import java.util.Arrays;

//  File: Bank.java
//  Purpose: Demonstrates the basics of array processing

//  This is a new version of our old friend the Bank class from previous units.

//  Although the implementation has been changed from an ArrayList to an array,
//  all software that works with the old version is guaranteed to work 
//  correctly with this one!

// This is an excellent example of the OOP principle of "information hiding"
// and one of the major reasons why the user of a Java class is forbidden 
// to access the implementation directly (i.e. why instance variables are 
// declared private

/**
   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 this Bank
   private static final int MAX_SIZE = 100 ;  // capacity of array
   
   /**
      Constructs a bank with no bank accounts.
   */
   public Bank()
   {
      accounts = new BankAccount[MAX_SIZE] ;
      // accounts can store up to MAX_SIZE BankAccount objects
   }

   /**
      Adds an account to this bank.
      @param a the account to add
   */
   public void addAccount(BankAccount newAccount)
   {
      // first, must check to see if array if full
      if ( count == accounts.length )     // array is full
      {
         this.resize() ;                  // make it bigger
      }
      
      // add newAccount to the Bank, in element "count"
      accounts[count] = newAccount ;
      count++ ;   // now we have one more account
   } 
   
   // utility method to make the array bigger when full
   private void resize()
   {
      // add another MAX_SIZE elements
      accounts = Arrays.copyOf(accounts, accounts.length + MAX_SIZE) ;
   }
      
   /**
      Print data for all accounts of this Bank
   */
   public void printList() 
   {
      // print headings
      System.out.printf("%15s%20s%n","Account Number","Account Balance") ;
      
      System.out.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
         System.out.printf("%15s     $%14.2f%n", current.getAccountNumber(),
                           current.getBalance()) ;
      }
   }
   
   /**
      Gets the sum of the balances of all accounts in this bank.
      @return the sum of the balances
   */
   public double getTotalBalance()
   {
      double total = 0;
      
      // for each account in this bank
      for ( int index = 0 ; index < count ; index++)
      {
          BankAccount current = accounts[index] ;   // get the account
          total = total + current.getBalance() ;  // add its balance to accum
      }
      return total ;
   }

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

   /**
      Linear search to find a bank account with a given account number.
      @param acctNum the number to find
      @return the account with the given number, or null if there
      is no such account
   */
   public BankAccount find(String acctNum)
   {
      for ( int i = 0 ; i < count ; i++ )
      {
         BankAccount current = accounts[i] ;              // get the account
	 String accountNum = current.getAccountNumber()	; // get account number
	 if ( accountNum.equals(acctNum) )  		  // found a match
             return current ;                             // we're done!			
      } 
      return null ; // No match in this Bank
   }

   /**
      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 is the largest 
      BankAccount largestYet = accounts[0] ;
      
      // for all other accounts
      for ( int i = 1; i < count ; i++ ) 
      {
         BankAccount current = accounts[i] ;		// get next account
         // is current account > highest so far?
         if (current.getBalance() > largestYet.getBalance())
            largestYet = current ;
      }
      return largestYet ;
   }
}