from typing import Optional
from sqlalchemy.orm import Session
from sqlalchemy.exc import IntegrityError

from models.grocery import Grocery
from schemas.grocery import GroceryCreate

def create_grocery(db: Session, grocery_data: GroceryCreate) -> Optional[Grocery]:
    """
    Creates a new grocery item in the database.

    Args:
        db (Session): The database session
        grocery_data (GroceryCreate): The data for the grocery item to create

    Returns:
        Optional[Grocery]: The newly created grocery object, or None if creation failed
    """
    try:
        normalized_name = normalize_grocery_name(grocery_data.name)
        db_grocery = Grocery(
            name=normalized_name,
            color=grocery_data.color,
            shape=grocery_data.shape
        )
        db.add(db_grocery)
        db.commit()
        db.refresh(db_grocery)
        return db_grocery
    except IntegrityError:
        db.rollback()
        return None

def get_grocery_by_name(db: Session, name: str) -> Optional[Grocery]:
    """
    Retrieves a grocery item by its name using the indexed name column.
    Returns the complete grocery object including the color and shape fields.

    Args:
        db (Session): The database session
        name (str): The name of the grocery item to retrieve

    Returns:
        Optional[Grocery]: The grocery object if found, otherwise None
    """
    normalized_name = normalize_grocery_name(name)
    return db.query(Grocery).filter(Grocery.name == normalized_name).first()

def validate_grocery_name(name: str) -> bool:
    """
    Validates the grocery name according to business rules.

    Args:
        name (str): The name to validate

    Returns:
        bool: True if the name is valid, False otherwise
    """
    if not name or not isinstance(name, str):
        return False
    
    # Remove leading/trailing whitespace and check length
    name = name.strip()
    if len(name) < 1:
        return False
    
    # Additional validation rules could be added here
    return True

def normalize_grocery_name(name: str) -> str:
    """
    Normalizes a grocery name for consistency in storage and indexing.
    Ensures consistent name format for the indexed name column.

    Args:
        name (str): The name to normalize

    Returns:
        str: The normalized name
    """
    if not name:
        raise ValueError("Grocery name cannot be empty")
        
    # Remove extra whitespace and capitalize first letter
    normalized = " ".join(name.split())
    return normalized.strip().capitalize()