/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package dev.metaschema.databind.io.xml;
   
   import org.apache.logging.log4j.LogManager;
   import org.apache.logging.log4j.Logger;
  
  import java.util.HashSet;
  import java.util.Set;
  
  import javax.xml.stream.events.Attribute;
  
  import dev.metaschema.core.model.IBoundObject;
  import dev.metaschema.core.model.util.XmlEventUtil;
  import dev.metaschema.core.qname.IEnhancedQName;
  import dev.metaschema.core.util.ObjectUtils;
  import dev.metaschema.databind.io.AbstractProblemHandler;
  import dev.metaschema.databind.model.IBoundDefinitionModelComplex;
  
  /**
   * Handles problems identified in the parsed XML.
   * <p>
   * The default problem handler will report unknown attributes, and provide empty
   * collections for multi-valued model items and default values for flags and
   * single valued fields.
   */
  public class DefaultXmlProblemHandler
      extends AbstractProblemHandler
      implements IXmlProblemHandler {
    private static final Logger LOGGER = LogManager.getLogger(DefaultXmlProblemHandler.class);
  
    /**
     * Construct a new problem handler with required field validation enabled.
     */
    public DefaultXmlProblemHandler() {
      super();
    }
  
    /**
     * Construct a new problem handler with the specified validation setting.
     *
     * @param validateRequiredFields
     *          {@code true} to validate that required fields are present,
     *          {@code false} to skip validation
     */
    public DefaultXmlProblemHandler(boolean validateRequiredFields) {
      super(validateRequiredFields);
    }
  
    private static final IEnhancedQName XSI_SCHEMA_LOCATION
        = IEnhancedQName.of("http://www.w3.org/2001/XMLSchema-instance", "schemaLocation");
    private static final Set<IEnhancedQName> IGNORED_QNAMES;
  
    static {
      IGNORED_QNAMES = new HashSet<>();
      IGNORED_QNAMES.add(XSI_SCHEMA_LOCATION);
    }
  
    @Override
    public boolean handleUnknownAttribute(
        IBoundDefinitionModelComplex parentDefinition,
        IBoundObject targetObject,
        Attribute attribute,
        IXmlParsingContext parsingContext) {
      IEnhancedQName qname = IEnhancedQName.of(ObjectUtils.requireNonNull(attribute.getName()));
      // check if warning is needed
      if (LOGGER.isWarnEnabled() && !IGNORED_QNAMES.contains(qname)) {
        LOGGER.atWarn().log("Skipping unrecognized attribute '{}'{}.",
            qname,
            XmlEventUtil.generateLocationMessage(
                ObjectUtils.notNull(attribute.getLocation()),
                parsingContext.getSource()));
      }
      // always ignore
      return true;
    }
  }