//This program compiled and ran until I put /*******/ on top of some words
// Login a user and ask for a change of password
#include <stdexcept>
#include <typeinfo>
#include <iostream>
#include <fstream>
#include "SecureBuffer.h"

using namespace std;


int main(int argc, char * argv[])
{
 try{

  if(argc !=1 )
  {
	cerr <<"Usage: use\n";
	exit(1);
  }

  Buffer id;
  SecureBuffer password;

  bool authenticated=false;

  fstream passwd("passwd", ios::in | ios::out);
  const int record_size= sizeof(Buffer)+sizeof(SecureBuffer);
  // Format of "passwd" is in list.cpp. File= record* blank*.
  //                                    record=Buffer SecureBuffer.

  if(!passwd)
  {
    throw runtime_error("File passwd can not be opened\n");
  }
  int number_of_recs;
  passwd.seekp(0, ios::end);
  number_of_recs=passwd.tellp()/record_size ;

  Buffer file_id;
  Buffer blank;// deleted data
  SecureBuffer file_password;

  int attempt=0;
  streampos user_position;

  while(not authenticated)
  {
	cout << "Input your user name: "; cin >> id;
	cout << "Input your password:  "; cin >> password;
	password.encrypt(id);

	attempt++;

	// find id in file
	int record_number;
	for(record_number=0; record_number<number_of_recs; record_number++)
	{
		passwd.seekg(record_size*record_number);
		passwd.read( (char*)&file_id, sizeof(id));
		if( file_id==id)
		{
		  // cerr << record_number <<" : "<< file_id << endl;
		  break;
		}
		if( file_id==blank)
		{
		  //cerr << record_number <<" : "<< "(blank record)" << endl;
		  break;
		}
	}//end for

	if( file_id == id )
        {
	   passwd.read( (char*)&file_password, sizeof(file_password) );
	   authenticated = (/*******/ == password);
	   user_position=record_size*record_number;
        }
	if(not authenticated and (attempt>10))
		throw runtime_error("Attacking Hacker");

   }//end while not authenticated

   cout << "Welcome "<< id << endl;
   // cerr << "user number " << user_position <<endl;

   // if id in file overwrite the password in the file

   cout << "Please input a new password: ";
   cin >> password;
   password.encrypt(id);
   // cerr << "Write "<< password<< " at "<< user_position + sizeof(id)<<endl;
   passwd.seekp(user_position, ios::beg);
   passwd.seekp(sizeof(/*******/), ios::cur);
   passwd.write( (char*)&/*******/, sizeof(password));

   passwd.close();

 }
 catch(exception &e)
 {
    cerr<< "Exception thrown: "<< typeid(e).name()<< " " << e.what()<<endl;
 } 

}