/*
 * <license>
 * Copyright 2006 by Mark Roth.  All rights reserved.
 * </license>
 */

package com.octagonsoftware.gwthangman.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.ClickListener;
import com.google.gwt.user.client.ui.FlowPanel;
import com.google.gwt.user.client.ui.Grid;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HasHorizontalAlignment;
import com.google.gwt.user.client.ui.HasVerticalAlignment;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Hyperlink;
import com.google.gwt.user.client.ui.Image;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.Panel;
import com.google.gwt.user.client.ui.RadioButton;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.SimplePanel;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;

/**
 * Entry point class for Hangman application build on Google's GWT
 *
 * @author Mark Roth
 */
public class GwtHangman
    implements EntryPoint
{
    /** UI Widgets */
    private RootPanel _contentPanel;
    private Panel _titlePanel;
    private HorizontalPanel _gamePanel;
    private Grid _wordPanel;
    private Grid _lettersPanel;
    private RadioButton _difficultyEasy;
    private RadioButton _difficultyMedium;
    private RadioButton _difficultyHard;
    private Label _guessesRemainingLabel;
    private Image _hangmanImage;
    private Label _gameOverLabel;
    private Button _playAgainButton;

    /** Number of guesses to assign when a new game starts */
    private int _newGameGuesses;
    
    /** Number of guesses remaining */
    private int _guesses;
    
    /** The word being guessed */
    private String _word;
    
    /** True if the game is over */
    private boolean _gameOver;
    
    /** True if the letter is guessed or false if not */
    private boolean[] _letterGuessed = new boolean[26];

    /**
     * Called when page loads.
     */
    public void onModuleLoad() {
        _contentPanel = RootPanel.get("contentPanel");
        _contentPanel.setWidth("640");
        
        createTitlePanel();
        createGamePanel();
        
        _contentPanel.add(_titlePanel);
        _newGameGuesses = 6;
    }
    
    private void createTitlePanel() {
        _titlePanel = new VerticalPanel();
        Label welcome = new Label("Welcome to GWT Hangman!");
        _titlePanel.add(welcome);
        _titlePanel.add(new HTML("<br>"));
        _difficultyEasy = new RadioButton("difficulty", "Easy (6 guesses)");
        _difficultyMedium = new RadioButton("difficulty", "Medium (5 guesses)");
        _difficultyHard = new RadioButton("difficulty", "Hard (4 guesses)");
        _difficultyEasy.addClickListener(new DifficultyClickListener(6));
        _difficultyMedium.addClickListener(new DifficultyClickListener(5));
        _difficultyHard.addClickListener(new DifficultyClickListener(4));
        _difficultyEasy.setChecked(true);
        _titlePanel.add(_difficultyEasy);
        _titlePanel.add(_difficultyMedium);
        _titlePanel.add(_difficultyHard);
        _titlePanel.add(new HTML("<br>"));
        Button playButton = new Button("Play!");
        _titlePanel.add(playButton);
        playButton.addClickListener(
            new ClickListener() {
                public void onClick(Widget sender) {
                    newGame();
                }
            }
        );
    }

    private void createGamePanel() {
        createWordPanel();
        createLettersPanel();
        _gamePanel = new HorizontalPanel();
        VerticalPanel leftPanel = new VerticalPanel();
        leftPanel.setVerticalAlignment(HasVerticalAlignment.ALIGN_MIDDLE);
        _guessesRemainingLabel = new Label("Guesses Remaining: ");
        leftPanel.add(_guessesRemainingLabel);
        leftPanel.add(_wordPanel);
        leftPanel.setCellHeight(_wordPanel, "130");
        _gameOverLabel = new Label("");
        _gameOverLabel.setVisible(false);
        leftPanel.add(_gameOverLabel);
        leftPanel.add(new HTML("<br>"));
        _playAgainButton = new Button("Play Again");
        _playAgainButton.setVisible(false);
        leftPanel.add(_playAgainButton);
        _playAgainButton.addClickListener(
            new ClickListener() {
                public void onClick(Widget sender) {
                    mainMenu();
                }
            }
        );
        leftPanel.add(_lettersPanel);
        leftPanel.setCellHeight(_lettersPanel, "130");
        _gamePanel.add(leftPanel);
        _gamePanel.setCellWidth(leftPanel, "440");
        _hangmanImage = new Image("hangman0.png");
        _gamePanel.add(_hangmanImage);
        _gamePanel.setCellHeight(leftPanel, "340");
    }

    private void createWordPanel() {
        _wordPanel = new Grid(1, 10);
        _wordPanel.setStyleName("gwthangman-bigfont");
    }

    private void createLettersPanel() {
        _lettersPanel = new Grid(2, 13);
        _lettersPanel.setStyleName("gwthangman-bigfont");
    }

    private void newGame() {
        _gameOver = false;
        _guesses = _newGameGuesses;
        for(int i = 0; i < _letterGuessed.length; i++) {
            _letterGuessed[i] = false;
        }
        updateLettersPanel();
        int wordIndex = (int)(Math.random() * Words.WORDS.length);
        _word = Words.WORDS[wordIndex];
        updateWordPanel();
        
        _contentPanel.remove(_titlePanel);
        _contentPanel.add(_gamePanel);
        _playAgainButton.setVisible(false);
        _gameOverLabel.setVisible(false);
        _lettersPanel.setVisible(true);
        
        updateGuessesRemaining();
    }
    
    private void updateGuessesRemaining() {
        _guessesRemainingLabel.setText("Guesses Remaining: " + _guesses);
        _hangmanImage.setUrl("hangman" + (6 - _guesses) + ".png");
        if(_guesses == 0) {
            gameOver();
        }
    }
    
    private void gameOver() {
        _gameOver = true;
        updateLettersPanel();
        _playAgainButton.setVisible(true);
        _gameOverLabel.setVisible(true);
        if(isWin()) {
            _gameOverLabel.setText("You win!");
            _gameOverLabel.setStyleName("gwthangman-win");
        }
        else {
            _gameOverLabel.setText("Game over");
            _gameOverLabel.setStyleName("gwthangman-lose");
        }
    }
    
    private void guess(char c) {
        if(_word.indexOf(c) == -1) {
            _guesses--;
        }
        int y = (c - 'A') / 13;
        int x = (c - 'A') % 13;
        _letterGuessed[c - 'A'] = true;
        updateGuessesRemaining();
        updateWordPanel();
        updateLettersPanel();
        if(isWin()) {
            gameOver();
        }
    }
    
    private boolean isWin() {
        boolean result = true;
        for(int i = 0; i < _word.length(); i++) {
            char c = _word.charAt(i);
            if(!_letterGuessed[c - 'A']) {
                result = false;
                break;
            }
        }
        return result;
    }
    
    private void mainMenu() {
        _contentPanel.remove(_gamePanel);
        _contentPanel.add(_titlePanel);
    }
    
    private void updateWordPanel() {
        for(int i = 0; i < 10; i++) {
            if(i < _word.length()) {
                char c = _word.charAt(i);
                if(_gameOver) {
                    HTML w = new HTML(c + "&nbsp;");
                    _wordPanel.setWidget(0, i, w);
                    if(!_letterGuessed[c - 'A']) {
                        w.setStyleName("gwthangman-missingletter");
                    }
                }
                else if(!_letterGuessed[c - 'A']) {
                    _wordPanel.setWidget(0, i, new HTML("_&nbsp;"));
                }
                else {
                    _wordPanel.setWidget(0, i, new HTML(c + "&nbsp;"));
                }
            }
            else {
                _wordPanel.setWidget(0, i, new HTML(""));
            }
        }
    }
    
    private void updateLettersPanel() {
        for(char c = 'A'; c <= 'Z'; c++) {
            int y = (c - 'A') / 13;
            int x = (c - 'A') % 13;
            Widget w;
            if(!_gameOver && !_letterGuessed[c - 'A']) {
                Hyperlink hyperlink = new Hyperlink("" + c, "" + c);
                final char ch = c;
                hyperlink.addClickListener(
                    new ClickListener() {
                        public void onClick(Widget sender) {
                            guess(ch);
                        }
                    }
                );
                w = hyperlink;
            }
            else {
                w = new Label("" + c);
                if(_letterGuessed[c - 'A']) {
                    w.setStyleName("gwthangman-guessed");
                }
            }
            _lettersPanel.setWidget(y, x, w);
        }
    }
    
    private class DifficultyClickListener
        implements ClickListener
    {
        private int _difficulty;
        
        public DifficultyClickListener(int difficulty) {
            _difficulty = difficulty;
        }
        
        public void onClick(Widget sender) {
            _newGameGuesses = _difficulty;
        }
    }
}