import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/*
 * The login dialog for SCorTrap.  It's on the screen on top of the main frame
 * whenever there is no operator logged in.  It disappears only after a valid
 * login.
 * 
 * I added an "exit" button to this dialog because it was a real nuisance to
 * have to log in just to end the program!  This was not required.
 *
 * Part of sample solution for Assignment 4, CISC 323, Winter 2006.
 * author: M. Lamb
 *//*
 * 
 */
public class LoginDialog extends JDialog implements ActionListener {
	
	// Fields for entering name and password.  A JPasswordField is just like a
	// JTextField, except the input is echoed as stars.
	private JTextField nameField;
	private JPasswordField passwordField;
	
	// button to submit login information
	private JButton loginButton;
	// button to exit the program
	private JButton exitButton;
	
	// the parent frame (a SCorTrap frame)
	private SCorTrap parent;
	// the database for looking up operator names and passwords
	private SCorTrapDatabase database;	
	
	// the name of the operator who logged on last time this dialog was used
	private String operatorName;
	
	// Accessor method for the name of the operator -- so other classes can
	// query this but not change it
	public String getOpName() {
		return operatorName;
	}
	
	/*
	 * Constructor -- creates this dialog at the beginning of the program.
	 * Does *not* make it visible.
	 * Parameters:
	 *   parent: the main frame, frozen while this dialog is visible
	 *   database: a database object for looking up operator names & passwords
	 */
  public LoginDialog(SCorTrap parent, SCorTrapDatabase database) {
  	super(parent, true); // set this up as a modal dialog, blocking the parent
  	this.database = database; // remember for future use
  	this.parent = parent;
  	
  	Container contents = getContentPane();
  	contents.setLayout(new GridLayout(0,1));
  	
    JLabel headerLabel = new JLabel("Please log in to SCorTrap");
    headerLabel.setFont(new Font("Serif", Font.BOLD, 20));
    
    JPanel nameRow = new JPanel();
    nameRow.add(new JLabel("name: "));
    nameField = new JTextField(20);
    nameRow.add(nameField);
    contents.add(nameRow);
    
    JPanel passwordRow = new JPanel();
    passwordRow.add(new JLabel("password: "));
    passwordField = new JPasswordField(10);
    passwordRow.add(passwordField);
    contents.add(passwordRow);
    
    JPanel buttonRow = new JPanel();
    loginButton = new JButton("log in");
    loginButton.addActionListener(this);
    buttonRow.add(loginButton);
    exitButton = new JButton("exit");
    exitButton.addActionListener(this);
    buttonRow.add(exitButton);
    contents.add(buttonRow);
    
    setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
    pack();
    // don't make the dialog visible yet  	
  } // end constructor
	
	
  // This method is called when a button is clicked.
  // It looks up the name and password in the database.  If they
  // match a real operator, this login dialog disappears.  If not,
  // pops up an error message.
	public void actionPerformed(ActionEvent e) {
		Object source = e.getSource();
		if (source == loginButton) {		
	    operatorName = nameField.getText();
	    // JPasswordField has a getText method, but for some reason it has
	    // been "deprecated" meaning that they're advising you not to use it
	    // in the newest versions of Java.  Intead, they have a getPassword
	    // method that returns an array of characters -- which I immediately
	    // convert to a String in the following line.
	    String password = new String(passwordField.getPassword());
	    Operator op = database.lookupOperator(operatorName);
	    if (op == null || !(password.equals(op.password))) {
	    	JOptionPane.showMessageDialog(this, "Error: bad name or password");
	    }
	    else {
	    	// Successful login.  Clear out text fields for next use and disappear.
	    	nameField.setText("");
	    	passwordField.setText("");
	    	// Tell main frame if new operator is an administrator
	    	parent.setAdminStatus(op.isAdmin);
	    	setVisible(false);
	    } // end if
		}
		else if (source == exitButton) {
			parent.endProgram();
		}
		else 
			JOptionPane.showMessageDialog(this, "internal error: unknown button");
	} // end actionPerformed

} //end class LoginDialog