#include "l8_common.h"

#define MAXBUF 576
volatile sig_atomic_t last_signal = 0;

void sigalrm_handler(int sig) { last_signal = sig; }

int make_socket()
{
    int sock;
    sock = socket(PF_INET, SOCK_DGRAM, 0);
    if (sock < 0)
        ERR("socket");
    return sock;
}

void usage(char *name) { fprintf(stderr, "USAGE: %s domain port file \n", name); }

void sendAndConfirm(int fd, struct sockaddr_in addr, char *sendbuf, char *recvbuf, ssize_t size)
{
    struct itimerval ts;
    if (TEMP_FAILURE_RETRY(sendto(fd, sendbuf, size, 0, (struct sockaddr *)&addr, sizeof(addr))) < 0)
        ERR("sendto:");
    memset(&ts, 0, sizeof(struct itimerval));
    ts.it_value.tv_usec = 500000;
    setitimer(ITIMER_REAL, &ts, NULL);
    last_signal = 0;
    while (recv(fd, recvbuf, size, 0) < 0)
    {
        if (EINTR != errno)
            ERR("recv:");
        if (SIGALRM == last_signal)
            break;
    }
}

void doClient(int fd, struct sockaddr_in addr, int file)
{
    char sendbuf[MAXBUF];
    char recvbuf[MAXBUF];
    int offset = 2 * sizeof(int32_t);
    int32_t chunkNo = 0;
    ssize_t size;
    int counter;
    do
    {
        memset(sendbuf, 0, MAXBUF);
        memset(recvbuf, 0, MAXBUF);

        if ((size = bulk_read(file, sendbuf + offset, MAXBUF - offset)) < 0)
            ERR("read from file:");
        *((int32_t *)sendbuf) = htonl(++chunkNo);
        if (size < MAXBUF - offset)
        {
            memset(sendbuf + offset + size, 0, MAXBUF - offset - size);
            *(((int32_t *)sendbuf) + 1) = htonl(1);
        }
        counter = 0;

        do
        {
            counter++;
            sendAndConfirm(fd, addr, sendbuf, recvbuf, MAXBUF);
        } while (*((int32_t *)recvbuf) != (int32_t)htonl(chunkNo) && counter <= 5);

        if (*((int32_t *)recvbuf) != (int32_t)htonl(chunkNo) && counter > 5)
            break;

    } while (size == MAXBUF - offset);
}

int main(int argc, char **argv)
{
    int fd, file;
    struct sockaddr_in addr;
    if (argc != 4)
    {
        usage(argv[0]);
        return EXIT_FAILURE;
    }
    if (sethandler(SIG_IGN, SIGPIPE))
        ERR("Seting SIGPIPE:");
    if (sethandler(sigalrm_handler, SIGALRM))
        ERR("Seting SIGALRM:");
    if ((file = TEMP_FAILURE_RETRY(open(argv[3], O_RDONLY))) < 0)
        ERR("open:");
    fd = make_socket();
    addr = make_address(argv[1], argv[2]);
    doClient(fd, addr, file);
    if (TEMP_FAILURE_RETRY(close(fd)) < 0)
        ERR("close");
    if (TEMP_FAILURE_RETRY(close(file)) < 0)
        ERR("close");
    return EXIT_SUCCESS;
}