"""Complex class example with properties, decorators, and advanced features."""

from datetime import datetime
from typing import Optional, List


class Product:
    """Product class with advanced Python features."""
    
    # Class variable
    total_products = 0
    
    def __init__(self, name: str, price: float, category: str):
        self._name = name
        self._price = price
        self._category = category
        self._created_at = datetime.now()
        self._discount = 0.0
        Product.total_products += 1
    
    @property
    def name(self) -> str:
        """Product name property."""
        return self._name
    
    @name.setter
    def name(self, value: str):
        if not value.strip():
            raise ValueError("Product name cannot be empty")
        self._name = value
    
    @property
    def price(self) -> float:
        """Product price with discount applied."""
        return self._price * (1 - self._discount)
    
    @property
    def original_price(self) -> float:
        """Original price before discount."""
        return self._price
    
    @original_price.setter
    def original_price(self, value: float):
        if value < 0:
            raise ValueError("Price cannot be negative")
        self._price = value
    
    def apply_discount(self, percentage: float):
        """Apply discount percentage."""
        if 0 <= percentage <= 100:
            self._discount = percentage / 100
    
    @staticmethod
    def validate_category(category: str) -> bool:
        """Validate if category is allowed."""
        allowed_categories = ["electronics", "clothing", "books", "food"]
        return category.lower() in allowed_categories
    
    @classmethod
    def create_book(cls, title: str, price: float):
        """Factory method to create a book product."""
        return cls(title, price, "books")
    
    @classmethod
    def get_total_products(cls) -> int:
        """Get total number of products created."""
        return cls.total_products
    
    def __str__(self) -> str:
        return f"{self._name} - ${self.price:.2f}"
    
    def __repr__(self) -> str:
        return f"Product(name='{self._name}', price={self._price}, category='{self._category}')"