import csv  

class Product:
    pay_rate = 0.8    # Class variable for a standard discount of 20%
    all = []
    def __init__(self, name, price, quantity):
        assert price >= 0, f"Product price {price} is not greater than or equal to zero!"
        assert quantity >= 0, f"Product quantity {quantity} is not greater than or equal to zero!"
        self.name = name
        self.price = price
        self.quantity = quantity
        
        # Action to execute
        Product.all.append(self)  # Store all instances in the class variable 'all'
        
    def calculate_total_price(self):
        return self.price * self.quantity   
    
    def apply_discount(self):
        return self.calculate_total_price() * (self.pay_rate)
    
    def __repr__(self):
        return f"Product('{self.name}', {self.price}, {self.quantity})" 
    
    @classmethod
    def instantiate_from_csv(cls):
        with open('items.csv', 'r') as f:
            reader = csv.DictReader(f)
            items = list(reader)

            for item in items:
                try:
                    name = item.get('name')
                    price_str = item.get('price')
                    quantity_str = item.get('quantity')
                    
                    if name is None or price_str is None or quantity_str is None:
                        raise ValueError(f"Missing data in row: {item}")
                    
                    price = float(price_str)
                    quantity = int(quantity_str)   
                    
                    Product(name, price, quantity)
                    print(f"Created: {name}, ${price:.2f}, {quantity}")
                    
                except (TypeError, ValueError) as e:
                    print(f"Skipping row due to error: {item} → {e}")


# Example usage:
if __name__ == "__main__":
    
    Product.instantiate_from_csv()   # Instantiate products from the CSV file 
    print("All Products", Product.all)  # Print all instances stored in the class variable 'all'
     
 
'''
    for instance in Product.all:
        if instance.name in ["Smartphone", "Monitor", "Keyboard"]:
            instance.pay_rate = 0.7  # Special discount of 30%
        elif instance.name == "Tablet":
            instance.pay_rate = 1.0  # No discount
        else:
            instance.pay_rate = 0.8  # Standard discount of 20%
        
        total_price = instance.calculate_total_price()
        discounted_price = instance.apply_discount()
        
        print(f"Product: {instance.name}, Total Price: ${total_price:.2f}, Price after Discount: ${discounted_price:.2f}")  
        
        print(repr(instance))  # Print the formal representation of the instance 
    print(Product.all)  # Print all instances stored in the class variable 'all'
'''