import cs1.Keyboard;
/**
   Simulate a bank account manager.
   @author Greg Vogl
   last modified 2003-10-11
*/
public class BankAccounts
{
   /**
      Use the BankAccount class to manage multiple bank accounts.
   */
   public static void main (String[] args) 
   {
      // Explain the program
      System.out.println("This program simulates a bank account manager.");

      // create an array of accounts
      accounts = new BankAccount[MAX_ACCOUNTS];

      int choice; // user's menu choice
      // loop until the user exits
      do 
      {
         displayActiveAccount();
         displayMenu();
         choice = Keyboard.readInt(); // get user's choice
         switch (choice) // view choice and perform action
         {
            case MENU_CREATE: create(); break;
            case MENU_DEPOSIT: deposit(); break;
            case MENU_WITHDRAW: withdraw(); break;
            case MENU_SELECT: select(); break;
            case MENU_DISPLAY_ACTIVE: displayActiveAccount(); break;
            case MENU_DISPLAY_ALL: displayAllAccounts(); break;
            case MENU_EXIT: break;
            default: System.out.println("Invalid menu selection, please try again."); break;
         }
      } while (choice != MENU_EXIT);
   }

   /**
      Display a menu of choices.
   */
   public static void displayMenu ()
   {
      System.out.println("Bank Account Menu");
      String[] choices = { "Create Account", "Deposit", "Withdrawal", "Select Account", "Display Active Account", "Display All Accounts", "Exit" };
      for (int i = 1; i <= choices.length; i++)
         System.out.println(i + " " + choices[i-1]);
      System.out.println("Type a number and press Enter.");
   }

   /**
      Create an account.
   */
   public static void create()
   {
      if (naccounts < MAX_ACCOUNTS)
      {
         System.out.println("Enter the account name.");
         String name = Keyboard.readString();
         activeAccount = naccounts;
         accounts[naccounts++] = new BankAccount(name);
      } else {
         System.out.println("Error: Not enough space in array to create a new account.");
      }
   }

   /**
      Deposit a non-negative amount into an account.
   */
   public static void deposit()
   {
      if (activeAccount == -1)
      {
         System.out.println("Error: No accounts exist.");
         return;
      }
      System.out.println("Enter a deposit");
      int amount = Keyboard.readInt();
      if (accounts[activeAccount].deposit(amount))
         System.out.println("Deposit succeeded.");
      else
         System.out.println("Deposit must be a positive number.");
   }

   /**
      Withdraw a non-negative amount from an account.
   */
   public static void withdraw()
   {
      if (activeAccount == -1)
      {
         System.out.println("Error: No accounts exist.");
         return;
      }
      System.out.println("Enter a withdrawal");
      int amount = Keyboard.readInt();
      if (accounts[activeAccount].withdraw(amount))
         System.out.println("Withdrawal succeeded.");
      else
         System.out.println("Withdrawal must be a positive number and not exceed the balance.");
   }

   /**
      Select an account.
   */
   public static void select()
   {
      System.out.println("Enter an account number.");
      int account = Keyboard.readInt();
      if (account < 0 || account >= naccounts) 
         System.out.println("Account does not exist.");
      else
         activeAccount = account;
   }

   /**
      Display the active account.
   */
   public static void displayActiveAccount()
   {
      System.out.println("\nActive Account: " + (activeAccount == -1 ? "None" : accounts[activeAccount].toString()));
   }

   /**
      Display all existing accounts.
   */
   public static void displayAllAccounts()
   {
      System.out.println(naccounts + " Bank Accounts:");
      for (int i=0; i<naccounts; i++)
         System.out.println(accounts[i]);
   }

   static BankAccount[] accounts; // array of bank accounts
   static int naccounts = 0; // number of accounts created so far
   static int activeAccount = -1; // the account in use
   static final int MAX_ACCOUNTS = 10; // maximum number of accounts that can be created
   static final int MENU_CREATE = 1;
   static final int MENU_DEPOSIT = 2;
   static final int MENU_WITHDRAW = 3;
   static final int MENU_SELECT = 4;
   static final int MENU_DISPLAY_ACTIVE = 5;
   static final int MENU_DISPLAY_ALL = 6;
   static final int MENU_EXIT = 7;
}