using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.IO;
 
 
namespace AutoUpdateServer.Core
{
  /// <summary> 載入資源中的動態(tài)鏈接庫(dll)文件
  /// </summary>
  static class LoadResourceDll
  {
    static Dictionary<string, Assembly> Dlls = new Dictionary<string, Assembly>();
    static Dictionary<string, object> Assemblies = new Dictionary<string, object>();
 
 
    static Assembly AssemblyResolve(object sender, ResolveEventArgs args)
    {
      //程序集
      Assembly ass;
      //獲取加載失敗的程序集的全名
      var assName = new AssemblyName(args.Name).FullName;
      //判斷Dlls集合中是否有已加載的同名程序集
      if (Dlls.TryGetValue(assName, out ass) && ass != null)
      {
        Dlls[assName] = null;//如果有則置空并返回
        return ass;
      }
      else
      {
        throw new DllNotFoundException(assName);//否則拋出加載失敗的異常
      }
    }
 
 
    /// <summary> 注冊資源中的dll
    /// </summary>
    public static void RegistDLL()
    {
      //獲取調用者的程序集
      var ass = new StackTrace(0).GetFrame(1).GetMethod().Module.Assembly;
      //判斷程序集是否已經處理
      if (Assemblies.ContainsKey(ass.FullName))
      {
        return;
      }
      //程序集加入已處理集合
      Assemblies.Add(ass.FullName, null);
      //綁定程序集加載失敗事件(這里我測試了,就算重復綁也是沒關系的)
      AppDomain.CurrentDomain.AssemblyResolve += AssemblyResolve;
      //獲取所有資源文件文件名
      var res = ass.GetManifestResourceNames();
      foreach (var r in res)
      {
        //如果是dll,則加載
        if (r.EndsWith(".dll", StringComparison.OrdinalIgnoreCase))
        {
          try
          {
            if (r.Contains("CryptEnDe.dll") 
              || r.Contains("CryptEnDe_d.dll"))
            {
              ExtractResourceToFile(r, PathUtils.GetUpdateDllPath() + @"/" + r.Substring(r.IndexOf('.') + 1));
            }
 
 
            var s = ass.GetManifestResourceStream(r);
            var bts = new byte[s.Length];
            s.Read(bts, 0, (int)s.Length);
            var da = Assembly.Load(bts);
            //判斷是否已經加載
            if (Dlls.ContainsKey(da.FullName))
            {
              continue;
            }
            Dlls[da.FullName] = da;
          }
          catch(Exception e)
          {
            //加載失敗就算了...
          }
        }
      }
    }
 
 
    private static void ExtractResourceToFile(string resourceName, string filename)
    {
      //if (!System.IO.File.Exists(filename))
      {
        using (System.IO.Stream s = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName))
        {
          using (System.IO.FileStream fs = new System.IO.FileStream(filename, System.IO.FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite))
          {
            byte[] b = new byte[s.Length];
            s.Read(b, 0, b.Length);
            fs.Write(b, 0, b.Length);
          }
        }
      }
    }
 
 
  }
}

public static string GetUpdateDllPath()
{
  string strPath = @"C:/LTShiyi/cache/updatedll";
  if (!Directory.Exists(strPath))
  {
    Directory.CreateDirectory(strPath);
  }
 
   return strPath;
}

static Program()
{
  AutoUpdateServer.Core.LoadResourceDll.RegistDLL();
}