/*-
 * ============LICENSE_START=======================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 */

package com.woorea.openstack.console;

import java.util.StringTokenizer;
import java.util.Vector;

public class CommandLineHelper {

    public static String[] parse(String input) {
        if (input == null || input.length() == 0) {
            //no command? no string
            return new String[0];
        }
        // parse with a simple finite state machine

        final int normal = 0;
        final int inQuote = 1;
        final int inDoubleQuote = 2;
        int state = normal;
        StringTokenizer tok = new StringTokenizer(input, "\"\' ", true);
        Vector v = new Vector();
        StringBuffer current = new StringBuffer();
        boolean lastTokenHasBeenQuoted = false;

        while (tok.hasMoreTokens()) {
            String nextTok = tok.nextToken();
            switch (state) {
            case inQuote:
                if ("\'".equals(nextTok)) {
                    lastTokenHasBeenQuoted = true;
                    state = normal;
                } else {
                    current.append(nextTok);
                }
                break;
            case inDoubleQuote:
                if ("\"".equals(nextTok)) {
                    lastTokenHasBeenQuoted = true;
                    state = normal;
                } else {
                    current.append(nextTok);
                }
                break;
            default:
                if ("\'".equals(nextTok)) {
                    state = inQuote;
                } else if ("\"".equals(nextTok)) {
                    state = inDoubleQuote;
                } else if (" ".equals(nextTok)) {
                    if (lastTokenHasBeenQuoted || current.length() != 0) {
                        v.addElement(current.toString());
                        current = new StringBuffer();
                    }
                } else {
                    current.append(nextTok);
                }
                lastTokenHasBeenQuoted = false;
                break;
            }
        }
        if (lastTokenHasBeenQuoted || current.length() != 0) {
            v.addElement(current.toString());
        }
        if (state == inQuote || state == inDoubleQuote) {
            throw new RuntimeException("unbalanced quotes in " + input);
        }
        String[] args = new String[v.size()];
        v.copyInto(args);
        return args;
    }

}