/*  VirtualTeller.java */

import sortedlist.*;

/**  An implementation of a virtual teller machine
 */
public class VirtualTeller {

  private static int nextAccountID = 100;

  /** Constructs a new virtual teller.
   */
  public VirtualTeller() {
    accounts = new SortedList();
  }

  /* Creates a new account for the customer `name'.
   *  @return the new account's ID number.
   */
  public int openAccount( String name ) {
    AccountData newData = new AccountData( name, nextAccountID );
    accounts.insert( newData );

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

  /** Withdraws `amount' dollars from the account whose  number is `acct'.  
   *  Assumes amount >= 0.
   *  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 );
    }
  }

  /** Deposits `amount' dollars into the bank account whose
   *  id number is `acct';  if `acct' is invalid, no action is taken.
   *  Assumes amount >= 0.
   *  @param acct is an account number.
   *  @param amount an amount of money.
   */
  public void deposit( int acct, int amount ) {
    AccountData account = findAccount( acct );

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

  /** Finds the balance on the account whose number is `acct'.
   *  If `acct' is an invalid number, returns -1.
   *  @param acct is an account number.
   *  @return the balance. 
   */
  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();
    }
  }

  /** Get the AccountData object associated with the account number 
   *  `acct'.  If `acct' does not refer to a valid account, returns null.
   *  @param acct is an account number.
   */
  private AccountData findAccount( int acct ) {
    AccountData account = (AccountData)accounts.find( acct );
    return account;
  }


  private SortedList accounts;
}