CafeManagementSystem.java

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class CafeManagementSystem {

    public static void displayMenu(
        String[] itemNames,
        double[] itemPrices,
        int itemCount
    ) {
        System.out.println("\n===== MENU =====");

        for (int i = 0; i < itemCount; i++) {
            System.out.printf(
                "%d. %s - %.2f\n",
                (i + 1),
                itemNames[i],
                itemPrices[i]
            );
        }
    }

    public static void saveMenuToFile(String[] itemNames, double[] itemPrices, int itemCount) {
        try {
            FileWriter fw = new FileWriter("menu.txt");
            PrintWriter pw = new PrintWriter(fw);

            for (int i = 0; i < itemCount; i++) {
                pw.println(itemNames[i] + "," + itemPrices[i]);
            }

            pw.close();
        } catch (IOException e) {
            System.out.println("Error saving menu.");
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        String[] itemNames = new String[20];
        double[] itemPrices = new double[20];
        int itemCount = 0;

        try {
            File file = new File("menu.txt");
            Scanner fileReader = new Scanner(file);

            while (fileReader.hasNextLine()) {
                String line = fileReader.nextLine();

                String[] parts = line.split(",");

                itemNames[itemCount] = parts[0];
                itemPrices[itemCount] = Double.parseDouble(parts[1]);
                itemCount++;
            }

            fileReader.close();
        } catch (FileNotFoundException e) {
            System.out.println("Menu file not found");
        }

        int choice;

        do {
            System.out.println("\n===== CAFE MANAGEMENT SYSTEM =====");
            System.out.println("1. Customer Panel");
            System.out.println("2. Admin Panel");
            System.out.println("3. Exit");
            System.out.print("Enter your choice: ");
            choice = sc.nextInt();

            switch (choice) {
                case 1 -> {
                    int customerChoice = 0;

                    do {
                        System.out.println("\n===== CUSTOMER PANEL =====");
                        System.out.println("1. View Menu");
                        System.out.println("2. Place Order");
                        System.out.println("3. Back");
                        System.out.print("Enter your choice: ");
                        customerChoice = sc.nextInt();

                        switch (customerChoice) {
                            case 1 -> displayMenu(
                                itemNames,
                                itemPrices,
                                itemCount
                            );
                            case 2 -> {
                                int itemChoice = 0;
                                double totalBill = 0;
                                String[] orderedItems = new String[20];
                                int[] orderedQuantities = new int[20];
                                int orderedCount = 0;

                                do {
                                    displayMenu(
                                        itemNames,
                                        itemPrices,
                                        itemCount
                                    );

                                    System.out.println(
                                        "Press 0 to confirm your order."
                                    );

                                    System.out.print("Enter your choice: ");
                                    itemChoice = sc.nextInt();

                                    if (
                                        itemChoice >= 1 &&
                                        itemChoice <= itemCount
                                    ) {
                                        System.out.print("Enter quantity: ");
                                        int quantity = sc.nextInt();

                                        totalBill +=
                                            quantity *
                                            itemPrices[itemChoice - 1];

                                        boolean found = false;

                                        for (int i = 0; i < orderedCount; i++) {
                                            if (
                                                orderedItems[i].equals(
                                                    itemNames[itemChoice - 1]
                                                )
                                            ) {
                                                orderedQuantities[i] +=
                                                    quantity;
                                                found = true;
                                            }
                                        }

                                        if (!found) {
                                            orderedItems[orderedCount] =
                                                itemNames[itemChoice - 1];
                                            orderedQuantities[orderedCount] =
                                                quantity;
                                            orderedCount++;
                                        }
                                    } else if (itemChoice != 0) {
                                        System.out.println(
                                            "Invalid choice! Try again."
                                        );
                                    }
                                } while (itemChoice != 0);

                                System.out.println(
                                    "\n===== CUSTOMER RECEIPT ====="
                                );

                                for (int i = 0; i < orderedCount; i++) {
                                    System.out.printf(
                                        "%s x%d%n",
                                        orderedItems[i],
                                        orderedQuantities[i]
                                    );
                                }

                                System.out.println("Total Bill: " + totalBill);

                                try {
                                    FileWriter fw = new FileWriter("orders.txt", true);
                                    PrintWriter pw = new PrintWriter(fw);

                                    pw.println("===== CUSTOMER RECEIPT =====");

                                    for(int i = 0; i < orderedCount; i++) {
                                        pw.printf("%s x%d%n", orderedItems[i], orderedQuantities[i]);
                                    }

                                    pw.println("Total Bill: " + totalBill);

                                    pw.println("------------------------");

                                    pw.close();

                                    System.out.println("Order saved to the file successfully.");
                                } catch (IOException e) {
                                    System.out.println("Error saving file.");
                                }
                            }
                            case 3 -> System.out.println("Going back...");
                            default -> System.out.println(
                                "Invalid choice! Try again."
                            );
                        }
                    } while (customerChoice != 3);
                }
                case 2 -> {
                    int adminChoice;

                    do {
                        System.out.println("\n===== ADMIN PANEL =====");
                        System.out.println("1. View Menu");
                        System.out.println("2. Add Item");
                        System.out.println("3. Remove Item");
                        System.out.println("4. Back");
                        System.out.print("Enter your choice: ");
                        adminChoice = sc.nextInt();

                        switch(adminChoice) {
                            case 1 -> displayMenu(itemNames, itemPrices, itemCount);
                            case 2 -> {
                                sc.nextLine();

                                System.out.print("Enter item name: ");
                                String itemName = sc.nextLine();

                                System.out.print("Enter item price: ");
                                double itemPrice = sc.nextDouble();

                                itemNames[itemCount] = itemName;
                                itemPrices[itemCount] = itemPrice;
                                itemCount++;

                                saveMenuToFile(itemNames, itemPrices, itemCount);

                                System.out.println("Item added successfully!");
                            }
                            case 3 -> {
                                displayMenu(itemNames, itemPrices, itemCount);

                                System.out.print("Enter item number: ");
                                int itemNumber = sc.nextInt();

                                for (int i = itemNumber - 1; i < itemCount - 1; i++) {
                                    itemNames[i] = itemNames[i + 1];
                                    itemPrices[i] = itemPrices[i + 1];
                                }

                                itemCount--;

                                saveMenuToFile(itemNames, itemPrices, itemCount);

                                System.out.println("Item removed successfully!");
                            }
                            case 4 -> System.out.println("Going back....");
                            default -> System.out.println("Invalid choice! Try again.");
                        }
                    } while (adminChoice != 4);
                }
                case 3 -> System.out.println("Exiting program...");
                default -> System.out.println("Invalid choice! Try again");
            }
        } while (choice != 3);
    }
}