#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 BUFFER_LENGTH 512
#define BACKLOG 1

void usage(char* programName);
int create_server_socket(int port);
struct sockaddr_in socket_server, socket_client;

int main(int argc, char** argv)
{
    int sfd, fd;
    long int n, m, count = 0;
    unsigned int nsid;
    ushort client_port;
    char buffer[BUFFER_LENGTH], 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];
    }

    // Open a TCP socket over IPv4
    sfd = socket(AF_INET, SOCK_SEQPACKET, 0);
	if (sfd == -1)
    {
        perror("socket fail");
        exit(EXIT_SUCCESS);
    }

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

    // Clear out the server socket address struct
	int sockaddr_size = sizeof(struct sockaddr_in);
	bzero(&socket_server, sockaddr_size);

    // Define properties of server socket address
	socket_server.sin_family = AF_INET;
	socket_server.sin_port = htons(port);
	socket_server.sin_addr.s_addr = htonl(0); // <-- 0.0.0.0, binds to all interfaces

    // Bind the socket to the address
    if (bind(sfd, (struct sockaddr*) &socket_server, sockaddr_size) == -1)
    {
        perror("bind fail");
        exit(EXIT_FAILURE);
    }

    // Clear message buffer
    bzero(buffer, BUFFER_LENGTH);

    // Start listening for connections, allowing a maximum of BACKLOG waiting connections
    listen(sfd, BACKLOG);

    // Block and accept incoming connection
    // TODO: Figure out what socklen actually is and why it's here
    socklen_t socklen;
    nsid = accept(sfd, (struct sockaddr*) &socket_client, &socklen);

    // 
    if (nsid == -1)
    {
        perror("accept fail");
        exit(EXIT_FAILURE);
    }

    if(inet_ntop(AF_INET, &socket_client.sin_addr, dst, INET_ADDRSTRLEN) == NULL)
    {
        perror("socket error");
        exit (4);
    }

    client_port = ntohs(socket_client.sin_port);
    printf("connection : %s:%d\n", dst, client_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, BUFFER_LENGTH);

    n = recv(nsid, buffer, BUFFER_LENGTH, 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, BUFFER_LENGTH);

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

    close(sfd);
    close(fd);

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