/* See LICENSE file for copyright and license details. */
#include <errno.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "util.h"

char *argv0;

static void
verr(const char *fmt, va_list ap)
{
	if (argv0 && strncmp(fmt, "usage", strlen("usage"))) {
		fprintf(stderr, "%s: ", argv0);
	}

	vfprintf(stderr, fmt, ap);

	if (fmt[0] && fmt[strlen(fmt) - 1] == ':') {
		fputc(' ', stderr);
		perror(NULL);
	} else {
		fputc('\n', stderr);
	}
}

void
warn(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	verr(fmt, ap);
	va_end(ap);
}

void
die(const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	verr(fmt, ap);
	va_end(ap);

	exit(1);
}

#define	INVALID  1
#define	TOOSMALL 2
#define	TOOLARGE 3

long long
strtonum(const char *numstr, long long minval, long long maxval,
         const char **errstrp)
{
	long long ll = 0;
	int error = 0;
	char *ep;
	struct errval {
		const char *errstr;
		int err;
	} ev[4] = {
		{ NULL,		0 },
		{ "invalid",	EINVAL },
		{ "too small",	ERANGE },
		{ "too large",	ERANGE },
	};

	ev[0].err = errno;
	errno = 0;
	if (minval > maxval) {
		error = INVALID;
	} else {
		ll = strtoll(numstr, &ep, 10);
		if (numstr == ep || *ep != '\0')
			error = INVALID;
		else if ((ll == LLONG_MIN && errno == ERANGE) || ll < minval)
			error = TOOSMALL;
		else if ((ll == LLONG_MAX && errno == ERANGE) || ll > maxval)
			error = TOOLARGE;
	}
	if (errstrp != NULL)
		*errstrp = ev[error].errstr;
	errno = ev[error].err;
	if (error)
		ll = 0;

	return ll;
}

char *
timestamp(time_t t, char buf[TIMESTAMP_LEN])
{
	strftime(buf, TIMESTAMP_LEN, "%a, %d %b %Y %T GMT", gmtime(&t));

	return buf;
}