package org.opentrafficsim.editor;
   
   import java.rmi.RemoteException;
   import java.util.ArrayList;
   import java.util.LinkedHashMap;
   import java.util.List;
   import java.util.Map;
   import java.util.Optional;
   
  import org.djutils.event.Event;
  import org.djutils.event.EventListener;
  import org.djutils.immutablecollections.Immutable;
  import org.djutils.immutablecollections.ImmutableArrayList;
  import org.djutils.immutablecollections.ImmutableList;
  import org.opentrafficsim.base.OtsRuntimeException;
  import org.opentrafficsim.base.logger.Logger;
  import org.opentrafficsim.editor.decoration.validation.XsdAllValidator;
  import org.w3c.dom.Node;
  
  /**
   * This class exists to keep {@code XsdTreeNode} at manageable size. It houses all static methods used in {@code XsdTreeNode}.
   * <p>
   * Copyright (c) 2023-2026 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
   * </p>
   * @author Wouter Schakel
   */
  public final class XsdTreeNodeUtil
  {
  
      /** Validators for xsd:all option nodes. This is maintained per root object (i.e. per tree) and xsd:all node. */
      private static final Map<XsdTreeNodeRoot, Map<String, XsdAllValidator>> XSD_ALL_VALIDATORS = new LinkedHashMap<>();
  
      /**
       * Private constructor.
       */
      private XsdTreeNodeUtil()
      {
  
      }
  
      /**
       * Add xsd:all validator to the given node.
       * @param shared shared xsd:all node.
       * @param node xsd:all node, or one of its children.
       */
      static void addXsdAllValidator(final XsdTreeNode shared, final XsdTreeNode node)
      {
          String path = shared.getPathString();
          XsdAllValidator validator = XSD_ALL_VALIDATORS.computeIfAbsent(shared.getRoot(), (r) -> new LinkedHashMap<>())
                  .computeIfAbsent(path, (p) -> new XsdAllValidator(node.getRoot()));
          node.addNodeValidator(validator);
          validator.addNode(node);
      }
  
      /**
       * Main expansion algorithm. Loops all child XSD nodes, and selects those that define next elements.
       * @param node node to get the children of.
       * @param parentNode parent node for the created children.
       * @param children list to add the children to. This may be different from {@code parentNode.children} due to layered choice
       *            structures.
       * @param hiddenNodes nodes between the XSD node of the parent, and this tree node's XSD node.
       * @param schema schema to get types and referred elements from.
       * @param flattenSequence when true, treats an xsd:sequence child as an extension of the node. In the context of a choice
       *            this should be {@code null}.
       * @param skip child index to skip, this is used when copying choice options from an option that is already created (i.e.
       *            {@code copyNode} in {@code XsdTreeNode.copyInto(copyNode)}).
       */
      static void addChildren(final Node node, final XsdTreeNode parentNode, final List<XsdTreeNode> children,
              final ImmutableList<Node> hiddenNodes, final Schema schema, final boolean flattenSequence, final int skip)
      {
          int skipIndex = skip;
          XsdTreeNode root = parentNode.getRoot();
          for (int childIndex = 0; childIndex < node.getChildNodes().getLength(); childIndex++)
          {
              Node child = node.getChildNodes().item(childIndex);
              switch (child.getNodeName())
              {
                  case "xsd:element":
                      if (children.size() == skipIndex)
                      {
                          skipIndex = -1;
                          break;
                      }
                      XsdTreeNode element;
                      Optional<String> ref = DocumentReader.getAttribute(child, "ref");
                      Optional<String> type = DocumentReader.getAttribute(child, "type");
                      if (ref.isPresent())
                      {
                          element = new XsdTreeNode(parentNode, ref(child, ref.get(), schema), append(hiddenNodes, node), child);
                      }
                      else if (type.isPresent())
                      {
                          Node typedNode = type(child, type.get(), schema);
                          if (typedNode == null)
                          {
                              // xsd:string or other basic type
                              element = new XsdTreeNode(parentNode, child, append(hiddenNodes, node));
                          }
                         else
                         {
                             element = new XsdTreeNode(parentNode, typedNode, append(hiddenNodes, node), child);
                         }
                     }
                     else
                     {
                         element = new XsdTreeNode(parentNode, child, append(hiddenNodes, node));
                     }
                     children.add(element);
                     root.fireEvent(XsdTreeNodeRoot.NODE_CREATED,
                             new Object[] {element, parentNode, parentNode.children.indexOf(element)});
                     break;
                 case "xsd:sequence":
                     if (children.size() == skipIndex)
                     {
                         skipIndex = -1;
                         break;
                     }
                     if (flattenSequence)
                     {
                         addChildren(child, parentNode, children, XsdTreeNodeUtil.append(hiddenNodes, node), schema, false, -1);
                     }
                     else
                     {
                         XsdTreeNode sequence = new XsdTreeNode(parentNode, child, append(hiddenNodes, node));
                         children.add(sequence);
                         root.fireEvent(XsdTreeNodeRoot.NODE_CREATED,
                                 new Object[] {sequence, parentNode, parentNode.children.indexOf(sequence)});
                     }
                     break;
                 case "xsd:choice":
                 case "xsd:all":
                     if (children.size() == skipIndex)
                     {
                         skipIndex = -1;
                         break;
                     }
                     XsdTreeNode choice = new XsdTreeNode(parentNode, child, append(hiddenNodes, node));
                     root.fireEvent(XsdTreeNodeRoot.NODE_CREATED,
                             new Object[] {choice, parentNode, parentNode.children.indexOf(choice)});
                     choice.createOptions();
                     children.add(choice);
                     choice.setOption(choice.options.get(0));
                     break;
                 case "xsd:extension":
                     if (children.size() == skipIndex)
                     {
                         skipIndex = -1;
                         break;
                     }
                     XsdTreeNode extension = new XsdTreeNode(parentNode, child, append(hiddenNodes, node));
                     root.fireEvent(XsdTreeNodeRoot.NODE_CREATED,
                             new Object[] {extension, parentNode, parentNode.children.indexOf(extension)});
                     children.add(extension);
                     break;
                 case "xsd:attribute":
                 case "xsd:annotation":
                 case "xsd:simpleType": // only defines xsd:restriction with xsd:pattern/xsd:enumeration
                 case "xsd:restriction":
                 case "xsd:simpleContent": // bit of a late capture, followed "type" attribute and did not check what it was
                 case "xsd:union":
                 case "#text":
                     // nothing, not even report ignoring, these are not relevant regarding element structure
                     break;
                 default:
                     Logger.ots().trace("Ignoring a {}", child.getNodeName());
             }
         }
     }
 
     /**
      * Returns the element referred to by ref={ref} in an xsd:element. Will return {@code XiIncludeNode.XI_INCLUDE} for
      * xi:include.
      * @param node node, must have ref={ref} attribute.
      * @param ref value of ref={ref}.
      * @param schema schema to take element from.
      * @return element referred to by ref={ref} in an xsd:element.
      */
     private static Node ref(final Node node, final String ref, final Schema schema)
     {
         if (ref.equals("xi:include"))
         {
             return XiIncludeNode.XI_INCLUDE;
         }
         return schema.getElement(ref)
                 .orElseThrow(() -> new OtsRuntimeException("Unable to load ref for " + ref + " from XSD schema."));
     }
 
     /**
      * Returns a copy of the input list, with the extra node appended at the end.
      * @param hiddenNodes hidden nodes list.
      * @param node node to append.
      * @return copy of the input list, with the extra node appended at the end.
      */
     private static ImmutableList<Node> append(final ImmutableList<Node> hiddenNodes, final Node node)
     {
         List<Node> list = new ArrayList<>(hiddenNodes.size() + 1);
         list.addAll(hiddenNodes.toCollection());
         list.add(node);
         return new ImmutableArrayList<>(list, Immutable.WRAP);
     }
 
     /**
      * Returns the element referred to by type={type} in an xsd:element. Returns {@code null} all types starting with "xsd:" as
      * these are standard types to which user input can be validated directly.
      * @param node node, must have type={type} attribute.
      * @param type value of type={type}.
      * @param schema schema to take type from.
      * @return element referred to by type={type} in an xsd:element or {@code null} for standard xsd types.
      */
     private static Node type(final Node node, final String type, final Schema schema)
     {
         if (type.startsWith("xsd:"))
         {
             return null;
         }
         return schema.getType(type)
                 .orElseThrow(() -> new OtsRuntimeException("Unable to load type for " + type + " from XSD schema."));
     }
 
     /**
      * Returns a list of options derived from a list of restrictions (xsd:restriction) based on their internal xsd:enumeration.
      * @param restrictions list of restrictions.
      * @return list of options.
      */
     static List<String> getOptionsFromRestrictions(final List<Node> restrictions)
     {
         List<String> options = new ArrayList<>();
         for (Node restriction : restrictions)
         {
             List<Node> enumerations = DocumentReader.getChildren(restriction, "xsd:enumeration");
             for (Node enumeration : enumerations)
             {
                 options.add(DocumentReader.getAttribute(enumeration, "value").get());
             }
         }
         return options;
     }
 
     /**
      * Recursively throws creation event on specific listener for all current nodes in the tree. This method is for
      * {@code XsdTreeNodeRoot}.
      * @param node node.
      * @param listener listener.
      * @throws RemoteException if event cannot be fired.
      */
     protected static void fireCreatedEventOnExistingNodes(final XsdTreeNode node, final EventListener listener)
             throws RemoteException
     {
         List<XsdTreeNode> subNodes = node.children == null ? new ArrayList<>() : new ArrayList<>(node.children);
         // only selected node extends towards choice, otherwise infinite recursion
         if (node.choice != null && node.choice.selected.equals(node))
         {
             subNodes.add(node.choice);
             subNodes.addAll(node.choice.options);
             subNodes.remove(node);
         }
         for (XsdTreeNode child : subNodes)
         {
             fireCreatedEventOnExistingNodes(child, listener);
         }
         Event event = new Event(XsdTreeNodeRoot.NODE_CREATED, new Object[] {node, node.getParent(), subNodes.indexOf(node)});
         listener.notify(event);
     }
 
     /**
      * Returns from the XSD definition the appropriate nodes to take children from at the level of the input node, in the order
      * in which they should appear. This is often the xsd:complexType within an xsd:element, but can become as complex as
      * containing multiple xsd:extension and their referred base types. An xsd:sequence is also common. Adding children in the
      * order as they appear per {@code Node}, and in the order the {@code Node}'s are given, results in an overall order
      * suitable for XML.
      * @param node node to expand further.
      * @param hiddenNodes nodes between the XSD node of the parent, and this tree node's XSD node.
      * @param schema schema to retrieve types.
      * @return map of nodes containing relevant children at the level of the input node, and their appropriate hidden nodes.
      */
     static Map<Node, ImmutableList<Node>> getRelevantNodesWithChildren(final Node node, final ImmutableList<Node> hiddenNodes,
             final Schema schema)
     {
         Node complexType = node.getNodeName().equals("xsd:complexType") ? node
                 : DocumentReader.getChild(node, "xsd:complexType").orElse(null);
         if (complexType != null)
         {
             Optional<Node> sequence = DocumentReader.getChild(complexType, "xsd:sequence");
             if (sequence.isPresent())
             {
                 return Map.of(sequence.get(), append(hiddenNodes, complexType));
             }
             Optional<Node> complexContent = DocumentReader.getChild(complexType, "xsd:complexContent");
             if (complexContent.isPresent())
             {
                 Optional<Node> extension = DocumentReader.getChild(complexContent.get(), "xsd:extension");
                 if (extension.isPresent())
                 {
                     ImmutableList<Node> hiddenExtension = append(append(hiddenNodes, complexType), complexContent.get());
                     LinkedHashMap<Node, ImmutableList<Node>> elements = new LinkedHashMap<>();
                     Optional<String> base = DocumentReader.getAttribute(extension.get(), "base");
                     if (base.isPresent())
                     {
                         Optional<Node> baseNode = schema.getType(base.get());
                         if (baseNode.isPresent())
                         {
                             elements.putAll(getRelevantNodesWithChildren(baseNode.get(),
                                     append(hiddenExtension, extension.get()), schema));
                         }
                     }
                     elements.put(extension.get(), hiddenExtension);
                     return elements;
                 }
             }
             return Map.of(complexType, hiddenNodes);
         }
         return Map.of(node, hiddenNodes);
     }
 
     /**
      * Returns whether nodes are of the same type. This regards the referring XSD node if it exists, otherwise it regards the
      * regular XSD node.
      * @param node1 node 1.
      * @param node2 node 2.
      * @return whether nodes are of the same type.
      */
     static boolean haveSameType(final XsdTreeNode node1, final XsdTreeNode node2)
     {
         return (node1.referringXsdNode != null && node1.referringXsdNode.equals(node2.referringXsdNode))
                 || (node1.referringXsdNode == null && node1.xsdNode.equals(node2.xsdNode));
     }
 
     /**
      * Returns whether the two values are equal, where {@code null} is considered equal to an empty string.
      * @param value1 value 1.
      * @param value2 value 2.
      * @return whether the two values are equal, where {@code null} is considered equal to an empty string.
      */
     public static boolean valuesAreEqual(final String value1, final String value2)
     {
         boolean value1Empty = value1 == null || value1.isEmpty();
         boolean value2Empty = value2 == null || value2.isEmpty();
         return (value1Empty && value2Empty) || (value1 != null && value1.equals(value2));
     }
 
     /**
      * Returns whether an XSD node defines an editable element, i.e. a simple type.
      * @param xsdNode XSD node
      * @param schema schema
      * @return whether an XSD node defines an editable element
      */
     static boolean isEditable(final Node xsdNode, final Schema schema)
     {
         return getValueDefiningNode(xsdNode, schema) != null;
     }
 
     /**
      * Returns the XSD node that defines the node value. Typically a simpleType or complexType containing a simpleContent.
      * @param xsdNode XSD node that defines the element or attribute type
      * @param schema schema
      * @return XSD node that defines the node value
      */
     static Node getValueDefiningNode(final Node xsdNode, final Schema schema)
     {
         if (xsdNode.equals(XiIncludeNode.XI_INCLUDE))
         {
             return null;
         }
         Node simpleType = xsdNode.getNodeName().equals("xsd:simpleType") ? xsdNode
                 : DocumentReader.getChild(xsdNode, "xsd:simpleType").orElse(null);
         if (simpleType != null)
         {
             return simpleType;
         }
         Node complexType = xsdNode.getNodeName().equals("xsd:complexType") ? xsdNode
                 : DocumentReader.getChild(xsdNode, "xsd:complexType").orElse(null);
         while (complexType != null)
         {
             Optional<Node> simpleContent = DocumentReader.getChild(complexType, "xsd:simpleContent");
             if (simpleContent.isPresent())
             {
                 return complexType;
             }
             Optional<Node> complexContent = DocumentReader.getChild(complexType, "xsd:complexContent");
             complexType = null;
             if (complexContent.isPresent())
             {
                 Node derivation = DocumentReader.getChild(complexContent.get(), "xsd:extension")
                         .orElse(DocumentReader.getChild(complexContent.get(), "xsd:restriction").orElse(null));
                 if (derivation != null)
                 {
                     String base = DocumentReader.getAttribute(derivation, "base").orElse(null);
                     complexType = schema.getType(base).orElse(null);
                 }
             }
         }
         Optional<String> type = DocumentReader.getAttribute(xsdNode, "type");
         if ((xsdNode.getNodeName().equals("xsd:element") || xsdNode.getNodeName().equals("xsd:attribute")) && type.isPresent()
                 && type.get().startsWith("xsd:"))
         {
             // standard simple xsd type, such as xsd:string, xsd:double
             return xsdNode;
         }
         if (type.isPresent())
         {
             Node typeNode = schema.getType(type.get()).orElse(null);
             if (typeNode != null)
             {
                 return getValueDefiningNode(typeNode, schema);
             }
         }
         return null;
     }
 
     /**
      * Class that holds two indices related to loading XML nodes in to a structure of {@code XsdTreeNode}. Both pertain to the
      * index in a list of child nodes.
      */
     static final class LoadingIndices
     {
         /** Index of XML node. */
         private int xmlNode;
 
         /** Index of XsdTreeNode. */
         private int xsdTreeNode;
 
         /**
          * Constructor.
          * @param xmlNode index of XML node
          * @param xsdTreeNode index of XsdTreeNode
          */
         LoadingIndices(final int xmlNode, final int xsdTreeNode)
         {
             this.xmlNode = xmlNode;
             this.xsdTreeNode = xsdTreeNode;
         }
 
         /**
          * Get XML node index.
          * @return XML node index
          */
         public int getXmlNode()
         {
             return this.xmlNode;
         }
 
         /**
          * Set XML node index.
          * @param xmlNode XML node index
          */
         public void setXmlNode(final int xmlNode)
         {
             this.xmlNode = xmlNode;
         }
 
         /**
          * Get XsdTreeNode index.
          * @return XsdTreeNode index
          */
         public int getXsdTreeNode()
         {
             return this.xsdTreeNode;
         }
 
         /**
          * Set XsdTreeNode index.
          * @param xsdTreeNode XsdTreeNode index
          */
         public void setXsdTreeNode(final int xsdTreeNode)
         {
             this.xsdTreeNode = xsdTreeNode;
         }
     }
 
     /**
      * Enum to specify what occurs is requested.
      */
     enum Occurs
     {
         /** Value for minOccurs. */
         MIN("minOccurs"),
 
         /** Value for maxOccurs. */
         MAX("maxOccurs");
 
         /** Node attribute. */
         private final String attribute;
 
         /**
          * Constructor.
          * @param attribute node attribute
          */
         Occurs(final String attribute)
         {
             this.attribute = attribute;
         }
 
         /**
          * Parses the minOcccurs or maxOccurs value from given node. If it is not supplied, the default of 1 is given.
          * @param node node.
          * @return value of occurs, -1 represents "unbounded".
          */
         public int get(final Node node)
         {
             Optional<String> occursValue = DocumentReader.getAttribute(node, this.attribute);
             if (occursValue.isEmpty())
             {
                 return 1;
             }
             if ("unbounded".equals(occursValue.orElse(null)))
             {
                 return -1;
             }
             return Integer.valueOf(occursValue.get());
         }
     }
 
 }