More guards against duplicate part swaps

src/c/main.c

@@ -74,6 +74,9 @@ static Animation *s_butt_raise_template;
 static Animation *s_butt_out_template;
 static Animation *s_butt_in_template;
 
+// guards for the swap scheduling
+static struct tm s_last_swap_time;
+
 // declare lookup tables
 #if PBL_DISPLAY_WIDTH <= 180
 static const uint8_t s_ones_offset[] = {0, 3, 6, 9, 12};
@@ -173,6 +176,10 @@ static void update_minute_60_out_handler(Animation *animation, bool finished, vo
 	bitmap_layer_set_bitmap(s_guy_butt_layer, s_butt);
 }
 
+static bool is_same_minute(const struct tm *a, const struct tm *b) {
+	return a->tm_mday == b->tm_mday && a->tm_hour == b->tm_hour && a->tm_min == b->tm_min;
+}
+
 static void minute_handler(struct tm *tick_time, TimeUnits units_changed) {
 	// time update
 	static char s_time_buffer[8];
@@ -225,13 +232,19 @@ static void minute_handler(struct tm *tick_time, TimeUnits units_changed) {
 	}
 
 	// animate swaps on half-hour boundaries (but not on first tick)
-	if (units_changed) {
-		if (tick_time->tm_min % 60 == 0) {
+	if (units_changed & MINUTE_UNIT) {
+		// ignore repeated callbacks for a minute that was already swapped: a duplicate
+		// tick or a clock correction can move the clock back onto :00/:30
+		if (!is_same_minute(tick_time, &s_last_swap_time)) {
+			if (tick_time->tm_min == 0) {
+				s_last_swap_time = *tick_time;
 				schedule_guy_animation(s_head_raise_template, s_head_out_template, s_head_in_template, update_minute_60_out_handler);
-		} else if (tick_time->tm_min % 30 == 0) {
+			} else if (tick_time->tm_min == 30) {
+				s_last_swap_time = *tick_time;
 				schedule_guy_animation(s_butt_raise_template, s_butt_out_template, s_butt_in_template, update_minute_30_out_handler);
 			}
 		}
+	}
 }
 
 static void time_bar_update_proc(Layer *layer, GContext *ctx) {
@@ -307,8 +320,10 @@ static void main_window_unload(Window *window) {
 	// destroy animation templates
 	animation_destroy(s_butt_raise_template);
 	animation_destroy(s_butt_out_template);
+	animation_destroy(s_butt_in_template);
 	animation_destroy(s_head_raise_template);
 	animation_destroy(s_head_out_template);
+	animation_destroy(s_head_in_template);
 }
 
 static void bluetooth_callback(bool connected) {