/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.team.internal.ccvs.core.client.listeners;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.eclipse.team.internal.ccvs.core.CVSException;
import org.eclipse.team.internal.ccvs.core.util.Assert;
import org.eclipse.team.internal.ccvs.core.Policy;

/**
 * This class extracts matches server lines to expected patterns and extracts
 * required information from the line.
 */
public class ServerMessageLineMatcher {

	protected static final Pattern VARIABLE_MATCHING_PATTERN = Pattern.compile("(\\((\\w*):.*:\\2\\))"); //$NON-NLS-1$
	
	Pattern pattern;
	String[] variables;

	public ServerMessageLineMatcher(String template, String[] expectedVariables) throws CVSException {
		// Extract the variable names from the template
		Matcher matcher = VARIABLE_MATCHING_PATTERN.matcher(template);
		List variables = new ArrayList();
		while (matcher.find()) {
			if (matcher.groupCount() != 2) {
				throw new CVSException(Policy.bind("ServerMessageLineMatcher.5", template)); //$NON-NLS-1$
			}
			variables.add(matcher.group(2));
		}
		ensureMatches(template, variables, expectedVariables);
		this.variables = (String[]) variables.toArray(new String[variables.size()]);

		// Modify the template so it can be used to match message lines from the server
		// (i.e. remove the variable markup)
		for (Iterator iter = variables.iterator(); iter.hasNext();) {
				String element = (String) iter.next();
				template = template.replaceAll(element + ":", ""); //$NON-NLS-1$ //$NON-NLS-2$
				template = template.replaceAll(":" + element, ""); //$NON-NLS-1$ //$NON-NLS-2$
		}

		// Ensure that the number of groups in the pattern match the number of variables
		int count = 0;
		int start = -1;
		while ((start = template.indexOf('(', start + 1)) != -1) {
			count++;
		}
		if (count != variables.size()) {
			throw new CVSException(Policy.bind("ServerMessageLineMatcher.6", template)); //$NON-NLS-1$
		}

		// Create the pattern fir matching lines from the server
		this.pattern = Pattern.compile(template);
	}

	/*
	 * Throw an exception if the found variables do not match the expected variables
	 */
	private void ensureMatches(String template, List variables, String[] expectedVariables) throws CVSException {
		for (int i = 0; i < expectedVariables.length; i++) {
			String expected = expectedVariables[i];
			if (!variables.contains(expected)) {
				throw new CVSException(Policy.bind("ServerMessageLineMatcher.7", expected, template)); //$NON-NLS-1$
			}
		}
	}

	public Map processServerMessage(String line) {
		Matcher matcher = pattern.matcher(line);
		if (!matcher.find()) return null;
		Assert.isTrue(matcher.groupCount() == variables.length);
		Map result = new HashMap();
		for (int i = 1; i <= matcher.groupCount(); i++) {
			result.put(variables[i - 1], matcher.group(i));
		}
		return result;
	}

	public boolean matches(String line) {
		Matcher matcher = pattern.matcher(line);
		return (matcher.find());
	}

}