using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Principal;
using System.Runtime.InteropServices;
using System.IO;

namespace Payroll.BO
{
    [Serializable]
   public class FileAccessWithImpersonation
    {

        #region Declaration

        string userName = string.Empty;// "chapal" ;
        string domain = string.Empty;// "CEL";
        string password = string.Empty;// "cpl!@#45";
        string target = string.Empty;// @"\\CEL02\d$\Images\";
        
        /// <summary>
        /// This is 9 if There is No Domain Defined and 2 otherwise
        /// </summary>
        public const int LOGON32_LOGON_INTERACTIVE = 9; //2;

       /// <summary>
        /// This is 3 if There is No Domain Defined and 0 otherwise
       /// </summary>
        public const int LOGON32_PROVIDER_DEFAULT = 3;//0;
        WindowsImpersonationContext impersonationContext;

        #endregion

        #region Functions

        [DllImport("advapi32.dll")]
        public static extern int LogonUserA(String lpszUserName,
            String lpszDomain,
            String lpszPassword,
            int dwLogonType,
            int dwLogonProvider,
            ref IntPtr phToken);
        [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern int DuplicateToken(IntPtr hToken,
            int impersonationLevel,
            ref IntPtr hNewToken);

        [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern bool RevertToSelf();

        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        public static extern bool CloseHandle(IntPtr handle);


        private bool impersonateValidUser()
        {
            WindowsIdentity tempWindowsIdentity;
            IntPtr token = IntPtr.Zero;
            IntPtr tokenDuplicate = IntPtr.Zero;

            domain = Ease.CoreV35.Utility.ConfigUtility.GetAppSettings("ADDomain");
            userName = Ease.CoreV35.Utility.ConfigUtility.GetAppSettings("ADUser");
            password = Ease.CoreV35.Utility.ConfigUtility.GetAppSettings("ADPassword");
            password = Ease.CoreV35.Utility.Global.CipherFunctions.Decrypt("Cel.Admin", password);    

            if (RevertToSelf())
            {
                if (LogonUserA(userName, domain, password, LOGON32_LOGON_INTERACTIVE,
                    LOGON32_PROVIDER_DEFAULT, ref token) != 0)
                {
                    if (DuplicateToken(token, 2, ref tokenDuplicate) != 0)
                    {
                        tempWindowsIdentity = new WindowsIdentity(tokenDuplicate);
                        impersonationContext = tempWindowsIdentity.Impersonate();
                        if (impersonationContext != null)
                        {
                            CloseHandle(token);
                            CloseHandle(tokenDuplicate);
                            return true;
                        }
                    }
                }
            }
            if (token != IntPtr.Zero)
                CloseHandle(token);
            if (tokenDuplicate != IntPtr.Zero)
                CloseHandle(tokenDuplicate);
            return false;
        }

        private void undoImpersonation()
        {
            if(impersonationContext!=null)
                impersonationContext.Undo();
        }

        public void UploadFile(string TargetFolder,string FullFilePath,string NewFileName)
        {
            //System.IO.FileStream fs = null;
            //fs = System.IO.File.Open(FullFilePath , System.IO.FileMode.Open);
            //byte[]  bytes = new byte[fs.Length];
            //fs.Read(bytes , 0 , Convert.ToInt32(fs.Length));
            byte[] bytes = File.ReadAllBytes(FullFilePath);
            try
            {
                if (impersonateValidUser())
                {
                    //string[] Files = Directory.GetFiles(TargetFolder);
                    string fullTargetPath = TargetFolder + "\\" + NewFileName;
                    File.WriteAllBytes(fullTargetPath, bytes);
                    
                }
            }
            finally
            {
                undoImpersonation();
            }
            
        }

        public byte[] GetFileInBytes(string SourceFolder, string FileName)
        {
            byte[] bytes = null;
            try
            {
                if (impersonateValidUser())
                {
                    string fullSourcePath = SourceFolder+ "\\" + FileName;
                    bytes = File.ReadAllBytes(fullSourcePath);
                    
                }
            }
            finally
            {
                undoImpersonation();
            }

            return bytes;
        }

        #endregion
    }
}