From 1609f11f494c2d4870857f47a87c0e1955fd43ba Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pj@pehjota.net>
Date: Sun, 29 Aug 2021 16:48:48 -0400
Subject: datetime: Support weekday-only dates

---
(limited to 'src/datetime.c')

diff --git a/src/datetime.c b/src/datetime.c
index c98f27a..797e955 100644
--- a/src/datetime.c
+++ b/src/datetime.c
@@ -38,6 +38,7 @@ datetime_parse(const char *input, time_t *arg_sec)
 	struct tm  arg_tm;
 	time_t     now_sec;
 	struct tm *now_tm;
+	int        wday;
 
 	for (i = 0; DATETIME_FMTS_[i] != NULL; ++i) {
 		arg_tm.tm_year  = INT_MIN;
@@ -61,14 +62,14 @@ datetime_parse(const char *input, time_t *arg_sec)
 	if (arg_tm.tm_sec == INT_MIN) {
 		arg_tm.tm_sec = 0;
 	}
-	/* TODO: Support %a-only dates */
-	if (arg_tm.tm_mday == INT_MIN) {
+	if (arg_tm.tm_mday == INT_MIN && arg_tm.tm_wday == INT_MIN) {
 		/* No date specified; try today. */
 		now_sec = time(NULL);
 		now_tm = localtime(&now_sec);
 		arg_tm.tm_year = now_tm->tm_year;
 		arg_tm.tm_mon  = now_tm->tm_mon;
 		arg_tm.tm_mday = now_tm->tm_mday;
+		arg_tm.tm_wday = now_tm->tm_wday;
 		*arg_sec = mktime(&arg_tm);
 		if (*arg_sec <= mktime(now_tm)) {
 			/* Specified time already happened today; use tomorrow.
@@ -82,6 +83,21 @@ datetime_parse(const char *input, time_t *arg_sec)
 			arg_tm.tm_mday = now_tm->tm_mday;
 			*arg_sec = mktime(&arg_tm);
 		}
+	} else if (arg_tm.tm_mday == INT_MIN) {
+		/* Only a weekday specified; try tomorrow or next week.  Uses
+		 * same shortcut as above. */
+		wday = arg_tm.tm_wday;
+		now_sec = time(NULL);
+		now_tm = localtime(&now_sec);
+		arg_tm.tm_year = now_tm->tm_year;
+		arg_tm.tm_mon  = now_tm->tm_mon;
+		arg_tm.tm_mday = now_tm->tm_mday;
+		arg_tm.tm_wday = now_tm->tm_wday;
+		if (wday <= now_tm->tm_wday) {
+			wday += 7;
+		}
+		*arg_sec = mktime(&arg_tm);
+		*arg_sec += (60 * 60 * 24) * (wday - now_tm->tm_wday);
 	} else if (arg_tm.tm_year == INT_MIN) {
 		/* No year specified; try this year. */
 		now_sec = time(NULL);
--
cgit v0.9.1