unreliablecode / Unity-AntiModLoader

using System;
using System.IO;
using UnityAntiModLoader.Models;

namespace UnityAntiModLoader.Detectors
{
    public static class MelonLoaderDetector
    {
        // Known MelonLoader directory structures
        private static readonly string[] s_KnownDirectories = new string[]
        {
            "MelonLoader",
            "MelonLoader/Dependencies",
            "MelonLoader/Managed",
            "MelonLoader/Libs",
            "Mods",
            "Plugins",
            "UserLibs",
            "UserData"
        };

        // Known MelonLoader binaries, proxies, and logfiles
        private static readonly string[] s_KnownFiles = new string[]
        {
            "version.dll",
            "winmm.dll",
            "MelonLoader/MelonLoader.dll",
            "MelonLoader/Dependencies/Bootstrap.dll",
            "MelonLoader/Dependencies/Harmony/0Harmony.dll",
            "MelonLoader/Dependencies/Il2CppAssemblyGenerator/Il2CppAssemblyGenerator.dll",
            "MelonLoader/Dependencies/Mono.Cecil.dll",
            "MelonLoader/Latest.log"
        };

        /// <summary>
        /// Scans the game directory for MelonLoader mod loader artifacts.
        /// </summary>
        /// <param name="gameRootDirectory">Base path of the game executable.</param>
        /// <returns>ModDetectionResult with detected files and directories.</returns>
        public static ModDetectionResult Scan(string gameRootDirectory)
        {
            var result = new ModDetectionResult
            {
                FrameworkName = "MelonLoader",
                DetectionTimestamp = DateTime.UtcNow
            };

            if (string.IsNullOrEmpty(gameRootDirectory) || !Directory.Exists(gameRootDirectory))
            {
                return result;
            }

            // 1. Check for known MelonLoader directories
            foreach (string relDir in s_KnownDirectories)
            {
                string fullDirPath = Path.Combine(gameRootDirectory, relDir);
                try
                {
                    if (Directory.Exists(fullDirPath))
                    {
                        result.DetectedArtifacts.Add($"Directory: {relDir}");
                    }
                }
                catch
                {
                    // Ignore filesystem access exceptions
                }
            }

            // 2. Check for known MelonLoader files & bootstrap hooks
            foreach (string relFile in s_KnownFiles)
            {
                string fullFilePath = Path.Combine(gameRootDirectory, relFile);
                try
                {
                    if (File.Exists(fullFilePath))
                    {
                        result.DetectedArtifacts.Add($"File: {relFile}");
                    }
                }
                catch
                {
                    // Ignore filesystem access exceptions
                }
            }

            // Evaluate severity
            if (result.DetectedArtifacts.Count > 0)
            {
                result.Severity = result.DetectedArtifacts.Count >= 2 ? DetectionSeverity.Critical : DetectionSeverity.High;
            }

            return result;
        }
    }
}