ClerkState.java

import java.util.*;
import java.text.*;
import java.io.*;

public class ClerkState extends WareState {
	 
    private BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    private WareContext context;
    private static ClerkState instance;
	private WaitList waitList;
	private ClientList clientList;
	private ProductList productList;
	private SupplierList supplierList;
	//functions
    private static final int EXIT = 0;
    private static final int ADD_CLIENT = 1;
    private static final int SHOW_CLIENT_LIST = 2;
    private static final int SHOW_PRODUCT_LIST = 3;
    private static final int SHOW_INVOICE_LIST = 4;
    private static final int SHOW_PRODUCT_WAITLIST = 5;
    private static final int SHIPMENT = 6;
    private static final int CLIENT_MENU = 7;
    private static final int HELP = 8;
	
    private ClerkState() {
        super();
		supplierList = SupplierList.instance();
		productList = ProductList.instance();
		clientList = ClientList.instance();
		waitList = WaitList.instance();
    }

    public static ClerkState instance() {
        if (instance == null) {
            instance = new ClerkState();
        }
        return instance;
    }
	public String getToken(String prompt) {
    	do {
      		try {
       			System.out.println(prompt);
        		String line = reader.readLine();
        		StringTokenizer tokenizer = new StringTokenizer(line,"\n\r\f");
        		if (tokenizer.hasMoreTokens()) {
          			return tokenizer.nextToken();
        		}
      			} catch (IOException ioe) {
        			System.exit(0);
      			}
    		} while (true);
  	}
	public int getCommand() {
    do {
      try {
        int value = Integer.parseInt(getToken("Enter command:" + HELP + " for help"));
        if (value >= EXIT && value <= HELP) {
          return value;
        }
      } catch (NumberFormatException nfe) {
        System.out.println("Enter a number");
      }
    } while (true);
  }
	public void addClient() {
		boolean successful;
		String clientName = getToken("Enter the client's name: ");
		String clientAddress = getToken("Enter the client's address: ");

		Client newClient = new Client(clientName, clientAddress); //DOESNT WANT TO CREATE THE CLIENT OR ADD TO LIST
		successful = clientList.insertMember(newClient);

		if (successful) {
			System.out.println("Client with details (" + newClient.toString() + ") added successfully");
		} else {
			System.out.println("Issue adding client!");
		}
		
	}
	public void clientLister () {
		(WareContext.instance()).changeState(5); //goes to client listing state
    }
	public void productLister () {
		Iterator<Product> P_Iterator = productList.getProducts();
        System.out.println("Printing Product List");		
		while (P_Iterator.hasNext()) {
			Product item = P_Iterator.next();
			System.out.println("ID: " + item.getId() + " Price: " + item.getPrice() + " Quantity: " + item.getQuantity());
		}
    }
	public void shipment () {
		int supplierID = Integer.parseInt(getToken("Enter the ID of the supplier to recieve shipment from"));
		int position1 = supplierList.IDcheck(supplierID);
		Supplier shipper = supplierList.get_listed_obj(position1);
		Iterator<Supply> shipment = shipper.shipment();
		while (shipment.hasNext()) {
			Supply item = shipment.next();
			int productID = item.print_name_id();
			int quantity = Integer.parseInt(getToken("Enter the quantity received of the product (0 if none)"));
			quantity = ShipmentWaitList(productID, quantity);
			int position2 = productList.IDcheck(productID);
			Product prod = productList.get_listed_obj(position2);
			quantity = quantity + prod.getQuantity();
			prod.setQuantity(quantity);
		}
	}
	public void invoiceLister () {
		int clientID = Integer.parseInt(getToken("Enter the ID of a client, to get invoices"));
		int position = clientList.IDcheck(clientID);
		if (position == -1) {
			System.out.println("Invalid ID, potentially no clients exist, add a client before trying to get invoices");
		} else {
			Client item = clientList.get_listed_obj(position);
			item.DisplayInvoices();
		}
	}
	public void productWait () {
		Iterator<Wait> W_Iterator = waitList.getWaits();
		int id = Integer.parseInt(getToken("Enter the ID of a product to get wait list"));
		System.out.println("Printing product's wait list");		
		while (W_Iterator.hasNext()) {
			Wait item = W_Iterator.next();
			if ((item.getProduct()).getId()== id)
				System.out.println("client id: " + (item.getClient()).getId() + " Client name: " + (item.getClient()).getName() + " quantity: " + item.getQuantity());
		}
	}
	public int ShipmentWaitList (int id, int quantity) {
		Iterator<Wait> W_Iterator = waitList.getWaits();
		while (W_Iterator.hasNext()) {
			Wait item = W_Iterator.next();
			if ((item.getProduct()).getId()== id) {
				System.out.println("Product in waitlist, information on waitlist below: ");
				System.out.println("client id: " + (item.getClient()).getId() + " Client name: " + (item.getClient()).getName() + " quantity: " + item.getQuantity());
				int answer = Integer.parseInt(getToken("Enter 0 to skip, any other number to not skip"));
				if (answer != 0) {
					if (quantity > item.getQuantity()) {
						quantity = quantity - item.getQuantity();
						waitList.delete_listed_obj(item);
						System.out.println("order filled, quantity of shipment remaining is not 0");
					} else {
						int quant = item.getQuantity() - quantity;
						quantity = 0;
						if (quant == 0) {
							waitList.delete_listed_obj(item);
							System.out.println("order filled, quantity of shipment remaining is now 0");
						} else {
							item.setQuantity(quant);
							System.out.println("order partially filled, quantity of shipment remaining is now 0");
						}
						return quantity;
					}
				}
			}
		}
		return quantity;
	}
	private void salesMenu(){
		int UID = Integer.parseInt(getToken("Enter the ID of the client to login as: "));
		(WareContext.instance()).setUID(UID);
		(WareContext.instance()).changeState(1); //go to clerk state
    }
    public void logout(){
        (WareContext.instance()).changeState(0); // exit
    }
    private void help () {
        System.out.println("Enter a number between " + EXIT + " and " + HELP + " as explained below:");
        System.out.println(EXIT + " to Exit\n");
        System.out.println(ADD_CLIENT+ " to add a client");
        System.out.println(SHOW_CLIENT_LIST + " to go to client listing state");
        System.out.println(SHOW_PRODUCT_LIST+ " to product list");
        System.out.println(SHOW_INVOICE_LIST + " to  display invoice list");
        
        System.out.println(SHOW_PRODUCT_WAITLIST + " to  display product waitlist");
        System.out.println(SHIPMENT + " recieve shipment");
        System.out.println(CLIENT_MENU + " to  switch to the Client menu");
        
        System.out.println(HELP + " for help");
    }
    public void process() {
        int command;
        help();
        while ((command = getCommand()) != EXIT){
            switch (command) {
                case ADD_CLIENT: addClient();
                                break;
                case SHOW_CLIENT_LIST: clientLister();
                                break;
                case SHOW_PRODUCT_LIST: productLister();
                                break;
                case SHOW_INVOICE_LIST: invoiceLister();
                                break;
                case SHOW_PRODUCT_WAITLIST: productWait();
                                break;
                case SHIPMENT: shipment();
                                break;             
                case CLIENT_MENU: salesMenu();
                                break;
                case HELP: help();
                                break;
            }
        }

        logout();
    }
	public void run() {
        process();
    }
}