// 源文件頭信息：
// copyright file="ControllersFactory.cs">
// Copyright(c)2014-2034 Kencery.All rights reserved.
// 創建人：韓迎龍(kencery)
// 創建時間：2015-6-18
// /copyright>

using System;
using System.Reflection;
using System.Web.Mvc;
using System.Web.Routing;
using System.Web.SessionState;

namespace BookSystem_Controllers
{
  /// summary>
  /// 重寫注冊控制器的方法，使之能夠將控制器管分離到其它類庫中實現
  /// auther>
  ///   name>kencery/name>
  ///   date>2015-6-18/date>
  /// /auther>
  /// /summary>
  /// 說明：IControllerFactory接口含有三個需要實現的方法：CreateController，GetControllerSessionBehavior，ReleaseController
  /// 使用：在MVC App_Start文件夾中的RouteConfig中的方法RegisterRoutes中的第一行中寫入下面注冊語句,Global.asax中也可注冊，放到注冊路由之前即可
  /// ControllerBuilder.Current.SetControllerFactory(new ControllersFactory("BookSystem_Controllers")); //BookSystem_Controllers為控制器的類庫
  public class ControllersFactory : IControllerFactory
  {
    private readonly string _assemblyName;
    private readonly string _controlerDefaultNameSpage;
    private Assembly _controllerAssembly;

    /// summary>
    /// 獲取控制器所在的程序集名稱
    /// /summary>
    public string AssemblyName
    {
      get { return _assemblyName; }
    }

    /// summary>
    /// 獲取控制器的默認命名空間
    /// /summary>
    public string ControlerDefaultNameSpage
    {
      get { return _controlerDefaultNameSpage; }
    }

    /// summary>
    /// 獲取控制器所在的程序集的Assembly實例
    /// /summary>
    public Assembly ControllerAssembly
    {
      get
      {
        return _controllerAssembly ?? (_controllerAssembly = Assembly.Load(AssemblyName)); //加載控制器信息
      }
    }

    /// summary>
    /// 構造函數實例化
    /// /summary>
    /// param name="assemblyName">/param>
    public ControllersFactory(string assemblyName)
    {
      _assemblyName = assemblyName;
    }

    /// summary>
    /// 構造函數實例化
    /// /summary>
    /// param name="assemblyName">/param>
    /// param name="controlerDefaultNameSpage">/param>
    public ControllersFactory(string assemblyName, string controlerDefaultNameSpage)
    {
      _assemblyName = assemblyName;
      _controlerDefaultNameSpage = controlerDefaultNameSpage;
    }

    /// summary>
    /// 獲取控制器類的全名
    /// /summary>
    /// param name="controllerName">控制器名稱/param>
    public string GetControllerFullName(string controllerName)
    {
      return string.Format("{0}.{1}Controller",
        string.IsNullOrEmpty(ControlerDefaultNameSpage) ? AssemblyName : ControlerDefaultNameSpage,
        controllerName);
    }

    /// summary>
    /// 獲取控制器實例對象，根據controllerName生成一個沒有請求上下文對象的空的控制器，在為此控制器制定ControllerContext對象，然后返回控制器實例
    /// /summary>
    /// param name="requestContext">/param>
    /// param name="controllerName">/param>
    public IController CreateController(RequestContext requestContext, string controllerName)
    {
      var controller = ControllerAssembly.CreateInstance(GetControllerFullName(controllerName)) as Controller;
      if (controller == null)
        return null;
      if (controller.ControllerContext == null)
      {
        controller.ControllerContext = new ControllerContext(requestContext, controller);
      }
      else
      {
        controller.ControllerContext.RequestContext = requestContext;
      }
      return controller;
    }

    /// summary>
    /// 返回請求的會話狀態的支持類型
    /// /summary>
    /// param name="requestContext">/param>
    /// param name="controllerName">/param>
    public SessionStateBehavior GetControllerSessionBehavior(RequestContext requestContext, string controllerName)
    {
      var controllerType = ControllerAssembly.GetType(GetControllerFullName(controllerName), true, true);
      var sessionStateAttr =
        Attribute.GetCustomAttribute(controllerType, typeof (SessionStateAttribute), false) as
          SessionStateAttribute;
      return sessionStateAttr == null ? SessionStateBehavior.Default : sessionStateAttr.Behavior;
    }

    /// summary>
    /// 釋放資源
    /// /summary>
    /// param name="controller">/param>
    public void ReleaseController(IController controller)
    {
      var idDisposable = controller as IDisposable;
      if (idDisposable != null)
      {
        idDisposable.Dispose();
      }
    }
  }
}

//系統默認路由
    routes.MapRoute(
      name: "Default",
      url: "{controller}/{action}/{id}",
      defaults: new {controller = "Login", action = "Index", id = UrlParameter.Optional},
      namespaces: new string[] {"BookSystem_Controllers"}
);