// Copyright 2007-2015 David Robillard <d@drobilla.net>
// SPDX-License-Identifier: GPL-3.0-or-later

#ifndef RAUL_SOCKET_HPP
#define RAUL_SOCKET_HPP

#include <netdb.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>

#include <cstdlib>
#include <cstring>
#include <memory>
#include <string>
#include <utility>

namespace raul {

/**
   A safe and simple interface for UNIX or TCP sockets.

   @ingroup raul
*/
class Socket
{
public:
  enum class Type { UNIX, TCP };

  /// Create a new unbound/unconnected socket of a given type
  explicit Socket(Type t);

  /// Wrap an existing open socket
  Socket(Type t, std::string uri, sockaddr* addr, socklen_t addr_len, int fd);

  Socket(const Socket&)            = delete;
  Socket& operator=(const Socket&) = delete;
  Socket(Socket&&)                 = delete;
  Socket& operator=(Socket&&)      = delete;

  ~Socket();

  /**
     Bind a server socket to an address.

     @param uri Address URI, e.g. unix:///tmp/foo, or tcp://hostname:1234.
     Use "*" as hostname to listen on all interfaces.

     @return True on success.
  */
  bool bind(const std::string& uri);

  /**
     Connect a client socket to a server address.

     @param uri Address URI, e.g. unix:///tmp/foo or tcp://somehost:1234
     @return True on success.
  */
  bool connect(const std::string& uri);

  /**
     Mark server socket as passive to listen for incoming connections.

     @return True on success.
  */
  bool listen();

  /**
     Accept a connection.

     @return An new open socket for the connection.
  */
  std::shared_ptr<Socket> accept();

  /// Return the file descriptor for the socket
  [[nodiscard]] int fd() const { return _sock; }

  [[nodiscard]] const std::string& uri() const { return _uri; }

  /// Close the socket
  void close();

  /**
     Shut down the socket.

     This terminates any connections associated with the socket, and will
     (unlike close()) cause a poll on the socket to return.
  */
  void shutdown();

private:
  bool set_addr(const std::string& uri);

  std::string _uri;
  sockaddr*   _addr;
  socklen_t   _addr_len;
  Type        _type;
  int         _sock;
};

#ifndef NI_MAXHOST
#  define NI_MAXHOST 1025
#endif

inline Socket::Socket(Type t)
  : _uri(t == Type::UNIX ? "unix:" : "tcp:")
  , _addr(nullptr)
  , _addr_len(0)
  , _type(t)
  , _sock(-1)
{
  switch (t) {
  case Type::UNIX:
    _sock = socket(AF_UNIX, SOCK_STREAM, 0);
    break;
  case Type::TCP:
    _sock = socket(AF_INET, SOCK_STREAM, 0);
    break;
  }
}

inline Socket::Socket(Type        t,
                      std::string uri,
                      sockaddr*   addr,
                      socklen_t   addr_len,
                      int         fd)
  : _uri(std::move(uri))
  , _addr(addr)
  , _addr_len(addr_len)
  , _type(t)
  , _sock(fd)
{}

inline Socket::~Socket()
{
  free(_addr);
  close();
}

inline bool
Socket::set_addr(const std::string& uri)
{
  free(_addr);
  if (_type == Type::UNIX && uri.substr(0, strlen("unix://")) == "unix://") {
    const std::string path = uri.substr(strlen("unix://"));
    auto* uaddr = static_cast<sockaddr_un*>(calloc(1, sizeof(sockaddr_un)));
    uaddr->sun_family = AF_UNIX;
    strncpy(uaddr->sun_path, path.c_str(), sizeof(uaddr->sun_path) - 1);
    _uri      = uri;
    _addr     = reinterpret_cast<sockaddr*>(uaddr);
    _addr_len = sizeof(sockaddr_un);
    return true;
  }

  if (_type == Type::TCP && uri.find("://") != std::string::npos) {
    const std::string authority = uri.substr(uri.find("://") + 3);
    const size_t      port_sep  = authority.find(':');
    if (port_sep == std::string::npos) {
      return false;
    }

    std::string       host = authority.substr(0, port_sep);
    const std::string port = authority.substr(port_sep + 1);
    if (host.empty() || host == "*") {
      host = "0.0.0.0"; // INADDR_ANY
    }

    addrinfo* ainfo = nullptr;
    if (getaddrinfo(host.c_str(), port.c_str(), nullptr, &ainfo)) {
      return false;
    }

    _uri      = uri;
    _addr     = static_cast<sockaddr*>(malloc(ainfo->ai_addrlen));
    _addr_len = ainfo->ai_addrlen;
    memcpy(_addr, ainfo->ai_addr, ainfo->ai_addrlen);
    freeaddrinfo(ainfo);
    return true;
  }

  return false;
}

inline bool
Socket::bind(const std::string& uri)
{
  return set_addr(uri) && ::bind(_sock, _addr, _addr_len) != -1;
}

inline bool
Socket::connect(const std::string& uri)
{
  return set_addr(uri) && ::connect(_sock, _addr, _addr_len) != -1;
}

inline bool
Socket::listen() // NOLINT(readability-make-member-function-const)
{
  return ::listen(_sock, 64) != -1;
}

inline std::shared_ptr<Socket>
Socket::accept()
{
  socklen_t   client_addr_len = _addr_len;
  auto* const client_addr = static_cast<sockaddr*>(calloc(1, client_addr_len));

  const int conn = ::accept(_sock, client_addr, &client_addr_len);
  if (conn == -1) {
    free(client_addr);
    return {};
  }

  std::string client_uri = _uri;
  if (_type != Type::UNIX) {
    char host[NI_MAXHOST];
    char serv[NI_MAXSERV];
    if (!getnameinfo(client_addr,
                     client_addr_len,
                     host,
                     sizeof(host),
                     serv,
                     sizeof(serv),
                     0)) {
      const std::string scheme = _uri.substr(0, _uri.find(':'));
      client_uri               = scheme + "://" + host + ":" + serv;
    }
  }

  return std::make_shared<Socket>(
    _type, client_uri, client_addr, client_addr_len, conn);
}

inline void
Socket::close()
{
  if (_sock != -1) {
    ::close(_sock);
    _sock = -1;
  }
}

inline void
Socket::shutdown() // NOLINT(readability-make-member-function-const)
{
  if (_sock != -1) {
    ::shutdown(_sock, SHUT_RDWR);
  }
}

} // namespace raul

#endif // RAUL_SOCKET_HPP