/* 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.rest.service.api.runtime.process;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.activiti.engine.ActivitiIllegalArgumentException;
import org.activiti.engine.runtime.ProcessInstance;
import org.activiti.rest.exception.ActivitiConflictException;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;


/**
 * @author Frederik Heremans
 */
@RestController
public class ProcessInstanceResource extends BaseProcessInstanceResource {

  @RequestMapping(value="/runtime/process-instances/{processInstanceId}", method = RequestMethod.GET, produces="application/json")
  public ProcessInstanceResponse getProcessInstance(@PathVariable String processInstanceId, HttpServletRequest request) {
    return restResponseFactory.createProcessInstanceResponse(getProcessInstanceFromRequest(processInstanceId));
  }
  
  @RequestMapping(value="/runtime/process-instances/{processInstanceId}", method = RequestMethod.DELETE)
  public void deleteProcessInstance(@PathVariable String processInstanceId, 
      @RequestParam(value="deleteReason", required=false) String deleteReason, HttpServletResponse response) {
    
    ProcessInstance processInstance = getProcessInstanceFromRequest(processInstanceId);
    
    runtimeService.deleteProcessInstance(processInstance.getId(), deleteReason);
    response.setStatus(HttpStatus.NO_CONTENT.value());
  }
  
  @RequestMapping(value="/runtime/process-instances/{processInstanceId}", method = RequestMethod.PUT, produces="application/json")
  public ProcessInstanceResponse performProcessInstanceAction(@PathVariable String processInstanceId, 
      @RequestBody ProcessInstanceActionRequest actionRequest, HttpServletRequest request) {
    
    ProcessInstance processInstance = getProcessInstanceFromRequest(processInstanceId);
    
    if (ProcessInstanceActionRequest.ACTION_ACTIVATE.equals(actionRequest.getAction())) {
      return activateProcessInstance(processInstance);
      
    } else if (ProcessInstanceActionRequest.ACTION_SUSPEND.equals(actionRequest.getAction())) {
      return suspendProcessInstance(processInstance);
    }
    throw new ActivitiIllegalArgumentException("Invalid action: '" + actionRequest.getAction() + "'.");
  }
  
  protected ProcessInstanceResponse activateProcessInstance(ProcessInstance processInstance) {
    if (!processInstance.isSuspended()) {
      throw new ActivitiConflictException("Process instance with id '" + 
          processInstance.getId() + "' is already active.");
    }
    runtimeService.activateProcessInstanceById(processInstance.getId());
   
    ProcessInstanceResponse response = restResponseFactory.createProcessInstanceResponse(processInstance);
    
    // No need to re-fetch the instance, just alter the suspended state of the result-object
    response.setSuspended(false);
    return response;
  }

  protected ProcessInstanceResponse suspendProcessInstance(ProcessInstance processInstance) {
    if (processInstance.isSuspended()) {
      throw new ActivitiConflictException("Process instance with id '" + 
          processInstance.getId() + "' is already suspended.");
    }
    runtimeService.suspendProcessInstanceById(processInstance.getId());
    
    ProcessInstanceResponse response = restResponseFactory.createProcessInstanceResponse(processInstance);
    
    // No need to re-fetch the instance, just alter the suspended state of the result-object
    response.setSuspended(true);
    return response;
  }
}