/* [ 10 Feb 1999 ] */
/* rdxml.c,v 1.6 1999/07/31 01:47:03 joe Exp */

/* 
 * KNOWN PROBLEMS:
 * 	Doesn't interpret system IDs.
 *	When it does, they will be file names, not URIs.
 *	Check NAMECASE problems.
 *	Add PI, NDATA, etc. handlers.
 *	Add PELs (maybe), REs (maybe).
 *
 * ALSO NEED:
 *	ParseXMLProc(), parse XML as a string.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "tcl.h"

#include "project.h"
#include "esis.h"
#include "pile.h"
#include "strmap.h"
#include "strmgt.h"
#include "esisp.h"
#include "tclcost.h"

#include "expat/xmlparse.h"

#define BUFFER_SIZE 4096

/* %%% TODO: insert PELs as needed
*/

static void StartElementHandler(
    void *userData,
    const XML_Char *name,
    const XML_Char **atts )
{
    ESISBuilder ep = (ESISBuilder)userData;
    ESISNode el = esis_open_node(ep,EN_EL);

    el->name = intern(name);
    while (atts && *atts)
    {
	ESISToken attname = intern(atts[0]);
	char *attval = pstrdup(ep->datapile, atts[1]);
        esis_create_attribute(el,attname,attval);
	atts += 2;
    }
}

static void EndElementHandler(void *userData, const XML_Char *name)
{
    ESISBuilder ep = (ESISBuilder)userData;
    /* ensure not PEL */
    esis_close_node(ep);
}

/*
 * EXPAT 1.3 passes record-ends as separate CharacterData events.
 * This is not documented, but we rely on it anyway %%%
 */
static void CharacterDataHandler(
    void *userData,
    const XML_Char *s,
    int len)
{
    ESISBuilder ep = (ESISBuilder)userData;
    char *data = palloc(ep->datapile, len + 1);
    strncpy(data, s, len);
    data[len] = '\0';
    esis_create_datanode(ep, strcmp(data, "\n") ? EN_CDATA : EN_RE, data);
}


static void ProcessingInstructionHandler(
    void *userData,
    const XML_Char *pitarget,
    const XML_Char *pivalue)
{
    ESISBuilder ep = (ESISBuilder)userData;
    int len = (pitarget ? strlen(pitarget) : 0) 
	    + (pivalue && *pivalue ?  1+strlen(pivalue) : 0);
    char *content = palloc(ep->datapile, len + 1);
    if (pitarget) strcpy(content, pitarget);
    if (pivalue && *pivalue) {
	strcat(content, " ");
	strcat(content, pivalue);
    }
    esis_create_datanode(ep, EN_PI, content);
}

/* %%% TO DO: Implement this.
 */
int ExternalEntityRefHandler(
    XML_Parser parser,
    const XML_Char *openEntityNames,
    const XML_Char *base,
    const XML_Char *systemId,
    const XML_Char *publicId)
{
    /* %%% Report error back to caller : incl. sysid, pubid. */
    return 0;
}

/* 
 * Top-level command procedure:
 * %%% Need: -baseURI argument.
 * %%% Need: -resolverProc argument (for processing external entity refs.)
 */
CMDPROC(CostLoadXMLProc)
{
    CostData *cd = (CostData *)clientData;
    char *handleName;
    XML_Parser parser;
    int mode;
    Tcl_Channel channel;
    ESISBuilder ep;
    int done;

    CHECKNARGS(1, "handle")
    handleName = argv[1];

    /*
     * Get the input channel:
     */
    channel = Tcl_GetChannel(interp, handleName, &mode);
    if (!channel) {
	Tcl_AppendResult(interp,"Invalid channel name ",handleName,NULL); 
	return TCL_ERROR;
    }
    if ((mode & TCL_WRITABLE) || !(mode & TCL_READABLE)) {
	Tcl_AppendResult(interp, handleName, " wrong mode", NULL);
	return TCL_ERROR;
    }

    /*
     * Create XML parser:
     */
    ep = esis_builder_start();
    parser = XML_ParserCreate(NULL);

    XML_SetUserData(parser, ep);
    XML_SetElementHandler(parser, StartElementHandler, EndElementHandler);
    XML_SetCharacterDataHandler(parser, CharacterDataHandler);
    XML_SetExternalEntityRefHandler(parser,ExternalEntityRefHandler);
    XML_SetProcessingInstructionHandler(parser, ProcessingInstructionHandler);

    /*
     * Parse away.
     */
    do 
    {
	static char buf[BUFFER_SIZE];
        int len = Tcl_Read(channel, buf, BUFFER_SIZE);
        done = len < BUFFER_SIZE;

        if (!XML_Parse(parser, buf, len, done))
	{
	    const char *errmsg = XML_ErrorString(XML_GetErrorCode(parser));
	    int lineno = XML_GetCurrentLineNumber(parser);

	    sprintf(buf, " %s line %d", handleName, lineno);
	    Tcl_AppendResult(interp,
		argv[0], ": ", errmsg, ", ", buf, NULL);

	    XML_ParserFree(parser);
	    esis_free_document(esis_builder_finish(ep));
	    return TCL_ERROR;
	}
    } while (!done);
    XML_ParserFree(parser);

    cd->current_document = esis_builder_finish(ep);
    cd->current_node = esis_rootnode(cd->current_document);

    CostRegisterDocument(interp, cd, cd->current_document);

    return TCL_OK;
}

/*EOF*/