package edu.princeton.toy;

import java.awt.*;
import java.awt.event.*;

import edu.princeton.swing.*;
import edu.princeton.swing.text.*;
import edu.princeton.toy.lang.*;

/**
 * TUncommentingAutoCompleter is an subclass of IndentingAutoCompleter which will also automatically
 * remove an entire autocomment when the user deletes the first or last character of it via the
 * delete key or backspace key, respectively.
 *
 * @version 7.1
 * @author btsang
 */

public class TUncommentingAutoCompleter extends IndentingAutoCompleter
{
    public TUncommentingAutoCompleter()
    {

    }

    /**
     * The PHighlightedTextArea will pass all key events to its auto-completer before processing
     * the event for itself.
     *
     * @param comp The component which recieved the KeyEvent.
     * @param e The event which occurred.
     * @return True if the component should ignore the KeyEvent (because this method already
     * performed a special action associated with it).  In either case, KeyListeners of the
     * component will still be informed of the event.
     */
    public boolean interceptKeyEvent(PHighlightedTextArea comp, KeyEvent e)
    {
        // Allow the indenter to try to intercept the KeyEvent
        if (super.interceptKeyEvent(comp, e))
            return true;


        // Check for the correct keystroke
        if (e.getID() == KeyEvent.KEY_PRESSED && e.getKeyCode() == KeyEvent.VK_BACK_SPACE)
        {
            int selectionDot = comp.getSelectionDot();

            // Make sure nothing is selected
            if (selectionDot != comp.getSelectionMark())
                return false;

            HighlightedDocument document = comp.getDocument();
            Point coordinate = document.offsetToCoordinate(selectionDot);

            // Make sure the caret is in the right location
            if (coordinate.x != TProgramDocument.COMMENT_COLUMN)
                return false;

            String line = document.getText(
                selectionDot - TProgramDocument.COMMENT_COLUMN,
                selectionDot
                );

            // Make sure the line is indeed an autocommented line
            if (!TWord.isCommand(line.substring(0, 8)))
                return false;
            

            // Ok, delete the autocomment
            document.remove(
                selectionDot - TProgramDocument.COMMENT_COLUMN + 7,
                TProgramDocument.COMMENT_COLUMN - 7,
                false
                );

            return true;
        }

        return false;
    }
}