/*
 * Copyright 2019 Google LLC.
 *
 * Licensed 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 com.google.cloud.tools.opensource.dashboard;

import java.nio.file.Path;
import java.nio.file.Paths;
import javax.annotation.Nullable;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.DefaultParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Option;
import org.apache.commons.cli.OptionGroup;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;

/**
 * Command-line option for {@link DashboardMain}. The tool takes either a pom.xml file path or Maven
 * coordinates for a BOM.
 */
final class DashboardArguments {
  private static final Options options = configureOptions();
  private static final HelpFormatter helpFormatter = new HelpFormatter();

  private final CommandLine commandLine;

  private DashboardArguments(CommandLine commandLine) {
    this.commandLine = commandLine;
  }

  /**
   * Returns true if the argument for a file is specified. False if the argument for coordinates is
   * specified.
   *
   * <p>It is guaranteed that either a file path or Maven coordinates for a BOM are available.
   */
  boolean hasFile() {
    return commandLine.hasOption('f');
  }

  /** Returns an absolute path to pom.xml file of a BOM. Null if file is not specified. */
  @Nullable
  Path getBomFile() {
    // Trim the value so that maven exec plugin can pass arguments with exec.arguments="-f pom.xml"
    return Paths.get(commandLine.getOptionValue('f').trim()).toAbsolutePath();
  }

  /** Returns the Maven coordinates of a BOM. Null if coordinates are not specified. */
  @Nullable
  String getBomCoordinates() {
    return commandLine.getOptionValue('c');
  }

  static DashboardArguments readCommandLine(String... arguments) throws ParseException {
    CommandLineParser parser = new DefaultParser();

    try {
      // Throws ParseException if required option group ('-f' or '-c') is not specified
      return new DashboardArguments(parser.parse(options, arguments));
    } catch (ParseException ex) {
      helpFormatter.printHelp("DashboardMain", options);
      throw ex;
    }
  }

  private static Options configureOptions() {
    Options options = new Options();
    OptionGroup inputGroup = new OptionGroup();
    inputGroup.setRequired(true);

    Option inputFileOption =
        Option.builder("f").longOpt("bom-file").hasArg().desc("File to a BOM (pom.xml)").build();
    inputGroup.addOption(inputFileOption);

    Option inputCoordinatesOption =
        Option.builder("c")
            .longOpt("bom-coordinates")
            .hasArg()
            .desc(
                "Maven coordinates of a BOM. For example"
                    + " com.google.cloud:cloud-oss-bom:1.0.0-SNAPSHOT")
            .build();
    inputGroup.addOption(inputCoordinatesOption);

    options.addOptionGroup(inputGroup);
    return options;
  }
}
