getLogger(__name__)


class AuthService:
    """Service class for authentication operations following the application's service pattern."""

    def __init__(self):
        """Class constructor."""
        self.auth_manager = AuthManager()

    def register_user(self, db: Session, user_data: UserRegister) -> User:
        """
        Register a new user.

        Args:
            db: Database session
            user_data: User registration data

        Returns:
            Created user object

        Raises:
            UserAlreadyExistsException: If email or username already exists
            ValidationException: If user data is invalid
        """
        try:
            # Check if email already exists
            if self._email_exists(db, user_data.email):
                raise UserAlreadyExistsException(
                    "Email already registered", field="email"
                )

            # Check if username already exists
            if self._username_exists(db, user_data.username):
                raise UserAlreadyExistsException(
                    "Username already taken", field="username"
                )

            # Hash password and create user
            hashed_password = self.auth_manager.hash_password(user_data.password)
            new_user = User(
                email=user_data.email,
                username=user_data.username,
                hashed_password=hashed_password,
                role="user",
                is_active=True,
            )

            db.add(new_user)
            db.commit()
            db.refresh(new_user)

            logger.info(f"New user registered: {new_user.username}")
            return new_user

        except UserAlreadyExistsException:
            raise  # Re-raise custom exceptions
        except Exception as e:
            db.rollback()
            logger.error(f"Error registering user: {str(e)}")
            raise ValidationException("Registration failed")

    def login_user(self, db: Session, user_credentials: UserLogin) -> dict[str, Any]:
        """
        Login user and return JWT token with user data.

        Args:
            db: Database session
            user_credentials: User login credentials

        Returns:
            Dictionary containing access token data and user object

        Raises:
            InvalidCredentialsException: If authentication fails
            UserNotActiveException: If user account is not active
        """
        try:
            user = self.auth_manager.authenticate_user(
                db, user_credentials.email_or_username, user_credentials.password
            )
            if not user:
                raise InvalidCredentialsException("Incorrect username or password")

            # Check if user is active
            if not user.is_active:
                raise UserNotActiveException("User account is not active")

            # Create access token
            token_data = self.auth_manager.create_access_token(user)

            logger.info(f"User logged in: {user.username}")
            return {"token_data": token_data, "user": user}

        except (InvalidCredentialsException, UserNotActiveException):
            raise  # Re-raise custom exceptions
        except Exception as e:
            logger.error(f"Error during login: {str(e)}")
            raise InvalidCredentialsException()

    def get_user_by_email(self, db: Session, email: str) -> User | None:
        """Get user by email."""
        try:
            return db.query(User).filter(User.email == email).first()
        except Exception as e:
            logger.error(f"Error getting user by email: {str(e)}")
            return None

    def get_user_by_username(self, db: Session, username: str) -> User | None:
        """Get user by username."""
        try:
            return db.query(User).filter(User.username == username).first()
        except Exception as e:
            logger.error(f"Error getting user by username: {str(e)}")
            return None

    def authenticate_user(
        self, db: Session, username: str, password: str
    ) -> User | None:
        """Authenticate user with username/password."""
        try:
            return self.auth_manager.authenticate_user(db, username, password)
        except Exception as e:
            logger.error(f"Error authenticating user: {str(e)}")
            return None

    def create_access_token(self, user: User) -> dict[str, Any]:
        """Create access token for user."""
        try:
            return self.auth_manager.create_access_token(user)
        except Exception as e:
            logger.error(f"Error creating access token: {str(e)}")
            raise ValidationException("Failed to create access token")

    def hash_password(self, password: str) -> str:
        """Hash password."""
        try:
            return self.auth_manager.hash_password(password)
        except Exception as e:
            logger.error(f"Error hashing password: {str(e)}")
            raise ValidationException("Failed to hash password")

    def verify_password(self, plain_password: str, hashed_password: str) -> bool:
        """Verify password against hash."""
        try:
            return self.auth_manager.verify_password(plain_password, hashed_password)
        except Exception as e:
            logger.error(f"Error verifying password: {str(e)}")
            return False

    def create_access_token_with_data(self, data: dict) -> dict:
        """
        Create JWT token with custom data payload.

        Useful for non-User entities like customers that need tokens.

        Args:
            data: Dictionary containing token payload data (must include 'sub')

        Returns:
            Dictionary with access_token, token_type, and expires_in
        """
        from datetime import datetime, timedelta

        from jose import jwt

        from app.core.config import settings

        try:
            expires_delta = timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
            expire = datetime.now(UTC) + expires_delta

            # Build payload with provided data
            payload = {
                **data,
                "exp": expire,
                "iat": datetime.now(UTC),
            }

            token = jwt.encode(payload, settings.SECRET_KEY, algorithm="HS256")

            return {
                "access_token": token,
                "token_type": "bearer",
                "expires_in": settings.ACCESS_TOKEN_EXPIRE_MINUTES * 60,
            }
        except Exception as e:
            logger.error(f"Error creating access token with data: {str(e)}")
            raise ValidationException("Failed to create access token")

    # Private helper methods
    def _email_exists(self, db: Session, email: str) -> bool:
        """Check if email already exists."""
        return db.query(User).filter(User.email == email).first() is not None

    def _username_exists(self, db: Session, username: str) -> bool:
        """Check if username already exists."""
        return db.query(User).filter(User.username == username).first() is not None


# Create service instance following the same pattern as other services
auth_service = AuthService()