/**
 *  file :  VirtualTeller.java
 *  desc :  An implementation of a virtual teller machine
 */

import HashTable.*;

public class VirtualTeller {

  private static int nextAccountID = 100;

  /**
   *  post :  creates a new virtual teller
   */
  public VirtualTeller() {
    accounts = new HashTable();
  }

  /**
   *  post :  creates a new account for the customer `name'.
   *          returns the new account's ID number
   */
  public int openAccount( String name ) {
    AccountNumber newAcctNumber = new AccountNumber( nextAccountID );
    AccountData newData = new AccountData( name );
    accounts.insert( newAcctNumber, newData );

    nextAccountID++;
    return newAcctNumber.getNumber();
  }

  /**
   *   pre :  amount >= 0
   *
   *  post :  withdraws `amount' dollars from the account whose
   *          number is `acct'.  if `acct' is invalid, no action
   *          is taken.
   */
  public void withdraw( int acct, int amount ) {
    AccountData account = findAccount( acct );

    if( account == null ) { // didn't find
      System.out.println( "Error:  Couldn't find account number `" +
			  acct + "'" );
    }
    else
      account.withdraw( amount );
  }

  /**
   *  post :  deposits `amount' dollars into the bank account whose
   *          id number is `acct';  if `acct' is invalid, no action
   *          is taken.
   */
  public void deposit( int acct, int amount ) {
    AccountData account = findAccount( acct );

    if( account == null ) { // didn't find
      System.out.println( "Error:  Couldn't find account number `" +
			  acct + "'" );
    }
    else
      account.deposit( amount );
  }

  /**
   *  post :  returns the balance on the account whose number is
   *          `acct'.
   *          If `acct' is an invalid number, returns -1.
   */
  public int balanceInquiry( int acct ) {
    AccountData account = findAccount( acct );

    if( account == null ) {
      System.out.println( "Error:  Couldn't find account number `" +
			  acct + "'" );
      return -1;
    }
    else
      return account.getBalance();
  }

  /**
   *  post :  returns the AccountData object associated with
   *          the account number `acct'.  If `acct' does not
   *          refer to a valid account, returns null.
   */
  private AccountData findAccount( int acct ) {
    AccountNumber acctNum = new AccountNumber( acct );
    AccountData account = (AccountData)accounts.find( acctNum );
    return account;
  }

  // fields
  private HashTable accounts;
}

// eof