/*
NAME : rpipe.C
TYPE : C++ SOURCE
AUTHOR : Arunkumar Elango
DESCRIPTION : 
This file contains the source code for the client. It takes the following command line as input :

				$ rpipe [-h hostname] [-p portnumber] executable_name

The client tries to connect to the server at the known portnumber and host. If it succeds in connecting, it sends 
a password and the executable_name. The server checks the validity of the password, and if it is right, sends back 
an acknowledgement. Else, the child server exits and the connection is lost. Once the client receives the 
acknowledgement, it reads its standard input and sends the data to the server through the socket. The server 
processes the request and sends the output back through the socket. The client just prints the output it recieved 
onto the screen and exits.

*/

#include <iostream.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <fcntl.h>
#include <memory.h>


const int MAXSTR=1024;
const long PORTNUM=54715;
const int PASSWORD = 21;

main( int argc, char *argv[])
{
int portNumber;
char executableName[MAXSTR],hostName[MAXSTR];
	if ( (argc != 6) && (argc != 4) && (argc != 2) )
	{
		cerr << "Invalid command line.\n";
		exit(1);
	}
	if ( argc == 2 )
	{
		strcpy(hostName,"ernie.eecs.uic.edu");
		portNumber = PORTNUM;
		strcpy(executableName,argv[1]);
	}
	else if (argc == 4 )
	{
		if (!strcmp(argv[1],"-h"))
		{
			strcpy(hostName,argv[2]);
			portNumber = PORTNUM;
		}
		else if (!strcmp(argv[1],"-p"))
		{
			portNumber = atoi(argv[2]);
			strcpy(hostName,"ernie.eecs.uic.edu");
		}
		else
		{
			cerr << "Invalid command line.\n";
			exit(1);
		}
		strcpy(executableName,argv[3]);
	}
	else
	{
		if ((!strcmp(argv[1],"-h")) && (!strcmp(argv[3],"-p")))
		{
			strcpy(hostName,argv[2]);
			portNumber = atoi(argv[4]);
		}
		else
		{
			cerr << "Invalid command line.\n";
			exit(1);
		}
		strcpy(executableName,argv[5]);
	}

	if (portNumber < 10000)
	{
		cerr << "Port number has to be atleast 10000.\n";
		exit(1);
	}
//	cerr << hostName << " " << portNumber << executableName <<"\n";

struct hostent *hostptr;
	if ((hostptr = gethostbyname(hostName)) == NULL)
	{
		cerr <<"Error locating host : "<<hostName<<"\n";
		exit(1);	
	}
struct sockaddr_in serv_addr;

	bzero((char *)&serv_addr,sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	memcpy((char *)&serv_addr.sin_addr,(char *)hostptr->h_addr,hostptr->h_length);
	serv_addr.sin_port = htons(portNumber);

int sockfd,newsockfd;
	if ((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
	{
		cerr << "client : socket error.\n";
		exit(1);
	}
	if ( connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) < 0)
	{
		cerr << "client : connect error.\n";
		exit(1);
	}
char buf[MAXSTR],ack[MAXSTR],data[MAXSTR];
char answer[MAXSTR];
int i=0;
char ch='0';

	sprintf(buf,"%d %s\n",PASSWORD,executableName);
	buf[strlen(buf)] = '\0';
	write(sockfd,buf,strlen(buf));	
	read(sockfd,(void *)ack,MAXSTR);

//	cerr << "got back " << ack << "from server";
	if (( ack[0] == 'N') && (ack[1] == 'O') )
	{
		cerr << "Connect request refused.\n";
		exit(1);
	}
	cin.getline(data,MAXSTR,'\0');
	data[strlen(data)] = '\0';
//	cerr << "Client : sending.." << data << endl;
	write(sockfd,data,strlen(data));	
	read(sockfd,(void *)answer,MAXSTR);
	cerr << answer <<endl;
	close(sockfd);
}