From 2c8489de438331ce1511b7e03e12ecae2cc0b3ac Mon Sep 17 00:00:00 2001
From: Taloth Saldono <Taloth@users.noreply.github.com>
Date: Thu, 14 Dec 2017 20:26:28 +0100
Subject: [PATCH] Progress reporting infrastructure.

---
 src/NzbDrone.Common/NzbDrone.Common.csproj    |   2 +
 .../Timeline/ProgressReporter.cs              |  77 ++++++++++++++
 .../Timeline/TimelineContext.cs               | 100 ++++++++++++++++++
 3 files changed, 179 insertions(+)
 create mode 100644 src/NzbDrone.Common/Timeline/ProgressReporter.cs
 create mode 100644 src/NzbDrone.Common/Timeline/TimelineContext.cs

diff --git a/src/NzbDrone.Common/NzbDrone.Common.csproj b/src/NzbDrone.Common/NzbDrone.Common.csproj
index 4305f2e02..030ee6c9f 100644
--- a/src/NzbDrone.Common/NzbDrone.Common.csproj
+++ b/src/NzbDrone.Common/NzbDrone.Common.csproj
@@ -215,9 +215,11 @@
     <Compile Include="ServiceFactory.cs" />
     <Compile Include="ServiceProvider.cs" />
     <Compile Include="Extensions\StringExtensions.cs" />
+    <Compile Include="Timeline\TimelineContext.cs" />
     <Compile Include="TinyIoC.cs" />
     <Compile Include="TPL\Debouncer.cs" />
     <Compile Include="TPL\LimitedConcurrencyLevelTaskScheduler.cs" />
+    <Compile Include="Timeline\ProgressReporter.cs" />
     <Compile Include="TPL\RateLimitService.cs" />
     <Compile Include="TPL\TaskExtensions.cs" />
     <Compile Include="Extensions\TryParseExtensions.cs" />
diff --git a/src/NzbDrone.Common/Timeline/ProgressReporter.cs b/src/NzbDrone.Common/Timeline/ProgressReporter.cs
new file mode 100644
index 000000000..6bf4ac6bb
--- /dev/null
+++ b/src/NzbDrone.Common/Timeline/ProgressReporter.cs
@@ -0,0 +1,77 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NzbDrone.Common.Timeline
+{
+    public interface IProgressReporter
+    {
+        long Raw { get; }
+        long Total { get; }
+        double Progress { get; }
+
+        void UpdateProgress(long currentProgress, long maxProgress);
+        void FinishProgress();
+    }
+
+    public class ProgressReporter : IProgressReporter
+    {
+        private readonly int _maxSteps;
+
+        public long Raw { get; protected set; }
+        public long Total { get; private set; }
+
+        public double Progress => Total == 0 ? 1.0 : Math.Min(Raw, Total) / Total;
+
+        //public TimeSpan? EstimatedDurationRemaining { get; private set; }
+
+        public ProgressReporter(long initialProgress, long maxProgress, int maxSteps = 100)
+        {
+            _maxSteps = maxSteps;
+
+            Raw = initialProgress;
+            Total = maxProgress;
+        }
+
+        public void UpdateProgress(long currentProgress, long maxProgress)
+        {
+            bool shouldRaiseEvent;
+
+            lock (this)
+            {
+                var oldRaw = Raw;
+                var oldTotal = Total;
+
+                Raw = currentProgress;
+                Total = Total;
+
+                var oldStep = oldTotal <= 0 ? _maxSteps : oldRaw * _maxSteps / oldTotal;
+                var newStep = Total <= 0 ? _maxSteps : Raw * _maxSteps / Total;
+
+                shouldRaiseEvent = (oldStep != newStep);
+            }
+
+            if (shouldRaiseEvent)
+            {
+                RaiseEvent();
+            }
+        }
+
+        public void FinishProgress()
+        {
+            lock (this)
+            {
+                Raw = Total;
+            }
+
+            RaiseEvent();
+        }
+
+        protected virtual void RaiseEvent()
+        {
+            // TODO
+        }
+
+    }
+}
diff --git a/src/NzbDrone.Common/Timeline/TimelineContext.cs b/src/NzbDrone.Common/Timeline/TimelineContext.cs
new file mode 100644
index 000000000..b140a4e6e
--- /dev/null
+++ b/src/NzbDrone.Common/Timeline/TimelineContext.cs
@@ -0,0 +1,100 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NzbDrone.Common.Timeline
+{
+    public enum TimelineState
+    {
+        Pending,
+        Started,
+        Completed,
+        Failed
+    }
+
+    public interface ITimelineContext : IProgressReporter
+    {
+        string Name { get; }
+        TimelineState State { get; }
+
+        void UpdateState(TimelineState state);
+        ITimelineContext AppendTimeline(string name, long initialProgress = 0, long maxProgress = 1);
+        void AppendTimeline(ITimelineContext timeline);
+    }
+
+    public class TimelineContext : ProgressReporter, ITimelineContext
+    {
+        private List<ITimelineContext> _timelines = new List<ITimelineContext>();
+
+        public string Name { get; private set; }
+        public TimelineState State { get; private set; }
+
+        public IEnumerable<ITimelineContext> Timelines
+        {
+            get
+            {
+                lock (this)
+                {
+                    return _timelines.ToArray();
+                }
+            }
+        }
+
+        public TimelineContext(string name, long initialProgress, long maxProgress)
+            : base(initialProgress, maxProgress)
+        {
+            Name = name;
+        }
+
+        public void UpdateState(TimelineState state)
+        {
+            lock (this)
+            {
+                State = state;
+
+                if (State == TimelineState.Completed || State == TimelineState.Failed)
+                {
+                    Raw = Total;
+                }
+            }
+
+            RaiseEvent();
+        }
+
+        public ITimelineContext AppendTimeline(string name, long initialProgress = 0, long maxProgress = 1)
+        {
+            lock (this)
+            {
+                var timeline = new TimelineContext(name, initialProgress, maxProgress);
+                _timelines.Add(timeline);
+                return timeline;
+            }
+        }
+
+        public void AppendTimeline(ITimelineContext timeline)
+        {
+            lock (this)
+            {
+                _timelines.Add(timeline);
+            }
+        }
+
+        protected override void RaiseEvent()
+        {
+            lock (this)
+            {
+                if (Raw == Total)
+                {
+                    State = TimelineState.Completed;
+                }
+                else
+                {
+                    State = TimelineState.Started;
+                }
+            }
+
+            base.RaiseEvent();
+        }
+    }
+}