/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.apache.myfaces.flow.builder;
  
  import javax.el.MethodExpression;
  import javax.el.ValueExpression;
  import javax.faces.context.FacesContext;
  import javax.faces.flow.Flow;
  import javax.faces.flow.builder.FlowBuilder;
  import javax.faces.flow.builder.FlowCallBuilder;
  import javax.faces.flow.builder.MethodCallBuilder;
  import javax.faces.flow.builder.NavigationCaseBuilder;
  import javax.faces.flow.builder.ReturnBuilder;
  import javax.faces.flow.builder.SwitchBuilder;
  import javax.faces.flow.builder.ViewBuilder;
  import org.apache.myfaces.flow.FlowImpl;
  import org.apache.myfaces.flow.ParameterImpl;
  
  /**
   *
   * @since 2.2
   * @author Leonardo Uribe
   */
  public class FlowBuilderImpl extends FlowBuilder
  {
  
      private static final Class[] EMPTY_PARAMS = new Class[]
      {
      };
      private FlowImpl _facesFlow;
      private FacesContext _facesContext;
  
      public FlowBuilderImpl()
      {
          _facesFlow = new FlowImpl();
      }
  
      public FlowBuilderImpl(FacesContext context)
      {
          super();
          _facesContext = context;
      }
  
      @Override
      public FlowBuilder id(String definingDocumentId, String id)
      {
          _facesFlow.setDefiningDocumentId(definingDocumentId);
          _facesFlow.setId(id);
          return this;
      }
  
      @Override
      public ViewBuilder viewNode(String viewNodeId, String vdlDocumentId)
      {
          return new ViewBuilderImpl(_facesFlow, viewNodeId, vdlDocumentId);
      }
  
      @Override
      public SwitchBuilder switchNode(String switchNodeId)
      {
          return new SwitchBuilderImpl(this, _facesFlow, switchNodeId);
      }
  
      @Override
      public ReturnBuilder returnNode(String returnNodeId)
      {
          return new ReturnBuilderImpl(this, _facesFlow, returnNodeId);
      }
  
      @Override
      public MethodCallBuilder methodCallNode(String methodCallNodeId)
      {
          return new MethodCallBuilderImpl(this, _facesFlow, methodCallNodeId);
      }
  
      @Override
      public FlowCallBuilder flowCallNode(String flowCallNodeId)
      {
          return new FlowCallBuilderImpl(this, _facesFlow, flowCallNodeId);
      }
  
      @Override
      public FlowBuilder initializer(MethodExpression methodExpression)
     {
         _facesFlow.setInitializer(methodExpression);
         return this;
     }
 
     @Override
     public FlowBuilder initializer(String methodExpression)
     {
         _facesFlow.setInitializer(createMethodExpression(methodExpression));
         return this;
     }
 
     @Override
     public FlowBuilder finalizer(MethodExpression methodExpression)
     {
         _facesFlow.setFinalizer(methodExpression);
         return this;
     }
 
     @Override
     public FlowBuilder finalizer(String methodExpression)
     {
         _facesFlow.setFinalizer(createMethodExpression(methodExpression));
         return this;
     }
 
     @Override
     public FlowBuilder inboundParameter(String name, ValueExpression value)
     {
         _facesFlow.putInboundParameter(name, new ParameterImpl(name, value));
         return this;
     }
 
     @Override
     public FlowBuilder inboundParameter(String name, String value)
     {
         _facesFlow.putInboundParameter(name, new ParameterImpl(name,
             createValueExpression(value)));
         return this;
     }
 
     @Override
     public Flow getFlow()
     {
         _facesContext = null;
         return _facesFlow;
     }
 
     /**
      * The idea is grab FacesContext just once and then when the flow is returned clear the variable.
      *
      * @return
      */
     FacesContext getFacesContext()
     {
         if (_facesContext == null)
         {
             _facesContext = FacesContext.getCurrentInstance();
         }
         return _facesContext;
     }
     
     public MethodExpression createMethodExpression(String methodExpression)
     {
         FacesContext facesContext = getFacesContext();
         return facesContext.getApplication().getExpressionFactory().createMethodExpression(
             facesContext.getELContext(), methodExpression, null, EMPTY_PARAMS);
     }
     
     public MethodExpression createMethodExpression(String methodExpression, Class[] paramTypes)
     {
         FacesContext facesContext = getFacesContext();
         return facesContext.getApplication().getExpressionFactory().createMethodExpression(
             facesContext.getELContext(), methodExpression, null, paramTypes);
     }
     
     public ValueExpression createValueExpression(String value)
     {
         FacesContext facesContext = getFacesContext();
         return facesContext.getApplication().getExpressionFactory()
             .createValueExpression(facesContext.getELContext(), value, Object.class); 
     }
 
     @Override
     public NavigationCaseBuilder navigationCase()
     {
         return new NavigationCaseBuilderImpl(this, _facesFlow);
     }
 }