chat_application/main.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>
#include <unistd.h>
#include <signal.h>

#include "message.h"
#include "user.h"
#include "easysock.h"
#include "file_helpers.h"
#include "message_helpers.h"

#define BUFFER_SIZE 10000
#define MAX_CONNECTIONS 100
#define DATA_SIZE 50000

User** create_user_list(char* filename);
void sigint_handler(int dummy);
User* fetch_user(char* username);

User** users;
int num_users;

bool stop_running;

int main() {
	stop_running = false;

	signal(SIGINT,sigint_handler);

	struct sockaddr temp_addr;
	socklen_t temp_addrlen;

	fd_set read_fd_set;
	int conn_sockets[MAX_CONNECTIONS] = {-1};
	User* to_user[MAX_CONNECTIONS] = {NULL};
	User* from_user[MAX_CONNECTIONS] = {NULL};
	FD_ZERO(&read_fd_set);
	char buffer[BUFFER_SIZE];
	char data[DATA_SIZE];

	num_users = num_of_lines("user_file.txt");
	users = create_user_list("user_file.txt");
	
	struct sockaddr addr_struct;
	int server_sock = create_local(4,'T',"127.0.0.1",30000,&addr_struct);
	conn_sockets[0] = server_sock;

	assert(listen(server_sock,MAX_CONNECTIONS) == 0);

	while (true) {
		FD_ZERO(&read_fd_set);
		for (int i=0; i < MAX_CONNECTIONS; i++) {
			if (conn_sockets[i] > 0) {
				FD_SET(conn_sockets[i],&read_fd_set);
			}
		}

		int num_conns = select(FD_SETSIZE, &read_fd_set, NULL, NULL, NULL);

		if (num_conns > 0) {
			if (FD_ISSET(conn_sockets[0],&read_fd_set)) {
				int client_sock = accept(conn_sockets[0],&temp_addr,&temp_addrlen);
				for (int i=0;i < MAX_CONNECTIONS; i++) {
					if (conn_sockets[i] <= 0) {
						conn_sockets[i] = client_sock;
						break;
					}
				}
			}

			for (int i=1; i < MAX_CONNECTIONS; i++) {
				if (FD_ISSET(conn_sockets[i],&read_fd_set)) {
					do {

						while ( strcmp(buffer,"END_OF_DATA\r\n") != 0 ) {
							int num_bytes_read = recv(conn_sockets[i],buffer,sizeof(buffer),0);
                                	                if (num_bytes_read <= 0) {
								close(conn_sockets[i]);
								conn_sockets[i] = 0;
								to_user[i] = NULL;
								GOTO continue_for_loop;
	                                                } 
							strcat(data, buffer);
						}

						strcat(data,"\0");

						if (num_bytes_read <= 0) {
							close(conn_sockets[i]);
							conn_sockets[i] = 0;
							to_user[i] = NULL;
							break;
						} else {
	
							if (from_user[i] == NULL) {
								from_user[i] = fetch_user(fetch_sender_user_string(buffer));
								if (from_user[i] == NULL) {
									printf("Please identify yourself.\n");
									raise(SIGINT);
									return 150;
								} else {
									printf("You are %s\n",from_user[i]->username);
								}
								continue;
							}
	
							if (to_user[i] == NULL) {
								to_user[i] = fetch_user(fetch_dest_user_string(buffer));
								if (to_user[i] == NULL) {
									printf("Invalid message format or User\n");
									raise(SIGINT);
								} else {
									printf("Message intended for %s\n",to_user[i]->username);
								}
								continue;
							}

							char* message = fetch_message_string(buffer);
							
						}

					} while (strcmp(buffer,"END_OF_DATA\r\n") != 0);

				}
				continue_for_loop:
			}
		}
		

	if (stop_running == true) {
		printf("Stopping...\n");
		for (int i=MAX_CONNECTIONS-1; i>= 0;  i--) {
			close(i);
			close(conn_sockets[i]);
		}
		return 130;
	}


	}

//	Message message = new_message("Hello, this is a text message",users[0],users[1]);



//	printf("Message was: %s\nSentfrom: %s\nSent to: %s\nWith password: %s\nSent at: %s\n",message.text, message.sender.username, message.recipient.username, message.recipient.password, asctime(&message.timeinfo));

	
}


User** create_user_list(char* filename) {

	/* Structure of user file - <username> <password> on every line */

	int num_users = num_of_lines(filename);
        char* file_str = file_to_string(filename);

        char* token = malloc(sizeof(char) * 30);
        User** users = malloc (num_users * sizeof(User*));

	for (int i=0;i<num_users;i++) {
		(*(users+i)) = malloc(sizeof(User));
	}

        token = strtok(file_str," \r\n");
        for (int i=0;i<num_users;i++) {
		(*(users + i))->username = strdup(token);
                token = strtok(NULL," \r\n");
                (*(users + i))->password = strdup(token);
                token = strtok(NULL," \r\n");
        }

	return users;

}

void sigint_handler(int dummy) {
	stop_running = true;	
}

User* fetch_user(char* username) {
	if (username == NULL) {
		return NULL;
	}

	for (int i=0;i<num_users;i++) {
		if (strcmp(users[i]->username, username) == 0) {
			return users[i];
		}
	}

	return NULL;
}