#include "git-compat-util.h"
#include <utime.h>

static const char usage_str[] = "(+|=|=+|=-|-)<seconds> <file>...";

#ifdef __MINGW32__
static inline void time_t_to_filetime(time_t t, FILETIME *ft)
{
	long long winTime = t * 10000000LL + 116444736000000000LL;
	ft->dwLowDateTime = winTime;
	ft->dwHighDateTime = winTime >> 32;
}

int git_utime (const char *file_name, const struct utimbuf *times)
{
	FILETIME mft, aft;
	int fh, rc;

	/* must have write permission */
	if ((fh = open(file_name, O_RDWR | O_BINARY)) < 0)
	        return -1;

	time_t_to_filetime(times->modtime, &mft);
	time_t_to_filetime(times->actime, &aft);
	if (!SetFileTime((HANDLE)_get_osfhandle(fh), NULL, &aft, &mft)) {
		errno = EINVAL;
		rc = -1;
	} else
		rc = 0;
	close(fh);
	return rc;
}

int git_utime(const char *file_name, const struct utimbuf *times);
#define utime git_utime
#endif /* __MINGW32__ */

int main(int argc, const char *argv[])
{
	int i;
	int set_eq;
	long int set_time;
	char *test;
	const char *timespec;

	if (argc < 3)
		goto usage;

	timespec = argv[1];
	set_eq = (*timespec == '=') ? 1 : 0;
	if (set_eq) {
		timespec++;
		if (*timespec == '+') {
			set_eq = 2; /* relative "in the future" */
			timespec++;
		}
	}
	set_time = strtol(timespec, &test, 10);
	if (*test) {
		fprintf(stderr, "Not a base-10 integer: %s\n", argv[1] + 1);
		goto usage;
	}
	if ((set_eq && set_time < 0) || set_eq == 2) {
		time_t now = time(NULL);
		set_time += now;
	}

	for (i = 2; i < argc; i++) {
		struct stat sb;
		struct utimbuf utb;

		if (stat(argv[i], &sb) < 0) {
			fprintf(stderr, "Failed to stat %s: %s\n",
			        argv[i], strerror(errno));
			return -1;
		}

		utb.actime = sb.st_atime;
		utb.modtime = set_eq ? set_time : sb.st_mtime + set_time;

		if (utime(argv[i], &utb) < 0) {
			fprintf(stderr, "Failed to modify time on %s: %s\n",
			        argv[i], strerror(errno));
			return -1;
		}
	}

	return 0;

usage:
	fprintf(stderr, "Usage: %s %s\n", argv[0], usage_str);
	return -1;
}