From ad3e0c4c08757bfa27e4d08f6bcb5ec3481ff9db Mon Sep 17 00:00:00 2001
From: rlauuzo <46294892+rlauuzo@users.noreply.github.com>
Date: Tue, 16 Apr 2024 18:19:05 +0200
Subject: [PATCH] Change task from being canceled to waiting (#118)

---
 .../Configuration/configPage.html             |  4 +-
 .../Entrypoint.cs                             | 22 ++++-----
 .../Plugin.cs                                 |  5 --
 .../ScheduledTasks/DetectCreditsTask.cs       | 22 +++++----
 .../ScheduledTasks/DetectIntrosCreditsTask.cs | 22 +++++----
 .../ScheduledTasks/DetectIntrosTask.cs        | 22 +++++----
 .../ScheduledTasks/ScheduledTaskSemaphore.cs  | 48 +++++++++++++++++++
 7 files changed, 97 insertions(+), 48 deletions(-)
 create mode 100644 ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/ScheduledTaskSemaphore.cs

diff --git a/ConfusedPolarBear.Plugin.IntroSkipper/Configuration/configPage.html b/ConfusedPolarBear.Plugin.IntroSkipper/Configuration/configPage.html
index 3d548f0..08aa02f 100644
--- a/ConfusedPolarBear.Plugin.IntroSkipper/Configuration/configPage.html
+++ b/ConfusedPolarBear.Plugin.IntroSkipper/Configuration/configPage.html
@@ -147,10 +147,10 @@
                             </div>
 
                             <div class="inputContainer">
-                                <label class="inputLabel inputLabelUnfocused" for="MaximumEpisodeCreditsDuration">
+                                <label class="inputLabel inputLabelUnfocused" for="MaximumCreditsDuration">
                                     Maximum credits duration (in seconds)
                                 </label>
-                                <input id="MaximumEpisodeCreditsDuration" type="number" is="emby-input" min="1" />
+                                <input id="MaximumCreditsDuration" type="number" is="emby-input" min="1" />
                                 <div class="fieldDescription">
                                     Similar sounding audio which is longer than this duration will not be considered credits.
                                 </div>
diff --git a/ConfusedPolarBear.Plugin.IntroSkipper/Entrypoint.cs b/ConfusedPolarBear.Plugin.IntroSkipper/Entrypoint.cs
index eb29368..ebddd78 100644
--- a/ConfusedPolarBear.Plugin.IntroSkipper/Entrypoint.cs
+++ b/ConfusedPolarBear.Plugin.IntroSkipper/Entrypoint.cs
@@ -211,11 +211,11 @@ public class Entrypoint : IHostedService, IDisposable
     /// </summary>
     private void StartTimer()
     {
-        if (Plugin.Instance!.AnalyzerTaskIsRunning)
+        if (Entrypoint.AutomaticTaskState == TaskState.Running)
         {
            _analyzeAgain = true; // Items added during a scan will be included later.
         }
-        else
+        else if (ScheduledTaskSemaphore.CurrentCount > 0)
         {
             _logger.LogInformation("Media Library changed, analyzis will start soon!");
             _queueTimer.Change(TimeSpan.FromMilliseconds(20000), Timeout.InfiniteTimeSpan);
@@ -243,7 +243,7 @@ public class Entrypoint : IHostedService, IDisposable
     private void PerformAnalysis()
     {
         _logger.LogInformation("Timer elapsed - start analyzing");
-        Plugin.Instance!.AnalyzerTaskIsRunning = true;
+        _autoTaskCompletEvent.Reset();
 
         using (_cancellationTokenSource = new CancellationTokenSource())
         {
@@ -291,8 +291,8 @@ public class Entrypoint : IHostedService, IDisposable
             }
         }
 
-        Plugin.Instance!.AnalyzerTaskIsRunning = false;
         _autoTaskCompletEvent.Set();
+        _cancellationTokenSource = null;
 
         // New item detected, start timer again
         if (_analyzeAgain)
@@ -306,17 +306,17 @@ public class Entrypoint : IHostedService, IDisposable
     /// <summary>
     /// Method to cancel the automatic task.
     /// </summary>
-    public static void CancelAutomaticTask()
+    /// <param name="cancellationToken">Cancellation token.</param>
+    public static void CancelAutomaticTask(CancellationToken cancellationToken)
     {
         if (_cancellationTokenSource != null)
         {
-            _cancellationTokenSource.Cancel();
+            if (!_cancellationTokenSource.IsCancellationRequested)
+            {
+                _cancellationTokenSource.Cancel();
+            }
 
-            _autoTaskCompletEvent.Wait(); // Wait for the signal
-            _autoTaskCompletEvent.Reset();  // Reset for the next task
-
-            _cancellationTokenSource.Dispose(); // Now safe to dispose
-            _cancellationTokenSource = null;
+            _autoTaskCompletEvent.Wait(TimeSpan.FromSeconds(60), cancellationToken); // Wait for the signal
         }
     }
 
diff --git a/ConfusedPolarBear.Plugin.IntroSkipper/Plugin.cs b/ConfusedPolarBear.Plugin.IntroSkipper/Plugin.cs
index ee23264..cdaf54e 100644
--- a/ConfusedPolarBear.Plugin.IntroSkipper/Plugin.cs
+++ b/ConfusedPolarBear.Plugin.IntroSkipper/Plugin.cs
@@ -140,11 +140,6 @@ public class Plugin : BasePlugin<PluginConfiguration>, IHasWebPages
         FFmpegWrapper.CheckFFmpegVersion();
     }
 
-    /// <summary>
-    /// Gets or sets a value indicating whether analysis is running.
-    /// </summary>
-    public bool AnalyzerTaskIsRunning { get; set; } = false;
-
     /// <summary>
     /// Gets the results of fingerprinting all episodes.
     /// </summary>
diff --git a/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectCreditsTask.cs b/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectCreditsTask.cs
index bacb457..2f43939 100644
--- a/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectCreditsTask.cs
+++ b/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectCreditsTask.cs
@@ -69,19 +69,22 @@ public class DetectCreditsTask : IScheduledTask
             throw new InvalidOperationException("Library manager was null");
         }
 
-        // abort if analyzer is already running
-        if (Plugin.Instance!.AnalyzerTaskIsRunning && Entrypoint.AutomaticTaskState == TaskState.Idle)
-        {
-            return Task.CompletedTask;
-        }
-        else if (Plugin.Instance!.AnalyzerTaskIsRunning && Entrypoint.AutomaticTaskState == TaskState.Running)
+        // abort automatic analyzer if running
+        if (Entrypoint.AutomaticTaskState == TaskState.Running || Entrypoint.AutomaticTaskState == TaskState.Cancelling)
         {
             _logger.LogInformation("Automatic Task is {0} and will be canceled.", Entrypoint.AutomaticTaskState);
-            Entrypoint.CancelAutomaticTask();
+            Entrypoint.CancelAutomaticTask(cancellationToken);
+        }
+
+        ScheduledTaskSemaphore.Wait(-1, cancellationToken);
+
+        if (cancellationToken.IsCancellationRequested)
+        {
+            ScheduledTaskSemaphore.Release();
+            return Task.CompletedTask;
         }
 
         _logger.LogInformation("Scheduled Task is starting");
-        Plugin.Instance!.AnalyzerTaskIsRunning = true;
 
         var baseCreditAnalyzer = new BaseItemAnalyzerTask(
             AnalysisMode.Credits,
@@ -91,8 +94,7 @@ public class DetectCreditsTask : IScheduledTask
 
         baseCreditAnalyzer.AnalyzeItems(progress, cancellationToken);
 
-        Plugin.Instance!.AnalyzerTaskIsRunning = false;
-
+        ScheduledTaskSemaphore.Release();
         return Task.CompletedTask;
     }
 
diff --git a/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectIntrosCreditsTask.cs b/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectIntrosCreditsTask.cs
index f58472c..2b465c5 100644
--- a/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectIntrosCreditsTask.cs
+++ b/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectIntrosCreditsTask.cs
@@ -68,19 +68,22 @@ public class DetectIntrosCreditsTask : IScheduledTask
             throw new InvalidOperationException("Library manager was null");
         }
 
-        // abort if analyzer is already running
-        if (Plugin.Instance!.AnalyzerTaskIsRunning && Entrypoint.AutomaticTaskState == TaskState.Idle)
-        {
-            return Task.CompletedTask;
-        }
-        else if (Plugin.Instance!.AnalyzerTaskIsRunning && Entrypoint.AutomaticTaskState == TaskState.Running)
+        // abort automatic analyzer if running
+        if (Entrypoint.AutomaticTaskState == TaskState.Running || Entrypoint.AutomaticTaskState == TaskState.Cancelling)
         {
             _logger.LogInformation("Automatic Task is {0} and will be canceled.", Entrypoint.AutomaticTaskState);
-            Entrypoint.CancelAutomaticTask();
+            Entrypoint.CancelAutomaticTask(cancellationToken);
+        }
+
+        ScheduledTaskSemaphore.Wait(-1, cancellationToken);
+
+        if (cancellationToken.IsCancellationRequested)
+        {
+            ScheduledTaskSemaphore.Release();
+            return Task.CompletedTask;
         }
 
         _logger.LogInformation("Scheduled Task is starting");
-        Plugin.Instance!.AnalyzerTaskIsRunning = true;
 
         var baseIntroAnalyzer = new BaseItemAnalyzerTask(
             AnalysisMode.Introduction,
@@ -98,8 +101,7 @@ public class DetectIntrosCreditsTask : IScheduledTask
 
         baseCreditAnalyzer.AnalyzeItems(progress, cancellationToken);
 
-        Plugin.Instance!.AnalyzerTaskIsRunning = false;
-
+        ScheduledTaskSemaphore.Release();
         return Task.CompletedTask;
     }
 
diff --git a/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectIntrosTask.cs b/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectIntrosTask.cs
index c92f800..c1f4f57 100644
--- a/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectIntrosTask.cs
+++ b/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/DetectIntrosTask.cs
@@ -68,19 +68,22 @@ public class DetectIntrosTask : IScheduledTask
             throw new InvalidOperationException("Library manager was null");
         }
 
-        // abort if analyzer is already running
-        if (Plugin.Instance!.AnalyzerTaskIsRunning && Entrypoint.AutomaticTaskState == TaskState.Idle)
-        {
-            return Task.CompletedTask;
-        }
-        else if (Plugin.Instance!.AnalyzerTaskIsRunning && Entrypoint.AutomaticTaskState == TaskState.Running)
+        // abort automatic analyzer if running
+        if (Entrypoint.AutomaticTaskState == TaskState.Running || Entrypoint.AutomaticTaskState == TaskState.Cancelling)
         {
             _logger.LogInformation("Automatic Task is {0} and will be canceled.", Entrypoint.AutomaticTaskState);
-            Entrypoint.CancelAutomaticTask();
+            Entrypoint.CancelAutomaticTask(cancellationToken);
+        }
+
+        ScheduledTaskSemaphore.Wait(-1, cancellationToken);
+
+        if (cancellationToken.IsCancellationRequested)
+        {
+            ScheduledTaskSemaphore.Release();
+            return Task.CompletedTask;
         }
 
         _logger.LogInformation("Scheduled Task is starting");
-        Plugin.Instance!.AnalyzerTaskIsRunning = true;
 
         var baseIntroAnalyzer = new BaseItemAnalyzerTask(
             AnalysisMode.Introduction,
@@ -90,8 +93,7 @@ public class DetectIntrosTask : IScheduledTask
 
         baseIntroAnalyzer.AnalyzeItems(progress, cancellationToken);
 
-        Plugin.Instance!.AnalyzerTaskIsRunning = false;
-
+        ScheduledTaskSemaphore.Release();
         return Task.CompletedTask;
     }
 
diff --git a/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/ScheduledTaskSemaphore.cs b/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/ScheduledTaskSemaphore.cs
new file mode 100644
index 0000000..67b41a2
--- /dev/null
+++ b/ConfusedPolarBear.Plugin.IntroSkipper/ScheduledTasks/ScheduledTaskSemaphore.cs
@@ -0,0 +1,48 @@
+using System;
+using System.Threading;
+
+namespace ConfusedPolarBear.Plugin.IntroSkipper;
+
+internal sealed class ScheduledTaskSemaphore : IDisposable
+{
+    private static readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
+
+    private ScheduledTaskSemaphore()
+    {
+    }
+
+    public static int CurrentCount => _semaphore.CurrentCount;
+
+    public static bool Wait(int timeout, CancellationToken cancellationToken)
+    {
+        return _semaphore.Wait(timeout, cancellationToken);
+    }
+
+    public static int Release()
+    {
+        return _semaphore.Release();
+    }
+
+    /// <summary>
+    /// Dispose.
+    /// </summary>
+    public void Dispose()
+    {
+        Dispose(true);
+        GC.SuppressFinalize(this);
+    }
+
+    /// <summary>
+    /// Protected dispose.
+    /// </summary>
+    /// <param name="disposing">Dispose.</param>
+    private void Dispose(bool disposing)
+    {
+        if (!disposing)
+        {
+            return;
+        }
+
+        _semaphore.Dispose();
+    }
+}