/**

  * Distribution License:

  * JSword is free software; you can redistribute it and/or modify it under

  * the terms of the GNU Lesser General Public License, version 2.1 or later

  * as published by the Free Software Foundation. This program is distributed

  * in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even

  * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

  * See the GNU Lesser General Public License for more details.

  *

  * The License is available on the internet at:

  *      http://www.gnu.org/copyleft/lgpl.html

  * or by writing to:

  *      Free Software Foundation, Inc.

  *      59 Temple Place - Suite 330

  *      Boston, MA 02111-1307, USA

  *

  * © CrossWire Bible Society, 2008 - 2016

  *

  */

 package org.crosswire.common.options;

 import java.util.ArrayList;

 import java.util.LinkedHashMap;

 import java.util.List;

 import java.util.Map;

 /**

  * GetOptions parses an argument list for requested arguments given by an

  * OptionList.<br><br>

  * 

  * This supports short and long options:<br>

  * Short Options have the following characteristics.

  * <ul>

  * <li>A single dash, '-', starts a flag or a flag sequence. An example of a

  * flag is '-c' and a flag sequence is '-xyz'.</li>

  * <li>A flag may have a required argument. The flag may or may not be separated

  * by a space from it's argument. For example, both -fbar and -f bar are

  * acceptable.</li>

  * <li>A flag may have an optional argument. The flag must not be separated by a

  * space from it's optional argument. For example, -fbar is acceptable provides

  * bar as the argument, but -f bar has bar as a non-option argument.</li>

  * <li>These rules can combine. For example, -xyzfoo can be the same as -x -y -z

  * foo</li>

  * <li>If an Option expects an argument, then that argument can have a leading

  * '-'. That is, if -x requires an option then the argument -y can be given as

  * -x-y or -x -y.</li>

  * </ul>

  * 

  * Long Options have the following characteristics:

  * <ul>

  * <li>A double dash '--' starts a single flag. For example --print. Note, a

  * long option is typically descriptive, but can be a single character.</li>

  * <li>An argument may be given in one of two ways --file=filename or --file

  * filename. That is, separated by an '=' sign or whitespace.</li>

  * </ul>

  * Note:

  * <ul>

  * <li>Options can be repeated. What that means is up to the program.</li>

  * <li>The '--' sequence terminates argument processing.</li>

  * <li>A '-' by itself is not a flag.</li>

  * <li>Unrecognized flags are an error.</li>

  * <li>Unrecognized arguments are moved after the processed flags.</li>

  * </ul>

  * 

  * @see gnu.lgpl.License The GNU Lesser General Public License for details.

  * @author DM Smith

  */

 public class GetOptions {

     public GetOptions(String programName, String[] args, OptionList programOptions) {

         this.programName = programName;

         this.args = args.clone();

         this.programOptions = programOptions;

         // Initially, we have not started to process an argument

         this.nonOptionArgs = new ArrayList<String>();

         this.suppliedOptions = new LinkedHashMap<Option, String>();

         parse();

     }

     /**

      * @return the programName

      */

     public String getProgramName() {

         return programName;

     }

     /**

      * @param programName

      *            the programName to set

      */

     public void setProgramName(String programName) {

         this.programName = programName;

     }

     private void parse() {

         int nargs = args.length;

         int skip = 0;

         for (int i = 0; i < nargs; i += 1 + skip) {

             skip = 0;

             String nextArg = args[i];

             // All options are 2 or more characters long and begin with a '-'.

             // If this is a non-option then note it and advance

             if (nextArg.length() < 2 || nextArg.charAt(0) != '-') {

                 nonOptionArgs.add(nextArg);

                 continue;

             }

             // If we are at the end of all options, '--', we need to skip this

             // and copy what follows to the end

             if ("--".equals(nextArg)) {

                 for (int j = i + 1; j < nargs; j++) {

                     nonOptionArgs.add(args[j]);

                 }

                 return;

             }

             // At this point we are on a short option, a short option sequence

             // or a long option.

             // Invariant: the length > 1.

             if (nextArg.charAt(1) == '-') {

                 // Process a long argument

                 // This can be of the form --flag or --flag argument or

                 // --flag=argument

                 int equalPos = nextArg.indexOf('=');

                 String flag = (equalPos != -1) ? nextArg.substring(2, equalPos) : nextArg.substring(2);

                 List<Option> opts = programOptions.getLongOptions(flag);

                 int count = opts.size();

                 if (count == 0) {

                     throw new IllegalArgumentException("Illegal option --" + flag);

                 }

                 if (count > 1) {

                     throw new IllegalArgumentException("Ambiguous option --" + flag);

                 }

                 Option option = opts.get(0);

                 if (option.getArgumentType().equals(ArgumentType.NO_ARGUMENT)) {

                     // Add option with null argument to options

                     suppliedOptions.put(option, null);

                     continue;

                 }

                 // An argument is allowed or required

                 if (equalPos != -1) {

                     // Add option with argument to options

                     // Check for empty argument

                     String argument = (equalPos + 1 < nextArg.length()) ? nextArg.substring(equalPos + 1) : "";

                     suppliedOptions.put(option, argument);

                     continue;

                 }

                 // An argument is required, so take the next one.

                 if (option.getArgumentType().equals(ArgumentType.REQUIRED_ARGUMENT)) {

                     if (i + 1 < nargs) {

                         // Add option with following argument to options

                         String argument = args[i];

                         skip = 1;

                         suppliedOptions.put(option, argument);

                         continue;

                     }

                     throw new IllegalArgumentException("Option missing required argument");

                 }

             } else {

                 // Process a short argument or short argument sequence

                 // for each letter after the '-'

                 int shortSeqSize = nextArg.length();

                 for (int j = 1; j < shortSeqSize; j++) {

                     char curChar = nextArg.charAt(j);

                     Option option = programOptions.getShortOption(curChar);

                     if (option == null) {

                         throw new IllegalArgumentException("Illegal option -" + curChar);

                     }

                     if (option.getArgumentType().equals(ArgumentType.NO_ARGUMENT)) {

                         // Add option with null argument to options

                         suppliedOptions.put(option, null);

                         continue;

                     }

                     // This option allows or requires an argument

                     if (j < shortSeqSize) {

                         // since there is stuff that follows the flag, it is the

                         // argument.

                         String argument = nextArg.substring(j + 1);

                         suppliedOptions.put(option, argument);

                         continue;

                     }

                     if (option.getArgumentType().equals(ArgumentType.REQUIRED_ARGUMENT)) {

                         if (i + 1 < nargs) {

                             // Add option with following argument to options

                             String argument = args[i];

                             skip = 1;

                             suppliedOptions.put(option, argument);

                             continue;

                         }

                         throw new IllegalArgumentException("Option missing required argument");

                     }

                 }

             }

         }

     }

     /**

      * Swap adjacent blocks in an array.

      * 

      * @param array

      *            The array to modify in place

      * @param firstStart

      *            the index of the start of the first block

      * @param firstEnd

      *            the index of the end of the first block

      * @param secondEnd

      *            the index of the end of the second block. Note: the start of

      *            the second block is firstEnd + 1

      */

     public static void swap(Object[] array, int firstStart, int firstEnd, int secondEnd) {

         // Note: this is currently unused.

         // If we implement the traditional GNU extensions GetOpts interface we

         // will need it.

         // We copy the smaller block to the longer block.

         // The performance of this is linear with respect to the size of the

         // larger block.

         // If the blocks are equal the number of swaps is equal to the "larger"

         // block size otherwise it is one greater.

         // if the first block is smaller we start at the start of both and swap

         // Otherwise we start at the end of both and swap from the end to the

         // start

         // Set variables for the second block to be larger

         int sourcePos = firstStart;

         int destPos = firstEnd + 1;

         int increment = 1;

         int destStop = secondEnd;

         int firstSize = firstEnd - firstStart + 1;

         int secondSize = secondEnd - firstEnd;

         int swapCount = secondSize + 1;

         if (firstSize > secondSize) {

             // first block is bigger or equal

             sourcePos = secondEnd;

             destPos = firstEnd;

             destStop = firstStart;

             increment = -1;

             swapCount = firstSize + 1;

         }

         if (firstSize == secondSize) {

             swapCount--;

         }

         while (swapCount-- > 0) {

             Object temp = array[destPos];

             array[destPos] = array[sourcePos];

             array[sourcePos] = temp;

             if (sourcePos != destStop) {

                 sourcePos += increment;

             }

             if (destPos != destStop) {

                 destPos += increment;

             }

         }

     }

     // public static void main(String[] args)

     // {

     // String[] a = {"a","b","c","d","e"};

     // swap(a, 0, 2, 4);

     // swap(a, 0, 1, 4);

     // swap(a, 0, 0, 1);

     // swap(a, 0, 0, 1);

     // swap(a, 1, 2, 4);

     // swap(a, 1, 2, 4);

     // }

     private String programName;

     private String[] args;

     private OptionList programOptions;

     /**

      * The position in the array that is currently being studied.

      */

     private List<String> nonOptionArgs;

     private Map<Option, String> suppliedOptions;

 }