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

int main(int argc, char **argv)
{

    const int port = 7332;
    struct sockaddr_in myaddr, endpoint;
    struct dirent **namelist;
    char buff[512];
    char name_file[512];
    char names_files[512];
    int sdsocket, sdconnection, addrlen, n, x, lenbyt, s;
connect:

    sdsocket = socket(AF_INET, SOCK_STREAM, 0);
    if (setsockopt(sdsocket, SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int)) < 0)
        printf("setsockopt(SO_REUSEADDR) failed");

    addrlen = sizeof(struct sockaddr_in);

    myaddr.sin_family = AF_INET;
    myaddr.sin_port = htons(port);
    myaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    if (bind(sdsocket, (struct sockaddr *)&myaddr, addrlen) < 0)
    {
        printf("bind() failed\n");
        return 1;
    }

    if (listen(sdsocket, 10) < 0)
    {
        printf("listen() failed\n");
        return 1;
    }

    while (1)
    {

        while ((sdconnection =
                    accept(sdsocket,
                           (struct sockaddr *)&endpoint,
                           &addrlen)) >= 0)
        {
        start:
            printf("CONNECT FROM : %s\n", inet_ntoa(endpoint.sin_addr));

            bzero(buff, 512);
            recv(sdconnection, buff, 512, 0);

            if (strncmp("GET_ALL_FILES", buff, 13) == 0)
            {

                printf("Sending list of names files\n");
                bzero(names_files, 512);
                bzero(name_file, 512);

                DIR *d = opendir(".");
                struct dirent *enterDirectory;

                if (d == NULL)
                {
                    printf("Open error\n");
                    return EXIT_FAILURE;
                }

                while ((enterDirectory = readdir(d)) != NULL)
                {
                    if (enterDirectory->d_type == DT_REG)
                    {

                        sprintf(name_file, "%s\n", enterDirectory->d_name);
                        strcat(names_files, name_file);
                    }
                }

                closedir(d);

                if (s = send(sdconnection, names_files, 512, 0) == 512)
                {
                    printf("Send success\n");
                    goto start;
                }
            }
            else if (strncmp("SEND", buff, 4) == 0)
            {
                ssize_t total = 0;
                strncpy(name_file, buff + 5, 508);
                printf("Name of file :%s\n", name_file);

                printf("I'm receving a file: %s\n", buff);

                FILE *file = fopen(name_file, "wb");
                if (file == NULL)
                {
                    printf("fopen() failed");
                }

                char length[512];
                recv(sdconnection, length, 512, 0);

                lenbyt = atoi(length);
                printf("File size: %d\n", lenbyt);

                char addr[INET_ADDRSTRLEN];
                printf("Downloading file: %s od %s\n", name_file, inet_ntop(AF_INET, &endpoint.sin_addr.s_addr, addr, INET_ADDRSTRLEN));

                ssize_t n;

                char package[4096] = {0};

                while (total < lenbyt)
                {
                    n = recv(sdconnection, package, 4096, 0);
                    total += n;
                    if (n == -1)
                    {
                        printf("recv() failed");
                    }

                    if (fwrite(package, sizeof(char), n, file) != n)
                    {
                        printf("fwrite() failed");
                    }
                    memset(package, 0, 4096);
                }
                printf("Downloading succes, numer of bytes = %ld\n", total);

                fclose(file);
                goto start;
            }
            else if (strncmp("EXIT", buff, 4) == 0)
            {
                printf("Server shut down..\n");

                close(sdsocket);
                return 0;
            }
            else if (strncmp("DISCONNECT", buff, 4) == 0)
            {
                printf("Server disconnect\n");
                close(sdconnection);
                close(sdsocket);
                goto connect;
            }
            else if (strncmp("FTP", buff, 3) == 0)
            {
                ssize_t count = 0;
                bzero(name_file, 512);
                strncpy(name_file, buff + 4, 509);
                printf("File to send :%s\n", name_file);

                FILE *file = fopen(name_file, "rb");
                if (file == NULL)
                {
                    printf("fopen() failed");
                }
                fseek(file, 0L, SEEK_END);

                long int res = ftell(file);
                printf("Size file: %ld\n", res);
                char length[512];
                sprintf(length, "%ld", res);
                send(sdconnection, length, 512, 0);

                rewind(file);

                char package[4096] = {0};
                while ((x = fread(package, sizeof(char), 4096, file)) > 0)
                {
                    count += x;

                    if (send(sdconnection, package, x, 0) == -1)
                    {
                        printf("send() failed");
                    }
                    memset(package, 0, 4096);
                }

                printf("Send success, number of bytes: %ld\n", count);

                fclose(file);
                goto start;
            }
            else
            {
                printf("Wrong query: %s\n", buff);
                send(sdconnection, "Wrong Query", 512, 0);

                goto start;
            }
        }
    }
    close(sdsocket);
    return 0;
}