/*
* echo_client.c
* Written by Jonghwa Park
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>

#define BUFSIZE 1024
void error_handling(char *message);

int main(int argc, char *argv[])
{
	int sock;
	char message[BUFSIZE];
	int str_len;
	struct sockaddr_in serv_addr;

	if (argc != 3)
	{
		printf("Usage: %s <IP> <port>\n",argv[0]);
		exit(1);
	}

	sock = socket(PF_INET, SOCK_STREAM, 0);

	if (sock == -1)
		error_handling("socket() error");
	printf("¼ÒÄÏ »ý¼º: ¼ÒÄÏ Descriptor = %d\n", sock);	

	memset(&serv_addr, 0, sizeof(serv_addr)); //
	/*
        ¼­¹ö ÁÖ¼ÒÁ¤º¸ ¼³Á¤
	1. sin_family : ÁÖ¼Ò Ã¼°è 
	2. sin_addr.s_addr : 32bit Ipv4 ÀÎÅÍ³Ý ÁÖ¼Ò 
	3. sin_port : ¼­¹ö Æ÷Æ® ¼³Á¤ 
	*/
	serv_addr.sin_family= AF_INET; //ipv4;
	serv_addr.sin_addr.s_addr = inet_addr(argv[1]); //
	serv_addr.sin_port = htons(atoi(argv[2])); //


	printf("¼­¹ö ±¸Á¶Ã¼ ÇÒ´ç : \n");
	printf("¼­¹ö ÁÖ¼Ò Á¤º¸ : serv_addr.sin_family = %d\n",serv_addr.sin_family);
	printf("¼­¹ö ÁÖ¼Ò Á¤º¸ : serv_addr.sin_addr.s_addr = %s\n",inet_ntoa(serv_addr.sin_addr));
	printf("¼­¹ö ÁÖ¼Ò Á¤º¸ : serv_addr.sin_port = %d\n",ntohs(serv_addr.sin_port));

	/*
	bind ÇÔ¼ö¸¦ ÅëÇؼ­ ¼ÒÄÏ¿¡ ÁÖ¼Ò¸¦ Á÷Á¢ ÇÒ´çÇÏÁö ¾Ê¾Æµµ connect ÇÔ¼ö 
        È£Ãâ½Ã ÀÚµ¿ÀûÀ¸·Î ¼ÒÄÏ¿¡ ÁÖ¼Ò¿Í port°¡ ÇÒ´çÀÌ µÈ´Ù.
        ¸í½ÃÀû È£ÃâÀÌ ÇÊ¿äÇÏÁö ¾Ê°Ô µÈ´Ù.	
	*/
	if (connect(sock,(struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1)
		error_handling("Connect() error!");
	
	while (1)
	{
		/* ¸Þ½ÃÁö ÀÔ·Â, Àü¼Û */
		fputs("Àü¼ÛÇÒ ¸Þ½ÃÁö¸¦ ÀÔ·ÂÇϼ¼¿ä (q to quit) : ", stdout);
		fgets(message, BUFSIZE, stdin);

		if (!strcmp(message, "q\n"))
			break;
		write(sock, message, strlen(message));
		printf("¼­¹ö·Î ¸Þ½ÃÁö Àü¼Û: %s\n", message);

		/* ¸Þ½ÃÁö ¼ö½Å, Ãâ·Â */
		str_len = read(sock, message, BUFSIZE-1);
		message[str_len] = 0;
		printf("\n\n ¼­¹ö·ÎºÎÅÍ Àü¼ÛµÈ ¸Þ½ÃÁö : %s\n", message);
	}
	close(sock);
	return 0;
}


void error_handling(char *message)
{
	fputs(message, stderr);
	fputc('\n',stderr);
	exit(1);
}