/*
 * Copyright (c) 2003-2004 Christopher Lenz and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     Christopher Lenz - initial API and implementation
 * 
 * $Id: CssTextUtils.java,v 1.1 2004-09-02 18:07:13 jsurfer Exp $
 */

package net.sourceforge.phpeclipse.css.core.internal.text;

import java.io.IOException;

import net.sourceforge.phpeclipse.css.core.CssCore;

import org.eclipse.jface.text.IDocument;

/**
 * Various utility methods for handling CSS source.
 * 
 * TODO Probably refactor so this class isn't needed
 */
public final class CssTextUtils {

	// Constructors ------------------------------------------------------------

	/**
	 * Hidden.
	 */
	private CssTextUtils() {
		// Hidden
	}

	// Public Methods ----------------------------------------------------------

	public static int findMatchingClosingPeer(IDocument document, int offset,
		char openingPeer) {
		try {
			CssCodeReader reader = new CssCodeReader(document, offset,
				document.getLength(), CssCodeReader.FORWARD);
			char closingChar = getPeerCharacter(openingPeer);
			int stack = 1;
			int c = reader.read();
			while (c != -1) {
				if ((c == openingPeer) && (c != closingChar)) {
					stack++;
				} else if (c == closingChar) {
					stack--;
				}
				if (stack == 0) {
					return reader.getOffset();
				}
				c = reader.read();
			}
		} catch (IOException e) {
			CssCore.log(
				"Failed to find matching closing peer for '" + //$NON-NLS-1$
				openingPeer + '\'', e);
		}
		return -1;
	}

	public static int findMatchingOpeningPeer(IDocument document, int offset,
		char closingPeer) {
		try {
			CssCodeReader reader = new CssCodeReader(document, offset + 1,
				document.getLength(), CssCodeReader.BACKWARD);
			char openingChar = getPeerCharacter(closingPeer);
			int stack = 1;
			int c = reader.read();
			while (c != -1) {
				if ((c == closingPeer) && (c != openingChar)) {
					stack++;
				} else if (c == openingChar) {
					stack--;
				}
				if (stack == 0) {
					return reader.getOffset();
				}
				c = reader.read();
			}
		} catch (IOException e) {
			CssCore.log(
				"Failed to find matching opening peer for '" + //$NON-NLS-1$
				closingPeer + '\'', e);
		}
		return	-1;
	}

	public static char getPeerCharacter(char c) {
		switch (c) {
			case '{': return '}';
			case '}': return '{';
			case '[': return ']';
			case ']': return '[';
			case '(': return ')';
			case ')': return '(';
			case '"': return '"';
			case '\'': return '\'';
			default: return 0;
		}
	}

	public static boolean isCssIdentifierPart(char c) {
		return ((c == '_') || Character.isLetterOrDigit(c) || (c == '-'));
	}

	public static boolean isCssIdentifierStart(char c) {
		return ((c == '_') || Character.isLetter(c));
	}

	public static boolean isCssNumberPart(char c) {
		return ((c == '.') || Character.isDigit(c));
	}

	public static boolean isCssNumberStart(char c) {
		return ((c == '-') || (c == '.') || Character.isDigit(c));
	}

	public static boolean isCssWhitespace(char c) {
		return Character.isWhitespace(c);
	}

}