#include <iostream>
#include <fstream>
#include <vector>
#include <string>

using namespace std;

class FoodItem {
    string name;
    double price;
public:
    FoodItem(string n, double p) : name(n), price(p) {}
    string getName() const { return name; }
    double getPrice() const { return price; }
};

class Order {
    vector<FoodItem> items;
public:
    void addItem(const FoodItem& item) {
        items.push_back(item);
    }
    
    double getTotal() const {
        double total = 0;
        for (const FoodItem& item : items) {
            total += item.getPrice();
        }
        return total;
    }
    
    void displayOrder() const {
        cout << "Order:" << endl;
        for (const FoodItem& item : items) {
            cout << item.getName() << " - " << item.getPrice() << " BDT" << endl;
        }
        cout << "Total: " << getTotal() << " BDT" << endl;
    }

    const vector<FoodItem>& getItems() const {
        return items;
    }
};

class Menu {
    vector<FoodItem> items;
public:
    Menu() {
        // Add menu items
        items.push_back(FoodItem("French Fry", 140));
        items.push_back(FoodItem("Chicken Cheese Burger", 230));
        items.push_back(FoodItem("Steamed Momo", 180));
        items.push_back(FoodItem("Chicken Strips", 160));
        items.push_back(FoodItem("Cold Drinks", 25));
        items.push_back(FoodItem("Water", 20));
    }
    
    void displayMenu() const {
        cout << "Menu:" << endl;
        for (size_t i = 0; i < items.size(); ++i) {
            cout << i+1 << ". " << items[i].getName() << " - " << items[i].getPrice() << " BDT" << endl;
        }
    }
    
    FoodItem getItem(int index) const {
        if (index >= 0 && index < items.size()) {
            return items[index];
        } else {
            throw out_of_range("Invalid menu item index");
        }
    }
};

class FileManager {
public:
    static void saveOrder(const Order& order, const string& filename) {
        ofstream file&#40;filename&#41;;
        if (file.is_open()) {
            for (const FoodItem& item : order.getItems()) {
                file << item.getName() << "," << item.getPrice() << endl;
            }
            file.close();
            cout << "Order saved to " << filename << endl;
        } else {
            cout << "Error: Unable to open file for saving order." << endl;
        }
    }

    static Order loadOrder(const string& filename) {
        Order order;
        ifstream file&#40;filename&#41;;
        if (file.is_open()) {
            string line;
            while (getline(file, line)) {
                size_t pos = line.find(",");
                if (pos != string::npos) {
                    string name = line.substr(0, pos);
                    double price = stod(line.substr(pos + 1));
                    order.addItem(FoodItem(name, price));
                }
            }
            file.close();
            cout << "Order loaded from " << filename << endl;
        } else {
            cout << "Error: Unable to open file for loading order." << endl;
        }
        return order;
    }
};

int main() {
    Menu menu;
    Order order;
    
    // Display a welcome message
    cout << "Welcome to the Food Ordering System!" << endl;
    
    // Main menu loop
    while (true) {
        cout << "\nMain Menu:" << endl;
        cout << "1. View Menu" << endl;
        cout << "2. Add Item to Order" << endl;
        cout << "3. View Order" << endl;
        cout << "4. Save Order" << endl;
        cout << "5. Load Order" << endl;
        cout << "6. Checkout and Exit" << endl;
        cout << "Enter your choice: ";
        
        int choice;
        cin >> choice;
        
        switch (choice) {
            case 1: // View Menu
                menu.displayMenu();
                break;
            case 2: // Add Item to Order
                int index;
                cout << "Enter the item number to add: ";
                cin >> index;
                try {
                    order.addItem(menu.getItem(index - 1));
                    cout << "Item added to order." << endl;
                } catch (const out_of_range& e) {
                    cout << "Error: " << e.what() << endl;
                }
                break;
            case 3: // View Order
                order.displayOrder();
                break;
            case 4: // Save Order
                FileManager::saveOrder(order, "order.txt");
                break;
            case 5: // Load Order
                order = FileManager::loadOrder("order.txt");
                break;
            case 6: // Checkout and Exit
                cout << "Total Bill: " << order.getTotal() << " BDT" << endl;
                cout << "Thank you for using the Food Ordering System!" << endl;
                return 0;
            default:
                cout << "Invalid choice. Please enter a number from 1 to 6." << endl;
                break;
        }
    }
    
    return 0;
}