public static()

in src/Microsoft.VisualStudio.SlnGen/SlnFile.cs [135:227]
70 lines of code
17 McCabe index (conditional complexity)

        public static (string solutionFileFullPath, int customProjectTypeGuidCount, int solutionItemCount, Guid solutionGuid) GenerateSolutionFile(ProgramArguments arguments, IEnumerable<Project> projects, ISlnGenLogger logger)
        {
            List<Project> projectList = projects.ToList();

            Project firstProject = projectList.First();

            IReadOnlyDictionary<string, Guid> customProjectTypeGuids = SlnProject.GetCustomProjectTypeGuids(firstProject);

            IReadOnlyCollection<string> solutionItems = SlnProject.GetSolutionItems(firstProject, logger).ToList();

            string solutionFileFullPath = arguments.SolutionFileFullPath?.LastOrDefault();

            if (solutionFileFullPath.IsNullOrWhiteSpace())
            {
                string solutionDirectoryFullPath = arguments.SolutionDirectoryFullPath?.LastOrDefault();

                if (solutionDirectoryFullPath.IsNullOrWhiteSpace())
                {
                    solutionDirectoryFullPath = firstProject.DirectoryPath;
                }

                string solutionFileName = Path.ChangeExtension(Path.GetFileName(firstProject.FullPath), "sln");

                solutionFileFullPath = Path.Combine(solutionDirectoryFullPath!, solutionFileName);
            }

            logger.LogMessageHigh($"Generating Visual Studio solution \"{solutionFileFullPath}\" ...");

            if (customProjectTypeGuids.Count > 0)
            {
                logger.LogMessageLow("Custom Project Type GUIDs:");
                foreach (KeyValuePair<string, Guid> item in customProjectTypeGuids)
                {
                    logger.LogMessageLow("  {0} = {1}", item.Key, item.Value);
                }
            }

            SlnFile solution = new SlnFile
            {
                Platforms = arguments.GetPlatforms(),
                Configurations = arguments.GetConfigurations(),
            };

            if (arguments.VisualStudioVersion.HasValue)
            {
                if (arguments.VisualStudioVersion.Version != null && Version.TryParse(arguments.VisualStudioVersion.Version, out Version version))
                {
                    solution.VisualStudioVersion = version;
                }

                if (solution.VisualStudioVersion == null)
                {
                    string devEnvFullPath = arguments.GetDevEnvFullPath(Program.CurrentDevelopmentEnvironment.VisualStudio);

                    if (!devEnvFullPath.IsNullOrWhiteSpace() && File.Exists(devEnvFullPath))
                    {
                        FileVersionInfo fileVersionInfo = FileVersionInfo.GetVersionInfo(devEnvFullPath);

                        solution.VisualStudioVersion = new Version(fileVersionInfo.ProductMajorPart, fileVersionInfo.ProductMinorPart, fileVersionInfo.ProductBuildPart, fileVersionInfo.FilePrivatePart);
                    }
                }
            }

            if (SlnFile.TryParseExistingSolution(solutionFileFullPath, out Guid solutionGuid, out IReadOnlyDictionary<string, Guid> projectGuidsByPath))
            {
                logger.LogMessageNormal("Updating existing solution file and reusing Visual Studio cache");

                solution.SolutionGuid = solutionGuid;
                solution.ExistingProjectGuids = projectGuidsByPath;

                arguments.LoadProjectsInVisualStudio = new[] { bool.TrueString };
            }

            solution.AddProjects(projectList, customProjectTypeGuids, arguments.IgnoreMainProject ? null : firstProject.FullPath);

            solution.AddSolutionItems(solutionItems);

            if (!arguments.EnableFolders())
            {
                foreach (SlnProject project in solution._projects.Distinct(new EqualityComparer<SlnProject>((x, y) => string.Equals(x.SolutionFolder, y.SolutionFolder)))
                    .Where(i => !string.IsNullOrWhiteSpace(i.SolutionFolder) && i.SolutionFolder.Contains(Path.DirectorySeparatorChar)))
                {
                    logger.LogError($"The value of SlnGenSolutionFolder \"{project.SolutionFolder}\" cannot contain directory separators.");
                }
            }

            if (!logger.HasLoggedErrors)
            {
                solution.Save(solutionFileFullPath, arguments.EnableFolders(), arguments.EnableCollapseFolders());
            }

            return (solutionFileFullPath, customProjectTypeGuids.Count, solutionItems.Count, solution.SolutionGuid);
        }