add shuffle sequence instruction (#1827)

ErsatzTV.Core/Scheduling/YamlScheduling/Handlers/YamlPlayoutShuffleSequenceHandler.cs

@@ -0,0 +1,51 @@
+using ErsatzTV.Core.Scheduling.YamlScheduling.Models;
+using Microsoft.Extensions.Logging;
+
+namespace ErsatzTV.Core.Scheduling.YamlScheduling.Handlers;
+
+public class YamlPlayoutShuffleSequenceHandler : IYamlPlayoutHandler
+{
+    public bool Reset => false;
+
+    public Task<bool> Handle(
+        YamlPlayoutContext context,
+        YamlPlayoutInstruction instruction,
+        ILogger<YamlPlayoutBuilder> logger,
+        CancellationToken cancellationToken)
+    {
+        if (instruction is not YamlPlayoutShuffleSequenceInstruction shuffleSequenceInstruction)
+        {
+            return Task.FromResult(false);
+        }
+
+        if (string.IsNullOrWhiteSpace(shuffleSequenceInstruction.ShuffleSequence))
+        {
+            logger.LogWarning("Sequence key is required to shuffle sequence");
+            return Task.FromResult(false);
+        }
+
+        string sequenceKey = shuffleSequenceInstruction.ShuffleSequence;
+
+        var groupedSequenceItems = context.Definition.Playout
+            .Where(i => i.SequenceKey == sequenceKey)
+            .GroupBy(i => i.SequenceGuid)
+            .ToList();
+
+        foreach (IGrouping<Guid, YamlPlayoutInstruction> grouping in groupedSequenceItems)
+        {
+            // shuffle, avoiding starting with the tail of the last shuffle
+            YamlPlayoutInstruction tail = grouping.Last();
+            var shuffledGroup = grouping.OrderBy(_ => Guid.NewGuid()).ToList();
+            while (shuffledGroup.Count > 1 && shuffledGroup.Head() == tail)
+            {
+                shuffledGroup = grouping.OrderBy(_ => Guid.NewGuid()).ToList();
+            }
+
+            int firstIndex = context.Definition.Playout.FindIndex(i => i.SequenceGuid == grouping.Key);
+            context.Definition.Playout.RemoveRange(firstIndex, shuffledGroup.Count);
+            context.Definition.Playout.InsertRange(firstIndex, shuffledGroup);
+        }
+
+        return Task.FromResult(true);
+    }
+}

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

@@ -13,4 +13,7 @@ public class YamlPlayoutInstruction
 
     [YamlIgnore]
     public string SequenceKey { get; set; }
+
+    [YamlIgnore]
+    public Guid SequenceGuid { get; set; }
 }

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

@@ -0,0 +1,9 @@
+using YamlDotNet.Serialization;
+
+namespace ErsatzTV.Core.Scheduling.YamlScheduling.Models;
+
+public class YamlPlayoutShuffleSequenceInstruction : YamlPlayoutInstruction
+{
+    [YamlMember(Alias = "shuffle_sequence", ApplyNamingConventions = false)]
+    public string ShuffleSequence { get; set; }
+}

ErsatzTV.Core/Scheduling/YamlScheduling/YamlPlayoutBuilder.cs

@@ -131,11 +131,14 @@ public class YamlPlayoutBuilder(
                         .Map(s => s.Items)
                         .Flatten();
 
+                    var sequenceGuid = Guid.NewGuid();
+
                     // insert all instructions from the sequence
                     foreach (YamlPlayoutInstruction i in sequenceInstructions)
                     {
-                        // maybe used for shuffling later?
+                        // used for shuffling
                         i.SequenceKey = sequenceInstruction.Sequence;
+                        i.SequenceGuid = sequenceGuid;
 
                         context.Definition.Playout.Add(i);
                     }
@@ -162,6 +165,7 @@ public class YamlPlayoutBuilder(
             YamlPlayoutRepeatInstruction => new YamlPlayoutRepeatHandler(),
             YamlPlayoutWaitUntilInstruction => new YamlPlayoutWaitUntilHandler(),
             YamlPlayoutNewEpgGroupInstruction => new YamlPlayoutNewEpgGroupHandler(),
+            YamlPlayoutShuffleSequenceInstruction => new YamlPlayoutShuffleSequenceHandler(),
             YamlPlayoutSkipItemsInstruction => new YamlPlayoutSkipItemsHandler(),
 
             // content handlers
@@ -207,6 +211,7 @@ public class YamlPlayoutBuilder(
                         { "pad_to_next", typeof(YamlPlayoutPadToNextInstruction) },
                         { "repeat", typeof(YamlPlayoutRepeatInstruction) },
                         { "sequence", typeof(YamlPlayoutSequenceInstruction) },
+                        { "shuffle_sequence", typeof(YamlPlayoutShuffleSequenceInstruction) },
                         { "skip_items", typeof(YamlPlayoutSkipItemsInstruction) },
                         { "wait_until", typeof(YamlPlayoutWaitUntilInstruction) }
                     };