#include <string.h>
/* Add your header comment here */
/* Do not use <sqlite3.h>! */
#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1

#include "zpm.h"
/* Insert your extension code here */

/* TODO: Change the entry point name so that "extension" is replaced by
** text derived from the shared library filename as follows:  Copy every
** ASCII alphabetic character from the filename after the last "/" through
** the next following ".", converting each character to lowercase, and
** discarding the first three characters if they are "lib".
*/

static int vercmp(void *not_used, int lena, const void *a,
		int lenb, const void *b) {
	int rv;
	char *bufa, *bufb;

	if (not_used != 0) fprintf(stderr, "sqlite vercmp not_used = %p\n",
			not_used);
	if (lena == 0 && lenb > 0) return 1;
	if (lenb == 0 && lena > 0) return -1;

	bufa = sqlite3_malloc(lena+1);
	bufb = sqlite3_malloc(lenb+1);

	strncpy(bufa, a, lena);
	strncpy(bufb, b, lenb);
	bufa[lena] = 0;
	bufb[lenb] = 0;

	rv = zpm_vercmp(bufa, bufb);
	sqlite3_free(bufa);
	sqlite3_free(bufb);
	return rv;
}

static void vercmpf(sqlite3_context *ctx, int nargs, sqlite3_value **vals) {
	int rv;
	if (nargs == 0) {
		rv = 0;
	} else if (nargs == 1) {
		rv = -1;
	} else {
		rv = zpm_vercmp(
				(const char *)sqlite3_value_text(vals[0]),
				(const char *)sqlite3_value_text(vals[1])
				);
	}
	sqlite3_result_int(ctx, rv);
}

static int zpm_sqlite_vercmp_init(sqlite3 *db, char **pzErrMsg, 
		const sqlite3_api_routines *pApi
		) {
	int rc = SQLITE_OK;
	SQLITE_EXTENSION_INIT2(pApi);
	rc = sqlite3_create_collation(db, "vercmp", SQLITE_UTF8, NULL, vercmp);
	rc = sqlite3_create_function_v2(db, "vercmp", 2,
		       	SQLITE_UTF8|SQLITE_DETERMINISTIC,
			NULL, vercmpf, NULL, NULL, NULL
			);
	/* Insert here calls to
	 **     sqlite3_create_function_v2(),
	 **     sqlite3_create_collation_v2(),
	 **     sqlite3_create_module_v2(), and/or
	 **     sqlite3_vfs_register()
	 ** to register the new features that your extension adds.
	 */
#if 0
	if (rc == SQLITE_OK) {
		fprintf(stderr, "vercmp collation created\n");
	}
#endif
	return rc;
}

void zpm_setup_extensions(void) {
	sqlite3_auto_extension( (void (*)(void))zpm_sqlite_vercmp_init);
	return;
}