/*
    * Copyright (C) 2013 4th Line GmbH, Switzerland
    *
    * The contents of this file are subject to the terms of either the GNU
    * Lesser General Public License Version 2 or later ("LGPL") or the
    * Common Development and Distribution License Version 1 or later
    * ("CDDL") (collectively, the "License"). You may not use this file
    * except in compliance with the License. See LICENSE.txt for more
    * information.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   */
  
  package org.fourthline.cling.model.action;
  
  import org.fourthline.cling.model.meta.LocalService;
  import org.fourthline.cling.model.meta.QueryStateVariableAction;
  import org.fourthline.cling.model.meta.StateVariable;
  import org.fourthline.cling.model.state.StateVariableAccessor;
  import org.fourthline.cling.model.types.ErrorCode;
  
  /**
   * Special executor for one action, the deprecated "query the value of the any state variable" action.
   * 
   * @author Christian Bauer
   */
  public class QueryStateVariableExecutor extends AbstractActionExecutor {
      
      @Override
      protected void execute(ActionInvocation<LocalService> actionInvocation, Object serviceImpl) throws Exception {
  
          // Querying a state variable doesn't mean an actual "action" method on this instance gets invoked
          if (actionInvocation.getAction() instanceof QueryStateVariableAction) {
              if (!actionInvocation.getAction().getService().isSupportsQueryStateVariables()) {
                  actionInvocation.setFailure(
                          new ActionException(ErrorCode.INVALID_ACTION, "This service does not support querying state variables")
                  );
              } else {
                  executeQueryStateVariable(actionInvocation, serviceImpl);
              }
          } else {
              throw new IllegalStateException(
                      "This class can only execute QueryStateVariableAction's, not: " + actionInvocation.getAction()
              );
          }
      }
  
      protected void executeQueryStateVariable(ActionInvocation<LocalService> actionInvocation, Object serviceImpl) throws Exception {
  
          LocalService service = actionInvocation.getAction().getService();
  
          String stateVariableName = actionInvocation.getInput("varName").toString();
          StateVariable stateVariable = service.getStateVariable(stateVariableName);
  
          if (stateVariable == null) {
              throw new ActionException(
                      ErrorCode.ARGUMENT_VALUE_INVALID, "No state variable found: " + stateVariableName
              );
          }
  
          StateVariableAccessor accessor;
          if ((accessor = service.getAccessor(stateVariable.getName())) == null) {
              throw new ActionException(
                      ErrorCode.ARGUMENT_VALUE_INVALID, "No accessor for state variable, can't read state: " + stateVariableName
              );
          }
  
          try {
              setOutputArgumentValue(
                      actionInvocation,
                      actionInvocation.getAction().getOutputArgument("return"),
                      accessor.read(stateVariable, serviceImpl).toString()
              );
          } catch (Exception ex) {
              throw new ActionException(ErrorCode.ACTION_FAILED, ex.getMessage());
          }
      }
  
  }