public static VirtualFileSystemPath GetAppPathByDll()

in resharper/resharper-unity/src/Unity/UnityEditorIntegration/UnityInstallationFinder.cs [265:324]
55 lines of code
15 McCabe index (conditional complexity)

        public static VirtualFileSystemPath GetAppPathByDll(XmlElement documentElement)
        {
            var referencePathElement = documentElement.ChildElements()
                .Where(a => a.Name == "ItemGroup").SelectMany(b => b.ChildElements())
                .Where(c => c.Name == "Reference" &&
                            (c.GetAttribute("Include").Equals("UnityEngine") // we can't use StartsWith here, some "UnityEngine*" libs are in packages
                             || c.GetAttribute("Include").Equals("UnityEngine.CoreModule") // Dll project may have this reference instead of UnityEngine.dll
                             || c.GetAttribute("Include").Equals("UnityEditor")))
                .SelectMany(d => d.ChildElements())
                .FirstOrDefault(c => c.Name == "HintPath");

            if (referencePathElement == null || string.IsNullOrEmpty(referencePathElement.InnerText))
                return null;

            var filePath = VirtualFileSystemPath.Parse(referencePathElement.InnerText, InteractionContext.SolutionContext);
            if (!filePath.IsAbsolute) // RIDER-21237
                return null;

            if (filePath.ExistsFile)
            {
                switch (PlatformUtil.RuntimePlatform)
                {
                    case JetPlatform.Windows:
                    {
                        return GoUpForUnityExecutable(filePath,$"{Unity}.exe", path => path.ExistsFile) 
                               ?? GoUpForUnityExecutable(filePath,$"{Tuanjie}.exe", path => path.ExistsFile);
                    }
                    case JetPlatform.Linux:
                    {
                        return GoUpForUnityExecutable(filePath, Unity, path => path.ExistsFile)
                               ?? GoUpForUnityExecutable(filePath, Tuanjie, path => path.ExistsFile);
                    }
                    case JetPlatform.MacOsX:
                    {
                        var result = GoUpForUnityExecutable(filePath, $"{Unity}.app", path => path.ExistsDirectory) 
                                     ?? GoUpForUnityExecutable(filePath, $"{Tuanjie}.app", path => path.ExistsDirectory);
                        // not sure, how this worked before: either older Unity versions or assembly is inside the Unity.app/Contents
                        if (result == null)
                        {
                            var appPath = filePath;
                            while (!appPath.Name.Equals("Contents"))
                            {
                                appPath = appPath.Directory;
                                if (!appPath.ExistsDirectory || appPath.IsEmpty)
                                    return null;
                            }

                            appPath = appPath.Directory;
                            return appPath;    
                        }
                        return result;
                    }
                    default:
                        ourLogger.Error("Unknown runtime platform");
                        break;
                }
            }

            return null;
        }