playlist timer pause/resume without affecting active feeds

internal/playback/playlist_timing.go

@@ -3,11 +3,14 @@ package playback
 import "time"
 
 type PlaylistTimingState struct {
-	Revision uint64
-	Duration time.Duration
-	Started  bool
-	Expired  bool
-	Deadline time.Time
+	Revision  uint64
+	Duration  time.Duration
+	Ready     bool
+	Started   bool
+	Paused    bool
+	Expired   bool
+	Remaining time.Duration
+	Deadline  time.Time
 }
 
 func NewPlaylistTiming(
@@ -15,9 +18,9 @@ func NewPlaylistTiming(
 	duration time.Duration,
 ) PlaylistTimingState {
 	return PlaylistTimingState{
-		Revision: revision,
-		Duration: duration,
-		Expired:  false,
+		Revision:  revision,
+		Duration:  duration,
+		Remaining: duration,
 	}
 }
 
@@ -29,12 +32,66 @@ func StartPlaylistTiming(
 	if revision != current.Revision ||
 		current.Duration <= 0 ||
 		current.Started ||
+		current.Paused ||
 		current.Expired {
 		return current, false
 	}
 	next := current
+	if next.Remaining <= 0 {
+		next.Remaining = next.Duration
+	}
+	next.Ready = true
 	next.Started = true
-	next.Deadline = now.Add(current.Duration)
+	next.Deadline = now.Add(next.Remaining)
+	return next, true
+}
+
+func PausePlaylistTiming(
+	current PlaylistTimingState,
+	revision uint64,
+	now time.Time,
+) (PlaylistTimingState, bool) {
+	if revision != current.Revision ||
+		current.Duration <= 0 ||
+		current.Paused ||
+		current.Expired {
+		return current, false
+	}
+
+	next := current
+	if next.Started {
+		next.Remaining = next.Deadline.Sub(now)
+		if next.Remaining < 0 {
+			next.Remaining = 0
+		}
+		if next.Remaining > next.Duration {
+			next.Remaining = next.Duration
+		}
+		next.Started = false
+		next.Deadline = time.Time{}
+	}
+	next.Paused = true
+	return next, true
+}
+
+func ResumePlaylistTiming(
+	current PlaylistTimingState,
+	revision uint64,
+	now time.Time,
+) (PlaylistTimingState, bool) {
+	if revision != current.Revision ||
+		current.Duration <= 0 ||
+		!current.Paused ||
+		current.Expired {
+		return current, false
+	}
+
+	next := current
+	next.Paused = false
+	if next.Ready {
+		next.Started = true
+		next.Deadline = now.Add(next.Remaining)
+	}
 	return next, true
 }
 
@@ -51,7 +108,9 @@ func ExpirePlaylistTiming(
 
 	next := current
 	next.Started = false
+	next.Paused = false
 	next.Deadline = time.Time{}
 	next.Expired = true
+	next.Remaining = 0
 	return next, true
 }