/*
* SubstCmd.java
*
* Copyright (c) 1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and
* redistribution of this file, and for a DISCLAIMER OF ALL
* WARRANTIES.
* 
* Included in SQLite3 port to C# for use in testharness only;  2008 Noah B Hart
*
* RCS @(#) $Id: SubstCmd.java,v 1.3 2003/01/09 02:15:39 mdejong Exp $
*
*/
using System.Text;
namespace tcl.lang
{

  /// <summary> This class implements the built-in "subst" command in Tcl.</summary>

  class SubstCmd : Command
  {
    private static readonly string[] validCmds = new string[] { "-nobackslashes", "-nocommands", "-novariables" };

    internal const int OPT_NOBACKSLASHES = 0;
    internal const int OPT_NOCOMMANDS = 1;
    internal const int OPT_NOVARS = 2;

    /// <summary> This procedure is invoked to process the "subst" Tcl command.
    /// See the user documentation for details on what it does.
    /// 
    /// </summary>
    /// <param name="interp">the current interpreter.
    /// </param>
    /// <param name="argv">command arguments.
    /// </param>
    /// <exception cref=""> TclException if wrong # of args or invalid argument(s).
    /// </exception>

    public TCL.CompletionCode cmdProc( Interp interp, TclObject[] argv )
    {
      int currentObjIndex, len, i;
      int objc = argv.Length - 1;
      bool doBackslashes = true;
      bool doCmds = true;
      bool doVars = true;
      StringBuilder result = new StringBuilder();
      string s;
      char c;

      for ( currentObjIndex = 1; currentObjIndex < objc; currentObjIndex++ )
      {

        if ( !argv[currentObjIndex].ToString().StartsWith( "-" ) )
        {
          break;
        }
        int opt = TclIndex.get( interp, argv[currentObjIndex], validCmds, "switch", 0 );
        switch ( opt )
        {

          case OPT_NOBACKSLASHES:
            doBackslashes = false;
            break;

          case OPT_NOCOMMANDS:
            doCmds = false;
            break;

          case OPT_NOVARS:
            doVars = false;
            break;

          default:
            throw new TclException( interp, "SubstCmd.cmdProc: bad option " + opt + " index to cmds" );

        }
      }
      if ( currentObjIndex != objc )
      {
        throw new TclNumArgsException( interp, currentObjIndex, argv, "?-nobackslashes? ?-nocommands? ?-novariables? string" );
      }

      /*
      * Scan through the string one character at a time, performing
      * command, variable, and backslash substitutions.
      */


      s = argv[currentObjIndex].ToString();
      len = s.Length;
      i = 0;
      while ( i < len )
      {
        c = s[i];

        if ( ( c == '[' ) && doCmds )
        {
          ParseResult res;
          try
          {
            interp.evalFlags = Parser.TCL_BRACKET_TERM;
            interp.eval( s.Substring( i + 1, ( len ) - ( i + 1 ) ) );
            TclObject interp_result = interp.getResult();
            interp_result.preserve();
            res = new ParseResult( interp_result, i + interp.termOffset );
          }
          catch ( TclException e )
          {
            i = e.errIndex + 1;
            throw;
          }
          i = res.nextIndex + 2;

          result.Append( res.value.ToString() );
          res.release();
        }
        else if ( c == '\r' )
        {
          /*
          * (ToDo) may not be portable on Mac
          */

          i++;
        }
        else if ( ( c == '$' ) && doVars )
        {
          ParseResult vres = Parser.parseVar( interp, s.Substring( i, ( len ) - ( i ) ) );
          i += vres.nextIndex;

          result.Append( vres.value.ToString() );
          vres.release();
        }
        else if ( ( c == '\\' ) && doBackslashes )
        {
          BackSlashResult bs = tcl.lang.Interp.backslash( s, i, len );
          i = bs.nextIndex;
          if ( bs.isWordSep )
          {
            break;
          }
          else
          {
            result.Append( bs.c );
          }
        }
        else
        {
          result.Append( c );
          i++;
        }
      }

      interp.setResult( result.ToString() );
      return TCL.CompletionCode.RETURN;
    }
  }
}