/**
 * Redistribution and use of this software and associated documentation ("Software"), with or
 * without modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions
 * must also contain a copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided with
 * the distribution.
 *
 * 3. The name "Exolab" must not be used to endorse or promote products derived from this Software
 * without prior written permission of Intalio, Inc. For written permission, please contact
 * info@exolab.org.
 *
 * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in
 * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of
 * Intalio, Inc.
 *
 * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTALIO, INC. OR ITS
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 * 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.
 *
 * Copyright 1999-2003 (C) Intalio Inc. All Rights Reserved.
 *
 * $Id$
 */

package org.exolab.castor.xml.schema.reader;

// -- imported classes and packages
import org.exolab.castor.xml.AttributeSet;
import org.exolab.castor.xml.Namespaces;
import org.exolab.castor.xml.XMLException;
import org.exolab.castor.xml.schema.Annotation;
import org.exolab.castor.xml.schema.ElementDecl;
import org.exolab.castor.xml.schema.Form;
import org.exolab.castor.xml.schema.IdentityConstraint;
import org.exolab.castor.xml.schema.Schema;
import org.exolab.castor.xml.schema.SchemaContext;
import org.exolab.castor.xml.schema.SchemaException;
import org.exolab.castor.xml.schema.SchemaNames;
import org.exolab.castor.xml.schema.XMLType;

/**
 * A class for Unmarshalling element definitions
 * 
 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
 *
 * @version $Revision$ $Date: 2003-03-03 02:57:21 -0700 (Mon, 03 Mar 2003) $
 */
public class ElementUnmarshaller extends ComponentReader {

  /**
   * The value of the maximum occurance wild card
   **/
  private static final String MAX_OCCURS_WILDCARD = "unbounded";

  // --------------------/
  // - Member Variables -/
  // --------------------/

  /**
   * The current ComponentReader
   **/
  private ComponentReader unmarshaller;

  /**
   * The current branch depth
   **/
  private int depth = 0;

  /**
   * The element reference for the element definition we are "unmarshalling".
   **/
  private ElementDecl _element = null;


  private CharacterUnmarshaller charUnmarshaller = null;

  private Schema _schema = null;

  private boolean foundAnnotation = false;
  private boolean foundIdentityConstraint = false;
  private boolean foundSimpleType = false;
  private boolean foundComplexType = false;
  private boolean foundTypeReference = false;

  // ----------------/
  // - Constructors -/
  // ----------------/

  /**
   * Creates a new ElementUnmarshaller.
   * 
   * @param schemaContext the {@link SchemaContext} to get some configuration settings from
   * @param schema the Schema to which the Element belongs
   * @param atts the AttributeList
   **/
  public ElementUnmarshaller(final SchemaContext schemaContext, final Schema schema,
      final AttributeSet atts) throws XMLException {
    super(schemaContext);

    this._schema = schema;

    _element = new ElementDecl(schema);

    String attValue = null;

    // -- @ref
    attValue = atts.getValue(SchemaNames.REF_ATTR);
    if (attValue != null) {
      _element.setReferenceName(attValue);
      // -- report error if name attr exists also
      if (atts.getValue(SchemaNames.NAME_ATTR) != null) {
        error("The attributes 'ref' and 'name' appearing on "
            + "element declarations are mutually exclusive.");
      }
      validateRefAtts(atts);
    }
    // -- @name
    else {
      _element.setName(atts.getValue(SchemaNames.NAME_ATTR));
    }

    // -- @abstract
    attValue = atts.getValue(SchemaNames.ABSTRACT);
    if (attValue != null) {
      _element.setAbstract(Boolean.parseBoolean(attValue));
    }

    // -- @block
    _element.setBlock(atts.getValue(SchemaNames.BLOCK_ATTR));

    // -- @default
    attValue = atts.getValue(SchemaNames.DEFAULT_ATTR);
    if (attValue != null) {
      if (_element.getFixedValue() != null)
        error("'default' and 'fixed' must not both be present.");
      _element.setDefaultValue(attValue);
    }

    // -- @final
    _element.setFinal(atts.getValue(SchemaNames.FINAL_ATTR));

    // -- @abstract
    final boolean isAbstract = Boolean.parseBoolean(atts.getValue(SchemaNames.ABSTRACT));
    if (isAbstract) {
      _element.setAbstract(isAbstract);
    }

    // -- @fixed
    attValue = atts.getValue(SchemaNames.FIXED_ATTR);
    if (attValue != null) {
      if (_element.getDefaultValue() != null)
        throw new IllegalArgumentException("'default' and 'fixed' must not both be present.");
      _element.setFixedValue(attValue);
    }

    // -- @form
    attValue = atts.getValue(SchemaNames.FORM);
    if (attValue != null) {
      _element.setForm(Form.valueOf(attValue));
    }

    // -- @id
    _element.setId(atts.getValue(SchemaNames.ID_ATTR));

    // -- @substitutionGroup
    attValue = atts.getValue(SchemaNames.SUBSTITUTION_GROUP_ATTR);
    if (attValue != null) {
      _element.setSubstitutionGroup(attValue);
    }

    // -- @type
    attValue = atts.getValue(SchemaNames.TYPE_ATTR);
    if (attValue != null) {
      foundTypeReference = true;
      _element.setTypeReference(attValue);
    }


    // -- @nillable
    attValue = atts.getValue(SchemaNames.NILLABLE_ATTR);
    if (attValue != null) {
      if (attValue.equals("true") || attValue.equals("1")) {
        _element.setNillable(true);
      } else if (!attValue.equals("false") && !attValue.equals("0")) {
        String err =
            "Invalid value for the 'nillable' attribute of " + "an element definition: " + attValue;
        throw new IllegalArgumentException(err);
      }
    }

    /*
     * @minOccurs if minOccurs is present the value is the int value of of the attribute, otherwise
     * minOccurs is 1.
     */
    attValue = atts.getValue(SchemaNames.MIN_OCCURS_ATTR);
    int minOccurs = 1;
    if (attValue != null) {
      minOccurs = toInt(attValue);
      _element.setMinOccurs(minOccurs);
    }

    /*
     * @maxOccurs If maxOccurs is present, the value is either unbounded or the int value of the
     * attribute, otherwise maxOccurs equals the minOccurs value.
     */
    attValue = atts.getValue(SchemaNames.MAX_OCCURS_ATTR);
    if (attValue != null) {
      if (MAX_OCCURS_WILDCARD.equals(attValue))
        attValue = "-1";
      int maxOccurs = toInt(attValue);
      _element.setMaxOccurs(maxOccurs);
    } else if (minOccurs > 1)
      _element.setMaxOccurs(minOccurs);

    charUnmarshaller = new CharacterUnmarshaller(getSchemaContext());
  } // -- ElementUnmarshaller

  // -----------/
  // - Methods -/
  // -----------/

  /**
   * Returns the name of the element that this ComponentReader handles
   * 
   * @return the name of the element that this ComponentReader handles
   **/
  public String elementName() {
    return SchemaNames.ELEMENT;
  } // -- elementName

  /**
   *
  **/
  public ElementDecl getElement() {
    return _element;
  } // -- getElement

  /**
   * Returns the Object created by this ComponentReader
   * 
   * @return the Object created by this ComponentReader
   **/
  public Object getObject() {
    return _element;
  } // -- getObject

  /**
   * Signals the start of an element with the given name.
   *
   * @param name the NCName of the element. It is an error if the name is a QName (ie. contains a
   *        prefix).
   * @param namespace the namespace of the element. This may be null. Note: A null namespace is not
   *        the same as the default namespace unless the default namespace is also null.
   * @param atts the AttributeSet containing the attributes associated with the element.
   * @param nsDecls the namespace declarations being declared for this element. This may be null.
   **/
  public void startElement(String name, String namespace, AttributeSet atts, Namespaces nsDecls)
      throws XMLException {

    // -- Do delagation if necessary
    if (unmarshaller != null) {
      unmarshaller.startElement(name, namespace, atts, nsDecls);
      ++depth;
      return;
    }

    if (SchemaNames.ANNOTATION.equals(name)) {
      if (foundSimpleType || foundIdentityConstraint || foundComplexType)
        error("An annotation may only appear as the first child " + "of an element definition.");


      if (foundAnnotation)
        error("Only one (1) 'annotation' is allowed as a child of " + "element definitions.");

      foundAnnotation = true;
      unmarshaller = new AnnotationUnmarshaller(getSchemaContext(), atts);
    } else if (SchemaNames.COMPLEX_TYPE.equals(name)) {

      if (foundComplexType)
        error("Only one (1) 'complexType' may appear in an " + "element definition.");
      if (foundSimpleType)
        error("Both 'simpleType' and 'complexType' cannot appear "
            + "in the same element definition.");
      if (foundTypeReference)
        error("Both 'type' attribute and 'complexType' element "
            + "cannot appear in the same element definition.");


      if (foundIdentityConstraint)
        error("A 'complexType' must appear before 'key', " + "'keyref' and 'unique' elements.");

      foundComplexType = true;
      unmarshaller = new ComplexTypeUnmarshaller(getSchemaContext(), _schema, atts);
    } else if (SchemaNames.SIMPLE_TYPE.equals(name)) {

      if (foundSimpleType)
        error("Only one (1) 'simpleType' may appear in an " + "element definition.");
      if (foundComplexType)
        error("Both 'simpleType' and 'complexType' cannot appear "
            + "in the same element definition.");
      if (foundTypeReference)
        error("Both 'type' attribute and 'simpleType' element "
            + "cannot appear in the same element definition.");

      if (foundIdentityConstraint)
        error("A 'simpleType' must appear before 'key', " + "'keyref' and 'unique' elements.");

      foundSimpleType = true;
      unmarshaller = new SimpleTypeUnmarshaller(getSchemaContext(), _schema, atts);
    } else if (SchemaNames.KEY.equals(name) || SchemaNames.KEYREF.equals(name)
        || SchemaNames.UNIQUE.equals(name)) {
      foundIdentityConstraint = true;
      unmarshaller = new IdentityConstraintUnmarshaller(getSchemaContext(), name, atts);
    } else
      illegalElement(name);

  } // -- startElement

  /**
   * Signals to end of the element with the given name.
   *
   * @param name the NCName of the element. It is an error if the name is a QName (ie. contains a
   *        prefix).
   * @param namespace the namespace of the element.
   **/
  public void endElement(String name, String namespace) throws XMLException {

    // -- Do delagation if necessary
    if ((unmarshaller != null) && (depth > 0)) {
      unmarshaller.endElement(name, namespace);
      --depth;
      return;
    }

    // -- check for name mismatches
    if ((unmarshaller != null) && (charUnmarshaller != unmarshaller)) {
      if (!name.equals(unmarshaller.elementName())) {
        String err = "missing end element for ";
        err += unmarshaller.elementName();
        throw new SchemaException(err);
      }
    }

    // -- call finish for any necessary cleanup
    unmarshaller.finish();

    if (SchemaNames.ANNOTATION.equals(name)) {
      Annotation ann = (Annotation) unmarshaller.getObject();
      _element.addAnnotation(ann);
    } else if (SchemaNames.COMPLEX_TYPE.equals(name)) {

      XMLType xmlType = ((ComplexTypeUnmarshaller) unmarshaller).getComplexType();

      _element.setType(xmlType);

    } else if (SchemaNames.SIMPLE_TYPE.equals(name)) {
      XMLType xmlType = ((SimpleTypeUnmarshaller) unmarshaller).getSimpleType();
      _element.setType(xmlType);
    } else if (SchemaNames.KEY.equals(name) || SchemaNames.KEYREF.equals(name)
        || SchemaNames.UNIQUE.equals(name)) {
      IdentityConstraint constraint = (IdentityConstraint) unmarshaller.getObject();
      _element.addIdentityConstraint(constraint);
    }

    unmarshaller = null;

  } // -- endElement

  public void characters(char[] ch, int start, int length) throws XMLException {
    // -- Do delagation if necessary
    if (unmarshaller != null) {
      unmarshaller.characters(ch, start, length);
    }
  } // -- characters

  /**
   * Makes sure only minOccurs, maxOccurs, id, and ref occur for element references.
   *
   * @param atts the AttributeSet to process
   */
  private static void validateRefAtts(AttributeSet atts) throws XMLException {

    StringBuffer errors = null;

    for (int i = 0; i < atts.getSize(); i++) {
      String name = atts.getName(i);
      if (SchemaNames.REF_ATTR.equals(name))
        continue;
      else if (SchemaNames.MAX_OCCURS_ATTR.equals(name))
        continue;
      else if (SchemaNames.MIN_OCCURS_ATTR.equals(name))
        continue;
      else if (SchemaNames.ID_ATTR.equals(name))
        continue;
      else {
        // -- check namespace
        String namespace = atts.getNamespace(i);

        // -- If we have no namespace (ie no prefix) or we
        // -- have the XSD Namespace then throw error
        if ((namespace == null) || (namespace.length() == 0)
            || namespace.equals(SchemaUnmarshaller.XSD_NAMESPACE)) {
          // -- unprefixed attribute...assume XML Schema namespace
          String error = "The attribute '" + name + "' must not appear on an element reference.";
          if (errors == null)
            errors = new StringBuffer(error);
          else
            errors.append(error);

          errors.append(System.getProperty("line.separator"));


        }
        // -- otherwise we have a namespaced attribute from a different
        // -- namespace..this is valid...continue
      }
    }

    if (errors != null)
      throw new XMLException(errors.toString());

  } // -- validateRefAtts

} // -- ElementUnmarshaller
