Add AdjustSkillExpForLowLevels to AddSkillPointsToPlayer (#738)

* Add AdjustSkillExpForLowLevels to AddSkillPointsToPlayer

* remove unused AdjustSkillExpForLowLevels

* format unit tests

* fix suggestions

* Revert "remove unused AdjustSkillExpForLowLevels"

This reverts commit 43e0ab654378ca7ba1140648b1624730d637073b.

* mark as obsolete

* fix log message

---------

Co-authored-by: rootdarkarchon <root.darkarchon@outlook.com>

Libraries/SPTarkov.Server.Core/Helpers/ProfileHelper.cs

@@ -494,30 +494,103 @@ public class ProfileHelper(
             return;
         }
 
+        // already max level, no need to do any further calculations
+        if (profileSkill.Progress >= 5100)
+        {
+            if (logger.IsLogEnabled(LogLevel.Debug))
+            {
+                logger.Debug($"Player already has max level in skill: {skill}, not adding points");
+            }
+
+            profileSkill.LastAccess = timeUtil.GetTimeStamp();
+            return;
+        }
+
         if (useSkillProgressRateMultiplier)
         {
             var skillProgressRate = databaseService.GetGlobals().Configuration.SkillsSettings.SkillProgressRate;
             pointsToAddToSkill *= skillProgressRate;
         }
 
-        if (InventoryConfig.SkillGainMultipliers.TryGetValue(skill.ToString(), out _))
+        if (InventoryConfig.SkillGainMultipliers.TryGetValue(skill.ToString(), out var multiplier))
         {
-            pointsToAddToSkill *= InventoryConfig.SkillGainMultipliers[skill.ToString()];
+            pointsToAddToSkill *= multiplier;
         }
 
-        profileSkill.Progress += pointsToAddToSkill;
+        var adjustedSkillProgress = AdjustSkillExpForLowLevels(profileSkill.Progress, pointsToAddToSkill);
+        profileSkill.Progress += adjustedSkillProgress;
         profileSkill.Progress = Math.Min(profileSkill.Progress, 5100); // Prevent skill from ever going above level 51 (5100)
 
-        profileSkill.PointsEarnedDuringSession += pointsToAddToSkill;
+        profileSkill.PointsEarnedDuringSession += adjustedSkillProgress;
 
         if (logger.IsLogEnabled(LogLevel.Debug))
         {
-            logger.Debug($"Added: {pointsToAddToSkill} points to skill: {skill}, new progress value is: {profileSkill.Progress}");
+            logger.Debug($"Added: {adjustedSkillProgress} points to skill: {skill}, new progress value is: {profileSkill.Progress}");
         }
 
         profileSkill.LastAccess = timeUtil.GetTimeStamp();
     }
 
+    /// <summary>
+    ///     This method calculates the adjusted skill progression for lower levels.
+    /// </summary>
+    /// <param name="currentProgress">Current internal progress value of the skill, used to determine current level</param>
+    /// <param name="visualProgressAmount">The amount of visual progress to add</param>
+    /// <returns>Scaled skill progress according to level</returns>
+    /// <remarks>
+    ///     It expects to be passed on a value as expected per the visual progress on the UI.
+    ///     It will return scaled internal progress according to the current skill level, to match Tarkovs skill progression curve.
+    ///     So passing on "0.4" will always yield +0.4 progress on the UI for the player.
+    /// </remarks>
+    public double AdjustSkillExpForLowLevels(double currentProgress, double visualProgressAmount)
+    {
+        var level = Math.Floor(currentProgress / 100d);
+
+        if (level >= 9)
+        {
+            return visualProgressAmount;
+        }
+
+        double internalAdded = 0;
+
+        // See "CalculateExpOnFirstLevels" in client for original logic
+        // loop until all visual progress has been used up
+        while (visualProgressAmount > 0)
+        {
+            // scale to apply for levels 1-10, decreasing as level goes higher
+            var uiMax = 10d * (level + 1d);
+            var factor = 100d / uiMax;
+
+            // remaining internal points in this level
+            var inLevel = currentProgress % 100d;
+            var internalRemaining = 100d - inLevel;
+
+            if (logger.IsLogEnabled(LogLevel.Debug))
+            {
+                logger.Debug($"currentLevelRemainingProgress: {internalRemaining}");
+            }
+
+            // visual needed to fill the rest of this internal level
+            var visualToLevelUp = internalRemaining / factor;
+
+            var spendVisual = Math.Min(visualProgressAmount, visualToLevelUp);
+            var addInternal = spendVisual * factor;
+
+            if (logger.IsLogEnabled(LogLevel.Debug))
+            {
+                logger.Debug($"Progress To Add Adjusted For Level: {addInternal}");
+            }
+
+            internalAdded += addInternal;
+            currentProgress += addInternal;
+            visualProgressAmount -= spendVisual;
+
+            level = Math.Floor(currentProgress / 100d);
+        }
+
+        return internalAdded;
+    }
+
     /// <summary>
     ///     Is the provided session id for a developer account
     /// </summary>

Libraries/SPTarkov.Server.Core/Helpers/QuestHelper.cs

@@ -110,6 +110,7 @@ public class QuestHelper(
     /// <param name="profileSkill">the skill experience is being added to</param>
     /// <param name="progressAmount">the amount of experience being added to the skill</param>
     /// <returns>the adjusted skill progress gain</returns>
+    [Obsolete("Will be removed in 4.1: Use ProfileHelper.AdjustSkillExpForLowLevels instead.")]
     public int AdjustSkillExpForLowLevels(CommonSkill profileSkill, int progressAmount)
     {
         // TODO: what used this? can't find any uses in node

Testing/UnitTests/Tests/Services/ProfileHelperTests.cs

@@ -0,0 +1,67 @@
+using NUnit.Framework;
+using SPTarkov.Server.Core.Helpers;
+using SPTarkov.Server.Core.Servers;
+using SPTarkov.Server.Core.Services;
+using SPTarkov.Server.Core.Utils;
+using UnitTests.Mock;
+
+namespace UnitTests.Tests.Services;
+
+[TestFixture]
+public class ProfileHelperTests
+{
+    private ProfileHelper _sut;
+
+    [SetUp]
+    public void Setup()
+    {
+        _sut = new ProfileHelper(
+            new MockLogger<ProfileHelper>(),
+            new SPTarkov.Server.Core.Utils.Cloners.FastCloner(),
+            DI.GetInstance().GetService<SaveServer>(),
+            DI.GetInstance().GetService<DatabaseService>(),
+            DI.GetInstance().GetService<Watermark>(),
+            DI.GetInstance().GetService<TimeUtil>(),
+            DI.GetInstance().GetService<ServerLocalisationService>(),
+            DI.GetInstance().GetService<ConfigServer>()
+        );
+    }
+
+    [Test]
+    [TestCaseSource(nameof(GetAdjustSkillExpForLowLevelsTestData))]
+    public void AdjustSkillExpForLowLevels(double startingProgress, double addedProgress, double expectedAdjustedProgress)
+    {
+        var result = _sut.AdjustSkillExpForLowLevels(startingProgress, addedProgress);
+        Assert.AreEqual(expectedAdjustedProgress, result, 0.001);
+    }
+
+    private static IEnumerable<double[]> GetAdjustSkillExpForLowLevelsTestData()
+    {
+        // tests for levels 1-10 with +1.0 progress added
+        yield return [0000, 01.0, 10.000]; //  1,  10.0 XP on UI, +1 => 1.0/ 10.0 = 10.000/100 internal
+        yield return [0100, 01.0, 05.000]; //  2,  20.0 XP on UI, +1 => 1.0/ 20.0 =  5.000/100 internal
+        yield return [0200, 01.0, 03.333]; //  3,  30.0 XP on UI, +1 => 1.0/ 30.0 =  3.333/100 internal
+        yield return [0300, 01.0, 02.500]; //  4,  40.0 XP on UI, +1 => 1.0/ 40.0 =  2.500/100 internal
+        yield return [0400, 01.0, 02.000]; //  5,  50.0 XP on UI, +1 => 1.0/ 50.0 =  2.000/100 internal
+        yield return [0500, 01.0, 01.667]; //  6,  60.0 XP on UI, +1 => 1.0/ 60.0 =  1.667/100 internal
+        yield return [0600, 01.0, 01.428]; //  7,  70.0 XP on UI, +1 => 1.0/ 70.0 =  1.428/100 internal
+        yield return [0700, 01.0, 01.250]; //  8,  80.0 XP on UI, +1 => 1.0/ 80.0 =  1.250/100 internal
+        yield return [0800, 01.0, 01.111]; //  9,  90.0 XP on UI, +1 => 1.0/ 90.0 =  1.111/100 internal
+        yield return [0900, 01.0, 01.000]; // 10, 100.0 XP on UI, +1 => 1.0/100.0 =  1.000/100 internal => no scaling
+        yield return [1000, 01.0, 01.000]; // 11, 100.0 XP on UI, +1 => 1.0/100.0 =  1.000/100 internal => no scaling
+        // level boundary tests for partial progress with +4.0 progress added
+        yield return [0098, 04.0, 21.000]; //  1-> 2,   98 =  9.8/ 10, +4.0 =  9.8-> 10 (+2, -0.2), remaining +3.8 (3.8/ 20) = 19.000/100 => 21.000 total
+        yield return [0198, 04.0, 14.000]; //  2-> 3,  198 = 19.6/ 20, +4.0 = 19.6-> 20 (+2, -0.4), remaining +3.6 (3.6/ 30) = 12.000/100 => 14.000 total
+        yield return [0298, 04.0, 10.500]; //  3-> 4,  298 = 29.4/ 30, +4.0 = 29.4-> 30 (+2, -0.6), remaining +3.4 (3.4/ 40) =  8.500/100 => 10.500 total
+        yield return [0398, 04.0, 08.400]; //  4-> 5,  398 = 39.2/ 40, +4.0 = 39.2-> 40 (+2, -0.8), remaining +3.2 (3.2/ 50) =  6.400/100 =>  8.400 total
+        yield return [0498, 04.0, 07.000]; //  5-> 6,  498 = 49.0/ 50, +4.0 = 49.0-> 50 (+2, -1.0), remaining +3.0 (3.0/ 60) =  5.000/100 =>  7.000 total
+        yield return [0598, 04.0, 06.000]; //  6-> 7,  598 = 58.8/ 60, +4.0 = 58.8-> 60 (+2, -1.2), remaining +2.8 (2.8/ 70) =  4.000/100 =>  6.000 total
+        yield return [0698, 04.0, 05.250]; //  7-> 8,  698 = 68.6/ 70, +4.0 = 68.6-> 70 (+2, -1.4), remaining +2.6 (2.6/ 80) =  3.250/100 =>  5.250 total
+        yield return [0798, 04.0, 04.667]; //  8-> 9,  798 = 78.4/ 80, +4.0 = 78.4-> 80 (+2, -1.6), remaining +2.4 (2.4/ 90) =  2.667/100 =>  4.667 total
+        yield return [0898, 04.0, 04.200]; //  9->10,  898 = 88.2/ 90, +4.0 = 88.2-> 90 (+2, -1.8), remaining +2.2 (2.2/100) =  2.200/100 =>  4.200 total
+        yield return [0998, 04.0, 04.000]; // 10->11,  998 = 98.0/100, +4.0 = 98.0->100 (+2, -2.0), remaining +2.0 (2.0/100) =  2.000/100 =>  4.000 total
+        yield return [1098, 04.0, 04.000]; // 11->12, 1098 = 98.0/100, +4.0 = 98.0->100 (+2, -2.0), remaining +2.0 (2.0/100) =  2.000/100 =>  4.000 total
+        // test multi level boundary jumps
+        yield return [050, 30.0, 166.667]; //  1-> 3,   50 =  5.0/ 10, +3.0 =  5.0-> 10 (+50, -5.0), remaining +25: 0.0->20 (+100, -20), remaining +5 (5.0/30) = 16.667/100 => 166.667 total
+    }
+}