/*
 * underlying for child_set and child_add, difference being
 * former raises on implicit copy, latter does not.
 */
static VALUE rxml_node_child_set_aux(VALUE self, VALUE rnode)
{
  xmlNodePtr pnode, chld, ret;

  if (rb_obj_is_kind_of(rnode, cXMLNode) == Qfalse)
    rb_raise(rb_eTypeError, "Must pass an XML::Node object");

  Data_Get_Struct(self, xmlNode, pnode);
  Data_Get_Struct(rnode, xmlNode, chld);

  if (chld->parent != NULL || chld->doc != NULL)
    rb_raise(
        rb_eRuntimeError,
        "Cannot move a node from one document to another with child= or <<.  First copy the node before moving it.");

  ret = xmlAddChild(pnode, chld);
  if (ret == NULL)
  {
    rxml_raise(&xmlLastError);
  }
  else if (ret == chld)
  {
    /* child was added whole to parent and we need to return it as a new object */
    return rxml_node_wrap(cXMLNode, chld);
  }
  /* else */
  /* If it was a text node, then ret should be parent->last, so we will just return ret. */
  return rxml_node_wrap(cXMLNode, ret);
}

/*
 * call-seq:
 *    node.prev -> XML::Node
 *
 * Obtain the previous sibling, if any.
 */
static VALUE rxml_node_prev_get(VALUE self)
{
  xmlNodePtr xnode;
  xmlNodePtr node;
  xnode = rxml_get_xnode(self);

  switch (xnode->type)
  {
  case XML_DOCUMENT_NODE:
#ifdef LIBXML_DOCB_ENABLED
    case XML_DOCB_DOCUMENT_NODE:
#endif
  case XML_HTML_DOCUMENT_NODE:
  case XML_NAMESPACE_DECL:
    node = NULL;
    break;
  case XML_ATTRIBUTE_NODE:
  {
    xmlAttrPtr attr = (xmlAttrPtr) xnode;
    node = (xmlNodePtr) attr->prev;
  }
    break;
  default:
    node = xnode->prev;
    break;
  }

  if (node == NULL)
    return (Qnil);
  else
    return (rxml_node_wrap(node));
}

/*
 * call-seq:
 *    XML::Node.new_pi(name, content = nil) -> XML::Node
 *
 * Create a new pi node, optionally setting
 * the node's content.
 *
 */
static VALUE rxml_node_new_pi(int argc, VALUE *argv, VALUE klass)
{
  VALUE name = Qnil;
  VALUE content = Qnil;
  xmlNodePtr xnode;

  rb_scan_args(argc, argv, "11", &name, &content);

  if (NIL_P(name))
  {
    rb_raise(rb_eRuntimeError, "You must provide me with a name for a PI.");
  }
  name = rb_obj_as_string(name);
  if (NIL_P(content))
  {
    xnode = xmlNewPI((xmlChar*) StringValuePtr(name), NULL);
  }
  else
  {
    content = rb_obj_as_string(content);
    xnode = xmlNewPI((xmlChar*) StringValuePtr(name), (xmlChar*) StringValueCStr(content));
  }

  if (xnode == NULL)
    rxml_raise(&xmlLastError);

  return rxml_node_wrap(xnode);
}

/*
 * call-seq:
 *    reader.expand -> node
 *
 * Returns the current node and its full subtree. Note the returned node
 * is valid ONLY until the next read call.  
 */
static VALUE rxml_reader_expand(VALUE self)
{
  xmlTextReaderPtr xreader = rxml_text_reader_get(self);
  xmlNodePtr xnode = NULL;

  /* At this point we need to wrap the reader's document as explained above. */
  xmlDocPtr xdoc = xmlTextReaderCurrentDoc(xreader);

  if (!xdoc)
    rb_raise(rb_eRuntimeError, "The reader does not have a document.  Did you forget to call read?");

  rxml_document_wrap(xdoc);

  /* And now hook in a mark function */
  RDATA(self)->dmark = (RUBY_DATA_FUNC)rxml_reader_mark;

  xnode = xmlTextReaderExpand(xreader);
  
  if (!xnode)
  {
    return Qnil;
  }
  else
  {
    return rxml_node_wrap(xnode);
  }
}

/*
 * call-seq:
 *    attr.parent -> node
 *
 * Obtain this attribute node's parent.
 */
static VALUE rxml_attr_parent_get(VALUE self)
{
  xmlAttrPtr xattr;
  Data_Get_Struct(self, xmlAttr, xattr);
  if (xattr->parent == NULL)
    return Qnil;
  else
    return rxml_node_wrap(xattr->parent);
}

/*
 * call-seq:
 *    attr.child -> node
 *
 * Obtain this attribute's child attribute(s).
 */
static VALUE rxml_attr_child_get(VALUE self)
{
  xmlAttrPtr xattr;
  Data_Get_Struct(self, xmlAttr, xattr);
  if (xattr->children == NULL)
    return Qnil;
  else
    return rxml_node_wrap((xmlNodePtr) xattr->children);
}

/*
 * call-seq:
 *    document.child -> node
 *
 * Get this document's child node.
 */
static VALUE rxml_document_child_get(VALUE self)
{
  xmlDocPtr xdoc;
  Data_Get_Struct(self, xmlDoc, xdoc);

  if (xdoc->children == NULL)
    return (Qnil);

  return rxml_node_wrap(xdoc->children);
}

/*
 * call-seq:
 *    context.node -> node
 *
 * Obtain the root node of this context.
 */
static VALUE rxml_parser_context_node_get(VALUE self)
{
  xmlParserCtxtPtr ctxt;
  Data_Get_Struct(self, xmlParserCtxt, ctxt);

  if (ctxt->node == NULL)
    return (Qnil);
  else
    return (rxml_node_wrap(ctxt->node));
}

/*
 * call-seq:
 *    node.first -> XML::Node
 *
 * Returns this node's first child node if any.
 */
static VALUE rxml_node_first_get(VALUE self)
{
  xmlNodePtr xnode;

  xnode = rxml_get_xnode(self);

  if (xnode->children)
    return (rxml_node_wrap(xnode->children));
  else
    return (Qnil);
}

/*
 * call-seq:
 *    node.parent -> XML::Node
 *
 * Obtain this node's parent node, if any.
 */
static VALUE rxml_node_parent_get(VALUE self)
{
  xmlNodePtr xnode;

  xnode = rxml_get_xnode(self);

  if (xnode->parent)
    return (rxml_node_wrap(xnode->parent));
  else
    return (Qnil);
}

/*
 * call-seq:
 *    node.parent -> XML::Node
 *
 * Obtain this node's parent node, if any.
 */
static VALUE rxml_node_parent_get(VALUE self)
{
  xmlNodePtr xnode;

  Data_Get_Struct(self, xmlNode, xnode);

  if (xnode->parent)
    return (rxml_node_wrap(xnode->parent));
  else
    return (Qnil);
}

/*
 * call-seq:
 *    node.first -> XML::Node
 *
 * Returns this node's first child node if any.
 */
static VALUE rxml_node_first_get(VALUE self)
{
  xmlNodePtr xnode;

  Data_Get_Struct(self, xmlNode, xnode);

  if (xnode->children)
    return (rxml_node_wrap(xnode->children));
  else
    return (Qnil);
}

static VALUE rxml_schema_type_node(VALUE self)
{
    xmlSchemaTypePtr xtype;

    Data_Get_Struct(self, xmlSchemaType, xtype);

    if(xtype->node != NULL)
        return rxml_node_wrap(xtype->node);
    else
        return Qnil;
}

/*
 * call-seq:
 *    XML::Node.new_text(content) -> XML::Node
 *
 * Create a new text node.
 *
 */
static VALUE rxml_node_new_text(VALUE klass, VALUE content)
{
  xmlNodePtr xnode;
  Check_Type(content, T_STRING);
  content = rb_obj_as_string(content);

  xnode = xmlNewText((xmlChar*) StringValueCStr(content));

  if (xnode == NULL)
    rxml_raise(&xmlLastError);

  return rxml_node_wrap(xnode);
}

/*
 * call-seq:
 *    document.root -> node
 *
 * Obtain the root node.
 */
static VALUE rxml_document_root_get(VALUE self)
{
  xmlDocPtr xdoc;

  xmlNodePtr root;

  Data_Get_Struct(self, xmlDoc, xdoc);
  root = xmlDocGetRootElement(xdoc);

  if (root == NULL)
    return (Qnil);

  return rxml_node_wrap(root);
}

/*
 * call-seq:
 *    reader.expand -> node
 *
 * Returns the current node and its full subtree. Note the returned node
 * is valid ONLY until the next read call.  
 */
static VALUE rxml_reader_expand(VALUE self)
{
  xmlTextReaderPtr xreader = rxml_text_reader_get(self);
  xmlNodePtr xnode = xmlTextReaderExpand(xreader);
  
  if (!xnode)
  {
    return Qnil;
  }
  else
  {
    return rxml_node_wrap(xnode);
  }
}

/*
 * call-seq:
 *    document.import(node) -> XML::Node
 *
 * Creates a copy of the node that can be inserted into the
 * current document.
 */
static VALUE rxml_document_import(VALUE self, VALUE node)
{
  xmlDocPtr xdoc;
  xmlNodePtr xnode, xresult;

  Data_Get_Struct(self, xmlDoc, xdoc);
  Data_Get_Struct(node, xmlNode, xnode);

  xresult = xmlDocCopyNode(xnode, xdoc, 1);

  if (xresult == NULL)
    rxml_raise(&xmlLastError);

  return rxml_node_wrap(xresult);
}

/*
 * call-seq:
 *    node.each -> XML::Node
 *
 * Iterates over this node's children, including text
 * nodes, element nodes, etc.  If you wish to iterate
 * only over child elements, use XML::Node#each_element.
 *
 *  doc = XML::Document.new('model/books.xml')
 *  doc.root.each {|node| puts node}
 */
static VALUE rxml_node_each(VALUE self)
{
  xmlNodePtr xnode;
  xmlNodePtr xchild;
  Data_Get_Struct(self, xmlNode, xnode);

  xchild = xnode->children;

  while (xchild)
  {
    rb_yield(rxml_node_wrap(cXMLNode, xchild));
    xchild = xchild->next;
  }
  return Qnil;
}

/*
 * call-seq:
 *    node.next = node
 *
 * Insert the specified node as this node's next sibling.
 */
static VALUE rxml_node_next_set(VALUE self, VALUE rnode)
{
  xmlNodePtr cnode, pnode, ret;

  if (rb_obj_is_kind_of(rnode, cXMLNode) == Qfalse)
    rb_raise(rb_eTypeError, "Must pass an XML::Node object");

  Data_Get_Struct(self, xmlNode, pnode);
  Data_Get_Struct(rnode, xmlNode, cnode);

  ret = xmlAddNextSibling(pnode, cnode);
  if (ret == NULL)
    rxml_raise(&xmlLastError);

  return (rxml_node_wrap(cXMLNode, ret));
}

/*
 * call-seq:
 *    document.root = node
 *
 * Set the root node.
 */
static VALUE rxml_document_root_set(VALUE self, VALUE node)
{
  xmlDocPtr xdoc;
  xmlNodePtr xroot, xnode;

  if (rb_obj_is_kind_of(node, cXMLNode) == Qfalse)
    rb_raise(rb_eTypeError, "must pass an XML::Node type object");

  Data_Get_Struct(self, xmlDoc, xdoc);
  Data_Get_Struct(node, xmlNode, xnode);

  xroot = xmlDocSetRootElement(xdoc, xnode);
  if (xroot == NULL)
    return (Qnil);

  return rxml_node_wrap(xroot);
}