from typing import List, Optional, Dict, Union
from datetime import datetime
from sqlalchemy.orm import Session
from sqlalchemy import desc
from models.shoe import Shoe
from schemas.shoe import ShoeCreate, ShoeUpdate

def get_shoes_by_name(db: Session, name: str) -> List[Shoe]:
    """
    Get shoes by name with case-insensitive search.
    
    Args:
        db: Database session
        name: Name to search for
        
    Returns:
        List of matching Shoe objects
    """
    return db.query(Shoe).filter(Shoe.name.ilike(f'%{name}%')).all()

def get_shoes_by_brand_and_size(db: Session, brand: str, size: int) -> List[Shoe]:
    """
    Get shoes filtered by brand and size.
    
    Args:
        db: Database session
        brand: Brand name to filter
        size: Shoe size to filter
        
    Returns:
        List of matching Shoe objects
    """
    return db.query(Shoe).filter(
        Shoe.brand == brand,
        Shoe.size == size
    ).all()

def validate_shoe_data(shoe_data: Union[ShoeCreate, ShoeUpdate]) -> Dict[str, str]:
    """
    Validate shoe data before creation/update.
    
    Args:
        shoe_data: Shoe data to validate
        
    Returns:
        Dict with error message if validation fails, empty dict if valid
    """
    errors = {}
    
    if shoe_data.size <= 0:
        errors["size"] = "Size must be positive"
        
    if shoe_data.price and shoe_data.price < 0:
        errors["price"] = "Price cannot be negative"
        
    if shoe_data.purchase_date and shoe_data.purchase_date > datetime.now():
        errors["purchase_date"] = "Purchase date cannot be in the future"
        
    return errors

def get_shoes_by_condition(db: Session, condition: str) -> List[Shoe]:
    """
    Get shoes filtered by condition.
    
    Args:
        db: Database session
        condition: Condition to filter by
        
    Returns:
        List of matching Shoe objects
    """
    return db.query(Shoe).filter(Shoe.condition == condition).all()

def calculate_collection_value(db: Session) -> Dict[str, Union[int, List[Dict[str, Any]]]]:
    """
    Calculate total value of shoe collection and get price breakdown.
    
    Args:
        db: Database session
        
    Returns:
        Dict containing total value and price breakdown by brand
    """
    shoes = db.query(Shoe).all()
    total_value = sum(shoe.price for shoe in shoes if shoe.price)
    
    brand_breakdown = {}
    for shoe in shoes:
        if shoe.price:
            brand_breakdown[shoe.brand] = brand_breakdown.get(shoe.brand, 0) + shoe.price
            
    return {
        "total_value": total_value,
        "brand_breakdown": [
            {"brand": brand, "value": value}
            for brand, value in brand_breakdown.items()
        ]
    }