/* By: Chris Kyle

* This program is based off the programming challenge

* Challenge #259 [Medium] IRC: Making a Connection

* www.reddit.com/r/dailyprogrammer/comments/4ad23z/20160314_challenge_258_easy_irc_making_a/

*/

#include <stdlib.h>

#include <stdio.h>

#include <unistd.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <netdb.h>

#include <assert.h>

#include <errno.h>

#define BUFFER_SIZE 1024

char buffer[BUFFER_SIZE];

size_t inbuf_used = 0;

void error(const char *msg) {

perror(msg);

exit(0);

}

void send_nickname(const char *nick, int sock) {

bzero(buffer,BUFFER_SIZE);

snprintf(buffer, sizeof buffer, "NICK %s\r\n", nick);

printf("%s", buffer);

int n = write(sock,buffer,strlen(buffer));

if (n < 0)

error("ERROR writing to socket");

}

void send_username(const char *user_name, const char *real_name, int sock) {

bzero(buffer,BUFFER_SIZE);

snprintf(buffer, sizeof buffer,

"USER %s 0 * :%s\r\n", user_name, real_name);

printf("%s", buffer);

int n = write(sock,buffer,strlen(buffer));

if (n < 0)

error("ERROR writing to socket");

}

// Check for MOTD code 376 and PING check.

void process_line(char *line, int fd) {

char *str = strdup(line);

char *strcpy = str;

assert(str != NULL);

if (strcmp(strsep(&str, " "), "PING") == 0){

char response[128];

snprintf(response, sizeof response,

"PONG %s\r\n", strsep(&str, " "));

int n = write(fd, response, strlen(response));

if (n < 0)

error("ERROR writing to socket");

printf("%s", response);

free(strcpy);

return;

}

if (strcmp(strsep(&str, " "), "376") == 0){

char *join_message = "JOIN #reddit-dailyprogrammer,#botters-test\r\n";

int n = write(fd, join_message, strlen(join_message));

if (n < 0)

error("ERROR writing to socket");

printf("%s\n", join_message);

free(strcpy);

return;

}

}

// Based off of the example provided by bdonlan at

// http://stackoverflow.com/questions/6090594/c-recv-read-until-newline-occurs

void read_lines(int fd) {

size_t buf_remain = sizeof(buffer) - inbuf_used;

if (buf_remain == 0) {

fprintf(stderr, "Line exceeded buffer length. \n");

}

ssize_t rv = read(fd, (void *)&buffer[inbuf_used], buf_remain);

if (rv == 0) {

exit(EXIT_SUCCESS);

}

if (rv < 0 && errno == EAGAIN) {

// Socket has no data for us

return;

}

if (rv < 0) {

printf("Connection error");

}

inbuf_used += rv;

char *line_start = buffer;

char *line_end;

while( (line_end = memchr((void*)line_start, '\n', inbuf_used - (line_start - buffer)))){

*line_end = 0;

printf("%s\n", line_start);

process_line(line_start, fd);

line_start = line_end + 1;

}

inbuf_used -= (line_start - buffer);

memmove(buffer, line_start, inbuf_used);

}

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

int sockfd, portno;

struct sockaddr_in serv_addr;

struct hostent *server;

if (argc != 2) {

printf("Usage: client <filename>");

exit(0);

}

FILE *address_file = fopen(argv[1], "r");

// Get address of the form www.example.com:1234

fgets(buffer, BUFFER_SIZE, address_file);

char *str = strdup(buffer);

char *web_address = strsep(&str, ":");

size_t port_number = atoi(strsep(&str, ":"));

// Get nickname and strip newlines.

fgets(buffer, BUFFER_SIZE, address_file);

char nickname[64];

strtok(buffer, "\n");

strcpy(nickname, buffer);

// Get username and strip newlines.

fgets(buffer, BUFFER_SIZE, address_file);

char username[64];

strtok(buffer, "\n");

strcpy(username, buffer);

// Get realname and strip newlines

fgets(buffer, BUFFER_SIZE, address_file);

char realname[64];

strtok(buffer, "\n");

strcpy(realname, buffer);

fclose(address_file);

// Connect to server

// This is based off of the C socket tutorial at

// http://www.linuxhowtos.org/C_C++/socket.htm

portno = port_number;

sockfd = socket(AF_INET, SOCK_STREAM, 0);

if (sockfd < 0)

error("ERROR opening socket");

server = gethostbyname(web_address);

if (server == NULL) {

fprintf(stderr,"ERROR, no such host\n");

exit(0);

}

bzero((char *) &serv_addr, sizeof(serv_addr));

serv_addr.sin_family = AF_INET;

bcopy((char *)server->h_addr,

(char *)&serv_addr.sin_addr.s_addr,

server->h_length);

serv_addr.sin_port = htons(portno);

if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)

error("ERROR connecting");

send_nickname(nickname, sockfd);

send_username(username, realname, sockfd);

// listen_to_server(sockfd);

while(1) {

read_lines(sockfd);

}

close(sockfd);

return 0;

}