#include <algorithm>
#include <cassert>
#include <iterator>
#include <fcntl.h>

#define Fdstreambuf_Implementation
#include <fdstreambuf.hh>

void copy(char const* source_file, char const* destination_file)
{
  auto const ensure = [](int fd) { if (fd < 0) { perror("copy: "); exit(1); } return fd; };

  fdstreambuf out = ensure(open(destination_file, O_WRONLY | O_CREAT, 0644));
  fdstreambuf in = ensure(open(source_file, O_RDONLY));

  std::copy(
    std::istreambuf_iterator<char>(&in), {},
    std::ostreambuf_iterator<char>(&out));

  out.sync();

  close(out.fd);
  close(in.fd);
}

int main()
{
  copy(__FILE__, __FILE__ ".1");
}

#include <ostream>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define Fdstreambuf_Implementation
#include <fdstreambuf.hh>

std::string_view Http_Header =
  "HTTP/1.1 200 OK\r\n"
  "Server: fdstreambuf example HTTP server\r\n"
  "Content-Type: text/html\r\n"
  "Connection: Closed\r\n"
  "\r\n";

void http()
{
  auto const ensure = [](int v) { if (v < 0) { perror("http: "); exit(1); } return v; };

  auto const sock = ensure(socket(AF_INET, SOCK_STREAM, 0));

  struct sockaddr_in sa;
  sa.sin_family = AF_INET;
  sa.sin_addr.s_addr = inet_addr("127.0.0.1");
  sa.sin_port = htons(8080);

  ensure(bind(sock, (struct sockaddr*)&sa, sizeof(sa)));
  ensure(listen(sock, 5));

  struct sockaddr incoming;
  socklen_t incoming_len = sizeof(incoming);
  for (size_t connections = 0;;) {
    fdstreambuf client = ensure(accept(sock, &incoming, &incoming_len));
    std::ostream response(&client);

    std::copy(Http_Header.begin(), Http_Header.end(), std::ostreambuf_iterator(&client));
    response << "<h1> Hello world! </h1>\n";
    response << "<p> This message has been send " << connections++ << " times </p>\n";

    auto status = client.sync();
    assert(status == 0);
    close(client.fd);
  }

  close(sock);
}