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/*

  (c) Jose Tejada Gomez, 9th May 2013

  You can use this file following the GNU GENERAL PUBLIC LICENSE version 3

  Read the details of the license in:

  http://www.gnu.org/licenses/gpl.txt

  Send comments to: jose.tejada at ieee.org

*/

#include <string>

#include <vector>

#include <algorithm>

#include <cstdlib>

#include <iostream>

typedef std::vector<struct argument_t*> arg_vector_t;

struct argument_t {

  std::string short_name, long_name;

  typedef enum { integer, text, flag } arg_type;

  arg_type type;

  std::string description;

  // possible states

  int integer_value;

  std::string string_value;

  bool state, req;

  argument_t( arg_vector_t& av, const char* long_name, arg_type type,

    const char* desc, bool required=false )

    : long_name(long_name), type( type ), description( desc ),

      req(required), state(false), integer_value(0)

  {

    if( !this->long_name.empty() ) {

      this->short_name = "-" + this->long_name.substr(0,1);

      this->long_name = "--" + this->long_name;

    }

    av.push_back(this);

  }

  void set() { state=true; }

  bool is_set() { return state; }

};

class Args {

  arg_vector_t& legal_args;

  argument_t* def_arg;

  std::string program_name;

  argument_t help_arg;

public:

  void throw_error( std::string x ) /*throw const char**/ { throw x.c_str(); }

  Args( int argc, char *argv[], arg_vector_t& legal_args ) //throw const char *

  : legal_args( legal_args ),

    help_arg( legal_args, "help", argument_t::flag, "Display usage information")

  {

    //std::copy( legal_args.begin(), legal_args.cnd(), legal_args.begin() );    

    if( argc== 1 ) help_arg.set(); // show help if there are no args.

    // look for default argument

    def_arg=NULL;

    for( int j=0; j<legal_args.size(); j++ ) {

      if ( legal_args[j]->short_name.empty() && legal_args[j]->long_name.empty() )

        if( def_arg==NULL ) def_arg = legal_args[j];

        else throw "Cannot set more than one default argument.";

    }

    if( def_arg && def_arg->type!=argument_t::integer && def_arg->type!=argument_t::text )

      throw "Default arguments can only be of type integer or text";

    program_name = argv[0];

    for( int k=1; k<argc; k++ ) {

      bool matched=false;

      for( int j=0; j<legal_args.size(); j++ ) {

        argument_t& a = *legal_args[j];

        if( a.long_name==argv[k] || a.short_name==argv[k] ) {

          if( a.type == argument_t::flag ) { a.set(); matched=true; continue; }

          if( a.type == argument_t::text ) {

            k++;

            if( k>=argc ) throw_error("Expecting input after "+a.long_name+" param");

            a.string_value = argv[k];

            a.set();

            matched=true;

            continue;

          }

          if( a.type == argument_t::integer ) {

            k++;

            if( k>=argc ) throw_error("Expecting input after "+a.long_name+" param");

            a.integer_value = atoi(argv[k]);

            a.set();

            matched=true;

            continue;

          }

        }

      }

      if( !matched && def_arg!=NULL )

        if( def_arg->state )

          throw_error( "Unknown parameter " + std::string(argv[k] ));

        else {

          if( def_arg->type==argument_t::integer ) def_arg->integer_value=atoi(argv[k]);

          if( def_arg->type==argument_t::text ) def_arg->string_value=argv[k];

          def_arg->set();

        }

    }

    if( help_arg.is_set() ) return; // do not perform more checks

    // check that all required parameters are present

    for( int j=0; j<legal_args.size(); j++ ) {

      argument_t& a = *legal_args[j];

      if( a.req && !a.state ) {

        std::string pname;

        if( !a.long_name.empty() ) pname=a.long_name;

        else if( !a.short_name.empty() ) pname=a.short_name;

        throw_error("Parameter "+pname+" is required.");

      }

    }

  }

  bool help_request() { if( help_arg.state ) show_help(); return help_arg.state; }

  std::string brackets( const argument_t& a, std::string s ) {

    return a.req ?  "<"+s+">" : "["+s+"]";

  }

  void show_help() {

    std::cout << "Usage: " << program_name << " ";

    if( def_arg!=NULL )

      std::cout << brackets( *def_arg, def_arg->description.empty() ? "parameter " : def_arg->description);

    std::cout << "\n";

    for( int j=0; j<legal_args.size(); j++ ) {

      argument_t& a = *legal_args[j];

      if( a.long_name.empty() && a.long_name.empty() ) continue;

      std::cout << "\t";

      std::string aux;

      if( !a.long_name.empty() ) aux = a.long_name;

      if( !a.long_name.empty() && !a.long_name.empty() ) aux += " | ";

      if( !a.short_name.empty() ) aux+= a.short_name;

      std::cout << brackets( a, aux );

      if( !a.description.empty() ) std::cout << ":  " << a.description;

      std::cout << "\n";

    }

  }

};