// Copyright (c) Benjamin Kietzman (github.com/bkietz)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#ifndef DBUS_WATCH_TIMEOUT_HPP
#define DBUS_WATCH_TIMEOUT_HPP

#include <dbus/dbus.h>
#include <boost/asio/generic/stream_protocol.hpp>
#include <boost/asio/steady_timer.hpp>

#include <chrono>

namespace dbus {
namespace detail {

static void watch_toggled(DBusWatch *dbus_watch, void *data);
struct watch_handler {
  DBusWatchFlags flags;
  DBusWatch *dbus_watch;
  watch_handler(DBusWatchFlags f, DBusWatch *w) : flags(f), dbus_watch(w) {}
  void operator()(boost::system::error_code ec, size_t) {
    if (ec) return;
    dbus_watch_handle(dbus_watch, flags);
    auto data = dbus_watch_get_data(dbus_watch);
    if (data != nullptr) {
      boost::asio::generic::stream_protocol::socket &socket =
          *static_cast<boost::asio::generic::stream_protocol::socket *>(data);

      watch_toggled(dbus_watch, &socket.get_io_service());
    }
  }
};
static void watch_toggled(DBusWatch *dbus_watch, void *data) {
  void *watch_data = dbus_watch_get_data(dbus_watch);
  if (watch_data == nullptr) {
    return;
  }

  auto socket =
      static_cast<boost::asio::generic::stream_protocol::socket *>(watch_data);
  if (dbus_watch_get_enabled(dbus_watch)) {
    if (dbus_watch_get_flags(dbus_watch) & DBUS_WATCH_READABLE)
      socket->async_read_some(boost::asio::null_buffers(),
                              watch_handler(DBUS_WATCH_READABLE, dbus_watch));

    if (dbus_watch_get_flags(dbus_watch) & DBUS_WATCH_WRITABLE)
      socket->async_write_some(boost::asio::null_buffers(),
                               watch_handler(DBUS_WATCH_WRITABLE, dbus_watch));

  } else {
    socket->cancel();
  }
}

static dbus_bool_t add_watch(DBusWatch *dbus_watch, void *data) {
  if (!dbus_watch_get_enabled(dbus_watch)) {
    return TRUE;
  }

  boost::asio::io_service &io = *static_cast<boost::asio::io_service *>(data);

  int fd = dbus_watch_get_unix_fd(dbus_watch);

  if (fd == -1)
    // socket based watches
    fd = dbus_watch_get_socket(dbus_watch);

  boost::asio::generic::stream_protocol::socket &socket =
      *new boost::asio::generic::stream_protocol::socket(io);

  socket.assign(boost::asio::generic::stream_protocol(0, 0), fd);

  dbus_watch_set_data(dbus_watch, &socket, NULL);

  watch_toggled(dbus_watch, &io);
  return TRUE;
}

static void remove_watch(DBusWatch *dbus_watch, void *data) {
  delete static_cast<boost::asio::generic::stream_protocol::socket *>(
      dbus_watch_get_data(dbus_watch));
}

struct timeout_handler {
  DBusTimeout *dbus_timeout;
  timeout_handler(DBusTimeout *t) : dbus_timeout(t) {}
  void operator()(boost::system::error_code ec) {
    if (ec) return;
    dbus_timeout_handle(dbus_timeout);
  }
};

static void timeout_toggled(DBusTimeout *dbus_timeout, void *data) {
  boost::asio::steady_timer &timer = *static_cast<boost::asio::steady_timer *>(
      dbus_timeout_get_data(dbus_timeout));

  if (dbus_timeout_get_enabled(dbus_timeout)) {
    boost::asio::steady_timer::duration interval =
        std::chrono::milliseconds(dbus_timeout_get_interval(dbus_timeout));
    timer.expires_from_now(interval);
    timer.cancel();
    timer.async_wait(timeout_handler(dbus_timeout));
  } else {
    timer.cancel();
  }
}

static dbus_bool_t add_timeout(DBusTimeout *dbus_timeout, void *data) {
  if (!dbus_timeout_get_enabled(dbus_timeout)) return TRUE;

  boost::asio::io_service &io = *static_cast<boost::asio::io_service *>(data);

  boost::asio::steady_timer &timer = *new boost::asio::steady_timer(io);

  dbus_timeout_set_data(dbus_timeout, &timer, NULL);

  timeout_toggled(dbus_timeout, &io);
  return TRUE;
}

static void remove_timeout(DBusTimeout *dbus_timeout, void *data) {
  delete static_cast<boost::asio::steady_timer *>(
      dbus_timeout_get_data(dbus_timeout));
}

struct dispatch_handler {
  boost::asio::io_service &io;
  DBusConnection *conn;
  dispatch_handler(boost::asio::io_service &i, DBusConnection *c)
      : io(i), conn(c) {}
  void operator()() {
    if (dbus_connection_dispatch(conn) == DBUS_DISPATCH_DATA_REMAINS)
      io.post(dispatch_handler(io, conn));
  }
};

static void dispatch_status(DBusConnection *conn, DBusDispatchStatus new_status,
                            void *data) {
  boost::asio::io_service &io = *static_cast<boost::asio::io_service *>(data);
  if (new_status == DBUS_DISPATCH_DATA_REMAINS)
    io.post(dispatch_handler(io, conn));
}

static void set_watch_timeout_dispatch_functions(DBusConnection *conn,
                                                 boost::asio::io_service &io) {
  dbus_connection_set_watch_functions(conn, &add_watch, &remove_watch,
                                      &watch_toggled, &io, NULL);

  dbus_connection_set_timeout_functions(conn, &add_timeout, &remove_timeout,
                                        &timeout_toggled, &io, NULL);

  dbus_connection_set_dispatch_status_function(conn, &dispatch_status, &io,
                                               NULL);
}

}  // namespace detail
}  // namespace dbus

#endif  // DBUS_WATCH_TIMEOUT_HPP