using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Xml.XPath;
using ToolsModule.ManagmentExtension;

namespace ToolsModule.ManagmentDependency
{
    /// <summary>
    /// Загрузчик данных
    /// </summary>
    public static partial class ServiceProviderLoader
	{
		private static readonly string _configFileName = "DepartmentPortal.config";

		/// <summary>
		/// Получение данных с файла настроек (для releaze версии сборки)
		/// </summary>
		/// <param name="key"></param>
		/// <returns></returns>
		public static string GetConfigData(string key)
		{
			var fileName = GetFile(_configFileName);
			if (!File.Exists(fileName))
			{
				return string.Empty;
			}

			var doc = new XPathDocument(fileName);
			var nav = doc.CreateNavigator();
			var data = nav.SelectDescendants(key, "", false);
			data.MoveNext();
			return data.Current.Value;
		}
		/// <summary>
		/// Загрузка всех классов-реализаций IImplementationExtension
		/// </summary>
		/// <returns></returns>
		public static List<IDependencyRegistration> GetImplementationExtensions()
		{
			var list = new List<IDependencyRegistration>();
			var files = Directory.GetFiles(TryGetImplementationExtensionsFolder(), "*.dll", SearchOption.AllDirectories);
			var loadedFiles = new List<string>();
			foreach (var file in files.Distinct())
			{
				if (loadedFiles.Contains(file.GetFileName()))
				{
					continue;
				}
				var asm = Assembly.LoadFrom(file);
				foreach (var t in asm.GetExportedTypes())
				{
					if (t.IsClass && typeof(IDependencyRegistration).IsAssignableFrom(t))
					{
						list.Add((IDependencyRegistration)Activator.CreateInstance(t));
					}
				}
				loadedFiles.Add(file.GetFileName());
			}
			return list;
		}

		/// <summary>
		/// Получение имени файла
		/// </summary>
		/// <param name="fileName"></param>
		/// <returns></returns>
		private static string GetFile(string fileName) => Path.Combine(Path.GetDirectoryName(Assembly.GetEntryAssembly().Location), fileName);

		private static string TryGetImplementationExtensionsFolder()
		{
			var directory = new DirectoryInfo(Directory.GetCurrentDirectory());
			while (directory != null && !directory.GetDirectories("ImplementationExtensions", SearchOption.AllDirectories).Any(x => x.Name == "ImplementationExtensions"))
			{
				directory = directory.Parent;
			}
			return $"{directory.FullName}\\ImplementationExtensions";
		}

	}
}