/*
    author: sotech117
    date: 9/25/2023
    course: csci1680
    description: listener for snowcast, a music streaming service

    enjoy :)
*/

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

#include "protocol.c"

main(int argc, char *argv[]) // no int here for good luck :)
{
    // CHECK AND USE ARGUMENTS
    // -------------------------------------------------------------------------------------------------
    if (argc != 2) {
        fprintf(stderr,"<udp port>\n");
        exit(1);
    }
    // get the udp port
    const char* udp_port = argv[1];

    // GET UDP SOCKET
    // -------------------------------------------------------------------------------------------------
    int sockfd, err;
    struct addrinfo hints, *servinfo, *p;
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_INET; // set to AF_INET to use IPv4
    hints.ai_socktype = SOCK_DGRAM;
    hints.ai_flags = AI_PASSIVE; // use my IP

    if ((err = getaddrinfo(NULL, udp_port, &hints, &servinfo)) != 0) {
        fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(err));
        return 1;
    }

    // loop through all the results and bind to the first we can
    for(p = servinfo; p != NULL; p = p->ai_next) {
        if ((sockfd = socket(p->ai_family, p->ai_socktype,
                p->ai_protocol)) == -1) {
            perror("listener: socket");
            continue;
        }

        if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
            close(sockfd);
            perror("listener: bind");
            continue;
        }

        break;
    }
    if (p == NULL) {
        fprintf(stderr, "listener: failed to bind socket\n");
        return 2;
    }
    freeaddrinfo(servinfo);

    // START READ/WRITE LOOP
    // -------------------------------------------------------------------------------------------------
    char buf[MAX_PACKET_SIZE];          // buffer for reading
    struct sockaddr_storage their_addr; // connector's address information
    socklen_t addr_len;
    while(1) {
        addr_len = sizeof their_addr;
        int numbytes;
        if ((numbytes = recvfrom(sockfd, buf, MAX_PACKET_SIZE , 0,
            (struct sockaddr *)&their_addr, &addr_len)) == -1) {
            perror("recvfrom");
            exit(1);
        }
        // print the buffer
        write(STDOUT_FILENO, buf, numbytes);

        memset(buf, 0, MAX_PACKET_SIZE);
    }

    close(sockfd);

    return 0;
}