#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 <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, sdconnection2, n, x;
    ssize_t count = 0;

    sdsocket = socket(AF_INET, SOCK_STREAM, 0);
    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)
        {
            printf("CONNECT FROM : %s\n ", inet_ntoa(endpoint.sin_addr));

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

            close(sdconnection);

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

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

                n = scandir("..", &namelist, NULL, alphasort);
                if (n == -1)
                {
                    perror("scandir");
                    exit(EXIT_FAILURE);
                }

                while (n--)
                {
                    sprintf(name_file, "%s\n", namelist[n]->d_name);
                    strcat(names_files, name_file);

                    free(namelist[n]);
                }
                free(namelist);

                while ((sdconnection2 =
                            accept(sdsocket,
                                   (struct sockaddr *)&endpoint,
                                   &addrlen)) >= 0)
                {

                    send(sdconnection2, names_files, 512, 0);

                    close(sdconnection2);
                    break;
                }
            }
            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 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 buff[4096] = {0};
                while ((sdconnection2 =
                            accept(sdsocket,
                                   (struct sockaddr *)&endpoint,
                                   &addrlen)) >= 0)
                {

                                        while ((n = recv(sdconnection2, buff, 4096, 0)) > 0)
                    {
                        total += n;
                        if (n == -1)
                        {
                            printf("recv() failed");
                        }

                        if (fwrite(buff, sizeof(char), n, file) != n)
                        {
                            printf("fwrite() failed");
                        }
                        memset(buff, 0, 4096);
                    }
                    printf("Downloading succes, numer of bytes = %ld\n", total);
                    fclose(file);
                    close(sdconnection2);
                    break;
                }
            }
            else if (strncmp("EXIT", buff, 4) == 0)
            {
                printf("Server shut down..\n");

                close(sdsocket);
                return 0;
            }
            else if (strncmp("FTP", buff, 3) == 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");
                }

                while ((sdconnection2 =
                            accept(sdsocket,
                                   (struct sockaddr *)&endpoint,
                                   &addrlen)) >= 0)
                {

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

                        if (send(sdconnection2, package, x, 0) == -1)
                        {
                            printf("send() failed");
                        }
                        memset(package, 0, 4096);
                    }

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

                    fclose(file);
                    close(sdconnection2);
                    break;
                }
            }
            else
            {
                printf("Wrong query: %s\n", buff);
                while ((sdconnection2 =
                            accept(sdsocket,
                                   (struct sockaddr *)&endpoint,
                                   &addrlen)) >= 0)
                {

                    send(sdconnection2, "Wrong query", 512, 0);

                    close(sdconnection2);
                    break;
                }
            }
        }
    }
    close(sdsocket);
    return 0;
}