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

int main(void){
        int socket_desc;
        struct sockaddr_in server_addr, client_addr;
        char server_message[2000];
        char client_message[2000];
        int client_struct_length = sizeof(client_addr);

    // Clean buffers:
    memset(server_message, '\0', sizeof(server_message));
    memset(client_message, '\0', sizeof(client_message));

    // Create UDP socket:
    socket_desc = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    if(socket_desc < 0){
        printf("Error while creating socket\n");
        return -1;
    }
    printf("Socket created successfully\n");

    // Set port and IP:
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(7789);
    server_addr.sin_addr.s_addr = inet_addr("192.168.3.1");

        // Bind to the set port and IP:
        if(bind(socket_desc, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0){
                printf("Couldn't bind to the port\n");
                printf("Did you set the ip with $ sudo ip addr add 192.168.3.1/24 dev enp5s0");
                return -1;
        }


        // send message:
        server_message[0] = '\0'; // empty frame, just to trigger the reponse

        // Set port and IP:
        client_addr.sin_family = AF_INET;
        client_addr.sin_port = htons(7789);
        client_addr.sin_addr.s_addr = inet_addr("192.168.3.10");


        if (sendto(socket_desc, server_message, strlen(server_message), 0,
                (struct sockaddr*)&client_addr, client_struct_length) < 0){
                printf("Can't send\n");
                return -1;
        } else {
                printf("enpty UDP frame send\n");
        }



       // Receive client's message:
        if (recvfrom(socket_desc, client_message, sizeof(client_message), 0,
                (struct sockaddr*)&client_addr, &client_struct_length) < 0){
                printf("Couldn't receive\n");
                return -1;
        }

        printf("Received message from IP: %s and port: %i\n",
        inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));

        printf("Msg from client: %s\n", client_message);







        // Close the socket:
        close(socket_desc);

        return 0;
}