#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>

#include <libxml/xmlmemory.h>
#include <libxml/parser.h>
#include <libxml/relaxng.h>

static void err_func(FILE *d, const char *msg, ...)
{
    va_list ap;
    va_start(ap, msg);
    fprintf(d, "START OUTPUT FROM err_func\n");
    vfprintf(d, msg, ap);
    fprintf(d, "END OUTPUT FROM error_func\n");
    va_end(ap);
}

static void test(const char *xml, const char *rng_schema, void *error_func)
{
    xmlDoc *doc;
    xmlRelaxNGPtr schema;
    xmlRelaxNGValidCtxtPtr validctxt;
    xmlRelaxNGParserCtxtPtr rngparser;

    doc = xmlParseFile(xml);
    rngparser = xmlRelaxNGNewParserCtxt(rng_schema);

    schema = xmlRelaxNGParse(rngparser);
    validctxt = xmlRelaxNGNewValidCtxt(schema);

    xmlRelaxNGSetValidErrors(validctxt, (xmlRelaxNGValidityErrorFunc) error_func, (xmlRelaxNGValidityWarningFunc) error_func, stderr);

    /* Setting this doesn't appear to do anything.*/
    xmlRelaxNGSetParserErrors(rngparser, (xmlRelaxNGValidityErrorFunc) error_func, (xmlRelaxNGValidityWarningFunc) error_func, stderr);
    xmlRelaxNGSetParserStructuredErrors(rngparser, (xmlStructuredErrorFunc) error_func, stderr);

    /* Setting this gives no error output. The error functions are still called but there is no error
     * message passed to them. */
    /*xmlRelaxNGSetValidStructuredErrors(validctxt, (xmlStructuredErrorFunc) error_func, stderr);*/

    /* Strange things happen when these are set multiple times */
    /*xmlSetGenericErrorFunc(stderr, (xmlGenericErrorFunc) error_func);*/
    /*xmlSetStructuredErrorFunc(stderr, (xmlStructuredErrorFunc) error_func);*/

    xmlRelaxNGValidateDoc(validctxt, doc);

    xmlRelaxNGFree(schema);
    xmlRelaxNGFreeValidCtxt(validctxt);
    xmlRelaxNGFreeParserCtxt(rngparser);
    xmlFreeDoc(doc);
}

int main(int argc, char *argv[])
{
    if (argc < 5) {
        fputs("./a.out #1-5 xml1.xml xml2.xml schema.rng\n", stderr);
        return 1;
    }

    if (*argv[1] == '1' || *argv[1] == '5') {
        puts("Test 1 - fprintf error handler");
        test(argv[2], argv[4], fprintf);
        puts("END Test 1\n");
    }

    if (*argv[1] == '2' || *argv[1] == '5') {
        puts("Test 2 - custom error handler");
        test(argv[2], argv[4], err_func);
        puts("END Test 2\n");
    }

    if (*argv[1] == '3' || *argv[1] == '5') {
        puts("Test 3 - fprintf structural error");
        test(argv[3], argv[4], fprintf);
        puts("END Test 3\n");
    }

    if (*argv[1] == '4' || *argv[1] == '5') {
        puts("Test 4 - custom error handler structural error");
        test(argv[3], argv[4], err_func);
        puts("END Test 4\n");
    }

    return 0;
}