Added custom achievement system, adds achievements on server start

Libraries/SPTarkov.Server.Core/Models/Spt/Templates/Templates.cs

@@ -102,6 +102,16 @@ public record Templates
         set;
     }
 
+    /// <summary>
+    /// Achievements
+    /// </summary>
+    [JsonPropertyName("customAchievements")]
+    public List<Achievement>? CustomAchievements
+    {
+        get;
+        set;
+    }
+
     /// <summary>
     /// Location services data
     /// </summary>

Libraries/SPTarkov.Server.Core/Services/DatabaseService.cs

@@ -191,6 +191,22 @@ public class DatabaseService(
         return _databaseServer.GetTables().Templates?.Achievements!;
     }
 
+    /// <returns> assets/database/templates/customAchievements.json </returns>
+    public List<Achievement> GetCustomAchievements()
+    {
+        if (_databaseServer.GetTables().Templates?.Achievements == null)
+        {
+            throw new Exception(
+                _localisationService.GetText(
+                    "database-data_at_path_missing",
+                    "assets/database/templates/customAchievements.json"
+                )
+            );
+        }
+
+        return _databaseServer.GetTables().Templates?.CustomAchievements!;
+    }
+
     /// <returns> assets/database/templates/customisation.json </returns>
     public Dictionary<string, CustomizationItem?> GetCustomization()
     {

Libraries/SPTarkov.Server.Core/Services/PostDbLoadService.cs

@@ -6,6 +6,7 @@ using SPTarkov.Server.Core.Servers;
 using SPTarkov.Server.Core.Utils;
 using SPTarkov.Server.Core.Utils.Cloners;
 using SPTarkov.Common.Annotations;
+using SPTarkov.Server.Core.Models.Eft.Common.Tables;
 
 namespace SPTarkov.Server.Core.Services;
 
@@ -50,6 +51,8 @@ public class PostDbLoadService(
 
         AddCustomLooseLootPositions();
 
+        MergeCustomAchievements();
+
         AdjustMinReserveRaiderSpawnChance();
 
         if (_coreConfig.Fixes.FixShotgunDispersion)
@@ -123,6 +126,23 @@ public class PostDbLoadService(
         _raidWeatherService.GenerateWeather(currentSeason);
     }
 
+    /// <summary>
+    /// Merge custom achievements into achievement db table 
+    /// </summary>
+    protected void MergeCustomAchievements()
+    {
+        var achievements = _databaseService.GetAchievements();
+        foreach (var customAchievement in _databaseService.GetCustomAchievements()) {
+            if (achievements.Exists((a) => a.Id == customAchievement.Id))
+            {
+                _logger.Warning($"Unable to add custom achievement as id: ${customAchievement.Id} already exists");
+                continue;
+            }
+
+            achievements.Add(customAchievement);
+        }
+    }
+
     private void RemoveNewBeginningRequirementFromPrestige()
     {
         var prestigeDb = _databaseService.GetTemplates().Prestige;