Merge PR #440 - fix countdown face issues

Avoid potential underflow when evaluating x - y with y > x.
Evaluate it only when y <= x instead.

Avoid clearing indicators in background task
since another watch face is likely active.

Reviewed-by: Matheus Afonso Martins Moreira <[email protected]>
GitHub-Pull-Request: #440

movement/watch_faces/complication/countdown_face.c

@@ -87,7 +87,10 @@ static void draw(countdown_state_t *state, uint8_t subsecond) {
 
     switch (state->mode) {
         case cd_running:
-            delta = state->target_ts - state->now_ts;
+            if (state->target_ts <= state->now_ts)
+                delta = 0;
+            else
+                delta = state->target_ts - state->now_ts;
             result = div(delta, 60);
             state->seconds = result.rem;
             result = div(result.quot, 60);
@@ -97,6 +100,7 @@ static void draw(countdown_state_t *state, uint8_t subsecond) {
             break;
         case cd_reset:
         case cd_paused:
+            watch_clear_indicator(WATCH_INDICATOR_BELL);
             sprintf(buf, "CD  %2d%02d%02d", state->hours, state->minutes, state->seconds);
             break;
         case cd_setting:
@@ -130,7 +134,6 @@ static void pause(countdown_state_t *state) {
 static void reset(countdown_state_t *state) {
     state->mode = cd_reset;
     movement_cancel_background_task();
-    watch_clear_indicator(WATCH_INDICATOR_BELL);
     load_countdown(state);
 }