/*
 * Copyright (c) 2010, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package com.sun.enterprise.util;

/** Provides some regex utilities.
 * @author Kedar Mhaswade (km@dev.java.net)
 * @since GF 3.1
 */
public class RegexUtil {
    /**
     * Convert a shell style glob regular expression to a
     * Java regular expression.
     * Code from: http://stackoverflow.com/questions/1247772
     */
    public static String globToRegex(String line) {
        line = line.trim();
        int strLen = line.length();
        StringBuilder sb = new StringBuilder(strLen);
        boolean escaping = false;
        int inCurlies = 0;
        for (char currentChar : line.toCharArray()) {
            switch (currentChar) {
            case '*':
                if (escaping)
                    sb.append("\\*");
                else
                    sb.append(".*");
                escaping = false;
                break;
            case '?':
                if (escaping)
                    sb.append("\\?");
                else
                    sb.append('.');
                escaping = false;
                break;
            case '.':
            case '(':
            case ')':
            case '+':
            case '|':
            case '^':
            case '$':
            case '@':
            case '%':
                sb.append('\\');
                sb.append(currentChar);
                escaping = false;
                break;
            case '\\':
                if (escaping) {
                    sb.append("\\\\");
                    escaping = false;
                } else
                    escaping = true;
                break;
            case '{':
                if (escaping) {
                    sb.append("\\{");
                } else {
                    sb.append('(');
                    inCurlies++;
                }
                escaping = false;
                break;
            case '}':
                if (inCurlies > 0 && !escaping) {
                    sb.append(')');
                    inCurlies--;
                } else if (escaping)
                    sb.append("\\}");
                else
                    sb.append("}");
                escaping = false;
                break;
            case ',':
                if (inCurlies > 0 && !escaping)
                    sb.append('|');
                else if (escaping)
                    sb.append("\\,");
                else
                    sb.append(",");
                break;
            default:
                escaping = false;
                sb.append(currentChar);
            }
        }
        return sb.toString();
    }
}