/*
    * Copyright (C) 2014 Atlassian
    *
    * 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.atlassian.jira.rest.client.api.domain;
  
  import com.google.common.base.Objects;
  import com.google.common.base.Optional;
  import com.google.common.collect.Iterables;
  
  import javax.annotation.Nullable;
  import java.util.Collections;
  
  /**
   * Represents operations group
   *
   * @since 2.0
   */
  public class OperationGroup implements Operation {
      @Nullable
      private final String id;
      @Nullable
      private final OperationHeader header;
      private final Iterable<OperationLink> links;
      private final Iterable<OperationGroup> groups;
      @Nullable
      private final Integer weight;
  
      public OperationGroup(@Nullable final String id, final Iterable<OperationLink> links,
                            final Iterable<OperationGroup> groups, @Nullable final OperationHeader header,
                            @Nullable final Integer weight) {
          this.id = id;
          this.header = header;
          this.links = links;
          this.groups = groups;
          this.weight = weight;
      }
  
      @Nullable
      public String getId() {
          return id;
      }
  
      @Override
      public <T> Optional<T> accept(final OperationVisitor<T> visitor) {
          final Optional<T> result = visitor.visit(this);
          if (result.isPresent()) {
              return result;
          } else {
              final Iterable<Operation> operations = Iterables.concat(
                      header != null ? Collections.singleton(header) : Collections.<Operation>emptyList(),
                      links, groups);
              return accept(operations, visitor);
          }
      }
  
      static <T> Optional<T> accept(final Iterable<? extends Operation> operations, final OperationVisitor<T> visitor) {
          for (Operation operation : operations) {
              Optional<T> result = operation.accept(visitor);
              if (result.isPresent()) {
                  return result;
              }
          }
          return Optional.absent();
      }
  
      @Nullable
      public OperationHeader getHeader() {
          return header;
      }
  
      public Iterable<OperationLink> getLinks() {
          return links;
      }
  
      public Iterable<OperationGroup> getGroups() {
          return groups;
      }
  
      @Nullable
      public Integer getWeight() {
          return weight;
      }
  
      @Override
      public int hashCode() {
          return Objects.hashCode(id, header, links, groups, weight);
     }
 
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
             return true;
         }
         if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
         final OperationGroup other = (OperationGroup) obj;
         return Objects.equal(this.id, other.id)
                 && Objects.equal(this.header, other.header)
                 && Iterables.elementsEqual(this.links, other.links)
                 && Iterables.elementsEqual(this.groups, other.groups)
                 && Objects.equal(this.weight, other.weight);
     }
 
     @Override
     public String toString() {
         return Objects.toStringHelper(this)
                 .add("id", id)
                 .add("header", header)
                 .add("links", Iterables.toString(links))
                 .add("groups", Iterables.toString(groups))
                 .add("weight", weight)
                 .toString();
     }
 }