protohackersc/server03.c

//
// Created by Ajurna on 29/07/2025.
//

#include "server03.h"

#include <pthread.h>

#include "data.h"
#include <stdio.h>
#include <ctype.h>
#include <stdbool.h>

pthread_mutex_t mutex;
pthread_cond_t cond;
#define WELCOME "Welcome to budgetchat! What shall I call you?\n"



int main() {
    SOCKET server = get_listen_socket();
    SOCKADDR_IN clientAddr;
    SOCKET client;
    connections_t *connections = connections_create(64);
    int clientAddrSize = sizeof(clientAddr);
    int connection_number = 1;
    printf("Listening for incoming connections...\n");
    while((client = accept(server, (SOCKADDR *)&clientAddr, &clientAddrSize)) != INVALID_SOCKET)
    {
        handle_args_t *args = malloc(sizeof(handle_args_t));
        args->client = client;
        args->connection = connection_number++;
        args->connections = *connections;
        pthread_t thread;
        pthread_create(&thread, nullptr, handle_connection, args);
    }
    connections_destroy(connections);
    return 0;
}

void *handle_connection(void *args) {
    handle_args_t *handleArgs = args;
    char buffer[1024] = {0};
    int bytesReceived;
    status_t status = CONNECTED;
    char *message = malloc(sizeof(char)*1024);
    char_array_t *data = char_array_create(1024);
    send(handleArgs->client, WELCOME, sizeof(WELCOME), 0);

    bytesReceived = recv(handleArgs->client, buffer, sizeof(buffer), 0);
    char_array_append(data, buffer, bytesReceived);
    char *username = char_array_get_until_char(data, '\n');
    if (username == NULL) {
        printf("{%d} Failed to parse username\n", handleArgs->connection);
        connections_remove(&handleArgs->connections, handleArgs->client);
        free(handleArgs);
        pthread_exit(NULL);
        exit(3);
    }
    username = trim(username);
    if (!username_is_valid(username)) {
        printf("{%d} Invalid username\n", handleArgs->connection);
        connections_remove(&handleArgs->connections, handleArgs->client);
        free(handleArgs);
        pthread_exit(NULL);
        exit(3);
    }
    pthread_mutex_lock(&mutex);
    sprintf(message, "* The room contains: ");
    for (int i = 0; i < handleArgs->connections.len; i++) {
        strcat(message, handleArgs->connections.clients[i].username);
        strcat(message, " ");
    }
    strcat(message, "\n");
    send(handleArgs->client, message, strlen(message), 0);
    pthread_mutex_unlock(&mutex);

    connections_append(&handleArgs->connections, handleArgs->client, username);
    sprintf(message, "* %s has entered the room\n", username);
    broadcast(&handleArgs->connections, &handleArgs->client, message);

    printf("{%d} Username: %s\n", handleArgs->connection, username);

    while ((bytesReceived = recv(handleArgs->client, buffer, sizeof(buffer), 0)) > 0) {
        printf("{%d} Client sent: |%d| \n", handleArgs->connection, bytesReceived);
        char_array_append(data, buffer, bytesReceived);
        char *request;
        while ((request = char_array_get_until_char(data, '\n')) != NULL) {
            sprintf(message, "[%s] %s\n", username, request);
        }
        memset(buffer, 0, sizeof(buffer));
    }
    free(message);
    free(args);
    return NULL;
}

connections_t *connections_create(const int size) {
    connections_t *connections = malloc(sizeof(connections_t));
    connections->size = size;
    connections->len = 0;
    connections->clients = calloc(size, sizeof(client_connection_t));
    return connections;
}
void connections_destroy(connections_t *connections) {
    free(connections->clients);
    free(connections);
}
void connections_append(connections_t *connections, SOCKET client, char *username) {
    if (connections == NULL) {
        exit(1);
    }
    pthread_mutex_lock(&mutex);
    size_t new_len = connections->len + 1;
    if (new_len > connections->size) {
        connections->size = connections->size+64;
        client_connection_t *new_array = realloc(connections->clients, connections->size * sizeof(client_connection_t));
        connections->clients = new_array;
        if (connections->clients == NULL) {
            printf("Failed to allocate memory for array\n");
        }
    }
    connections->clients[connections->size].client = client;
    connections->clients[connections->size].username = username;
    connections->len = new_len;
    printf("{%llu} Connection added\n", connections->size);
    pthread_mutex_unlock(&mutex);


};
void connections_remove(connections_t *connections, SOCKET client) {
    if (connections == NULL) {
        exit(1);
    }
    pthread_mutex_lock(&mutex);

    for (int i = 0; i < connections->size; i++) {
        if (connections->clients[i].client == client) {
            closesocket(connections->clients[i].client);
            free(connections->clients[i].username);
            for (int j = i; j < connections->size; j++) {
                connections->clients[j] = connections->clients[j+1];
            }
            connections->size--;
            printf("{%llu} Connection removed\n", connections->size);
            pthread_mutex_unlock(&mutex);
            return;
        }
    }
}

void broadcast(const connections_t *connections, const SOCKET *source, const char *message) {
    pthread_mutex_lock(&mutex);
    for (size_t i = 0; i < connections->size; i++) {
        if (connections->clients[i].client != *source) {
            send(connections->clients[i].client, message, strlen(message), 0);
        }
    }
    pthread_mutex_unlock(&mutex);
}
char *trim(char *str) {
    char *end;
    while (isspace(*str)) str++;
    if (*str == 0) return str;
    end = str + strlen(str) - 1;
    while (end > str && isspace(*end)) end--;
    end[1] = '\0';
    return str;
}
bool username_is_valid(const char *username) {
    if (username == NULL) {
        return false;
    }
    for (int i = 0; i < strlen(username); i++) {
        if (!isalnum(username[i])) {
            return false;
        }
    }
    return true;
}