"""Authentication service"""
import bcrypt
from app.models.user import User


def verify_credentials(username, password):
    """Verify username and password

    Args:
        username: Username to check
        password: Plain text password to verify

    Returns:
        User or None: User object if credentials valid, None otherwise
    """
    if not username or not password:
        return None

    user = User.get_by_username(username)

    if not user or not user.is_active:
        return None

    if user.check_password(password):
        return user

    return None


def hash_password(password):
    """Hash password using bcrypt

    Args:
        password: Plain text password

    Returns:
        str: Hashed password
    """
    return User.hash_password(password)


def check_password(password, password_hash):
    """Check password against hash

    Args:
        password: Plain text password
        password_hash: Bcrypt hash to check against

    Returns:
        bool: True if password matches, False otherwise
    """
    return bcrypt.checkpw(password.encode('utf-8'), password_hash.encode('utf-8'))