package com.excelsior.xds.ui.editor.commons.text;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.Region;

/**
 * Utilities to work with text in text editor
 * @author lsa80
 */
public final class EditorTextUtils {
	public static IRegion findWord(IDocument document, int offset) {
		int start = -2;
		int end = -1;

		try {

			int pos = offset;
			char c;

			while (pos >= 0) {
				c = document.getChar(pos);
				if (!Character.isUnicodeIdentifierPart(c)) {
					break;
				}
				--pos;
			}

			start = pos;

			pos = offset;
			int length = document.getLength();

			while (pos < length) {
				c = document.getChar(pos);
				if (!Character.isUnicodeIdentifierPart(c)) {
					break;
				}
				++pos;
			}

			end = pos;

		} catch (BadLocationException x) {
		}

		if (start >= -1 && end > -1) {
			if (start == offset && end == offset) {
				return new Region(offset, 0);
			} else if (start == offset) {
				return new Region(start, end - start);
			} else {
				return new Region(start + 1, end - start - 1);
			}
		}

		return null;
	}

	/**
	 * Only static methods allowed
	 */
	private EditorTextUtils(){
	}
}
