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

#ifdef __OpenBSD__
#include <unistd.h>
#endif /* __OpenBSD__ */

#include "util.h"

char *argv0;

static void
verr(const char *fmt, va_list ap)
{
	if (argv0 && strncmp(fmt, "usage", sizeof("usage") - 1)) {
		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);
}

void
epledge(const char *promises, const char *execpromises)
{
	(void)promises;
	(void)execpromises;

#ifdef __OpenBSD__
	if (pledge(promises, execpromises) == -1) {
		die("pledge:");
	}
#endif /* __OpenBSD__ */
}

void
eunveil(const char *path, const char *permissions)
{
	(void)path;
	(void)permissions;

#ifdef __OpenBSD__
	if (unveil(path, permissions) == -1) {
		die("unveil:");
	}
#endif /* __OpenBSD__ */
}

int
timestamp(char *buf, size_t len, time_t t)
{
	struct tm tm;

	if (gmtime_r(&t, &tm) == NULL ||
	    strftime(buf, len, "%a, %d %b %Y %T GMT", &tm) == 0) {
		return 1;
	}

	return 0;
}

int
esnprintf(char *str, size_t size, const char *fmt, ...)
{
	va_list ap;
	int ret;

	va_start(ap, fmt);
	ret = vsnprintf(str, size, fmt, ap);
	va_end(ap);

	return (ret < 0 || (size_t)ret >= size);
}

int
prepend(char *str, size_t size, const char *prefix)
{
	size_t len = strlen(str), prefixlen = strlen(prefix);

	if (len + prefixlen + 1 > size) {
		return 1;
	}

	memmove(str + prefixlen, str, len + 1);
	memcpy(str, prefix, prefixlen);

	return 0;
}

void
html_escape(const char *src, char *dst, size_t dst_siz)
{
	const struct {
		char c;
		char *s;
	} escape[] = {
		{ '&',  "&amp;"  },
		{ '<',  "&lt;"   },
		{ '>',  "&gt;"   },
		{ '"',  "&quot;" },
		{ '\'', "&#x27;" },
	};
	size_t i, j, k, esclen;

	for (i = 0, j = 0; src[i] != '\0'; i++) {
		for (k = 0; k < LEN(escape); k++) {
			if (src[i] == escape[k].c) {
				break;
			}
		}
		if (k == LEN(escape)) {
			/* no escape char at src[i] */
			if (j == dst_siz - 1) {
				/* silent truncation */
				break;
			} else {
				dst[j++] = src[i];
			}
		} else {
			/* escape char at src[i] */
			esclen = strlen(escape[k].s);

			if (j >= dst_siz - esclen) {
				/* silent truncation */
				break;
			} else {
				memcpy(&dst[j], escape[k].s, esclen);
				j += esclen;
			}
		}
	}
	dst[j] = '\0';
}

char*
replace(const char *src, const char *old, const char* new) {
  int old_len = strlen(old);
  int new_len = strlen(new);
  int src_len = strlen(src);

  /* Count needed replacements */
  const char* tmp = src;
  int replc=0;
  while ((tmp=strstr(tmp, old))) {
    replc++;
    tmp += old_len;
  }

  /* Allocate enough space for the new string */
  char *buf = malloc( (sizeof(char)*src_len) + (sizeof(char)*replc*(new_len-old_len)) + 1);

  /* Now start replacing */
  const char *srcidx = src;
  const char *srcidx_old = src;
  char *bufidx = buf;

  while (replc--) {
    srcidx_old = strstr(srcidx, old);

    bufidx = strncpy(bufidx, srcidx, srcidx_old - srcidx) + (srcidx_old-srcidx);
    bufidx = strcpy(bufidx, new) + new_len;

    srcidx = srcidx_old+old_len;
  }

  strncpy(bufidx, srcidx, strlen(srcidx)); // copy tail

  return buf;
}

#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;
}

/*
 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
 */
#define MUL_NO_OVERFLOW	((size_t)1 << (sizeof(size_t) * 4))

void *
reallocarray(void *optr, size_t nmemb, size_t size)
{
	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
	    nmemb > 0 && SIZE_MAX / nmemb < size) {
		errno = ENOMEM;
		return NULL;
	}
	return realloc(optr, size * nmemb);
}