// kill -9 $(lsof -ti :8080)

// TCP Server
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#define PORT 8080

int main()
{
    struct sockaddr_in serverAddr, clientAddr;
    int serverAddrLen = sizeof(serverAddr);
    int clientAddrLen = sizeof(clientAddr);

    // Create a socket
    int server_fd = socket(AF_INET, SOCK_STREAM, 0);

    if (server_fd < 0)
    {
        perror("nCouldn't create socket");
        exit(EXIT_FAILURE);
    }

    // Initialize the server address structure
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = INADDR_ANY;
    serverAddr.sin_port = htons(PORT);

    // Bind the socket to the server address
    if (bind(server_fd, (struct sockaddr *)&serverAddr;, serverAddrLen) < 0)
    {
        perror("nCouldn't bind");
        exit(EXIT_FAILURE);
    }

    // Start listening for incoming connections
    if (listen(server_fd, 10) < 0)
    {
        perror("nCouldn't listen");
        exit(EXIT_FAILURE);
    }

    // Accept a client connections
    // int comm_fd = accept(server_fd, (struct sockaddr *)&serverAddr;, (socklen_t *)&serverAddrLen;);
    int comm_fd = accept(server_fd, (struct sockaddr *)&clientAddr;, &clientAddrLen;);

    if (comm_fd < 0)
    {
        perror("nCouldn't accept");
        exit(EXIT_FAILURE);
    }

    char messageReceived[100];

    while (1)
    {
        bzero(messageReceived, 100);
        
        // Receive data from the client
        recv(comm_fd, messageReceived, 100, 0);

        printf("nMessage from client:n%s", messageReceived);

        // Send the received data back to the client
        send(comm_fd, messageReceived, strlen(messageReceived), 0);

        if(strncmp(messageReceived, "Exit", 4) == 0) {
            printf("nServer exiting...n");
            break;
        }
    }
    // Close the client connection
    close(comm_fd);
    close(server_fd);
}

// TCP Client

#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#define PORT 8080

int main()
{
    struct sockaddr_in serverAddr;

    // Create a socket
    int client_fd = socket(AF_INET, SOCK_STREAM, 0);

    if (client_fd < 0)
    {
        perror("nCouldn't create socket");
        exit(EXIT_FAILURE);
    }

    // Initialize the server address structure
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    serverAddr.sin_port = htons(PORT);

    // if (inet_pton(AF_INET, "127.0.0.1", &serverAddr;.sin_addr) <= 0)
    // {
    //     printf("nInvalid address / Address not supported");
    //     exit(EXIT_FAILURE);
    // }

    // Establish a connection to the server
    if (connect(client_fd, (struct sockaddr *)&serverAddr;, sizeof(serverAddr)) < 0)
    {
        perror("nCouldn't connect");
        exit(EXIT_FAILURE);
    }

    char messageSent[100];
    char messageReceived[100];

    while (1)
    {
        bzero(messageSent, 100);
        bzero(messageReceived, 100);

        // Read a line of text from the user
        printf("nEnter message:n");
        fgets(messageSent, 100, stdin);

        // Send the user's input to the server
        send(client_fd, messageSent, sizeof(messageSent), 0);
        
        // Receive the response from the server
        recv(client_fd, messageReceived, 100, 0);

        // Print the server's response
        printf("nMessage from server(echo):n%s", messageReceived);

        if (strncmp(messageSent, "Exit", 4) == 0)
        {
            printf("nClient exiting...n");
            break;
        }
    }

    close(client_fd);
}

// UDP Server

#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#define PORT 8080

int main()
{
    struct sockaddr_in serverAddr, clientAddr;

    // Create a socket
    int server_fd = socket(AF_INET, SOCK_DGRAM, 0);

    if (server_fd < 0)
    {
        perror("nCouldn't create socket");
        exit(EXIT_FAILURE);
    }

    // Initialize the server address structure
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = INADDR_ANY;
    serverAddr.sin_port = htons(PORT);

    // Bind the socket to the server address
    if (bind(server_fd, (struct sockaddr *)&serverAddr;, sizeof(serverAddr)) < 0)
    {
        perror("nCouldn't bind");
        exit(EXIT_FAILURE);
    }

    char messageReceived[100];
    socklen_t clientAddrLen = sizeof(clientAddr);

    while (1)
    {
        bzero(messageReceived, 100);

        // Receive data from the client
        recvfrom(server_fd, messageReceived, 100, 0, (struct sockaddr *)&clientAddr;, &clientAddrLen;);

        printf("nMessage from client:n%s", messageReceived);

        // Send the received data back to the client
        sendto(server_fd, messageReceived, strlen(messageReceived), 0, (struct sockaddr *)&clientAddr;, clientAddrLen);

        if(strncmp(messageReceived, "Exit", 4) == 0) {
            printf("nServer exiting...n");
            break;
        }
    }
    
    close(server_fd);
}

// UDP Client

#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#define PORT 8080

int main()
{
    struct sockaddr_in serverAddr;

    // Create a socket
    int client_fd = socket(AF_INET, SOCK_DGRAM, 0);

    if (client_fd < 0)
    {
        perror("nCouldn't create socket");
        exit(EXIT_FAILURE);
    }

    // Initialize the server address structure
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(PORT);
    serverAddr.sin_addr.s_addr = INADDR_ANY;

    char messageSent[100];
    char messageReceived[100];
    socklen_t serverAddrLen = sizeof(serverAddr);

    while (1)
    {
        bzero(messageSent, 100);
        bzero(messageReceived, 100);

        // Read a line of text from the user
        printf("nEnter message:n");
        fgets(messageSent, 100, stdin);

        // Send the user's input to the server
        sendto(client_fd, messageSent, sizeof(messageSent), 0, (struct sockaddr *)&serverAddr;, serverAddrLen);

        // Receive the response from the server
        recvfrom(client_fd, messageReceived, 100, 0, (struct sockaddr *)&serverAddr;, &serverAddrLen;);

        // Print the server's response
        printf("nMessage from server(echo):n%s", messageReceived);

        if(strncmp(messageSent, "Exit", 4) == 0) {
            printf("nClient exiting...n");
            break;
        }
    }

    close(client_fd);
}

// Chat Server

#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#define PORT 8080

int main()
{
    struct sockaddr_in serverAddr;
    int serverAddrLen = sizeof(serverAddr);

    // Create a socket
    int server_fd = socket(AF_INET, SOCK_STREAM, 0);

    if (server_fd < 0)
    {
        perror("nCouldn't create socket");
        exit(EXIT_FAILURE);
    }

    // Initialize the server address structure
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = INADDR_ANY;
    serverAddr.sin_port = htons(PORT);

    // Bind the socket to the server address
    if (bind(server_fd, (struct sockaddr *)&serverAddr;, sizeof(serverAddr)) < 0)
    {
        perror("nCouldn't bind");
        exit(EXIT_FAILURE);
    }

    // Start listening for incoming connections
    if (listen(server_fd, 10) < 0)
    {
        perror("nCouldn't listen");
        exit(EXIT_FAILURE);
    }

    // Accept a client connections
    int comm_fd = accept(server_fd, (struct sockaddr *)&serverAddr;, (socklen_t *)&serverAddrLen;);

    if (comm_fd < 0)
    {
        perror("nCouldn't accept");
        exit(EXIT_FAILURE);
    }

    while (1)
    {
        char messageReceived[100];
        char messageSent[100];

        // Receive data from the client
        recv(comm_fd, messageReceived, 100, 0);

        printf("nMessage from client:n%s", messageReceived);

        printf("nEnter message:n");
        fgets(messageSent, 100, stdin);

        // Send the received data back to the client
        send(comm_fd, messageSent, strlen(messageSent), 0);

        if(strncmp(messageSent, "Exit", 4) == 0) {
            printf("nServer exiting...n");
            break;
        }
    }

    // Close the client connection
    close(comm_fd);
    close(server_fd);
}

// Chat Client

#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#define PORT 8080

int main()
{
    struct sockaddr_in serverAddr;

    // Create a socket
    int client_fd = socket(AF_INET, SOCK_STREAM, 0);

    if (client_fd < 0)
    {
        perror("nCouldn't create socket");
        exit(EXIT_FAILURE);
    }

    // Initialize the server address structure
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(PORT);

    if (inet_pton(AF_INET, "127.0.0.1", &serverAddr;.sin_addr) <= 0)
    {
        printf("nInvalid address / Address not supported");
        exit(EXIT_FAILURE);
    }

    // Establish a connection to the server
    if (connect(client_fd, (struct sockaddr *)&serverAddr;, sizeof(serverAddr)) < 0)
    {
        perror("nCouldn't connect");
        exit(EXIT_FAILURE);
    }

    while (1)
    {
        char messageSent[100];
        char messageReceived[100];
        
        // Read a line of text from the user
        printf("nEnter message:n");
        fgets(messageSent, 100, stdin);

        // Send the user's input to the server
        send(client_fd, messageSent, sizeof(messageSent), 0);

        // Receive the response from the server
        recv(client_fd, messageReceived, 100, 0);

        // Print the server's response
        printf("nMessage from server:n%s", messageReceived);

        if(strncmp(messageReceived, "Exit", 4) == 0) {
            printf("nClient exiting...n");
            break;
        }
    }
    
    close(client_fd);
}