datamodel.h

//class for product, Item, Cart
#include <unordered_map>
#include <string>
using namespace std;

//forward declaration
class Item;
class Cart;



class Product{
	int id;
	string name;
	int price;

public:
	Product(){
		
	}
	Product(int  u_id, string name, int price){
		id = u_id;
		this -> name = name;
		this -> price = price;
	}	
	string getDisplayName(){
		return name + " : Rs " + to_string(price) + "\n";
	}
	string getShortName(){
		return name.substr(0,1);
	}
	friend class Item;
	friend class Cart;
};



class Item{
	Product product;
	int quantity;
	
public:
	Item(){
		
	}
	Item(Product p, int q):product(p), quantity(q){}
	
	int getItemPrice(){
		return quantity*product.price;
		
	}
	string getItemInfo(){
		return to_string(quantity) + " x " + product.name + " Rs. " + to_string(quantity*product.price) + "\n";
	}
	
	friend class Cart;
};




class Cart{
	
	unordered_map<int,Item> items;

public:
	void addProduct(Product product){
		if(items.count(product.id)==0){
			Item newItem(product,1);
			items[product.id] = newItem;
		}
		else{
			items[product.id].quantity += 1;
		}
	}
	
	int getTotal(){
		int total = 0;
		for(auto itemPair : items){
			auto item = itemPair.second;
			total += item.getItemPrice();
		}
		return total;
	}
	
	string viewCart(){
		if(items.empty()){
			return "Cart is empty";
		}
		
		string itemizedList;
		int cart_total = getTotal();
		
		for(auto itemPair : items){
			auto item = itemPair.second;
			itemizedList.append(item.getItemInfo());
		}
		
		return itemizedList + "\n Total Amount : Rs. " + to_string(cart_total) + '\n'; 	
	}
	
	
	bool isEmpty(){
		return items.empty();
	}
};