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

#define LENGTH 512 // Buffer length

int main(int argc, char *argv[])
{
    int sockfd;
    char recvbuf[LENGTH];
    struct sockaddr_in remote_addr; 
    char *server;
    
    if(argc < 4){
        printf("Too few arguments. \nUsage : myftpdc <filename> <server> <port>\n");
    }

    server = argv[2];
    int port = atoi(argv[3]);

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        printf("Socket creation failed!\n");
        return (0);
    }

    remote_addr.sin_family = AF_INET; 
    remote_addr.sin_port = htons(port); 
    
    inet_pton(AF_INET, server, &remote_addr.sin_addr); 

    if (connect(sockfd, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) == -1)
    {
        printf ("Failed to connect to the host!\n");
        return (0);
    }
    else printf("Connected ...!\n");

    char* f_name = argv[1];
    FILE *fp = fopen(f_name, "a");
    if(fp == NULL) 
    {
        printf("File %s cannot be opened. Check permissions\n", f_name);
    }
    else
    {
        bzero(recvbuf, LENGTH);
        int f_block_sz;
        
        while(f_block_sz = recv(sockfd, recvbuf, LENGTH, 0))
        {
            int write_sz = fwrite(recvbuf, sizeof(char), f_block_sz, fp);
            if(write_sz < f_block_sz)
            {
                printf("File write failed.\n");
                break;
            }
            if(f_block_sz < 0)
            {
                printf("Receive file error.\n");
                break;
            }
            else if(f_block_sz = 0){
                printf("No more data. Closing connection.\n");
                break;   
            }
            bzero(recvbuf, LENGTH);
        }
    }
    close (sockfd);
    printf("Connection ended.\n");
    return (0);
}