/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    *  contributor license agreements.  See the NOTICE file distributed with
    *  this work for additional information regarding copyright ownership.
    *  The ASF licenses this file to You 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.
   */
  
  package org.apache.commons.exec;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import java.util.StringTokenizer;
  import java.util.Vector;
  
  import org.apache.commons.exec.util.StringUtils;
  
  /**
   * CommandLine objects help handling command lines specifying processes to execute. The class can be used to a command line by an application.
   */
  public class CommandLine {
  
      /**
       * Encapsulates a command line argument.
       */
      static final class Argument {
  
          private final String value;
          private final boolean handleQuoting;
  
          private Argument(final String value, final boolean handleQuoting) {
              this.value = value.trim();
              this.handleQuoting = handleQuoting;
          }
  
          private String getValue() {
              return value;
          }
  
          private boolean isHandleQuoting() {
              return handleQuoting;
          }
      }
  
      /**
       * Create a command line from a string.
       *
       * @param line the first element becomes the executable, the rest the arguments.
       * @return the parsed command line.
       * @throws IllegalArgumentException If line is null or all whitespace.
       */
      public static CommandLine parse(final String line) {
          return parse(line, null);
      }
  
      /**
       * Create a command line from a string.
       *
       * @param line            the first element becomes the executable, the rest the arguments.
       * @param substitutionMap the name/value pairs used for substitution.
       * @return the parsed command line.
       * @throws IllegalArgumentException If line is null or all whitespace.
       */
      public static CommandLine parse(final String line, final Map<String, ?> substitutionMap) {
  
          if (line == null) {
              throw new IllegalArgumentException("Command line can not be null");
          }
          if (line.trim().isEmpty()) {
              throw new IllegalArgumentException("Command line can not be empty");
          }
          final String[] tmp = translateCommandline(line);
  
          final CommandLine cl = new CommandLine(tmp[0]);
          cl.setSubstitutionMap(substitutionMap);
          for (int i = 1; i < tmp.length; i++) {
              cl.addArgument(tmp[i]);
          }
  
          return cl;
      }
  
      /**
       * Crack a command line.
       *
       * @param toProcess the command line to process.
       * @return the command line broken into strings. An empty or null toProcess parameter results in a zero sized array.
      */
     private static String[] translateCommandline(final String toProcess) {
         if (toProcess == null || toProcess.trim().isEmpty()) {
             // 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;
         final StringTokenizer tok = new StringTokenizer(toProcess, "\"\' ", true);
         final ArrayList<String> list = new ArrayList<>();
         StringBuilder current = new StringBuilder();
         boolean lastTokenHasBeenQuoted = false;
 
         while (tok.hasMoreTokens()) {
             final 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) {
                         list.add(current.toString());
                         current = new StringBuilder();
                     }
                 } else {
                     current.append(nextTok);
                 }
                 lastTokenHasBeenQuoted = false;
                 break;
             }
         }
 
         if (lastTokenHasBeenQuoted || current.length() != 0) {
             list.add(current.toString());
         }
 
         if (state == inQuote || state == inDoubleQuote) {
             throw new IllegalArgumentException("Unbalanced quotes in " + toProcess);
         }
 
         final String[] args = new String[list.size()];
         return list.toArray(args);
     }
 
     /**
      * The arguments of the command.
      */
     private final Vector<Argument> arguments = new Vector<>();
 
     /**
      * The program to execute.
      */
     private final String executable;
 
     /**
      * A map of name value pairs used to expand command line arguments.
      */
     private Map<String, ?> substitutionMap; // N.B. This can contain values other than Strings.
 
     /**
      * Tests whether a file was used to set the executable.
      */
     private final boolean isFile;
 
     /**
      * Copy constructor.
      *
      * @param other the instance to copy.
      */
     public CommandLine(final CommandLine other) {
         this.executable = other.getExecutable();
         this.isFile = other.isFile();
         this.arguments.addAll(other.arguments);
 
         if (other.getSubstitutionMap() != null) {
             this.substitutionMap = new HashMap<>(other.getSubstitutionMap());
         }
     }
 
     /**
      * Create a command line without any arguments.
      *
      * @param executable the executable file.
      */
     public CommandLine(final File executable) {
         this.isFile = true;
         this.executable = toCleanExecutable(executable.getAbsolutePath());
     }
 
     /**
      * Create a command line without any arguments.
      *
      * @param executable the executable.
      * @throws NullPointerException     on null input.
      * @throws IllegalArgumentException on empty input.
      */
     public CommandLine(final String executable) {
         this.isFile = false;
         this.executable = toCleanExecutable(executable);
     }
 
     /**
      * Add a single argument. Handles quoting.
      *
      * @param argument The argument to add.
      * @return The command line itself.
      * @throws IllegalArgumentException If argument contains both single and double quotes.
      */
     public CommandLine addArgument(final String argument) {
         return addArgument(argument, true);
     }
 
     /**
      * Add a single argument.
      *
      * @param argument      The argument to add.
      * @param handleQuoting Add the argument with/without handling quoting.
      * @return The command line itself.
      */
     public CommandLine addArgument(final String argument, final boolean handleQuoting) {
 
         if (argument == null) {
             return this;
         }
 
         // check if we can really quote the argument - if not throw an
         // IllegalArgumentException
         if (handleQuoting) {
             StringUtils.quoteArgument(argument);
         }
 
         arguments.add(new Argument(argument, handleQuoting));
         return this;
     }
 
     /**
      * Add multiple arguments. Handles parsing of quotes and whitespace. Please note that the parsing can have undesired side-effects therefore it is
      * recommended to build the command line incrementally.
      *
      * @param addArguments An string containing multiple arguments.
      * @return The command line itself.
      */
     public CommandLine addArguments(final String addArguments) {
         return addArguments(addArguments, true);
     }
 
     /**
      * Add multiple arguments. Handles parsing of quotes and whitespace. Please note that the parsing can have undesired side-effects therefore it is
      * recommended to build the command line incrementally.
      *
      * @param addArguments  An string containing multiple arguments.
      * @param handleQuoting Add the argument with/without handling quoting.
      * @return The command line itself.
      */
     public CommandLine addArguments(final String addArguments, final boolean handleQuoting) {
         if (addArguments != null) {
             final String[] argumentsArray = translateCommandline(addArguments);
             addArguments(argumentsArray, handleQuoting);
         }
 
         return this;
     }
 
     /**
      * Add multiple arguments. Handles parsing of quotes and whitespace.
      *
      * @param addArguments An array of arguments.
      * @return The command line itself.
      */
     public CommandLine addArguments(final String[] addArguments) {
         return addArguments(addArguments, true);
     }
 
     /**
      * Add multiple arguments.
      *
      * @param addArguments  An array of arguments.
      * @param handleQuoting Add the argument with/without handling quoting.
      * @return The command line itself.
      */
     public CommandLine addArguments(final String[] addArguments, final boolean handleQuoting) {
         if (addArguments != null) {
             for (final String addArgument : addArguments) {
                 addArgument(addArgument, handleQuoting);
             }
         }
         return this;
     }
 
     /**
      * Expand variables in a command line argument.
      *
      * @param argument the argument.
      * @return the expanded string.
      */
     private String expandArgument(final String argument) {
         final StringBuffer stringBuffer = StringUtils.stringSubstitution(argument, getSubstitutionMap(), true);
         return stringBuffer.toString();
     }
 
     /**
      * Gets the expanded and quoted command line arguments.
      *
      * @return The quoted arguments.
      */
     public String[] getArguments() {
 
         Argument currArgument;
         String expandedArgument;
         final String[] result = new String[arguments.size()];
 
         for (int i = 0; i < result.length; i++) {
             currArgument = arguments.get(i);
             expandedArgument = expandArgument(currArgument.getValue());
             result[i] = currArgument.isHandleQuoting() ? StringUtils.quoteArgument(expandedArgument) : expandedArgument;
         }
 
         return result;
     }
 
     /**
      * Gets the executable.
      *
      * @return The executable.
      */
     public String getExecutable() {
         // Expand the executable and replace '/' and '\\' with the platform
         // specific file separator char. This is safe here since we know
         // that this is a platform specific command.
         return StringUtils.fixFileSeparatorChar(expandArgument(executable));
     }
 
     /**
      * Gets the substitution map.
      *
      * @return the substitution map.
      */
     public Map<String, ?> getSubstitutionMap() {
         return substitutionMap;
     }
 
     /**
      * Tests whether a file was used to set the executable.
      *
      * @return true whether a file was used for setting the executable.
      */
     public boolean isFile() {
         return isFile;
     }
 
     /**
      * Sets the substitutionMap to expand variables in the command line.
      *
      * @param substitutionMap the map
      */
     public void setSubstitutionMap(final Map<String, ?> substitutionMap) {
         this.substitutionMap = substitutionMap;
     }
 
     /**
      * Cleans the executable string. The argument is trimmed and '/' and '\\' are replaced with the platform specific file separator char
      *
      * @param dirtyExecutable the executable.
      * @return the platform-specific executable string.
      * @throws NullPointerException     on null input.
      * @throws IllegalArgumentException on empty input.
      */
     private String toCleanExecutable(final String dirtyExecutable) {
         Objects.requireNonNull(dirtyExecutable, "dirtyExecutable");
         if (dirtyExecutable.trim().isEmpty()) {
             throw new IllegalArgumentException("Executable can not be empty");
         }
         return StringUtils.fixFileSeparatorChar(dirtyExecutable);
     }
 
     /**
      * Stringify operator returns the command line as a string. Parameters are correctly quoted when containing a space or left untouched if the are already
      * quoted.
      *
      * @return the command line as single string.
      */
     @Override
     public String toString() {
         return "[" + String.join(", ", toStrings()) + "]";
     }
 
     /**
      * Converts the command line as an array of strings.
      *
      * @return The command line as an string array.
      */
     public String[] toStrings() {
         final String[] result = new String[arguments.size() + 1];
         result[0] = getExecutable();
         System.arraycopy(getArguments(), 0, result, 1, result.length - 1);
         return result;
     }
 }