#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <netdb.h> //addrinfo

/*SYNTAX   ./serverTCPs */

char PORT[] = "47200";
#define BUF_SIZE 500

int main(void)
{
    char buf[BUF_SIZE];
    int s, n, ns;
    struct sockaddr_storage from_addr;
    socklen_t from_addr_len;
    unsigned char ip[50] = "";
    struct addrinfo hints, *result, *tmp;

    memset(&hints, 0, sizeof(hints)); /*It is important to reset all to NULL*/

    hints.ai_family = AF_INET; //IPv4, AF_INET6, o AF_UNSPEC
    hints.ai_socktype = SOCK_STREAM; //TCP (other values: SOCK_DGRAM or 0)
    hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV; //Wildcard IP address, service name is numeric

    if ((getaddrinfo(NULL, PORT, &hints, &result)) != 0) /*Checking status of getaddrinfo result*/
    {
        fprintf(stderr, "getaddrinfo error\n");
        exit(EXIT_FAILURE);
    }
    
    /* getaddrinfo() returns in "result" a list of address structures.
    Try each address until we successfully bind.
    If socket (or bind) fails, we (close the socket
    and) try the next address. */

    for (tmp = result; tmp != NULL; tmp = tmp -> ai_next) {
        s = socket(tmp->ai_family, tmp->ai_socktype, tmp->ai_protocol);
        if (s == -1)  continue;
        if (bind(s, tmp -> ai_addr, tmp -> ai_addrlen) == 0)
            break; //Success
        close(s);        
    }
    
    freeaddrinfo(result); //No longer needed

    if (tmp == NULL) {
        fprintf(stderr, "Could not bind\n");
        exit(EXIT_FAILURE);
    }

    /* Listen for connections.  */
    listen(s, 5);

    /* Accept a connection.  */
    from_addr_len = sizeof(from_addr);
    ns = accept(s, (struct sockaddr *)&from_addr, &from_addr_len);

    //Convert IPv4 address to string (presentation layer)
    inet_ntop(AF_INET, &(((struct sockaddr_in *)&from_addr)->sin_addr), ip, sizeof(ip)); 
    
    /* Read from the socket until end-of-file and
     * print what we get on the standard output.  */    
    while ((n = recv(ns, buf, sizeof(buf), 0)) > 0){
        buf[n] = '\0';
        printf("Connection from: %s \nMessage: %s\n", ip, buf);}
    close(ns);
    close(s);
    exit(0);
}