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

void handle_client(int client_sock) {
    char client_message[2000];
    int read_size;
    
    // Send a message to the client
    char *message = "Hello Client...\n";
    write(client_sock, message, strlen(message));
    
    // Receive messages from client
    while ((read_size = recv(client_sock, client_message, 2000, 0)) > 0) {
        // End of string marker
        client_message[read_size] = '\0';
        
        // Print the received message
        printf("Client: %s\n", client_message);
        
        // Send the message back to client
        write(client_sock, client_message, strlen(client_message));
        
        // Clear the message buffer
        memset(client_message, 0, 2000);
        
        if (strncmp(client_message, "exit", 4) == 0) {
            break;
        }
    }
    
    if (read_size == 0) {
        puts("Client disconnected");
    } else if (read_size == -1) {
        perror("recv failed");
    }
    
    close(client_sock);
}

int main(int argc, char *argv[]) {
    int socket_desc, client_sock, c, *new_sock;
    struct sockaddr_in server, client;
    pid_t child_pid;

    if (argc < 2) {
        printf("Usage: %s <port>\n", argv[0]);
        return 1;
    }

    // Create socket
    socket_desc = socket(AF_INET, SOCK_STREAM, 0);
    if (socket_desc == -1) {
        printf("Could not create socket");
        return 1;
    }
    puts("Socket created");

    // Prepare the sockaddr_in structure
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    int port = atoi(argv[1]);
    server.sin_port = htons(port);

    // Bind
    if (bind(socket_desc, (struct sockaddr *)&server, sizeof(server)) < 0) {
        perror("bind failed. Error");
        return 1;
    }
    puts("bind done");

    // Listen
    listen(socket_desc, 3);

    // Accept an incoming connection
    puts("Waiting for incoming connections...");
    c = sizeof(struct sockaddr_in);

    while ((client_sock = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c))) {
        puts("Connection accepted");

        child_pid = fork();
        if (child_pid == 0) { // Child process
            // In the child process, handle the client
            handle_client(client_sock);
            exit(0); // Exit the child process when done
        } else if (child_pid < 0) {
            perror("could not fork");
            return 1;
        }

        // Parent process closes the client socket
        close(client_sock);
    }

    if (client_sock < 0) {
        perror("accept failed");
        return 1;
    }

    return 0;
}