From 9be36230f9bd5825aafc5b5f664480d76bdf43fb Mon Sep 17 00:00:00 2001
From: ekrctb <ekrctb@gmail.com>
Date: Thu, 6 May 2021 21:43:30 +0900
Subject: [PATCH] Introduce AutoGenerator subclass for frame based replay
 generation

---
 osu.Game/Rulesets/Replays/AutoGenerator.cs    | 27 +++++-------
 .../Rulesets/Replays/FramedAutoGenerator.cs   | 44 +++++++++++++++++++
 2 files changed, 54 insertions(+), 17 deletions(-)
 create mode 100644 osu.Game/Rulesets/Replays/FramedAutoGenerator.cs

diff --git a/osu.Game/Rulesets/Replays/AutoGenerator.cs b/osu.Game/Rulesets/Replays/AutoGenerator.cs
index b3c609f2f4..4bdd5b094d 100644
--- a/osu.Game/Rulesets/Replays/AutoGenerator.cs
+++ b/osu.Game/Rulesets/Replays/AutoGenerator.cs
@@ -1,4 +1,4 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Game.Beatmaps;
@@ -7,34 +7,27 @@ using osu.Game.Rulesets.Objects;
 
 namespace osu.Game.Rulesets.Replays
 {
-    public abstract class AutoGenerator : IAutoGenerator
+    public abstract class AutoGenerator
     {
         /// <summary>
-        /// Creates the auto replay and returns it.
-        /// Every subclass of OsuAutoGeneratorBase should implement this!
+        /// The default duration of a key press in milliseconds.
         /// </summary>
-        public abstract Replay Generate();
-
-        #region Parameters
+        public const double KEY_UP_DELAY = 50;
 
         /// <summary>
-        /// The beatmap we're making.
+        /// The beatmap the autoplay is generated for.
         /// </summary>
-        protected IBeatmap Beatmap;
-
-        #endregion
+        protected IBeatmap Beatmap { get; }
 
         protected AutoGenerator(IBeatmap beatmap)
         {
             Beatmap = beatmap;
         }
 
-        #region Constants
-
-        // Shared amongst all modes
-        public const double KEY_UP_DELAY = 50;
-
-        #endregion
+        /// <summary>
+        /// Generate the replay of the autoplay.
+        /// </summary>
+        public abstract Replay Generate();
 
         protected virtual HitObject GetNextObject(int currentIndex)
         {
diff --git a/osu.Game/Rulesets/Replays/FramedAutoGenerator.cs b/osu.Game/Rulesets/Replays/FramedAutoGenerator.cs
new file mode 100644
index 0000000000..091eb00232
--- /dev/null
+++ b/osu.Game/Rulesets/Replays/FramedAutoGenerator.cs
@@ -0,0 +1,44 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+#nullable enable
+
+using System.Collections.Generic;
+using System.Linq;
+using osu.Game.Beatmaps;
+using osu.Game.Replays;
+
+namespace osu.Game.Rulesets.Replays
+{
+    public abstract class FramedAutoGenerator<TFrame> : AutoGenerator
+        where TFrame : ReplayFrame
+    {
+        /// <summary>
+        /// The replay frames of the autoplay.
+        /// </summary>
+        protected readonly List<TFrame> Frames = new List<TFrame>();
+
+        protected TFrame? LastFrame => Frames.Count == 0 ? null : Frames[^1];
+
+        protected FramedAutoGenerator(IBeatmap beatmap)
+            : base(beatmap)
+        {
+        }
+
+        public sealed override Replay Generate()
+        {
+            Frames.Clear();
+            GenerateFrames();
+
+            return new Replay
+            {
+                Frames = Frames.OrderBy(frame => frame.Time).Cast<ReplayFrame>().ToList()
+            };
+        }
+
+        /// <summary>
+        /// Generate the replay frames of the autoplay and populate <see cref="Frames"/>.
+        /// </summary>
+        protected abstract void GenerateFrames();
+    }
+}