using System.Text.RegularExpressions;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;

namespace mScriptableCS25;

public class MainScriptingObject : IDisposable
{
  SortedDictionary<string, string> scrInp1 = new(StringComparer.OrdinalIgnoreCase);
  SortedDictionary<string, string> scrInp2 = new(StringComparer.OrdinalIgnoreCase);    //This will have the STRIPUNPRINTABLES applied to it
  string scriptSource = string.Empty;
  string tempPath = Path.GetTempPath();
  Dictionary<Guid, Dictionary<string, string>>? dctCache = null;
  Dictionary<string, MdlVbsSources> dctFileCache = new(StringComparer.OrdinalIgnoreCase);
  Random rn = new();
  List<string> lstFilesToRemove = new();
  bool removedOldScripts = false;

  public void Dispose()
  {
    if (dctCache != null)
      dctCache.Clear();
  }

  public bool HadErrors { get; set; } = false;
  public bool DebugMode { get; set; } = false;
  public bool UseCache { get; set; } = true;
  public bool AllowRemovalOfOldScripts { get; set; } = true;

  public string ScriptSource
  {
    get { return scriptSource; }
    set
    {
      scriptSource = CleanUserCode(value);
      dctCache = new();
    }
  }

  public string TempPath
  {
    get { return tempPath; }
    set
    {
      string f = Path.Combine(value, "_test.txt");

      if (!Directory.Exists(Path.GetDirectoryName(f)))
        Directory.CreateDirectory(Path.GetDirectoryName(f));

      try
      {
        using (var sw = new StreamWriter(f, false))
        {
          sw.WriteLine();
        }
        if (File.Exists(f))
          File.Delete(f);
      }
      catch
      {
        tempPath = Path.GetTempPath();
      }
    }
  }

  public bool SetScriptFromFile(string VBScriptPath)
  {
    var rv = false;

    if (dctFileCache.ContainsKey(VBScriptPath))
    {
      scriptSource = dctFileCache[VBScriptPath].VbsScriptSource;
      dctCache = dctFileCache[VBScriptPath].CacheDict;
      rv = true;
    }
    else
    {
      if (!File.Exists(VBScriptPath))
      {
        scriptSource = string.Empty;
        dctCache = null;
        rv = false;
      }
      else
      {
        var z = new MdlVbsSources();
        using (var sr = new StreamReader(VBScriptPath))
          scriptSource = sr.ReadToEnd();

        z.VbsScriptSource = scriptSource;
        dctCache = z.CacheDict;
        dctFileCache[VBScriptPath] = z;
        rv = true;
      }
    }
    return rv;
  }

  public void ClearScriptInputs()
  {
    scrInp1.Clear();
    scrInp2.Clear();
  }

  public void SetScriptInputs(Dictionary<string, string> z)
  {
    foreach (var kvp in z)
    {
      scrInp1[kvp.Key] = kvp.Value;
      scrInp2[kvp.Key] = StripUnprintables(kvp.Value);
    }
  }

  public void AddScriptInput(string VariableName, string Value)
  {
    scrInp1[VariableName] = Value;
    scrInp2[VariableName] = StripUnprintables(Value);
  }

  public void RemoveOldScripts()
  {
    if (AllowRemovalOfOldScripts && !removedOldScripts)
    {
      removedOldScripts = true;
      foreach (var f0 in Directory.GetFiles(tempPath, "TmpVbsScript*.*"))
      {
        var fif = new FileInfo(f0);

        if (DateTime.UtcNow.Subtract(fif.LastWriteTimeUtc).TotalHours > 24)
          try { File.Delete(f0); } catch { }
      }
    }
  }

  public Dictionary<string, string> RunScript()
  {
    var tStamp = string.Format("TmpVbsScript-{0:yyyyMMddHHmmssfff}-{1}", DateTime.Now, Guid.NewGuid().ToString("N").Substring(0, 12));
    var outFile = Path.Combine(tempPath, tStamp + ".txt");
    var scriptFile = Path.Combine(tempPath, tStamp + ".vbs");
    var iKey = ToGuid(string.Join('\t', scrInp2.ToArray()));
    Dictionary<string, string> toReturn = new(StringComparer.OrdinalIgnoreCase);
    var retVals = string.Empty;
    var varName = string.Empty;
    var varVal = string.Empty;

    HadErrors = false;
    lstFilesToRemove.Add(outFile);
    lstFilesToRemove.Add(scriptFile);
    if (UseCache && dctCache.ContainsKey(iKey))
      toReturn = dctCache[iKey];
    else
    {
      var genCodeHeader = new StringBuilder();
      var genCodeFooter = new StringBuilder();

      RemoveOldScripts();

      genCodeHeader.AppendLine("'*************************************************");
      genCodeHeader.AppendLine("'* VBScript generated by the mScript class       *");
      genCodeHeader.AppendLine("'* for dynamic scripting of .NET applications    *");
      genCodeHeader.AppendLine("'* this file can be safely delted.               *");
      genCodeHeader.AppendLine("'*                                               *");
      genCodeHeader.AppendLine("'* mScriptable was created by Don Smith          *");
      genCodeHeader.AppendLine("'* <don.c.smith@gmail.com>                       *");
      genCodeHeader.AppendLine("'* You may use mScriptable however you like      *");
      genCodeHeader.AppendLine("'* as long as you give credit to me (Don) for    *");
      genCodeHeader.AppendLine("'* mScriptable.                                  *");
      genCodeHeader.AppendLine("'* Revised in 2015 by KeyMotive LLC (Rich Deck)  *");
      genCodeHeader.AppendLine("'*************************************************");

      genCodeHeader.AppendLine("outFile = \"" + outFile + "\"");
      //get our file I/O initialized.  This assumes we have write 
      //access to the current directory.
      genCodeHeader.AppendLine("Set oFsObj = CreateObject(\"Scripting.FileSystemObject\")");
      genCodeHeader.AppendLine("Set oFHnd = oFsObj.CreateTextFile(outFile, true)");

      //a wrapper function with a shorter name to access the supplied inputs
      genCodeHeader.AppendLine("Function iv(variableName)");
      genCodeHeader.AppendLine("  iv = inpVal(variableName)");
      genCodeHeader.AppendLine("End Function ' iv()");

      //a function to allow the user script to access supplied inputs
      genCodeHeader.AppendLine("Function inpVal(variableName)");
      genCodeHeader.AppendLine("  Select Case UCase(variableName)");

      /*
        This takes all of the script inputs and places them inside of a VBScript
        Select Case statement in the inpVal() function so the supplied VBScript can
        retrieve the values by name.
      */

      foreach (var kvp in scrInp1)
      {
        if (!string.IsNullOrWhiteSpace(kvp.Key))
        {
          if (decimal.TryParse(kvp.Value, out _))
            varVal = kvp.Value.ToString();
          else
          {
            if (kvp.Value == null || Convert.IsDBNull(kvp.Value))
              varVal = string.Empty;
            else
              varVal = string.Format("\"{0}\"", kvp.Value.ToString().Replace("\"", "\"\""));
          }

          varVal = Regex.Replace(varVal, "(\r\n|\n\r|\r|\n)", "\"\n\"");
          varName = "\"" + kvp.Key.ToUpper().Replace("\"", "\"\"") + "\"";
          genCodeHeader.AppendLine("    Case " + varName);
          genCodeHeader.AppendLine("      retVal = " + varVal);
        }
      }

      //finish the case/function
      genCodeHeader.AppendLine("    Case Else");
      genCodeHeader.AppendLine("      retVal = \"\"");
      genCodeHeader.AppendLine("  End Select");
      genCodeHeader.AppendLine("  inpVal = retVal");
      genCodeHeader.AppendLine("End Function ' inpVal()\n");

      //subroutine allowing the script to return a variable
      genCodeHeader.AppendLine("Sub return(varName, retVal)");
      genCodeHeader.AppendLine("  While InStr(1, retVal, vbNewLine, vbTextCompare) >= 1");
      genCodeHeader.AppendLine("    retVal = replace(retVal, vbNewLine, \"~NewLine~\")");
      genCodeHeader.AppendLine("  Wend");
      genCodeHeader.AppendLine("  oFHnd.WriteLine varName & vbTab & retVal");
      genCodeHeader.AppendLine("End Sub ' return()\n");

      //close our output file handle
      genCodeFooter.AppendLine("\n\noFHnd.Close");

      //All code
      using (var sw = new StreamWriter(scriptFile, false))
        sw.WriteLine(genCodeHeader.ToString() + scriptSource + genCodeFooter.ToString());

      // Run the script!
      try
      {
        using (var px = new Process())
        {
          var pInfo = new ProcessStartInfo() { FileName = "wscript.exe", Arguments = scriptFile };

          px.StartInfo = pInfo;
          px.Start();

          if (!px.HasExited)
            px.WaitForInputIdle();
          px.WaitForExit(60000);

          if (!px.HasExited)
          {
            HadErrors = true;
            px.Kill();
          }
        }

        if (File.Exists(outFile))
        {
          using (var sr = new StreamReader(outFile))
            retVals = sr.ReadToEnd();
        }

        toReturn.Clear();
        foreach (var f0 in Regex.Split(retVals, "(\r\n|\n\r|\r|\n)"))
        {
          if (f0.Length >= 3 && f0.IndexOf('\t') > 0)
          {
            var nvp = f0.Split('\t');

            nvp[1] = Regex.Replace(nvp[1], "\x7eNewLine\x7e", "\n");
            toReturn[nvp[0]] = nvp[1];
          }
        }

        if (UseCache)
          dctCache[iKey] = toReturn;
      }
      catch (Exception ex)
      {
        using (var sw = new StreamWriter(outFile, true))
          sw.WriteLine(ex.ToString());
      }
    }
    return toReturn;
  }


  #region "Maint routines"
  string CleanUserCode(string ScriptCode)
  {
    string workCode = ScriptCode;
    Regex? re = null;
    string inpVal_re = @"Function\s+inpVal\s*?\([^)]+\)(.*?)End\s+Function";
    string iv_re = @"Function\s+iv\s*?\([^)]+\)(.*?)End\s+Function";
    string return_re = @"Sub\s+return\s*?\([^)]+\)(.*?)End\s+Sub";

    //remove conflicting "inpVal" functions
    re = new Regex(inpVal_re, RegexOptions.Singleline | RegexOptions.IgnoreCase);
    if (re.IsMatch(workCode))
      workCode = re.Replace(workCode, "");

    //remove conflicting "iv" functions
    re = new Regex(iv_re, RegexOptions.Singleline | RegexOptions.IgnoreCase);
    if (re.IsMatch(workCode))
      workCode = re.Replace(workCode, "");

    //remove conflicting "return" subroutine
    re = new Regex(return_re, RegexOptions.Singleline | RegexOptions.IgnoreCase);
    if (re.IsMatch(workCode))
      workCode = re.Replace(workCode, "");

    return workCode;
  }

  string StripUnprintables(string inp)
  {
    var rv = Regex.Replace(inp, "[^\x20-\x7E]", " ");
    rv = Regex.Replace(rv, "  +", " ").Trim();
    return rv;
  }

  Guid ToGuid(string strToHash)
  {
    var gx = Guid.Empty;
    using (var mD = System.Security.Cryptography.MD5.Create())
    {
      var stringBuilder = new StringBuilder();
      byte[] array = mD.ComputeHash(Encoding.UTF8.GetBytes(strToHash));
      for (int i = 0; i < array.Length; i++)
        stringBuilder.Append(array[i].ToString("X2"));

      gx = Guid.Parse(stringBuilder.ToString());
    }
    return gx;
  }

  #endregion

  #region "Models and Such"
  internal class MdlVbsSources : IDisposable
  {
    public void Dispose()
    {
      CacheDict.Clear();
    }

    public string VbsScriptSource { get; set; } = string.Empty;
    public Dictionary<Guid, Dictionary<string, string>> CacheDict { get; set; } = new();
  }
  #endregion

}