/*
 * @author doug
 * 
 * Guess it had to happen eventually. Finally hit an un-work-aroundable bug.
 * 
 * In this case, all the methods for setting the caret at the beginning of a line invariably
 * place it at the end of the previous line. SetCaretOffset is replaced here with a version that
 * uses the OFFSET_LEADING alignment.
 * 
 * Use PStyledText wherever StyledText was used. This technique works only for classes that
 * the project uses directly. Corrections to intermediate classes that use StyledText require 
 * replacing the defective class entirely.
 */
package org.eclipse.swt.custom;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.TextLayout;
import org.eclipse.swt.widgets.Composite;

public class PStyledText extends StyledText {
	public PStyledText(Composite parent, int style) {
		super(parent, style);
	}

	@Override
	public void setCaretOffset(int offset) {
		checkWidget();
		int length = getCharCount();
		if (length > 0 && offset != caretOffset) {
			if (offset < 0) {
				offset = 0;
			} else if (offset > length) {
				offset = length;
			} else {
				if (isLineDelimiter(offset)) {
					// offset is inside a multi byte line delimiter. This is an 
					// illegal operation and an exception is thrown. Fixes 1GDKK3R
					SWT.error(SWT.ERROR_INVALID_ARGUMENT);
				}
			}
//*****			setCaretOffset(offset, PREVIOUS_OFFSET_TRAILING);
			setCaretOffset(offset, OFFSET_LEADING);
			// clear the selection if the caret is moved.
			// don't notify listeners about the selection change.
			if (blockSelection) {
				clearBlockSelection(true, false);
			} else {
				clearSelection(false);
			}
		}
		setCaretLocation();
	}

	public int getOffsetAtYLimit(int y) {
		/* 20120713 dmm. Derived from getOffsetAtPoint. Find the character index at the end of the line that
		 * falls completely within y.
		 */
		/* if (inTextOnly && y + getVerticalScrollOffset() < 0 || x + horizontalScrollOffset < 0) {
		 * return -1;
		 * }
		 */
		int lineIndex = getLineIndex(y);
		int lineOffset = content.getOffsetAtLine(lineIndex);
		TextLayout layout = renderer.getTextLayout(lineIndex);
		y -= getLinePixel(lineIndex);
		
		int li = layout.getLineCount()-1;
		while (li >= 0) {
			Rectangle rect = layout.getLineBounds(li);

			if (rect.y + rect.height <= y)
				break;
			li--;
		}
		int[] lineOffsets = layout.getLineOffsets();
		renderer.disposeTextLayout(layout);
		return lineOffsets[li + 1] + lineOffset;
	}
}