/*********************************************************************************************
 * Copyright 2004 - Volian Enterprises, Inc. All rights reserved.
 * Volian Enterprises - Proprietary Information - DO NOT COPY OR DISTRIBUTE
 * ------------------------------------------------------------------------------
 * $Workfile: VETempFile.cs $     $Revision: 1 $
 * $Author: Kathy $   $Date: 7/27/04 8:45a $
 *
 * $History: VETempFile.cs $
 * 
 * *****************  Version 1  *****************
 * User: Kathy        Date: 7/27/04    Time: 8:45a
 * Created in $/LibSource/VENetwork
 *********************************************************************************************/

using System;
using System.IO;
using System.Windows.Forms;


namespace VENetwork
{
	// this class manages the temps directory for multi-user support in ve-proms.
	// The temps directory is used to handle a user's temporary files in support of 
	// printing, etc.
	public class VETempFile
	{
		public string TemporaryDirectoryName;
		private string TemporaryFileName;
		public string TempNum;
		FileStream tmpFs;
		private string CurrentDir;

		public VETempFile(string cd)
		{
			CurrentDir = cd;
			tmpFs=null;
		}
	
		~ VETempFile()
		{
			CloseTempProc();
		}
		
		// Converts the userid, num & PorD (characters 'P' or 'D') into a file-
		// name to be used for temporary file support. This creates the file-
		// name. The userid is extended to 8 characters with '_'s.
		public string MakeTempName(string userid, string num, char PorD)
		{
			// first, make the temp directory, i.e. temps, if it doesn't
			// exist.
			DirectoryInfo di = new DirectoryInfo(CurrentDir + "temps");
			if (!di.Exists) di.Create();
			string tmpuid = userid.PadRight(8,'_');
			string tpath = "temps" + "\\" + tmpuid + "." + PorD.ToString() + num;
			return tpath;
		}

		// This method truncates the temp file (user___.P##) and then closes it.
		public void CloseTempProc()
		{
			if(tmpFs!=null)
			{
				try
				{
					// if called from a destructor, the file may have been closed - reopen
					// it if we can't write
					if (tmpFs.CanWrite==false)
					{
						tmpFs=null;
						tmpFs = new FileStream(TemporaryFileName,FileMode.OpenOrCreate,FileAccess.ReadWrite,FileShare.None);
					}
					tmpFs.Seek(0L,SeekOrigin.Begin);
					tmpFs.SetLength(0L);   // truncate the file
					tmpFs.Close();
					tmpFs=null;
					TemporaryDirectoryName=null;
				}
				catch (Exception e)
				{
					MessageBox.Show(e.Message,this.TemporaryDirectoryName);
				}
			}
		}

		// make all subdirectories, if not exist
		private void MakeAllNecessaryDirectories(string path)
		{
			if (Directory.Exists(CurrentDir + path)) return;

			// Create the directory, and any subdirectories
			DirectoryInfo di = Directory.CreateDirectory(CurrentDir + path);
		}

		// sets class variables based on input.
		private void SetUpTempDir(string userid, string num)
		{
			string TempPath = MakeTempName(userid,num,'D'); 
			MakeAllNecessaryDirectories(TempPath);
			TemporaryDirectoryName = TempPath + "\\";
		}

		// This method attempts to attach to the specified temp file.
		// Userid and num are combined to create a process name and
		// TempPathDirectory. If the file is successfully opened and
		// a connection is established, a byte count matching the process
		// number is written to the file and the file is held open. (This
		// byte count is actually written in the connection logic,
		// veconn.cs, after a connection is successfully made.)
		public bool AttachSpecificTemp(string userid, string num)
		{
			// if already open, close.
			CloseTempProc();
			string pname = CurrentDir + MakeTempName(userid,num,'P');

			// check to see if this user can use the file, i.e. open
			// exclusively.
			try
			{
				tmpFs = new FileStream(pname,FileMode.OpenOrCreate,FileAccess.ReadWrite,FileShare.None);
			}
			catch
			{
				return false;
			}
			TemporaryFileName = pname;
			TempNum = num;
			SetUpTempDir(userid,num);
			return true;
		}

		// if len is !0, try to delete files of the specified length.
		// zero length files are normally in transition and will be 
		// deleted by their owners.
		public void DeleteFiles(string tmp, int len)
		{	
			DirectoryInfo di = new DirectoryInfo(Directory.GetCurrentDirectory());
			FileInfo [] fis = di.GetFiles(tmp);
			foreach (FileInfo fi in fis)
			{
				if (len==0 || len==fi.Length) fi.Delete();
			}
		}

		// find the next available temp directory for a given userid.
		public bool FindAvailableTempDir(string userid)
		{
			// first look for existing temp files for this user to see if any
			// can be used.
			int i;
			string ptmp = MakeTempName(userid,"*",'P'); // create a template

			// check to see if any exist.
			DirectoryInfo di = new DirectoryInfo(CurrentDir);
			FileInfo [] fis = di.GetFiles(ptmp);
			for (i=0;i<fis.Length;i++)
			{
				FileInfo fi = fis[i];
				string ptr = fi.Name.Substring(fi.Name.IndexOf(".")+2);
				if (AttachSpecificTemp(userid,ptr))
				{
					if (fi.Length>0)
					{
						// this was left from a reboot or something.
						// delete ownership and wrq files of the
						// specified size. Check to see if it is
						// consistent with the process file first.
						DeleteFiles("*.own",(int)fi.Length);
						DeleteFiles("*.wrq",(int)fi.Length);
					}
					return true;
				}
			}
			fis = null;

			// Couldn't use an existing one, find a new one.
			for (i=0;i<99;i++)
				if (AttachSpecificTemp(userid,i.ToString("d2"))) return true;
			
			// if the user got this far, something's wrong - report error & exit.
			MessageBox.Show("Too many temporary process files for user.","VE-PROMS error");
			return false;
		}

		// this method writes out the requested number of bytes to the file.
		public void WriteBytes(int num)
		{
			if (tmpFs != null)
			{
				while (num>0)
				{	
					tmpFs.WriteByte((byte)'x');
					num--;
				}
				tmpFs.Flush();

			}
		}
	}
}