/*
 * [Password.java]
 *
 * Summary: Generates unguessable passwords.
 *
 * Copyright: (c) 2003-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2003-06-23 initial version
 *  1.1 2006-01-01
 *  1.2 2006-03-06 reformat with IntelliJ, add Javadoc
 *  1.3 2007-05-12 bigger type, add logo and pad, adjust spacing.
 *  1.4 2008-04-03 add build to title, tidy code
 *  1.5 2010-02-04 optionally includes punctuation in generated passwords.
 *  1.6 2010-07-28 ensure one char of each class appears in generated password.
 *  1.7 2011-12-01 configurable L&F, fine control over chars to include in passwords.
 *  1.8 2012-06-27 default length=12, default punct on, double check that one of each category
 *  1.9 2014-04-04 no longer use ? in passwords. Chapters Indigo rejects them.
 */
package com.mindprod.password;

import com.mindprod.common18.Build;
import com.mindprod.common18.CMPAboutJBox;
import com.mindprod.common18.FontFactory;
import com.mindprod.common18.HybridJ;
import com.mindprod.common18.JEButton;
import com.mindprod.common18.Laf;
import com.mindprod.common18.VersionCheck;
import com.mindprod.fastcat.FastCat;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JRadioButton;
import javax.swing.JSpinner;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SpinnerNumberModel;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.security.SecureRandom;
import java.util.Random;

import static java.lang.System.*;

/**
 * Generates unguessable passwords.
 * <p/>
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.9 2014-04-04 no longer use ? in passwords. Chapters Indigo rejects them.
 * @noinspection FieldCanBeLocal
 * @since 2003-06-23
 */
public final class Password extends JApplet implements ActionListener, ChangeListener
    {
    /**
     * height of Applet box in pixels. Does not include surrounding frame.
     */
    private static final int APPLET_HEIGHT = 420;

    /**
     * Width of Applet box in pixels.
     */
    private static final int APPLET_WIDTH = 480;

    /**
     * basic font size
     */
    private static final int basicFontSize = 14;

    private static final Font FONT_FOR_EDITABLE =
            FontFactory.build( "Dialog",
                    Font.PLAIN,
                    basicFontSize );

    private static final Font FONT_FOR_LABEL =
            FontFactory.build( "Dialog",
                    Font.PLAIN,
                    basicFontSize );

    private static final Font FONT_FOR_RESULT = FontFactory.build( "Dialog",
            Font.BOLD,
            basicFontSize + 2 );
    // leave out 0 1 because they looks like O and I l

    /**
     * default length of generated passwords
     */
    private static final int DEFAULT_PW_LENGTH = 12;

    private static final int FIRST_COPYRIGHT_YEAR = 2003;

    /**
     * leave out l. It/ looks too much like 1
     * leave out 0. It looks too much like O*
     */
    private static final String CAST_OF_DIGITS = "23456789"; // 8-possibilities

    /**
     * leave out l, looks too much like 1
     */
    private static final String CAST_OF_LOWER_CASE_LETTERS = "abcdefghijkmnopqrstuvwxyz"; // 25 possibilities

    /**
     * leave out | <>()[]{}/\ //,.:;?   colon is often used to separate userid:pw
     */
    private static final String CAST_OF_PUNCTUATION_LETTERS = "!#$%&*+-=@^`~"; // 13 possibilities.

    /**
     * leave out O, looks too much like 0, leave out I.
     */
    private static final String CAST_OF_UPPER_CASE_LETTERS = "ABCDEFGHJKLMNPQRSTUVWXYZ";  // 24 possibilities

    /**
     * copyright not displayed
     *
     * @noinspection UnusedDeclaration
     */
    private static final String EMBEDDED_COPYRIGHT =
            "Copyright: (c) 2003-2017 Roedy Green, Canadian Mind Products, http://mindprod.com";

    private static final String RELEASE_DATE = "2014-04-04";

    private static final String TITLE_STRING = "Password Generator";

    private static final String VERSION_STRING = "1.9";

    private static final Color BACKGROUND_FOR_APPLET = new Color( 0xfaf0e6 )/* linen */;

    /**
     * background colour for instructions.  Default grey is too dark
     */
    private static final Color BACKGROUND_FOR_INSTRUCTIONS = new Color( 0xf8f8f8 );

    private static final Color BACKGROUND_FOR_LABEL = new Color( 0xfaf0e6 )/* linen */;

    private static final Color BACKGROUND_FOR_RESULT = new Color( 0xebfff7 );

    private static final Color FOREGROUND_FOR_APPLET = new Color( 0x1e90ff )/* dodger blue */;

    /**
     * instruction normal color
     */
    private static final Color FOREGROUND_FOR_INSTRUCTIONS = new Color( 0x339911 );

    private static final Color FOREGROUND_FOR_LABEL = new Color( 0x0000b0 );

    private static final Color FOREGROUND_FOR_RESULT = new Color( 0x226622 );

    /**
     * for titles
     */
    private static final Color FOREGROUND_FOR_TITLE = new Color( 0xdc143c );

    /**
     * instructions font
     */
    private static final Font FONT_FOR_INSTRUCTIONS = com.mindprod.common18.FontFactory.build( "Dialog",
            Font.PLAIN,
            12 );

    /**
     * for for titles and About buttons
     */
    private static final Font FONT_FOR_TITLE = FontFactory.build( "Dialog", Font.BOLD, 16 );

    /**
     * for for title second line
     */
    private static final Font FONT_FOR_TITLE2 = FontFactory.build( "Dialog", Font.PLAIN, 14 );

    /**
     * space to leave around the applet
     */
    private static final int[] margin = { 12, 15, 12, 15 }/* t l b r */;

    /**
     * high quality random number generator, actually final, but compiler cannot be sure of that
     */
    private static Random wheel;

    static
        {
        try
            {
            wheel = SecureRandom.getInstance( "SHA1PRNG", "SUN" );
            }
        catch ( Exception e )
            {
            out.println(
                    "Reverting to lower quality random number generator" );
            wheel = new Random();
            }
        }

    /**
     * button to request another password
     */
    private JButton another;

    /**
     * label for pwLength
     */
    private JLabel pwLengthLabel;

    /**
     * Displayed title
     */
    private JLabel title;

    /**
     * title, second line
     */
    private JLabel title2;

    /**
     * radio button selected if include digits
     */
    private JRadioButton includeDigits;

    /**
     * radio button selected if include lower case
     */
    private JRadioButton includeLowerCase;

    /**
     * radio button selected if include punctuation
     */
    private JRadioButton includePunctuation;

    /**
     * radio button selected if include upper case
     */
    private JRadioButton includeUpperCase;

    /**
     * how long a password do you want
     */
    private JSpinner pwLength;

    /**
     * displayed instructions on how to use
     */
    private JTextArea instructions;

    /**
     * Generated suggested password.
     */
    private JTextField suggestedPassword;

    /**
     * helper for pwlength.
     */
    private SpinnerNumberModel pwLengthModel;

    /**
     * allocate all components
     */
    private void buildComponents()
        {
        title = new JLabel( TITLE_STRING + " " + VERSION_STRING );
        title.setForeground( FOREGROUND_FOR_TITLE );
        title.setFont( FONT_FOR_TITLE );
        title2 = new JLabel(
                "released:" +
                RELEASE_DATE +
                " build:" +
                Build.BUILD_NUMBER
        );
        title2.setFont( FONT_FOR_TITLE2 );
        title2.setForeground( FOREGROUND_FOR_TITLE );
        pwLength = new JSpinner();
        Dimension d = new Dimension( 60, 25 );
        pwLength.setMinimumSize( d );
        pwLength.setPreferredSize( d );
        pwLength.setMaximumSize( d );
        pwLengthModel = new SpinnerNumberModel( DEFAULT_PW_LENGTH /* initial value */,
                4  /* min, don't put below 4 or impossible to get all 4 categories. */,
                40 /* max */,
                1  /* step */ );
        pwLength.setModel( pwLengthModel );
        pwLengthLabel = new JLabel( "Length" );
        pwLengthLabel.setBackground( BACKGROUND_FOR_LABEL );
        pwLengthLabel.setFont( FONT_FOR_LABEL );
        pwLengthLabel.setForeground( FOREGROUND_FOR_LABEL );
        includeDigits = new JRadioButton( "include digits", true );
        includeDigits.setBackground( BACKGROUND_FOR_LABEL );
        includeDigits.setFont( FONT_FOR_EDITABLE );
        includeDigits.setForeground( FOREGROUND_FOR_LABEL );
        includeLowerCase = new JRadioButton( "include lower case letters", true );
        includeLowerCase.setBackground( BACKGROUND_FOR_LABEL );
        includeLowerCase.setFont( FONT_FOR_EDITABLE );
        includeLowerCase.setForeground( FOREGROUND_FOR_LABEL );
        includeUpperCase = new JRadioButton( "include uppercase letters", true );
        includeUpperCase.setBackground( BACKGROUND_FOR_LABEL );
        includeUpperCase.setFont( FONT_FOR_EDITABLE );
        includeUpperCase.setForeground( FOREGROUND_FOR_LABEL );
        includePunctuation = new JRadioButton( "include punctuation", true );
        includePunctuation.setBackground( BACKGROUND_FOR_LABEL );
        includePunctuation.setFont( FONT_FOR_EDITABLE );
        includePunctuation.setForeground( FOREGROUND_FOR_LABEL );
        another = new JEButton( "Another" );
        another.setToolTipText( "Generate another password" );
        // make JTextField, unfortunately no copy/paste in old Javas.
        suggestedPassword = new JTextField( "", JLabel.LEFT );
        suggestedPassword.setBackground( BACKGROUND_FOR_RESULT );
        suggestedPassword.setEditable( false );
        suggestedPassword.setFont( FONT_FOR_RESULT );
        suggestedPassword.setForeground( FOREGROUND_FOR_RESULT );
        suggestedPassword.setMargin( new Insets( 2, 2, 2, 2 ) );
        suggestedPassword.setOpaque( true );
        /////////////////////////////////////////////////////////////////////////////////////////////////////
        instructions = new JTextArea( "Select which characters to include in your new password (the more you\n" +
                                      "include the more secure) and the password length (the longer the more\n" +
                                      "secure), then click ANOTHER. Then for one final tweak, change one or two\n" +
                                      "characters of the result before use. To avoid confusion, generated passwords\n" +
                                      "never contain the characters Il1| or O0." );
        instructions.setEditable( false );
        instructions.setMargin( new Insets( 4, 4, 4, 4 ) );
        instructions.setBackground( BACKGROUND_FOR_INSTRUCTIONS );
        instructions.setFont( FONT_FOR_INSTRUCTIONS );
        instructions.setForeground( FOREGROUND_FOR_INSTRUCTIONS );
        }

    /**
     * build a menu with Look & Feel and About across the top
     */
    private void buildMenu()
        {
        // turn on anti-alias
        System.setProperty( "swing.aatext", "true" );
        final JMenuBar menubar = new JMenuBar();
        setJMenuBar( menubar );
        final JMenu lafMenu = Laf.buildLookAndFeelMenu();
        if ( lafMenu != null )
            {
            menubar.add( lafMenu );
            }
        final JMenu menuHelp = new JMenu( "Help" );
        menubar.add( menuHelp );
        final JMenuItem aboutItem = new JMenuItem( "About" );
        menuHelp.add( aboutItem );
        aboutItem.addActionListener( new ActionListener()
            {
            public void actionPerformed( ActionEvent e )
                {
                // open aboutbox frame
                // open aboutbox frame
                new CMPAboutJBox( TITLE_STRING,
                        VERSION_STRING,
                        "Generates random passwords.",
                        "",
                        "freeware",
                        RELEASE_DATE,
                        FIRST_COPYRIGHT_YEAR,
                        "Roedy Green",
                        "PASSWORD",
                        "1.8" );
                }
            } );
        }

    /**
     * What happens after ANOTHER button hit.
     */
    private void hit()
        {
        int pwLengthValue = ( ( Number ) pwLengthModel.getValue() ).intValue();
        boolean needsDigits = false;
        boolean needsLowerCase = false;
        boolean needsUpperCase = false;
        boolean needsPunctuation = false;
        final FastCat sb = new FastCat( 4 );
        if ( includeDigits.isSelected() )
            {
            needsDigits = true;
            sb.append( CAST_OF_DIGITS );
            }
        if ( includeLowerCase.isSelected() )
            {
            needsLowerCase = true;
            sb.append( CAST_OF_LOWER_CASE_LETTERS );
            }
        if ( includeUpperCase.isSelected() )
            {
            needsUpperCase = true;
            sb.append( CAST_OF_UPPER_CASE_LETTERS );
            }
        if ( includePunctuation.isSelected() )
            {
            needsPunctuation = true;
            sb.append( CAST_OF_PUNCTUATION_LETTERS );
            }
        // if they turned everything off, treat as if asked for digits only.
        if ( sb.length() == 0 )
            {
            needsDigits = true;
            includeDigits.setSelected( true );
            sb.append( CAST_OF_DIGITS );
            }
        suggestedPassword.setText( spin( pwLengthValue, sb.toString(), needsDigits, needsLowerCase, needsUpperCase,
                needsPunctuation ) );
        suggestedPassword.requestFocus();
        }

    /**
     * Install listeners
     */
    private void installHooks()
        {
        another.addActionListener( this );
        includeDigits.addActionListener( this );
        includeUpperCase.addActionListener( this );
        includeLowerCase.addActionListener( this );
        includePunctuation.addActionListener( this );
        pwLength.addChangeListener( this );
        }

    /**
     * Layout components in a GridBag
     *
     * @param contentPane JApplet contentPane.
     */
    private void layoutComponents( Container contentPane )
        {
        // layout
        // ---0---1-------------2------- 3---- 0
        // 0---- title -------  ----- title2---
        // 1 includedigits
        // 2 includelower   ~length----length 2
        // 3 includeupper      -------------- 3
        // 4 includepunct  -------------------4
        // 5 ----------suggested password---- 5
        // 6 -------------------------ANOTHER 6
        // 7 ----------instructions---------- 7
        // 1 is dummy column to absorb extra space
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( title,
                new GridBagConstraints( 0,
                        0,
                        3,
                        1,
                        0.0,
                        0.0,
                        GridBagConstraints.WEST,
                        GridBagConstraints.NONE,
                        new Insets( margin[ 0 ],
                                margin[ 1 ],
                                5,
                                5 ),
                        0,
                        0
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( title2,
                new GridBagConstraints( 2,
                        0,
                        2,
                        1,
                        0.0,
                        0.0,
                        GridBagConstraints.EAST,
                        GridBagConstraints.NONE,
                        new Insets( margin[ 0 ],
                                5,
                                5,
                                margin[ 3 ] ),
                        0,
                        0
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( includeDigits,
                new GridBagConstraints( 0,
                        1,
                        1,
                        1,
                        0.0,
                        0.0,
                        GridBagConstraints.WEST,
                        GridBagConstraints.NONE,
                        new Insets( 1,
                                margin[ 1 ],
                                2,
                                2 ),
                        0,
                        0
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( includeLowerCase,
                new GridBagConstraints( 0,
                        2,
                        1,
                        1,
                        0.0,
                        0.0,
                        GridBagConstraints.WEST,
                        GridBagConstraints.NONE,
                        new Insets( 2,
                                margin[ 1 ],
                                1,
                                2 ),
                        0,
                        0
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( pwLength,
                new GridBagConstraints( 3,
                        2,
                        1,
                        2,
                        0.0,
                        0.0,
                        GridBagConstraints.EAST,
                        GridBagConstraints.NONE,
                        new Insets( 2,
                                2,
                                2,
                                margin[ 3 ] ),
                        0,
                        0
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( includeUpperCase,
                new GridBagConstraints( 0,
                        3,
                        1,
                        1,
                        0.0,
                        0.0,
                        GridBagConstraints.WEST,
                        GridBagConstraints.NONE,
                        new Insets( 1,
                                margin[ 1 ],
                                2,
                                2 ),
                        0,
                        0
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( includePunctuation,
                new GridBagConstraints( 0,
                        4,
                        1,
                        1,
                        0.0,
                        0.0,
                        GridBagConstraints.WEST,
                        GridBagConstraints.NONE,
                        new Insets( 1,
                                margin[ 1 ],
                                2,
                                2 ),
                        0,
                        0
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( suggestedPassword,
                new GridBagConstraints( 0,
                        5,
                        4,
                        1,
                        1.0,
                        .25,
                        GridBagConstraints.WEST,
                        GridBagConstraints.HORIZONTAL,
                        new Insets( 2,
                                margin[ 1 ],
                                5,
                                margin[ 3 ] ),
                        40,
                        20
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( another,
                new GridBagConstraints( 1,
                        6,
                        3,
                        1,
                        0.0,
                        0.0,
                        GridBagConstraints.EAST,
                        GridBagConstraints.NONE,
                        new Insets( 5,
                                5,
                                5,
                                margin[ 3 ] ),
                        20,
                        10
                )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( instructions,
                new GridBagConstraints( 0,
                        7,
                        4,
                        1,
                        1.0,
                        .75,
                        GridBagConstraints.WEST,
                        GridBagConstraints.HORIZONTAL,
                        new Insets( 5,
                                margin[ 1 ],
                                margin[ 2 ],
                                margin[ 3 ] ),
                        0,
                        0
                )
        );
        }

    /**
     * Guts of the Applet; all the rest in GUI bubblegum. Generate a random password
     *
     * @param pwlength           how long a password do you want
     * @param possibleCharacters cast of characters allowed in generated password
     * @param needsDigits        true if there needs to be at least one digit in the generated password.
     * @param needsLowerCase     true if there needs to be at least one lower case char in the generated password.
     * @param needsUpperCase     true if there needs to be at least one upper chase char in the generated password.
     * @param needsPunctuation   true if there needs to be at least one punctuation character in the generated password.
     *
     * @return Password string containing letters and digits, lower and upper case.
     */
    private String spin( int pwlength,
                         String possibleCharacters,
                         boolean needsDigits,
                         boolean needsLowerCase,
                         boolean needsUpperCase,
                         boolean needsPunctuation )
        {
        boolean missingDigits;
        boolean missingLowerCase;
        boolean missingUpperCase;
        boolean missingPunctuation;
        // ensure has at least one of each category of character requested
        final char[] accum = new char[ pwlength ];
        do
            {
            missingDigits = needsDigits;
            missingLowerCase = needsLowerCase;
            missingUpperCase = needsUpperCase;
            missingPunctuation = needsPunctuation;
            for ( int i = 0; i < pwlength; i++ )
                {
                int index = wheel.nextInt( possibleCharacters.length() );
                char letter = possibleCharacters.charAt( index );
                if ( missingDigits && CAST_OF_DIGITS.indexOf( letter ) >= 0 )
                    {
                    missingDigits = false;
                    }
                if ( missingLowerCase && CAST_OF_LOWER_CASE_LETTERS.indexOf( letter ) >= 0 )
                    {
                    missingLowerCase = false;
                    }
                if ( missingUpperCase && CAST_OF_UPPER_CASE_LETTERS.indexOf( letter ) >= 0 )
                    {
                    missingUpperCase = false;
                    }
                if ( missingPunctuation && CAST_OF_PUNCTUATION_LETTERS.indexOf( letter ) >= 0 )
                    {
                    missingPunctuation = false;
                    }
                accum[ i ] = letter;
                } // end for
            }
        // keep going until have a password with at least one of each of the desired categories in it.
        while ( missingDigits || missingLowerCase || missingUpperCase || missingPunctuation );
        return new String( accum );
        }

    /**
     * Allow JApplet to be run as an Application
     *
     * @param args not used.
     */
    public static void main( String[] args )
        {
        HybridJ.fireup( new Password(),
                TITLE_STRING + " " + VERSION_STRING,
                APPLET_WIDTH,
                APPLET_HEIGHT );
        }

    /**
     * Invoked when an action occurs.
     *
     * @param e event, not used
     */
    public void actionPerformed( ActionEvent e )
        {
        hit();
        }

    /**
     * Called by the browser or Applet viewer to inform
     * this Applet that it is being reclaimed and that it should destroy
     * any resources that it has allocated.
     */
    @Override
    public void destroy()
        {
        another = null;
        instructions = null;
        pwLengthLabel = null;
        title2 = null;
        title = null;
        includeDigits = null;
        includeUpperCase = null;
        includeLowerCase = null;
        includePunctuation = null;
        pwLength = null;
        suggestedPassword = null;
        pwLengthModel = null;
        }

    /**
     * Called by the browser or Applet viewer to inform
     * this Applet that it has been loaded into the system.
     */
    @Override
    public void init()
        {
        Container contentPane = this.getContentPane();
        if ( !VersionCheck.isJavaVersionOK( 1, 7, 0, contentPane ) )
            {
            // effectively abort
            return;
            }
        buildMenu(); // also initial L&F
        contentPane.setLayout( new GridBagLayout() );
        contentPane.setBackground( BACKGROUND_FOR_APPLET );
        contentPane.setForeground( FOREGROUND_FOR_APPLET );
        buildComponents();
        layoutComponents( contentPane );
        installHooks();
        this.validate();
        this.setVisible( true );
        }

    /**
     * Applet has scrolled onscreen.
     */
    public void start()
        {
        hit();
        validate();
        }

    /**
     * Invoked when the target of the listener has changed its state.
     *
     * @param e a ChangeEvent object, not used
     */
    public void stateChanged( ChangeEvent e )
        {
        hit();
        }

    /**
     * Applet scrolled offscreen
     */
    public void stop()
        {
        }
    }