yaml sequence improvements

CHANGELOG.md

@@ -35,6 +35,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Add health check error when invalid VAAPI device and VAAPI driver combination is used in an active ffmpeg profile
   - This makes it obvious when hardware acceleration will not work as configured
 - Add button in schedule editor to clone schedule item
+- Allow YAML playout sequence definitions to reference other sequences
+  - Playout builder will behave in unexpected ways if nesting is too deep
+- Add `repeat` property to YAML sequence instruction
+  - This tells the playout builder how many times this sequence should repeat
+  - Omitting this value is the same as setting it to `1`
 
 ### Changed
 - Start to make UI minimally responsive (functional on smaller screens)

ErsatzTV.Core/Scheduling/YamlScheduling/Models/YamlPlayoutSequenceInstruction.cs

@@ -3,4 +3,5 @@ namespace ErsatzTV.Core.Scheduling.YamlScheduling.Models;
 public class YamlPlayoutSequenceInstruction : YamlPlayoutInstruction
 {
     public string Sequence { get; set; }
+    public int Repeat { get; set; }
 }

ErsatzTV.Core/Scheduling/YamlScheduling/YamlPlayoutBuilder.cs

@@ -127,7 +127,19 @@ public class YamlPlayoutBuilder(
             }
         }
 
+        int flattenCount = 0;
+        while (context.Definition.Playout.Any(x => x is YamlPlayoutSequenceInstruction))
+        {
+            if (flattenCount > 10)
+            {
+                logger.LogError(
+                    "YAML playout definition contains sequence nesting that is too deep; this introduces undefined behavior");
+                break;
+            }
+
             FlattenSequences(context);
+            flattenCount++;
+        }
 
         // handle all playout instructions
         while (context.CurrentTime < finish)
@@ -204,10 +216,14 @@ public class YamlPlayoutBuilder(
                         .Filter(s => s.Key == sequenceInstruction.Sequence)
                         .HeadOrNone()
                         .Map(s => s.Items)
-                        .Flatten();
+                        .Flatten()
+                        .ToList();
 
                     var sequenceGuid = Guid.NewGuid();
+                    int repeat = sequenceInstruction.Repeat > 0 ? sequenceInstruction.Repeat : 1;
 
+                    for (var r = 0; r < repeat; r++)
+                    {
                         // insert all instructions from the sequence
                         foreach (YamlPlayoutInstruction i in sequenceInstructions)
                         {
@@ -223,6 +239,8 @@ public class YamlPlayoutBuilder(
 
                             context.Definition.Playout.Add(i);
                         }
+                    }
+
                     break;
                 default:
                     context.Definition.Playout.Add(instruction);