/*
    * 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.rat.help;
  
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Iterator;
  import java.util.List;
  import java.util.function.Function;
  
  import org.apache.commons.cli.HelpFormatter;
  import org.apache.commons.cli.Option;
  import org.apache.commons.cli.Options;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.text.WordUtils;
  import org.apache.rat.OptionCollectionParser;
  import org.apache.rat.VersionInfo;
  import org.apache.rat.ui.UIOptionCollection;
  
  import static java.lang.String.format;
  
  /**
   * The base class to perform Help processing for programs.
   */
  public abstract class AbstractHelp {
      /** Text to display when multiple options are supported */
      private static final String END_OF_OPTION_MSG = " Multiple values may be specified. " +
              "Note that '--' or a following option is required when using this parameter.";
  
      /** The width of the help report in chars. */
      public static final int HELP_WIDTH = 120;
      /** The number of chars to indent output with. */
      public static final int HELP_PADDING = 4;
  
      /** The help formatter for this instance */
      protected final RatHelpFormatter helpFormatter;
      /** The version info for this instance */
      protected final VersionInfo versionInfo;
      /**
       * Base class to perform help output.
       */
      protected AbstractHelp(final UIOptionCollection<?>  uiOptionCollection) {
          helpFormatter = new RatHelpFormatter(uiOptionCollection);
          versionInfo = new VersionInfo();
      }
  
      /** Function to format deprecated display */
      public static final Function<Option, String> DEPRECATED_MSG = o -> {
          StringBuilder sb = new StringBuilder("[").append(o.getDeprecated().toString()).append("]");
          if (o.getDescription() != null) {
              sb.append(" ").append(o.getDescription());
          }
          return sb.toString();
      };
  
      /**
       * Create a padding.
       * @param len The length of the padding in characters.
       * @return a string with len blanks.
       */
      public static String createPadding(final int len) {
          char[] padding = new char[len];
          Arrays.fill(padding, ' ');
          return new String(padding);
      }
  
      /**
       * Create a section header for the output.
       * @param txt the text to put in the header.
       * @return the Header string.
       */
      public static String header(final String txt) {
          return String.format("%n====== %s ======%n", WordUtils.capitalizeFully(txt));
      }
  
      /**
       * Provides help for formatting text.
       */
      public class RatHelpFormatter extends HelpFormatter {
          /** The UIOptionCollection to report help for. */
          private final UIOptionCollection<?> uiOptionCollection;
  
         /**
          * Create formatter with given UIOptionCollection.
          * @param uiOptionCollection the UIOptionCollection to report help for.
          */
         RatHelpFormatter(final UIOptionCollection<?> uiOptionCollection) {
             super();
             this.uiOptionCollection = uiOptionCollection;
             this.optionComparator = OptionCollectionParser.OPTION_COMPARATOR;
             this.setWidth(HELP_WIDTH);
         }
 
         /**
          * Prints the help text.
          * @param writer the writer to write to.
          * @param cmdLineSyntax The command line syntax for the program.
          * @param header Additional information to proceed the Options descriptions.
          * @param options the Options to output help for.
          * @param footer Additional information to follow the Options descriptions.
          */
         public void printHelp(final PrintWriter writer, final String cmdLineSyntax, final String header, final Options options, final String footer) {
             if (StringUtils.isEmpty(cmdLineSyntax)) {
                 throw new IllegalArgumentException("cmdLineSyntax not provided");
             }
 
             helpFormatter.printUsage(writer, HELP_WIDTH, cmdLineSyntax);
 
             if (header != null && !header.isEmpty()) {
                 helpFormatter.printWrapped(writer, HELP_WIDTH, header);
             }
             printOptions(writer, HELP_WIDTH, options, helpFormatter.getLeftPadding(), helpFormatter.getDescPadding());
             if (footer != null && !footer.isEmpty()) {
                 helpFormatter.printWrapped(writer, helpFormatter.getWidth(), footer);
             }
         }
 
         @Override
         protected StringBuffer renderOptions(final StringBuffer sb, final int width, final Options options, final int leftPad, final int descPad) {
             final String lpad = createPadding(leftPad);
             final String dpad = createPadding(descPad);
             // first create list containing only <lpad>-a,--aaa where
             // -a is option and --aaa is long option; in parallel look for
             // the longest option string; this list will then be used to
             // sort options ascending
             int max = 0;
             final List<StringBuffer> prefixList = new ArrayList<>();
             final List<Option> optList = new ArrayList<>(options.getOptions());
             optList.sort(helpFormatter.getOptionComparator());
 
             for (final Option option : optList) {
                 final StringBuffer optBuf = new StringBuffer();
                 if (option.getOpt() == null) {
                     optBuf.append(lpad).append("   ").append(getLongOptPrefix()).append(option.getLongOpt());
                 } else {
                     optBuf.append(lpad).append(getOptPrefix()).append(option.getOpt());
                     if (option.hasLongOpt()) {
                         optBuf.append(',').append(getLongOptPrefix()).append(option.getLongOpt());
                     }
                 }
                 if (option.hasArg()) {
                     final String argName = option.getArgName();
                     if (argName != null && argName.isEmpty()) {
                         // if the option has a blank argName
                         optBuf.append(' ');
                     } else {
                         optBuf.append(option.hasLongOpt() ? helpFormatter.getLongOptSeparator() : " ");
                         optBuf.append("<").append(argName != null ? option.getArgName() : getArgName()).append(">");
                     }
                 }
                 prefixList.add(optBuf);
                 max = Math.max(optBuf.length(), max);
             }
             int x = 0;
             for (final Iterator<Option> it = optList.iterator(); it.hasNext();) {
                 final Option option = it.next();
                 final StringBuilder optBuf = new StringBuilder(prefixList.get(x++).toString());
                 if (optBuf.length() < max) {
                     optBuf.append(createPadding(max - optBuf.length()));
                 }
                 optBuf.append(dpad);
                 final int nextLineTabStop = max + descPad;
                 // check for deprecation
                 if (option.isDeprecated()) {
                     optBuf.append(DEPRECATED_MSG.apply(option).trim());
                 } else if (option.getDescription() != null) {
                     optBuf.append(option.getDescription());
                 }
                 // check for multiple values
                 if (option.hasArgs()) {
                     optBuf.append(END_OF_OPTION_MSG);
                 }
                 // check for default value
                 String defaultValue = uiOptionCollection.defaultValue(option);
                 if (defaultValue != null) {
                     optBuf.append(format(" (Default value = %s)", defaultValue));
                 }
                 renderWrappedText(sb, width, nextLineTabStop, optBuf.toString());
                 if (it.hasNext()) {
                     sb.append(getNewLine());
                 }
             }
             return sb;
         }
     }
 }