/*!
 * \file
 *   Snel.cpp
 * \brief   A shell implementation for A.U.TH (Operating systems Lab)
 *
 *  Created on: Feb, 2019
 *      Author: Christos Choutouridis AEM: 8997
 *      email : <cchoutou@ece.auth.gr>
 */
#include "sequencer.h"

/*!
 * \mainpage
 *    Snel is a shell implementation for A.U.TH (Operating systems Lab).
 *    The shell execute the user commands in separate child processes.
 *
 *    It supports:
 *    * Interactive mode
 *    * Batch mode
 *    * # line comments
 *    * std redirection
 *    * &&, || operators and ; seperator
 *    * pipes
 *
 *    The implementation is based on a 2 dimensional sequencer. One dimension
 *    is the command chains, namely the commands separated with ';' and the other
 *    is the chains (the commands to run as one expression like ls && date).
 *    For more information look at \see Sequencer.
 */

/*!
 * Main program routine
 */
int main(int argc, char* argv[]) try {
   snel::Sequencer seq{};
   std::string     line, filtered;

   if (argc > 1) {   // batch mode
      std::ifstream file(argv[1]);

      while (std::getline (file, line, '\n')) {
         //^ We use \n as delimiter. No further parsing here
         filtered = snel::filter(line);   // simple filtering
         if (filtered == "quit")
            break;
         seq.parse(filtered).execute();
      }
   }
   else {   // interactive mode
      std::cout << "Snel. A shell implementation for A.U.TH (OS Lab)." << std::endl;
      do {
         std::cout << "Choutouridis_8997>";
         std::getline (std::cin, line, '\n');   //< We use \n as delimiter. No parsing here
         filtered = snel::filter(line);         // simple filtering
         if (filtered == "quit")
            break;
         seq.parse(filtered).execute();
      } while (1);
   }
   return 0;

} catch (std::exception& e) {
   // we probably pollute the user's screen. Comment `cerr << ...` if you don't like it.
   // std::cerr << e.what() << '\n';
   exit(1);
}