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NitroxModel/Discovery/InstallationFinders/EnvironmentFinder.cs

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+using System;
+using NitroxModel.Discovery.InstallationFinders.Core;
+using static NitroxModel.Discovery.InstallationFinders.Core.GameFinderResult;
+
+namespace NitroxModel.Discovery.InstallationFinders;
+
+/// <summary>
+/// Trying to find the path in environment variables by the key {GAMEINFO FULLNAME}_INSTALLATION_PATH that contains the installation directory.
+/// <list>
+///     <item>SUBNAUTICA_INSTALLATION_PATH</item>
+///     <item>SUBNAUTICAZERO_INSTALLATION_PATH</item>
+/// </list>
+/// </summary>
+public sealed class EnvironmentFinder : IGameFinder
+{
+    public GameFinderResult FindGame(GameInfo gameInfo)
+    {
+        string path = Environment.GetEnvironmentVariable($"{gameInfo.Name.ToUpper()}_INSTALLATION_PATH");
+        if (string.IsNullOrEmpty(path))
+        {
+            return Error($"Configured game path with environment variable {gameInfo.Name.ToUpper()}_INSTALLATION_PATH was found empty");
+        }
+
+        if (!GameInstallationHelper.HasValidGameFolder(path, gameInfo))
+        {
+            return Error($"Game installation directory '{path}' is invalid. Please enter the path to the '{gameInfo.Name}' installation");
+        }
+
+        return Ok(path);
+    }
+}