/*
    * 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.statistics.examples.distribution;
  
  import java.util.ArrayList;
  import java.util.List;
  import org.apache.commons.statistics.distribution.ContinuousDistribution;
  import org.apache.commons.statistics.distribution.GammaDistribution;
  import picocli.CommandLine.ArgGroup;
  import picocli.CommandLine.Command;
  import picocli.CommandLine.Option;
  
  /**
   * Command for the {@link GammaDistribution}.
   */
  @Command(name = "gamma",
           aliases = {"gam"},
           description = "Gamma distribution.",
           subcommands = {
               GammaCommand.Check.class,
               GammaCommand.PDF.class,
               GammaCommand.LPDF.class,
               GammaCommand.CDF.class,
               GammaCommand.SF.class,
               GammaCommand.ICDF.class,
               GammaCommand.ISF.class,
           })
  class GammaCommand extends AbstractDistributionCommand {
  
      /** Base command for the distribution that defines the parameters. */
      private abstract static class BaseCommand extends AbstractContinuousDistributionCommand {
          /** Distribution parameters. */
          @ArgGroup(validate = false, heading = "Distribution parameters:%n", order = 1)
          private Params params = new Params();
  
          /** Parameters class. */
          static class Params {
              /** The distribution shape. */
              @Option(names = {"-k", "--shape"},
                      arity = "1..*",
                      split = ",",
                      description = {"shape (default: ${DEFAULT-VALUE})."})
              private double[] shape = {1, 2, 3, 5, 9, 7.5, 0.5};
  
              /** The distribution scale. */
              @Option(names = {"-t", "--scale"},
                      arity = "1..*",
                      split = ",",
                      description = {"scale (default: ${DEFAULT-VALUE})."})
              private double[] scale = {2, 2, 2, 1, 0.5, 1, 1};
          }
  
          /** Extend the options to set the default values for this distribution. */
          static final class Options extends ContinuousDistributionOptions {
              /** Set defaults. */
              private Options() {
                  min = 0;
                  max = 20;
              }
          }
  
          @Override
          protected List<Distribution<ContinuousDistribution>> getDistributions() {
              double[] shape = params.shape;
              double[] scale = params.scale;
              final int n = DistributionUtils.validateLengths(shape.length, scale.length);
  
              shape = DistributionUtils.expandToLength(shape, n);
              scale = DistributionUtils.expandToLength(scale, n);
  
              // Create distributions
              final ArrayList<Distribution<ContinuousDistribution>> list = new ArrayList<>();
              for (int i = 0; i < n; i++) {
                  final ContinuousDistribution d = GammaDistribution.of(shape[i], scale[i]);
                  list.add(new Distribution<>(d, "shape=" + shape[i] + ",scale=" + scale[i]));
              }
              return list;
          }
      }
  
      /** Base command for the distribution that defines the parameters. */
      private abstract static class ProbabilityCommand extends BaseCommand {
          /** The distribution options. */
          @ArgGroup(validate = false, heading = "Evaluation options:%n", order = 2)
          private Options distributionOptions = new Options();
 
         @Override
         protected DistributionOptions getDistributionOptions() {
             return distributionOptions;
         }
     }
 
     /** Base command for the distribution that defines the parameters for inverse probability functions. */
     private abstract static class InverseProbabilityCommand extends BaseCommand {
         /** The distribution options. */
         @ArgGroup(validate = false, heading = "Evaluation options:%n", order = 2)
         private InverseContinuousDistributionOptions distributionOptions = new InverseContinuousDistributionOptions();
 
         @Override
         protected DistributionOptions getDistributionOptions() {
             return distributionOptions;
         }
     }
 
     /** Verification checks command. */
     @Command(name = "check",
              hidden = true,
              description = "Gamma distribution verification checks.")
     static class Check extends ProbabilityCommand {}
 
     /** PDF command. */
     @Command(name = "pdf",
              description = "Gamma distribution PDF.")
     static class PDF extends ProbabilityCommand {}
 
     /** LPDF command. */
     @Command(name = "lpdf",
              description = "Gamma distribution natural logarithm of the PDF.")
     static class LPDF extends ProbabilityCommand {}
 
     /** CDF command. */
     @Command(name = "cdf",
              description = "Gamma distribution CDF.")
     static class CDF extends ProbabilityCommand {}
 
     /** SF command. */
     @Command(name = "sf",
              description = "Gamma distribution survival probability.")
     static class SF extends ProbabilityCommand {}
 
     /** ICDF command. */
     @Command(name = "icdf",
              description = "Gamma distribution inverse CDF.")
     static class ICDF extends InverseProbabilityCommand {}
 
     /** ISF command. */
     @Command(name = "isf",
              description = "Gamma distribution inverse SF.")
     static class ISF extends InverseProbabilityCommand {}
 }