#include "load_features.h"
#include <libxml/parser.h>
#include <stdbool.h>
#include <asn.h>
#include <objgbseq.h>

/*
 * An NCBI GBSeq structure to hold the data for the current record.
 */
GBSeqPtr g;

bool in_element;

static void
lf_startDocument (void *ctx ATTRIBUTE_UNUSED)
{
  printf ("SAX.startDocument()\n");

  return;
}

static void
lf_endDocument (void *ctx ATTRIBUTE_UNUSED)
{
  printf ("SAX.endDocument()\n");

  return;
}

static xmlEntityPtr
lf_getEntity (void *ctx ATTRIBUTE_UNUSED, const xmlChar *name)
{
  printf("SAX.getEntity(%s)\n", name);

  return (NULL);
}

static void
lf_startElement(void *ctx ATTRIBUTE_UNUSED,
		const xmlChar *name, const xmlChar **atts)
{
  int i;

  fprintf(stdout, "SAX.startElement(%s", (char *) name);
  if (atts != NULL) {
    for (i = 0;(atts[i] != NULL);i++) {
      fprintf(stdout, ", %s='", atts[i++]);
      if (atts[i] != NULL)
	fprintf(stdout, "%s'", atts[i]);
    }
  }
  fprintf(stdout, ")\n");

  in_element = true;

  return;
}

static void
lf_endElement(void *ctx ATTRIBUTE_UNUSED, const xmlChar *name)
{
  printf("SAX.endElement(%s)\n", (char *) name);
  in_element = false;

  return;
}

static void
lf_characters(void *ctx ATTRIBUTE_UNUSED, const xmlChar *ch, int len)
{
  if (!in_element)
    return;

  char output[40];
  int i;

  for (i = 0;(i<len) && (i < 30);i++)
    output[i] = ch[i];
  output[i] = 0;

  printf("SAX.characters(%s, %d)\n", output, len);
}

/*
 * 1. Parse and load the XML file into memory.
 * 2. Insert the XML into HDF5.
 * For an example of parsing XML with libxml2 and SAX see:
 * [http://git.gnome.org/browse/libxml2/tree/testSAX.c].
 */
void
load_features (hid_t file_id, const char* file_name)
{
  g = GBSeqNew ();

  LIBXML_TEST_VERSION;

  in_element = false;
  
  static xmlSAXHandler emptySAXHandlerStruct = {
    NULL, /* internalSubset */
    NULL, /* isStandalone */
    NULL, /* hasInternalSubset */
    NULL, /* hasExternalSubset */
    NULL, /* resolveEntity */
    lf_getEntity, /* getEntity */
    NULL, /* entityDecl */
    NULL, /* notationDecl */
    NULL, /* attributeDecl */
    NULL, /* elementDecl */
    NULL, /* unparsedEntityDecl */
    NULL, /* setDocumentLocator */
    lf_startDocument, /* startDocument */
    lf_endDocument, /* endDocument */
    lf_startElement, /* startElement */
    lf_endElement, /* endElement */
    NULL, /* reference */
    lf_characters, /* characters */
    NULL, /* ignorableWhitespace */
    NULL, /* processingInstruction */
    NULL, /* comment */
    NULL, /* xmlParserWarning */
    NULL, /* xmlParserError */
    NULL, /* xmlParserError */
    NULL, /* getParameterEntity */
    NULL, /* cdataBlock; */
    NULL, /* externalSubset; */
    1,
    NULL,
    NULL, /* startElementNs */
    NULL, /* endElementNs */
    NULL  /* xmlStructuredErrorFunc */
  };
 
  static xmlSAXHandlerPtr emptySAXHandler = &emptySAXHandlerStruct;

  FILE *f = fopen (file_name, "r");

  if (f != NULL)
    {
      int ret;
      char chars[10];
      xmlParserCtxtPtr ctxt;
  
      ret = fread (chars, 1, 4, f);
      if (ret > 0)
	{
	  ctxt = xmlCreatePushParserCtxt (emptySAXHandler, NULL, 
					  chars, ret, file_name);
	  while ((ret = fread(chars, 1, 3, f)) > 0)
	    {
	      xmlParseChunk (ctxt, chars, ret, 0);
	    }
	  xmlParseChunk (ctxt, chars, 0, 1);
	  xmlFreeParserCtxt(ctxt);
	}
      fclose (f);
    }
  else
    {
      xmlGenericError (xmlGenericErrorContext,
		       "Cannot read file.");
    }

  GBSeqFree (g);

  return;
}