/*
 File that provides the entry point for an event driven XML parser
 that performs callbacks to the different user-level functions in
 the closure passed to it.

 * See Copyright for the license status of this software.

 */

#include "EventParse.h"
#include "Utils.h" /* For the findFunction and invokeFunction. */

#include "RSCommon.h"

/*
  Read the specified file as an XML document and invoke functions/methods in
  the handlers closure object when each node in the tree is encountered by 
  the parser. These events are startElement,endElement, character data, etc.
  The remaining arguments control how the calls to the user level functions
  are made. The first (addContext) indicates whether information about the position
  in the tree (an integer index path)

 */

extern void RS_XML(libXMLEventParse)(const char *fileName, RS_XMLParserData *parserData, int asText);

USER_OBJECT_ 
RS_XML(Parse)(USER_OBJECT_ fileName, USER_OBJECT_ handlers, USER_OBJECT_ addContext, 
               USER_OBJECT_ ignoreBlanks,  USER_OBJECT_ useTagName, USER_OBJECT_ asText,
                 USER_OBJECT_ trim, USER_OBJECT_ useExpat)
{
#ifdef LIBEXPAT
  FILE *file = NULL;
  int expat = 0;
#endif
  char *name;
  int asTextBuffer;
  RS_XMLParserData *parserData;

  asTextBuffer = LOGICAL_DATA(asText)[0];

#ifdef LIBEXPAT
   expat = LOGICAL_DATA(useExpat)[0];
  if(expat && asTextBuffer == 0) {
#ifdef USE_R
    name = R_ExpandFileName(CHAR(STRING(fileName)[0]));
#else
    name = CHARACTER_DATA(fileName)[0];
#endif
    file = fopen(name,"r");
    if(file == NULL) {
      PROBLEM "Can't find file %s", name
      ERROR;
    }

  } else
#endif /* ifdef LIBEXPAT */
  name = strdup(CHAR_DEREF(STRING_ELT(fileName, 0)));

  parserData = RS_XML(createParserData)(handlers);
  parserData->fileName         = name; 
  parserData->callByTagName    = LOGICAL_DATA(useTagName)[0]; 
  parserData->addContextInfo   = LOGICAL_DATA(addContext)[0]; 
  parserData->trim             = LOGICAL_DATA(trim)[0]; 
  parserData->ignoreBlankLines = LOGICAL_DATA(ignoreBlanks)[0]; 

#ifdef LIBEXPAT
  if(expat) {
      if(asTextBuffer == 0) {
     	RS_XML(parseWithParserData)(file, parserData);
      } else {
     	parserData->fileName = "<buffer>"; 
     	RS_XML(parseBufferWithParserData)(name, parserData);
     	free(name); /* match the strdup() above */
      }
  } else 
#endif /* ifdef LIBEXPAT */
   RS_XML(libXMLEventParse)(name, parserData, asTextBuffer);

  free(parserData);

  return(handlers);
}



/**
Handler that receives declarations of unparsed entities. These are entity declarations that have a notation (NDATA) field: 

                  <!ENTITY logo SYSTEM "images/logo.gif" NDATA gif>
*/
void 
RS_XML(entityDeclarationHandler)(void *userData, const XML_Char *entityName, 
                                 const XML_Char *base, const XML_Char *systemId, 
                                   const XML_Char *publicId, const XML_Char *notationName)
{
 RS_XMLParserData *parserData = (RS_XMLParserData*)userData;
 USER_OBJECT_ opArgs;
 int i, num;
  const XML_Char *xml_args[5];

   num = sizeof(xml_args)/sizeof(xml_args[0]);

   xml_args[0] = entityName; xml_args[1] = base;
   xml_args[2] = systemId; xml_args[3] = publicId;
   xml_args[4] = notationName;

  opArgs = NEW_LIST(num);
  for(i =0;i < num; i++) {
   SET_VECTOR_ELT(opArgs, i,  NEW_CHARACTER(1));
   SET_STRING_ELT(VECTOR_ELT(opArgs, i), 0, COPY_TO_USER_STRING(xml_args[i] ? xml_args[i] : "")); 
  }

 RS_XML(callUserFunction)("entityDeclaration", (const char*)NULL, parserData, opArgs);
}


void 
RS_XML(startElement)(void *userData, const char *name, const char **atts)
{
  USER_OBJECT_ opArgs;

  PROTECT(opArgs = NEW_LIST(2));
  SET_VECTOR_ELT(opArgs, 0, NEW_CHARACTER(1));
  SET_STRING_ELT(VECTOR_ELT(opArgs, 0), 0, COPY_TO_USER_STRING(name)); 

  /* Now convert the attributes list. */
   SET_VECTOR_ELT(opArgs, 1, RS_XML(createAttributesList)(atts));
   RS_XML(callUserFunction)("startElement", name, ((RS_XMLParserData*) userData), opArgs);
   UNPROTECT(1);
}

void 
RS_XML(commentHandler)(void *userData, const XML_Char *data)
{
  USER_OBJECT_ opArgs = NEW_LIST(2);
  PROTECT(opArgs);
  SET_VECTOR_ELT(opArgs, 0, NEW_CHARACTER(1));
     SET_STRING_ELT(VECTOR_ELT(opArgs, 0), 0, COPY_TO_USER_STRING(data));
  RS_XML(callUserFunction)("comment", (const char *)NULL, ((RS_XMLParserData*)userData), opArgs);
  UNPROTECT(1);
}


USER_OBJECT_ 
RS_XML(createAttributesList)(const char **atts) {
  int n=0, i;
  const char **ptr = atts;
  USER_OBJECT_ attr_names;
  USER_OBJECT_ attr_values;
  while(ptr && ptr[0]) {
    n++;
    ptr += 2;
  }
 
  if(n < 1)
    return(NULL_USER_OBJECT);

  PROTECT(attr_values = NEW_CHARACTER(n));
  PROTECT(attr_names = NEW_CHARACTER(n));
     ptr = atts;
     for(i=0; i < n; i++, ptr+=2) {
      SET_STRING_ELT(attr_values, i, COPY_TO_USER_STRING(ptr[1]));
      SET_STRING_ELT(attr_names, i,  COPY_TO_USER_STRING(ptr[0]));
     }
    SET_NAMES(attr_values, attr_names);
  UNPROTECT(2);

  return(attr_values);
}

void RS_XML(endElement)(void *userData, const char *name)
{
 USER_OBJECT_ opArgs;
 ((RS_XMLParserData*)userData)->depth++;

  PROTECT(opArgs = NEW_LIST(1));
  SET_VECTOR_ELT(opArgs, 0, NEW_CHARACTER(1));
     SET_STRING_ELT(VECTOR_ELT(opArgs, 0), 0, COPY_TO_USER_STRING(name));

   RS_XML(callUserFunction)("endElement", NULL, ((RS_XMLParserData*) userData), opArgs);
   UNPROTECT(1);
}

/**
 Called for inline expressions of the form
  <?target data-text>
 such as 
  <?R plot(1:10)>
*/
void 
RS_XML(processingInstructionHandler)(void *userData, const XML_Char *target, const XML_Char *data) 
{
 USER_OBJECT_ opArgs;

 PROTECT(opArgs = NEW_LIST(2));
 SET_VECTOR_ELT(opArgs, 0, NEW_CHARACTER(1));
   SET_STRING_ELT(VECTOR_ELT(opArgs, 0), 0, COPY_TO_USER_STRING(target));
 SET_VECTOR_ELT(opArgs, 1, NEW_CHARACTER(1));
   SET_STRING_ELT(VECTOR_ELT(opArgs, 1), 0, COPY_TO_USER_STRING(data));
  RS_XML(callUserFunction)("processingInstruction", (const char *)NULL, (RS_XMLParserData*)userData, opArgs);
  UNPROTECT(1);
}

void 
RS_XML(endCdataSectionHandler)(void *userData) 
{
}

void 
RS_XML(startCdataSectionHandler)(void *userData) 
{
}


void 
RS_XML(textHandler)(void *userData,  const XML_Char *s, int len)
{
 char *tmpString, *tmp;
 USER_OBJECT_ opArgs = NULL;
 RS_XMLParserData *parserData = (RS_XMLParserData*)userData; 

  if(s == (XML_Char*)NULL || s[0] == (XML_Char)NULL || len == 0 || (len == 1 && s[0] == '\n'))
    return;

           /* 1 more than length so we can put a \0 on the end. */
    tmp = tmpString = (char*)calloc(len+1, sizeof(char));
    strncpy(tmpString, s, len);
 
    if(parserData->trim) {
      tmpString = trim(tmpString);
      len = strlen(tmpString);
    }

  if(len > 0 || parserData->ignoreBlankLines == 0 ) {
    PROTECT(opArgs = NEW_LIST(1));
     SET_VECTOR_ELT(opArgs, 0, NEW_CHARACTER(1));
     SET_STRING_ELT(VECTOR_ELT(opArgs, 0), 0, COPY_TO_USER_STRING(tmpString));
  }

  free(tmp);

    /* If we are ignoring blanks and the potentiall newly computed length is non-zero, then
       call the user function.
     */

  if(opArgs != NULL) {
     RS_XML(callUserFunction)("text", (const char *)NULL, ((RS_XMLParserData*) userData), opArgs);
     UNPROTECT(1);
  }
}


int
RS_XML(notStandAloneHandler)(void *userData)
{
  /*  printf("In NotStandalone handler\n"); */
 return(1);
}


/**
  Create the parser data which contains the 
  the collection of functions to call for each 
  event type.

  This allocates the parser memory using calloc.
  The caller should arrange to free it.
*/
RS_XMLParserData *
RS_XML(createParserData)(USER_OBJECT_ handlers) 
{
 RS_XMLParserData *parser = calloc(1, sizeof(RS_XMLParserData));

 parser->methods = handlers;

return(parser);
}

/**
  Routine that locates and invokes the R function in the collection of handlers.
*/
USER_OBJECT_
RS_XML(callUserFunction)(char *opName, const char *preferredName, RS_XMLParserData *parserData, USER_OBJECT_ opArgs) 
{
  USER_OBJECT_ fun = NULL;
  USER_OBJECT_ _userObject = parserData->methods;

  if(preferredName && parserData->callByTagName) {
    fun = RS_XML(findFunction)(preferredName, _userObject);
  }

  if(fun == NULL) 
    fun = RS_XML(findFunction)(opName, _userObject);

  if(fun == NULL || isFunction(fun) == 0) {
      /* FAILED */
   return(NULL_USER_OBJECT);
  }

  return(RS_XML(invokeFunction)(fun, opArgs));
}