#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <time.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <strings.h>
#include <getopt.h>

#define BUFFERT 512
#define BACKLOG 1

void usage(char* programName);
int create_server_socket(int port);
struct sockaddr_in sock_serv, sock_clt;

int main(int argc, char** argv)
{
    int sfd, fd;
    unsigned int length = sizeof(struct sockaddr_in);
    long int n, m, count = 0;
    unsigned int nsid;
    ushort clt_port;
    char buffer[BUFFERT], filename[256];
    char dst[INET_ADDRSTRLEN];
	time_t intps;
	struct tm* tmi;

    // Parse options
    char argchar;
    while ((argchar = getopt(argc, argv, "")) != -1)
    {
        switch (argchar)
        {
            default:
                break;
        }
    }

    // Parse positional arguments
    int port;
    char* file_path;
    if (argv[optind] == NULL || argv[optind + 1] == NULL)
    {
        usage(argv[0]);
        exit(3);
    }
    else
    {
        port = atoi(argv[optind]);
        file_path = argv[optind + 1];
    }


    int l;
    int yes = 1;

    /* The following function call should use; Internet version 4 protocols with a sequenced, reliable, two-way connection based byte streams */
	sfd = socket( /* Q) What goes here?  */ , /* Q) What goes here? */ , 0);
    /* See; man socket */


	if (sfd == -1)
    {
        perror("socket fail");
        return EXIT_SUCCESS;
    }

    if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1 )
    {
        perror("setsockopt error");
        exit(5);
    }

	l = sizeof(struct sockaddr_in);
	bzero(&sock_serv, l);

    /* The following assignment should use; Internet version 4 protocols constant */
	sock_serv.sin_family =/* Q) What goes here? */;
    /* See; man socket */

	sock_serv.sin_port = htons(atoi(argv[1]));

    /* Set the IP address to allow connections on any network interface on the server */
	sock_serv.sin_addr.s_addr = htonl(/* Q) What goes here? */);
    /* See; man 4 ip */

    if (bind(sfd, (struct sockaddr*) &sock_serv, l) == -1)
    {
        perror("bind fail");
        exit(EXIT_FAILURE);
    }

    bzero(buffer,BUFFERT);
    listen(sfd,BACKLOG);

    /* accept() takes "struct sockaddr_in" and returns non-negative integer that is a descriptor for the accepted socket.
     * The missing arguement in the line below will need to have the *address* of the variable required, as the value is updated when the socket is update. eg, &variable
     */
    nsid = accept(sfd, (struct sockaddr*) &sock_clt, /* Q) What goes here?  */);
    /* See; man 2 accept */


    if (nsid == -1)
    {
        perror("accept fail");
        return EXIT_FAILURE;
    }
    else
    {
        if(inet_ntop(AF_INET, &sock_clt.sin_addr, dst, INET_ADDRSTRLEN) == NULL)
        {
            perror("socket error");
            exit (4);
        }

        clt_port = ntohs(sock_clt.sin_port);
        printf("connection : %s:%d\n", dst, clt_port);

        bzero(filename, 256);

        intps = time(NULL);
        tmi = localtime(&intps);

        bzero(filename, 256);

        sprintf(filename, "saved-file.%d.%d.%d.%d.%d.%d", tmi->tm_mday, tmi->tm_mon+1, 1900+tmi->tm_year, tmi->tm_hour, tmi->tm_min, tmi->tm_sec);
        printf("Creating the copied output file : %s\n", filename);

        if ((fd = open(filename, O_CREAT | O_WRONLY, 0600)) == -1)
        {
            perror("open fail");
            exit(3);
        }

        bzero(buffer, BUFFERT);

        n = recv(nsid, buffer, BUFFERT, 0);

        while(n)
        {
            if (n==-1)
            {
                perror("recv fail");
                exit(5);
            }

            if ((m=write(fd,buffer,n))==-1)
            {
                perror("write fail");
                exit(6);
            }

            count += m;

            bzero(buffer, BUFFERT);

            n = recv(nsid, buffer, BUFFERT, 0);
        }

        close(sfd);
        close(fd);
    }

    close(nsid);
    printf("End of transmission with %s.%d\n", dst, clt_port);

    /* Select the appropriate variable in the following function call argument */
    printf("Number of octets received : %ld \n", /* Q) What goes here? */);

    return EXIT_SUCCESS;
}

void usage(char* programName)
{
    fprintf(stderr, "Usage: %s [OPTIONS] <port-number> <file-to-send>\n", programName);
}