/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
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 * You may not use this file except in compliance with the License.
 *
 * See LICENSE.txt included in this distribution for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at LICENSE.txt.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
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/*
 * Copyright (c) 2007, 2014, Oracle and/or its affiliates. All rights reserved.
 */
package org.opensolaris.opengrok.util;

import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;

/**
 * A simple implementation of the getopt(3c). It does just implement what I
 * need ;-) Please note that I dislike the way GNU getopt allows mixing of
 * options and arguments, so this version will stop processing options as soon
 * as it encounters an argument.
 *
 */
public class Getopt {
    private static class Option {
        char option;
        String argument;
    }

    private final List<Option> options;
    private int current;
    private int optind;
    private final String[] argv;
    private final String opts;

    /**
     * Creates a new instance of Getopt
     * @param argv argument vector
     * @param opts the list of allowed options
     */
    public Getopt(String[] argv, String opts) {
        options = new ArrayList<>();
        current = -1;
        optind = -1;
        this.argv = argv.clone();
        this.opts = opts;
    }

    /**
     * Parse the command line options
     * @throws ParseException if an illegal argument is passed
     */
    public void parse() throws ParseException {

        int ii = 0;
        while (ii < argv.length) {
            char[] chars = argv[ii].toCharArray();
            if (chars.length > 0 && chars[0] == '-') {
                if (argv[ii].equals("--")) {
                    // End of command line options ;)
                    optind = ii + 1;
                    break;
                }

                for (int jj = 1; jj < chars.length; ++jj) {
                    int idx = opts.indexOf(chars[jj]);
                    if (idx == -1) {
                        throw new ParseException("Unknown argument: " + argv[ii].substring(jj), ii);
                    }

                    Option option = new Option();
                    option.option = chars[jj];
                    options.add(option);
                    // does this option take an argument?
                    if ((idx + 1) < opts.length() && (opts.charAt(idx + 1) ==':')) {
                        // next should be an argument
                        if ((jj + 1) < chars.length) {
                            // Rest of this is the argument
                            option.argument = argv[ii].substring(jj + 1);
                            break;
                        }
                        // next argument vector contains the argument
                        ++ii;
                        if (ii < argv.length) {
                            option.argument = argv[ii];
                        } else {
                            throw new ParseException("Option " + chars[jj] + " requires an argument", ii);
                        }
                    }
                }
                ++ii;
            } else {
                // End of options
                optind = ii;
                break;
            }
        }
    }

    /**
     * Get the next option in the options string.
     * @return the next valid option, or -1 if all options are processed
     */
    public int getOpt() {
        int ret = -1;

        ++current;
        if (current < options.size()) {
            ret = options.get(current).option;
        }

        return ret;
    }

    /**
     * Reset the current pointer so we may traverse all the options again..
     */
    public void reset() {
        current = -1;
    }

    /**
     * Get the argument to the current option
     * @return the argument or null if none present (or allowed)
     */
    public String getOptarg() {
        String ret = null;

        if (current < options.size()) {
            ret = options.get(current).argument;
        }
        return ret;
    }

    /**
     * Get the index of the first argument
     * @return the index of the first argument in the original array
     */
    public int getOptind() {
        return optind;
    }
}