/* 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 org.activiti.engine.impl.cmd;

import java.io.Serializable;
import java.util.List;

import org.activiti.engine.ActivitiIllegalArgumentException;
import org.activiti.engine.ActivitiObjectNotFoundException;
import org.activiti.engine.history.HistoricIdentityLink;
import org.activiti.engine.history.HistoricTaskInstance;
import org.activiti.engine.impl.interceptor.Command;
import org.activiti.engine.impl.interceptor.CommandContext;
import org.activiti.engine.impl.persistence.entity.HistoricIdentityLinkEntity;
import org.activiti.engine.impl.persistence.entity.HistoricTaskInstanceEntity;
import org.activiti.engine.task.IdentityLinkType;


/**
 * @author Frederik Heremans
 */
public class GetHistoricIdentityLinksForTaskCmd implements Command<List<HistoricIdentityLink>>, Serializable {
  
  private static final long serialVersionUID = 1L;
  protected String taskId;
  protected String processInstanceId;

  public GetHistoricIdentityLinksForTaskCmd(String taskId, String processInstanceId) {
    if(taskId == null && processInstanceId == null) {
      throw new ActivitiIllegalArgumentException("taskId or processInstanceId is required");
    }
    this.taskId = taskId;
    this.processInstanceId = processInstanceId;
  }
  
  public List<HistoricIdentityLink> execute(CommandContext commandContext) {
    if(taskId != null) {
      return getLinksForTask(commandContext);
    } else {
      return getLinksForProcessInstance(commandContext);
    }
  }
  
  @SuppressWarnings({"unchecked", "rawtypes" })
  protected List<HistoricIdentityLink> getLinksForTask(CommandContext commandContext) {
    HistoricTaskInstanceEntity task = commandContext
      .getHistoricTaskInstanceEntityManager()
      .findHistoricTaskInstanceById(taskId);
    
    if(task == null) {
      throw new ActivitiObjectNotFoundException("No historic task exists with the given id: " + taskId, HistoricTaskInstance.class);
    }

    List<HistoricIdentityLink> identityLinks = (List) commandContext
            .getHistoricIdentityLinkEntityManager()
            .findHistoricIdentityLinksByTaskId(taskId);
    
    // Similar to GetIdentityLinksForTask, return assignee and owner as identity link
    if (task.getAssignee() != null) {
      HistoricIdentityLinkEntity identityLink = new HistoricIdentityLinkEntity();
      identityLink.setUserId(task.getAssignee());
      identityLink.setTaskId(task.getId());
      identityLink.setType(IdentityLinkType.ASSIGNEE);
      identityLinks.add(identityLink);
    }
    if (task.getOwner() != null) {
      HistoricIdentityLinkEntity identityLink = new HistoricIdentityLinkEntity();
      identityLink.setTaskId(task.getId());
      identityLink.setUserId(task.getOwner());
      identityLink.setType(IdentityLinkType.OWNER);
      identityLinks.add(identityLink);
    }
    
    return identityLinks;
  }
  
  @SuppressWarnings({"unchecked", "rawtypes" })
  protected List<HistoricIdentityLink> getLinksForProcessInstance(CommandContext commandContext) {
   return (List) commandContext
            .getHistoricIdentityLinkEntityManager()
            .findHistoricIdentityLinksByProcessInstanceId(processInstanceId);
  }
  
}