/*
 * 2ooM: The Master of Orion II Reverse Engineering Project
 * Helper functions for liblbx command-line applications.
 * Copyright © 2013 Nick Bowler
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdarg.h>
#include <limits.h>
#include <inttypes.h>
#include <assert.h>

#include "tools.h"

static const char *progname, *argv0;

void tool_init(const char *name, int argc, char **argv)
{
	progname = name;
	argv0 = argv[0] ? argv[0] : progname;
}

void tool_version(void)
{
	assert(argv0 != NULL);
	printf("%s (%s) %s\n", progname, PACKAGE_NAME, PACKAGE_VERSION);
	printf("Copyright (C) 2013 Nick Bowler.\n");
	puts("License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.");
	puts("This is free software: you are free to change and redistribute it.");
	puts("There is NO WARRANTY, to the extent permitted by law.");
}

const char *tool_invocation(void)
{
	assert(argv0 != NULL);
	return argv0;
}

/* Saturating addition. */
static size_t add_size(size_t a, size_t b)
{
	if (a >= (size_t)-1 - b)
		return (size_t)-1;
	return a + b;
}

static int vfmsg_internal(FILE *f, int err, const char *fmt, va_list ap)
{
	size_t invokelen, fmtlen, errlen, totlen;
	char *newfmt, *errmsg;
	int rc;

	invokelen = strlen(tool_invocation());
	fmtlen = fmt ? strlen(fmt) : 0;
	errlen = err > 0 ? strlen(errmsg = strerror(err)) : 0;

	totlen = add_size(invokelen, sizeof "\n");
	if (fmtlen > 0) {
		totlen = add_size(totlen, strlen(": "));
		totlen = add_size(totlen, fmtlen);
	}
	if (errlen > 0) {
		totlen = add_size(totlen, strlen(": "));
		totlen = add_size(totlen, errlen);
	}

	if (totlen == (size_t)-1 || totlen > INT_MAX)
		return -1;

	newfmt = malloc(totlen);
	if (!newfmt)
		return -1;

	if (errlen && fmtlen)
		rc = sprintf(newfmt, "%s: %s: %s\n", argv0, fmt, errmsg);
	else if (errlen)
		rc = sprintf(newfmt, "%s: %s\n", argv0, errmsg);
	else if (fmtlen)
		rc = sprintf(newfmt, "%s: %s\n", argv0, fmt);
	else
		rc = sprintf(newfmt, "%s\n", argv0);

	assert(rc < totlen);
	if (rc < 0)
		goto out;

	rc = vfprintf(f, newfmt, ap);
out:
	free(newfmt);
	return rc;
}

int tool_vmsg(const char *fmt, va_list ap)
{
	return vfmsg_internal(stdout, -1, fmt, ap);
}

int tool_verr(int err, const char *fmt, va_list ap)
{
	return vfmsg_internal(stderr, err == 0 ? errno : err, fmt, ap);
}

int tool_msg(const char *fmt, ...)
{
	va_list ap;
	int rc;

	va_start(ap, fmt);
	rc = tool_vmsg(fmt, ap);
	va_end(ap);

	return rc;
}

int tool_err(int err, const char *fmt, ...)
{
	va_list ap;
	int rc;

	va_start(ap, fmt);
	rc = tool_verr(err, fmt, ap);
	va_end(ap);

	return rc;
}