/*

    Mosh: the mobile shell

    Copyright 2012 Keith Winstein

    This program is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.

    This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License

    along with this program.  If not, see <http://www.gnu.org/licenses/>.

    In addition, as a special exception, the copyright holders give

    permission to link the code of portions of this program with the

    OpenSSL library under certain conditions as described in each

    individual source file, and distribute linked combinations including

    the two.

    You must obey the GNU General Public License in all respects for all

    of the code used other than OpenSSL. If you modify file(s) with this

    exception, you may extend this exception to your version of the

    file(s), but you are not obligated to do so. If you do not wish to do

    so, delete this exception statement from your version. If you delete

    this exception statement from all source files in the program, then

    also delete it here.

*/

#include <cassert>

#include "terminaluserinput.h"

using namespace Terminal;

std::string UserInput::input( const Parser::UserByte* act, bool application_mode_cursor_keys )

{

  /* The user will always be in application mode. If stm is not in

     application mode, convert user's cursor control function to an

     ANSI cursor control sequence */

  /* We need to look ahead one byte in the SS3 state to see if

     the next byte will be A, B, C, or D (cursor control keys). */

  /* This doesn't handle the 8-bit SS3 C1 control, which would be

     two octets in UTF-8. Fortunately nobody seems to send this. */

  switch ( state ) {

    case Ground:

      if ( act->c == 0x1b ) { /* ESC */

        state = ESC;

      }

      return std::string( &act->c, 1 );

    case ESC:

      if ( act->c == 'O' ) { /* ESC O = 7-bit SS3 */

        state = SS3;

        return std::string();

      }

      state = Ground;

      return std::string( &act->c, 1 );

    case SS3:

      state = Ground;

      if ( ( !application_mode_cursor_keys ) && ( act->c >= 'A' ) && ( act->c <= 'D' ) ) {

        char translated_cursor[2] = { '[', act->c };

        return std::string( translated_cursor, 2 );

      } else {

        char original_cursor[2] = { 'O', act->c };

        return std::string( original_cursor, 2 );

      }

    default:

      assert( !"unexpected state" );

      state = Ground;

      return std::string();

  }

}