filesender_client

#include <cstdlib>
#include <fstream>
#include <iostream>
#include <netdb.h>
#include <stdint.h>
#include <string>
#include <sys/socket.h>
#include <unistd.h>

void error(const char *message) {
  std::cout << message << "\n";
  exit(EXIT_FAILURE);
}

void check_write(int sockfd, const void *data, size_t size) {
  if (write(sockfd, data, size) != size) {
    error("Failed to write to socket");
  }
}

int check_connect(const addrinfo *ai) {
  int sockfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  if (sockfd == -1)
    error("Failed to open socket");
  if (connect(sockfd, ai->ai_addr, ai->ai_addrlen) != 0)
    error("Failed to connect socket");
  return sockfd;
}

void send_file(int sockfd, const char *filename) {
  std::ifstream file(filename, std::ifstream::binary);
  if (file) {
    file.seekg(0, file.end);
    size_t file_size = file.tellg();
    file.seekg(0, file.beg);

    uint32_t net_len = htonl(strlen(filename));
    check_write(sockfd, &net_len, sizeof(net_len));
    check_write(sockfd, filename, strlen(filename));
    uint32_t net_file_size = htonl(file_size);
    check_write(sockfd, &net_file_size, sizeof(net_file_size));
    char buffer[4096];
    do {
      file.read(buffer, 4096);
      check_write(sockfd, buffer, file.gcount());
    } while (file);
  } else {
    error("Failed to open file");
  }
}

void connect_and_send_file(const addrinfo *ai, const char *filename) {
  int sockfd = check_connect(ai);
  send_file(sockfd, filename);
  close(sockfd);
}

void resolve_host_and_send_file(const char *host, const char *port,
                                const char *filename) {
  addrinfo *ai = NULL;
  if (getaddrinfo(host, port, NULL, &ai) == 0) {
    connect_and_send_file(ai, filename);
    freeaddrinfo(ai);
  } else {
    error("Failed to resolve service");
  }
}

int main(int argc, char *argv[]) {
  if (argc == 4) {
    resolve_host_and_send_file(argv[1], argv[2], argv[3]);
  } else {
    error("Usage: client <host> <port> <file_name>");
  }
  return EXIT_SUCCESS;
}