/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

package gamegui;

import java.awt.event.ActionEvent;
import java.util.Collections;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JTextArea;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.BadLocationException;

/**
 *
 * @author Andrea Grandi
 */
class Autocomplete  implements DocumentListener {
    private static final String COMMIT_ACTION = "commit";
    public static enum Mode { INSERT, COMPLETION };
    public List<String> words;
    public Mode mode = Mode.INSERT;


    private JTextArea textArea;

    public Autocomplete(JTextArea textArea){
        this.textArea = textArea;
        InputMap im = textArea.getInputMap();
        ActionMap am = textArea.getActionMap();
        im.put(KeyStroke.getKeyStroke("ENTER"), COMMIT_ACTION);
        am.put(COMMIT_ACTION, new CommitAction(textArea));
    }

    public void changedUpdate(DocumentEvent ev) {
    }

    public void removeUpdate(DocumentEvent ev) {
    }

    public void insertUpdate(DocumentEvent ev) {

        if (ev.getLength() != 1) {
            return;
        }

        int pos = ev.getOffset();
        String content = null;
        try {
            content = textArea.getText(0, pos + 1);
        } catch (BadLocationException e) {
            e.printStackTrace();
        }

        // Find where the word starts
        int w;
        for (w = pos; w >= 0; w--) {
            if (! Character.isLetter(content.charAt(w))) {
                break;
            }
        }
        if (pos - w < 2) {
            // Too few chars
            return;
        }

        String prefix = content.substring(w + 1).toLowerCase();
        int n = Collections.binarySearch(words, prefix);
        if (n < 0 && -n <= words.size()) {
            String match = words.get(-n - 1);
            if (match.startsWith(prefix)) {
                // A completion is found
                String completion = match.substring(pos - w);
                // We cannot modify Document from within notification,
                // so we submit a task that does the change later

                System.out.println("Completo con: " + completion);

                SwingUtilities.invokeLater(
                        new CompletionTask(completion, pos + 1, textArea));
            }
        } else {
            // Nothing found
            mode = Mode.INSERT;
        }
    }

    private class CompletionTask implements Runnable {
        String completion;
        int position;
        JTextArea textArea;

        CompletionTask(String completion, int position, JTextArea textArea) {
            this.completion = completion;
            this.position = position;
            this.textArea = textArea;
        }

        public void run() {
            textArea.insert(completion, position);
            textArea.setCaretPosition(position + completion.length());
            textArea.moveCaretPosition(position);
            mode = Mode.COMPLETION;
        }
    }

    private class CommitAction extends AbstractAction {
        JTextArea textArea;

        public CommitAction(JTextArea textArea) {
            this.textArea = textArea;
        }


        public void actionPerformed(ActionEvent ev) {
            if (mode == Mode.COMPLETION) {
                int pos = textArea.getSelectionEnd();
                // textArea.insert(" ", pos);
                textArea.setCaretPosition(pos);
                mode = Mode.INSERT;
            } else {
                textArea.replaceSelection("\n");
            }
        }
    }
}