From acf3de5e25f343f492bbf33135bb2160126a94e6 Mon Sep 17 00:00:00 2001
From: Dan Balasescu <smoogipoo@smgi.me>
Date: Fri, 24 Nov 2023 13:22:46 +0900
Subject: [PATCH] Add CatchHealthProcessor, following legacy calculations

---
 .../Scoring/CatchHealthProcessor.cs           | 160 ++++++++++++++++++
 1 file changed, 160 insertions(+)

diff --git a/osu.Game.Rulesets.Catch/Scoring/CatchHealthProcessor.cs b/osu.Game.Rulesets.Catch/Scoring/CatchHealthProcessor.cs
index 7e8162bdfa..1f6a696f98 100644
--- a/osu.Game.Rulesets.Catch/Scoring/CatchHealthProcessor.cs
+++ b/osu.Game.Rulesets.Catch/Scoring/CatchHealthProcessor.cs
@@ -1,15 +1,175 @@
 // 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 System;
+using System.Collections.Generic;
+using System.Linq;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.Timing;
+using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Judgements;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Scoring;
 
 namespace osu.Game.Rulesets.Catch.Scoring
 {
     public partial class CatchHealthProcessor : DrainingHealthProcessor
     {
+        public Action<string>? OnIterationFail;
+        public Action<string>? OnIterationSuccess;
+
+        private double lowestHpEver;
+        private double lowestHpEnd;
+        private double hpRecoveryAvailable;
+        private double hpMultiplierNormal;
+
         public CatchHealthProcessor(double drainStartTime)
             : base(drainStartTime)
         {
         }
+
+        public override void ApplyBeatmap(IBeatmap beatmap)
+        {
+            lowestHpEver = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.DrainRate, 0.975, 0.8, 0.3);
+            lowestHpEnd = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.DrainRate, 0.99, 0.9, 0.4);
+            hpRecoveryAvailable = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.DrainRate, 0.04, 0.02, 0);
+
+            base.ApplyBeatmap(beatmap);
+        }
+
+        protected override void Reset(bool storeResults)
+        {
+            hpMultiplierNormal = 1;
+            base.Reset(storeResults);
+        }
+
+        protected override double ComputeDrainRate()
+        {
+            double testDrop = 0.00025;
+            double currentHp;
+            double currentHpUncapped;
+
+            while (true)
+            {
+                currentHp = 1;
+                currentHpUncapped = 1;
+
+                double lowestHp = currentHp;
+                double lastTime = DrainStartTime;
+                int currentBreak = 0;
+                bool fail = false;
+
+                List<HitObject> allObjects = EnumerateHitObjects(Beatmap).Where(h => h is Fruit || h is Droplet || h is Banana).ToList();
+
+                for (int i = 0; i < allObjects.Count; i++)
+                {
+                    HitObject h = allObjects[i];
+
+                    double localLastTime = lastTime;
+                    double breakTime = 0;
+
+                    if (Beatmap.Breaks.Count > 0 && currentBreak < Beatmap.Breaks.Count)
+                    {
+                        BreakPeriod e = Beatmap.Breaks[currentBreak];
+
+                        if (e.StartTime >= localLastTime && e.EndTime <= h.StartTime)
+                        {
+                            // consider break start equal to object end time for version 8+ since drain stops during this time
+                            breakTime = (Beatmap.BeatmapInfo.BeatmapVersion < 8) ? (e.EndTime - e.StartTime) : e.EndTime - localLastTime;
+                            currentBreak++;
+                        }
+                    }
+
+                    reduceHp(testDrop * (h.StartTime - lastTime - breakTime));
+
+                    lastTime = h.GetEndTime();
+
+                    if (currentHp < lowestHp)
+                        lowestHp = currentHp;
+
+                    if (currentHp <= lowestHpEver)
+                    {
+                        fail = true;
+                        testDrop *= 0.96;
+                        OnIterationFail?.Invoke($"FAILED drop {testDrop}: hp too low ({currentHp} < {lowestHpEver})");
+                        break;
+                    }
+
+                    increaseHp(h);
+                }
+
+                if (!fail && currentHp < lowestHpEnd)
+                {
+                    fail = true;
+                    testDrop *= 0.94;
+                    hpMultiplierNormal *= 1.01;
+                    OnIterationFail?.Invoke($"FAILED drop {testDrop}: end hp too low ({currentHp} < {lowestHpEnd})");
+                }
+
+                double recovery = (currentHpUncapped - 1) / allObjects.Count;
+
+                if (!fail && recovery < hpRecoveryAvailable)
+                {
+                    fail = true;
+                    testDrop *= 0.96;
+                    hpMultiplierNormal *= 1.01;
+                    OnIterationFail?.Invoke($"FAILED drop {testDrop}: recovery too low ({recovery} < {hpRecoveryAvailable})");
+                }
+
+                if (!fail)
+                {
+                    OnIterationSuccess?.Invoke($"PASSED drop {testDrop}");
+                    return testDrop;
+                }
+            }
+
+            void reduceHp(double amount)
+            {
+                currentHpUncapped = Math.Max(0, currentHpUncapped - amount);
+                currentHp = Math.Max(0, currentHp - amount);
+            }
+
+            void increaseHp(HitObject hitObject)
+            {
+                double amount = healthIncreaseFor(hitObject.CreateJudgement().MaxResult);
+                currentHpUncapped += amount;
+                currentHp = Math.Max(0, Math.Min(1, currentHp + amount));
+            }
+        }
+
+        protected override double GetHealthIncreaseFor(JudgementResult result) => healthIncreaseFor(result.Type);
+
+        private double healthIncreaseFor(HitResult result)
+        {
+            double increase = 0;
+
+            switch (result)
+            {
+                case HitResult.SmallTickMiss:
+                    return 0;
+
+                case HitResult.LargeTickMiss:
+                case HitResult.Miss:
+                    return IBeatmapDifficultyInfo.DifficultyRange(Beatmap.Difficulty.DrainRate, -0.03, -0.125, -0.2);
+
+                case HitResult.SmallTickHit:
+                    increase = 0.0015;
+                    break;
+
+                case HitResult.LargeTickHit:
+                    increase = 0.015;
+                    break;
+
+                case HitResult.Great:
+                    increase = 0.03;
+                    break;
+
+                case HitResult.LargeBonus:
+                    increase = 0.0025;
+                    break;
+            }
+
+            return hpMultiplierNormal * increase;
+        }
     }
 }