/*
    * 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;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.Writer;
  
  import org.apache.commons.cli.Options;
  import org.apache.commons.io.function.IOSupplier;
  import org.apache.rat.commandline.ArgumentContext;
  import org.apache.rat.document.RatDocumentAnalysisException;
  import org.apache.rat.help.Help;
  import org.apache.rat.utils.DefaultLog;
  
  import static java.lang.String.format;
  
  /**
   * The CLI based configuration object for report generation.
   */
  public final class Report {
      /**
       * The option collection that this report is using.
       */
      private static final CLIOptionCollection OPTION_COLLECTION = new CLIOptionCollection();
  
      /**
       * Processes the command line and builds a configuration and executes the
       * report.
       *
       * @param args the arguments.
       * @throws Exception on error.
       */
      public static void main(final String[] args) throws Exception {
          DefaultLog.getInstance().info(new VersionInfo().toString());
  
          if (args == null || args.length == 0) {
              DefaultLog.getInstance().info("Please use the \"--help\" option to see a " +
                      "list of valid commands and options, as you did not provide any arguments.");
              return;
          }
          OptionCollectionParser<CLIOption> cliOptionParser = new OptionCollectionParser<>(OPTION_COLLECTION);
          ArgumentContext argumentContext = cliOptionParser.parseCommands(new File("."), args);
          ReportConfiguration configuration = argumentContext.getConfiguration();
  
          if (argumentContext.hasOption(CLIOptionCollection.HELP)) {
              printUsage(OPTION_COLLECTION.getOptions(), configuration.getOutput());
          } else if (!configuration.hasSource()) {
              String msg = "No directories or files specified for scanning. Did you forget to close a multi-argument option?";
              DefaultLog.getInstance().error(msg);
              printUsage(OPTION_COLLECTION.getOptions(), configuration.getOutput());
          } else {
              configuration.validate(DefaultLog.getInstance()::error);
              Reporter.Output output = new Reporter(configuration).execute();
              output.format(argumentContext.getConfiguration());
              output.writeSummary(DefaultLog.getInstance().asWriter());
  
              if (configuration.getClaimValidator().hasErrors()) {
                  configuration.getClaimValidator().logIssues(output.getStatistic());
                  throw new RatDocumentAnalysisException(format("Issues with %s",
                          String.join(", ",
                                  configuration.getClaimValidator().listIssues(output.getStatistic()))));
              }
          }
      }
  
      /**
       * Prints the usage message on the output stream from {@code out}.
       * @param opts the defined options.
       * @param out a supplier of an OutputStream.
       */
      private static void printUsage(final Options opts, final IOSupplier<OutputStream> out) {
          try (Writer writer = new OutputStreamWriter(out.get())) {
              new Help(OPTION_COLLECTION, writer).printUsage(opts);
          } catch (IOException e) {
              DefaultLog.getInstance().error("Unable to open output stream", e);
          }
      }
  
      private Report() {
          // do not instantiate
     }
 }