#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>       	// struct sockaddr_in, htons, htonl

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <netdb.h>		// struct hostent, gethostbyname()
#include <string.h>

#include "stream.h"		// MAX_BLOCK_SIZE, readn(), writen()
#define  SERV_TCP_PORT 40005	// default server listening port

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

	int sd, n, nr, nw, i=0;
	char buf[MAX_BLOCK_SIZE], host[60];
	unsigned short port;
	struct sockaddr_in ser_addr; struct hostent *hp;

	// Get server host name and port number
	// assume server running on the local host and on default port
	if (argc == 1) {
		gethostname(host, sizeof(host));
		port = SERV_TCP_PORT;
	// use the given host name
	} else if (argc == 2) {
		strcpy(host, argv[1]);
		port = SERV_TCP_PORT;
	// use given host and port for server
	} else if (argc == 3) {
		strcpy(host, argv[1]);
		int n = atoi(argv[2]);
		if (n >= 1024 && n < 65536) {
			port = n;
		} else {
			printf("Error: server port number must be between 1024 and 65535\n");
			exit(1);
		}
	} else {
		printf("Usage: %s [ <server host name> [ <server listening port> ] ]\n", argv[0]);
		exit(1);
	}

	// get host address, & build a server socket address
	bzero((char *) &ser_addr, sizeof(ser_addr));
	ser_addr.sin_family = AF_INET;
	ser_addr.sin_port = htons(port);
	if ((hp = gethostbyname(host)) == NULL) {
		printf("host %s not found\n", host);
		exit(1);
	}
	ser_addr.sin_addr.s_addr = * (u_long *) hp->h_addr;

	// create TCP socket & connect socket to server address
	sd = socket(PF_INET, SOCK_STREAM, 0);
	if (connect(sd, (struct sockaddr *) &ser_addr, sizeof(ser_addr)) < 0) {
		perror("Client: Connect Error");
		exit(1);
	}

	while (++i) {
		printf("Client Input[%d]: ", i);
		fgets(buf, sizeof(buf), stdin); nr = strlen(buf);

		if (buf[nr-1] == '\n') {
			buf[nr-1] = '\0';
			--nr;
		}

		if (strcmp(buf, "quit") == 0) {
			printf("Bye from client\n");
			exit(0);
		}

		if (nr > 0) {
			if ((nw=writen(sd, buf, nr)) < nr) {
				printf("Client: Send Error\n");
				exit(1);
			}

			if ((nr=readn(sd, buf, sizeof(buf))) <= 0) {
				printf("Client: Receive Error\n");
				exit(1);
			}

			buf[nr] = '\0';
			printf("Server Output[%d]: %s\n", i, buf);
		}
	}
}