/*
    * 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();
 	}
 }