//  File: Bank.java

//  Array version of our old friend, the Bank class.  Same methods, but the
//  implementation has been changed from an ArrayList to an array.

//  Note that the test class did not have to be modified at all because the
//  "interface" - the set of public methods - remains the same.  This is an 
//  example of the OOP principle of "information hiding."  And why we never 
//  allow programmers using our classes to access the instance variables 
//  without going through the methods of the class.
//
//  Data file oriented.


import java.io.FileWriter;
import java.util.ArrayList ;
import java.io.PrintWriter ;    // for output file
import java.io.IOException ;    // for output file

/**
   This bank contains a collection of bank accounts.
*/
public class Bank
{   
   private BankAccount [] accounts ;         // a list of BankAccount objects
   private int count ;                       // number of accounts in the bank
   private static final int MAX_SIZE = 100 ; // maximum number of accounts
   
   /**
      Create a new Bank with no accounts
   */
   public Bank()
   {
      accounts = new BankAccount[MAX_SIZE] ;
      count = 0 ; // no accounts yet
   }

   /**
      Adds an account to this bank.
      @param a the account to add
   */
   public void addAccount(BankAccount a)
   {
      // store new account at index "count"
      accounts[count] = a ;
      
      // update number of accounts (and index where next one will be stored)
      count++ ;               
   } 
   
   /**
      Print data for all accounts
   */
   public void printList() throws IOException 
   {
      // create output file in default folder
      FileWriter myFileWriter = new FileWriter("BankAccounts.out") ;
      PrintWriter toFile = new PrintWriter(myFileWriter);
            
      // print headings to screen and to file
      System.out.printf("%15s%20s%n","Account Number","Account Balance") ;
      System.out.printf("%15s%20s%n","==============","===============") ;
                         
      toFile.printf("%15s%20s%n","Account Number","Account Balance") ;
      toFile.printf("%15s%20s%n","==============","===============") ;

      // for each account in this bank...
      for ( int i = 0 ; i < count ; i++ )
      {
         BankAccount current = accounts[i] ;	  // get next account
         
         // print account number and balamce to screen and to file
         System.out.printf("%15s     $%14.2f%n",current.getAccountNumber(),
                           current.getBalance()) ;
         toFile.printf("%15s     $%14.2f%n",current.getAccountNumber(),
                           current.getBalance()) ;
      }
      toFile.close() ;	// always remember to close file!
   }
   
   /**
      Gets the sum of the balances of all accounts in this bank.
      @return the sum of the balances
   */
   public double getTotalBalance()
   {
      double total = 0 ;   // accumulator for total balances
      
      // for each account in this bank...
      for ( int i = 0 ; i < count ; i++ )
      {
         BankAccount current = accounts[i] ;       // get the account
         total = total + current.getBalance() ;	   // add its balance to total
      }
      return total ;
   }

   /**
      Counts the number of bank accounts whose balance is at
      least a specified minimum
      @param atLeast the balance required to count an account
      @return the number of accounts having least the given balance
   */
   public int count(double atLeast)
   {
      int matches = 0 ;    // counts for number of qualifying accounts
      
      // for each account in the bank...
      for ( int i = 0 ; i < count ; i++ )
      {
         BankAccount current = accounts[i] ;	// get the account
         if (current.getBalance() >= atLeast) 	// if it qualifies...
           matches++ ;                          // ...increment the counter 
      }
      return matches ;
   }

   /**
      Linear search to find a bank account with a given account number.
      @param target the number to find
      @return the account with the given number, or null if there
      is no such account
   */
   public BankAccount find(String target)
   {
      // for each account in the bank...
      for ( int i = 0 ; i < count ; i++ )
      {
         BankAccount next = accounts[i] ;	    // get the account
	 String acctNum = next.getAccountNumber() ; // get the account number
	 if ( acctNum.equals(target) )              // if it matches the target
            return next ;                           // ...we're done
      } 
      return null ; // no match in the entire array list
   }

   /**
      Gets the bank account with the largest balance.
      @return the account with the largest balance, or null if the
      bank has no accounts
   */
   public BankAccount getMaximum()
   {
      if (count == 0) 	// if no accounts, return null
        return null;
      
      // assume first account has largest balance
      BankAccount largest = accounts[0] ;
      
      // for all other accounts...
      for ( int i = 1; i < count ; i++ ) 
      {
         BankAccount current = accounts[i] ;             // get next account
         double currentBalance = current.getBalance() ;  // get its balance
         // see if current account balance > highest so far
         if ( currentBalance > largest.getBalance())     // if so...
            largest = current ;                          // update largest
      }
      return largest ;
   }
}