ConfigurationFileProvider.cs

// Licensed to Elasticsearch B.V under one or more agreements.
// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information

using System.IO.Abstractions;
using System.Text.RegularExpressions;
using Elastic.Documentation.Configuration.Assembler;
using Elastic.Documentation.Configuration.Converters;
using Elastic.Documentation.Configuration.Serialization;
using Elastic.Documentation.Configuration.Toc;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using YamlDotNet.Serialization;
using YamlDotNet.Serialization.NamingConventions;

namespace Elastic.Documentation.Configuration;

public partial class ConfigurationFileProvider
{
	private readonly IFileSystem _fileSystem;
	private readonly string _assemblyName;
	private readonly ILogger<ConfigurationFileProvider> _logger;

	public static IDeserializer Deserializer { get; } = new StaticDeserializerBuilder(new YamlStaticContext())
		.WithNamingConvention(UnderscoredNamingConvention.Instance)
		.WithTypeConverter(new HintTypeSetConverter())
		.WithTypeConverter(new TocItemCollectionYamlConverter())
		.WithTypeConverter(new TocItemYamlConverter())
		.WithTypeConverter(new SiteTableOfContentsCollectionYamlConverter())
		.WithTypeConverter(new SiteTableOfContentsRefYamlConverter())
		.WithTypeConverter(new ApiConfigurationConverter())
		.Build();

	public static IDeserializer NavV2Deserializer { get; } = new StaticDeserializerBuilder(new YamlStaticContext())
		.WithNamingConvention(UnderscoredNamingConvention.Instance)
		.WithTypeConverter(new NavV2FileYamlConverter())
		.Build();

	public ConfigurationSource ConfigurationSource { get; }

	public string? GitReference { get; }

	public ConfigurationFileProvider(
		ILoggerFactory logFactory,
		IFileSystem fileSystem,
		bool skipPrivateRepositories = false,
		ConfigurationSource? configurationSource = null
	)
	{
		_logger = logFactory.CreateLogger<ConfigurationFileProvider>();
		_fileSystem = fileSystem;
		_assemblyName = typeof(ConfigurationFileProvider).Assembly.GetName().Name!;
		SkipPrivateRepositories = skipPrivateRepositories;
		// Use a unique subdirectory per instance to avoid file-locking collisions when
		// multiple processes or parallel tests share the same ApplicationData path.
		var configRuntimeDir = Path.Join(Paths.ApplicationData.FullName, "config-runtime", Guid.NewGuid().ToString("N"));
		TemporaryDirectory = fileSystem.DirectoryInfo.New(configRuntimeDir);
		TemporaryDirectory.Create();

		// TODO: This doesn't work as expected if a github actions consumer repo has a `config` directory.
		// ConfigurationSource = configurationSource ?? (
		// 	fileSystem.Directory.Exists(LocalConfigurationDirectory)
		// 		? ConfigurationSource.Local : ConfigurationSource.Embedded
		// 	);
		if (configurationSource is { } source)
			ConfigurationSource = source;
		else
		{
			string[] spotChecks = ["navigation.yml", "versions.yml", "products.yml", "assembler.yml", "search.yml"];
			var defaultSource =
				fileSystem.Directory.Exists(LocalConfigurationDirectory)
					&& spotChecks.All(f => fileSystem.File.Exists(Path.Join(LocalConfigurationDirectory, f)))
				? ConfigurationSource.Local
				: ConfigurationSource.Embedded;
			ConfigurationSource = defaultSource;
		}

		if (ConfigurationSource == ConfigurationSource.Local && !fileSystem.Directory.Exists(LocalConfigurationDirectory))
			throw new Exception($"Required directory form {nameof(ConfigurationSource)}.{nameof(ConfigurationSource.Local)} directory {LocalConfigurationDirectory} does not exist.");

		if (ConfigurationSource == ConfigurationSource.Remote && !fileSystem.Directory.Exists(AppDataConfigurationDirectory))
			throw new Exception($"Required directory form {nameof(ConfigurationSource)}.{nameof(ConfigurationSource.Remote)} directory {AppDataConfigurationDirectory} does not exist.");

		var path = GetAppDataPath("git-ref.txt");
		if (_fileSystem.File.Exists(path))
			GitReference = _fileSystem.File.ReadAllText(path);
		else if (ConfigurationSource == ConfigurationSource.Remote)
			throw new Exception($"Can not read git-ref.txt in directory {LocalConfigurationDirectory}");

		if (ConfigurationSource == ConfigurationSource.Remote)
		{
			_logger.LogInformation("{ConfigurationSource}: git ref '{GitReference}', in {Directory}",
				$"{nameof(ConfigurationSource)}.{nameof(ConfigurationSource.Remote)}", GitReference, AppDataConfigurationDirectory);
		}

		if (ConfigurationSource == ConfigurationSource.Local)
		{
			_logger.LogInformation("{ConfigurationSource}: located {Directory}",
				$"{nameof(ConfigurationSource)}.{nameof(ConfigurationSource.Local)}", LocalConfigurationDirectory);
		}
		if (ConfigurationSource == ConfigurationSource.Embedded)
		{
			_logger.LogInformation("{ConfigurationSource} using embedded in binary configuration",
				$"{nameof(ConfigurationSource)}.{nameof(ConfigurationSource.Embedded)}");
		}

		VersionFile = CreateTemporaryConfigurationFile("versions.yml");
		ProductsFile = CreateTemporaryConfigurationFile("products.yml");
		AssemblerFile = CreateTemporaryConfigurationFile("assembler.yml");
		NavigationFile = CreateTemporaryConfigurationFile("navigation.yml");
		NavigationV2File = TryCreateTemporaryConfigurationFile("navigation-v2.yml");
		LegacyUrlMappingsFile = CreateTemporaryConfigurationFile("legacy-url-mappings.yml");
		// reading from synonyms.yml is temporary. If you spot this again as a future reader, feel free to remove it.
		SearchFile = CreateTemporaryConfigurationFile("search.yml", "synonyms.yml");
	}

	public bool SkipPrivateRepositories { get; }

	private IDirectoryInfo TemporaryDirectory { get; }

	public IFileInfo NavigationFile { get; private set; }

	/// <summary>Optional — present only when <c>config/navigation-v2.yml</c> exists.</summary>
	public IFileInfo? NavigationV2File { get; }

	public IFileInfo VersionFile { get; }

	public IFileInfo ProductsFile { get; }

	public IFileInfo AssemblerFile { get; }

	public IFileInfo LegacyUrlMappingsFile { get; }

	public IFileInfo SearchFile { get; }
	public IFileInfo CreateNavigationFile(AssemblyConfiguration configuration)
	{
		var privateRepositories = configuration.PrivateRepositories;
		if (privateRepositories.Count == 0 || !SkipPrivateRepositories)
			return NavigationFile;

		var targets = string.Join("|", privateRepositories.Keys);

		var tempFile = Path.Join(TemporaryDirectory.FullName, "navigation.filtered.yml");
		if (_fileSystem.File.Exists(tempFile))
			return NavigationFile;

		_logger.LogInformation("Filtering navigation file to remove private repositories");

		// This routine removes `toc: `'s linking to private repositories and reindents any later lines if needed.
		// This will make any public children in the nav move up one place.
		var spacing = -1;
		var reindenting = -1;
		foreach (var l in _fileSystem.File.ReadAllLines(NavigationFile.FullName))
		{
			var line = l;
			if (spacing > -1 && !string.IsNullOrWhiteSpace(line) && !line.StartsWith(new string(' ', spacing), StringComparison.Ordinal))
			{
				spacing = -1;
				reindenting = -1;
			}

			if (spacing != -1 && Regex.IsMatch(line, $@"^\s{{{spacing}}}\S"))
			{
				spacing = -1;
				reindenting = -1;
			}

			else if (spacing != -1 && Regex.IsMatch(line, $@"^(\s{{{spacing + 3},}})\S"))
			{
				var matches = Regex.Match(line, $@"^(?<spacing>\s{{{spacing}}})(?<remainder>.+)$");
				line = $"{new string(' ', Math.Max(0, spacing - 4))}{matches.Groups["remainder"].Value}";
				reindenting = spacing;
			}

			if (spacing == -1 && TocPrefixRegex().IsMatch(line))
			{
				var matches = Regex.Match(line, $@"^(?<spacing>\s+)-\s?toc:\s?(?:{targets})\:");
				if (matches.Success)
					spacing = matches.Groups["spacing"].Value.Length;
				if (spacing == 0)
					spacing = -1;
			}

			if (spacing == -1 || reindenting > 0)
				_fileSystem.File.AppendAllLines(tempFile, [line]);
		}

		if (configuration.AvailableRepositories.TryGetValue("docs-builder", out var docsBuildRepository) && docsBuildRepository is { Skip: false, Path: not null })
		{
			// language=yaml
			_fileSystem.File.AppendAllText(tempFile,
				"""

						  - toc: docs-builder://
						    path_prefix: reference/docs-builder
						    children:
						      - toc: docs-builder://development
						        path_prefix: reference/docs-builder/dev
						        children:
						          - toc: docs-builder://development/link-validation
						            path_prefix: reference/docs-builder/dev/link-val
						""");
		}
		NavigationFile = _fileSystem.FileInfo.New(tempFile);
		return NavigationFile;


	}

	private IFileInfo? TryCreateTemporaryConfigurationFile(string fileName)
	{
		if (ConfigurationSource == ConfigurationSource.Local)
		{
			var localPath = GetLocalPath(fileName);
			if (!_fileSystem.File.Exists(localPath))
				return null;
		}
		else if (ConfigurationSource == ConfigurationSource.Remote)
		{
			var appDataPath = GetAppDataPath(fileName);
			if (!_fileSystem.File.Exists(appDataPath))
				return null;
		}
		else
		{
			// Embedded — check if resource exists
			var resourceName = $"{_assemblyName}.{fileName}";
			if (typeof(ConfigurationFileProvider).Assembly.GetManifestResourceStream(resourceName) is null)
				return null;
		}

		return CreateTemporaryConfigurationFile(fileName);
	}

	private IFileInfo CreateTemporaryConfigurationFile(string fileName, string? fallback = null)
	{
		using var stream = GetLocalOrEmbedded(fileName, fallback);
		var context = stream.ReadToEnd();
		var fi = _fileSystem.FileInfo.New(Path.Join(TemporaryDirectory.FullName, fileName));
		_fileSystem.File.WriteAllText(fi.FullName, context);
		return fi;
	}

	private StreamReader GetLocalOrEmbedded(string fileName, string? fallback = null)
	{
		var localPath = GetLocalPath(fileName);
		if (ConfigurationSource == ConfigurationSource.Local)
		{
			if (_fileSystem.File.Exists(localPath))
			{
				var reader = _fileSystem.File.OpenText(localPath);
				return reader;
			}
			var fallbackPath = fallback is not null ? GetLocalPath(fallback) : null;
			if (fallbackPath is not null && _fileSystem.File.Exists(fallbackPath))
			{
				var reader = _fileSystem.File.OpenText(fallbackPath);
				return reader;
			}
			throw new Exception($"Can not read {fileName} in directory {LocalConfigurationDirectory}");
		}

		var appDataPath = GetAppDataPath(fileName);
		if (ConfigurationSource == ConfigurationSource.Remote)
		{
			if (_fileSystem.File.Exists(appDataPath))
			{
				var reader = _fileSystem.File.OpenText(appDataPath);
				return reader;
			}
			var fallbackPath = fallback is not null ? GetAppDataPath(fallback) : null;
			if (fallbackPath is not null && _fileSystem.File.Exists(fallbackPath))
			{
				var reader = _fileSystem.File.OpenText(fallbackPath);
				return reader;
			}
			throw new Exception($"Can not read {fileName} in directory {AppDataConfigurationDirectory}");
		}
		return GetEmbeddedStream(fileName);
	}

	private StreamReader GetEmbeddedStream(string fileName)
	{
		var resourceName = $"{_assemblyName}.{fileName}";
		var resourceStream = typeof(ConfigurationFileProvider).Assembly.GetManifestResourceStream(resourceName)!;
		var reader = new StreamReader(resourceStream, leaveOpen: false);
		return reader;
	}

	public static string AppDataConfigurationDirectory { get; } = Path.Join(Paths.ApplicationData.FullName, "config-clone", "config");
	public static string LocalConfigurationDirectory { get; } = Path.Join(Directory.GetCurrentDirectory(), "config");

	private static string GetLocalPath(string file) => Path.Join(LocalConfigurationDirectory, file);
	private static string GetAppDataPath(string file) => Path.Join(AppDataConfigurationDirectory, file);

	[GeneratedRegex(@"^\s+-?\s?toc:\s?")]
	private static partial Regex TocPrefixRegex();
}

public static class ConfigurationFileProviderServiceCollectionExtensions
{
	public static IServiceCollection AddConfigurationFileProvider(this IServiceCollection services,
		bool skipPrivateRepositories,
		ConfigurationSource? configurationSource,
		Action<IServiceCollection, ConfigurationFileProvider> configure)
	{
		using var sp = services.BuildServiceProvider();
		var logFactory = sp.GetRequiredService<ILoggerFactory>();
		var provider = new ConfigurationFileProvider(logFactory, FileSystemFactory.RealRead, skipPrivateRepositories, configurationSource);
		_ = services.AddSingleton(provider);
		configure(services, provider);
		return services;
	}
}