/*
    * (c) Copyright 2006-2020 by rapiddweller GmbH & Volker Bergmann. All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, is permitted under the terms of the
    * GNU General Public License.
    *
    * For redistributing this software or a derivative work under a license other
    * than the GPL-compatible Free Software License as defined by the Free
   * Software Foundation or approved by OSI, you must first obtain a commercial
   * license to this software product from rapiddweller GmbH & Volker Bergmann.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
   * REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
   * HEREBY EXCLUDED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  package com.rapiddweller.benerator.engine.parser.xml;
  
  import com.rapiddweller.benerator.engine.Statement;
  import com.rapiddweller.benerator.engine.statement.IfStatement;
  import com.rapiddweller.benerator.engine.statement.SequentialStatement;
  import com.rapiddweller.common.CollectionUtil;
  import com.rapiddweller.common.xml.XMLUtil;
  import com.rapiddweller.script.Expression;
  import org.w3c.dom.Element;
  
  import java.util.List;
  import java.util.Objects;
  import java.util.Set;
  
  import static com.rapiddweller.benerator.engine.DescriptorConstants.ATT_TEST;
  import static com.rapiddweller.benerator.engine.DescriptorConstants.EL_COMMENT;
  import static com.rapiddweller.benerator.engine.DescriptorConstants.EL_ELSE;
  import static com.rapiddweller.benerator.engine.DescriptorConstants.EL_IF;
  import static com.rapiddweller.benerator.engine.DescriptorConstants.EL_THEN;
  import static com.rapiddweller.benerator.engine.parser.xml.DescriptorParserUtil.parseBooleanExpressionAttribute;
  
  /**
   * Parses an &lt;if&gt; element.<br/><br/>
   * Created: 19.02.2010 09:07:51
   *
   * @author Volker Bergmann
   * @since 0.6.0
   */
  public class IfParser extends AbstractBeneratorDescriptorParser {
  
    private static final Set<String> STRICT_CHILDREN = CollectionUtil.toSet(
        EL_THEN, EL_ELSE, EL_COMMENT);
  
    /**
     * Instantiates a new If parser.
     */
    public IfParser() {
      super(EL_IF, CollectionUtil.toSet(ATT_TEST), null);
    }
  
    @Override
    public Statementm/rapiddweller/benerator/engine/Statement.html#Statement">Statement doParse(Element ifElement, Statement[] parentPath, BeneratorParseContext context) {
      Expression<Boolean> condition = parseBooleanExpressionAttribute(ATT_TEST, ifElement);
      Element[] thenElements = XMLUtil.getChildElements(ifElement, false, "then");
      if (thenElements.length > 1) {
        syntaxError("Multiple <then> elements", ifElement);
      }
      Element thenElement = (thenElements.length == 1 ? thenElements[0] : null);
      Element[] elseElements = XMLUtil.getChildElements(ifElement, false, "else");
      if (elseElements.length > 1) {
        syntaxError("Multiple <else> elements", ifElement);
      }
      Element elseElement = (elseElements.length == 1 ? elseElements[0] : null);
      List<Statement> thenStatements = null;
      List<Statement> elseStatements = null;
      IfStatemente/statement/IfStatement.html#IfStatement">IfStatement ifStatement = new IfStatement(condition);
      Statement[] ifPath = context.createSubPath(parentPath, ifStatement);
      if (elseElement != null) {
        // if there is an 'else' element, there must be an 'if' element too
        if (thenElement == null) {
          syntaxError("'else' without 'then'", elseElement);
        }
        thenStatements = context.parseChildElementsOf(thenElement, ifPath);
        elseStatements = context.parseChildElementsOf(elseElement, ifPath);
        // check that no elements conflict with 'then' and 'else'
        assertThenElseChildren(ifElement);
      } else {
        thenStatements = context.parseChildElementsOf(Objects.requireNonNullElse(thenElement, ifElement), ifPath);
      }
      ifStatement.setThenStatement(new SequentialStatement(thenStatements));
      ifStatement.setElseStatement(new SequentialStatement(elseStatements));
      return ifStatement;
    }
 
   private static void assertThenElseChildren(Element ifElement) {
     for (Element child : XMLUtil.getChildElements(ifElement)) {
       if (!STRICT_CHILDREN.contains(child.getNodeName())) {
         syntaxError("Illegal child element: ", child);
       }
     }
   }
 
 }