/*
    * Copyright 2010-2013 smartics, Kronseder & Reiner GmbH
    *
    * 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 de.smartics.testdoc.collect.extractor;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.lang.model.element.Element;
  import javax.lang.model.element.ElementKind;
  import javax.lang.model.element.ExecutableElement;
  import javax.lang.model.element.TypeElement;
  import javax.lang.model.element.VariableElement;
  
  import de.smartics.testdoc.annotations.Uut;
  import de.smartics.testdoc.collect.extractor.TestDocAnnotationExtractor.UutInfo;
  import de.smartics.testdoc.core.doc.ScenarioTestDoc;
  import de.smartics.testdoc.core.doc.UnitTestDoc;
  
  /**
   * Extracts unit test doc information from a specified variable.
   *
   * @todo Currently only fields and no inline variables are supported. This is
   *       due to the fact that the APT parser does not return variable
   *       information.
   * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
   * @version $Revision:591 $
   */
  public final class TestDocVariableExtractor extends AbstractExtractor
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * The element that contains information about a variable in the test case
     * class that points to the unit under test.
     */
    private final VariableElement declaredUutField;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     *
     * @param config the configuration to access processing information.
     * @param declaredUutField the element that contains information about a
     *          variable in the test case class that points to the unit under
     *          test.
     * @throws IllegalArgumentException if the <code>declaredUutField</code> is
     *           not a field declaration within a class or any of the arguments is
     *           <code>null</code>.
     * @throws ExtractorException if there is a {@link Uut} annotation at type and
     *           field level.
     */
    public TestDocVariableExtractor(final ExtractorConfig config,
        final VariableElement declaredUutField) throws IllegalArgumentException,
      ExtractorException
    {
      super(config, initTypeElement(declaredUutField));
      this.declaredUutField = declaredUutField;
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    private static void checkArguments(final VariableElement declaredUutField)
    {
      if (null == declaredUutField)
      {
        throw new IllegalArgumentException(
            "The field, declared in the test case, that points to the UUT is required.");
      }
    }
  
    private static TypeElement initTypeElement(
        final VariableElement declaredUutField) throws IllegalArgumentException,
      ExtractorException
    {
      checkArguments(declaredUutField);
 
     Element current = declaredUutField;
     while (current != null)
     {
       final ElementKind kind = current.getKind();
       if (ElementKind.CLASS.equals(kind))
       {
         final TypeElement selected = (TypeElement) current;
         if (hasAnnotation(selected, Uut.class))
         {
           throw new ExtractorException(
               "Uut annotation not allowed at type and field"
                   + " level at the same time.");
         }
         return selected;
       }
       current = current.getEnclosingElement();
     }
 
     throw new IllegalArgumentException("Declaration of UUT '"
                                        + declaredUutField.asType()
                                        + "' is not within a test case class.");
   }
 
   // --- get&set --------------------------------------------------------------
 
   // --- business -------------------------------------------------------------
 
   /**
    * Reads the test documentation from the element the extractor instance is
    * associated with.
    *
    * @return the test documentation read.
    */
   public UnitTestDoc readTestDoc()
   {
     final String testCaseType = calcTestCaseType();
     final UutInfo uutInfo = uutExtractor.read(declaredUutField);
     final List<ScenarioTestDoc> scenarios =
         calcScenarios(uutInfo, testCaseType);
 
     // We ignore the type information from the UUT annotation.
     final String uutType = calcUutTypeName();
 
     final UnitTestDoc testDoc = new UnitTestDoc(uutType, scenarios);
 
     return testDoc;
   }
 
   private String calcTestCaseType()
   {
     return testCaseType.asType().toString();
   }
 
   private String calcUutTypeName()
   {
     return declaredUutField.asType().toString();
   }
 
   private List<ScenarioTestDoc> calcScenarios(final UutInfo uutInfo,
       final String testCaseTypeName) throws ExtractorException
   {
     final List<ScenarioTestDoc> scenarios = new ArrayList<ScenarioTestDoc>();
 
     for (final Element element : elementUtils.getAllMembers(testCaseType))
     {
       if (isTestMethodWithoutUutAnnotation(element))
       {
         final ExecutableElement testMethod = (ExecutableElement) element;
         final ScenarioTestDoc scenario =
             createScenarioIfElementIsTestMethod(uutInfo, testCaseTypeName,
                 testMethod);
         if (scenario != null)
         {
           scenarios.add(scenario);
         }
       }
     }
 
     return scenarios;
   }
 
   // --- object basics --------------------------------------------------------
 
 }