/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2010 Tatsuhiro Tsujikawa
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#include "KqueueEventPoll.h"

#include <cerrno>
#include <cstring>
#include <algorithm>
#include <numeric>

#include "Command.h"
#include "LogFactory.h"
#include "Logger.h"
#include "util.h"
#include "fmt.h"

#ifdef KEVENT_UDATA_INTPTR_T
#define PTR_TO_UDATA(X) (reinterpret_cast<intptr_t>(X))
#else // !KEVENT_UDATA_INTPTR_T
#define PTR_TO_UDATA(X) (X)
#endif // !KEVENT_UDATA_INTPTR_T

namespace aria2 {

KqueueEventPoll::KSocketEntry::KSocketEntry(sock_t s)
    : SocketEntry<KCommandEvent, KADNSEvent>(s)
{
}

int accumulateEvent(int events, const KqueueEventPoll::KEvent& event)
{
  return events | event.getEvents();
}

size_t KqueueEventPoll::KSocketEntry::getEvents(struct kevent* eventlist)
{
  int events;
#ifdef ENABLE_ASYNC_DNS
  events =
      std::accumulate(adnsEvents_.begin(), adnsEvents_.end(),
                      std::accumulate(commandEvents_.begin(),
                                      commandEvents_.end(), 0, accumulateEvent),
                      accumulateEvent);
#else  // !ENABLE_ASYNC_DNS
  events = std::accumulate(commandEvents_.begin(), commandEvents_.end(), 0,
                           accumulateEvent);
#endif // !ENABLE_ASYNC_DNS
  EV_SET(&eventlist[0], socket_, EVFILT_READ,
         EV_ADD |
             ((events & KqueueEventPoll::IEV_READ) ? EV_ENABLE : EV_DISABLE),
         0, 0, PTR_TO_UDATA(this));
  EV_SET(&eventlist[1], socket_, EVFILT_WRITE,
         EV_ADD |
             ((events & KqueueEventPoll::IEV_WRITE) ? EV_ENABLE : EV_DISABLE),
         0, 0, PTR_TO_UDATA(this));
  return 2;
}

KqueueEventPoll::KqueueEventPoll()
    : kqEventsSize_(KQUEUE_EVENTS_MAX),
      kqEvents_(make_unique<struct kevent[]>(kqEventsSize_))
{
  kqfd_ = kqueue();
}

KqueueEventPoll::~KqueueEventPoll()
{
  if (kqfd_ != -1) {
    int r = close(kqfd_);
    int errNum = errno;
    if (r == -1) {
      A2_LOG_ERROR(fmt("Error occurred while closing kqueue file descriptor"
                       " %d: %s",
                       kqfd_, util::safeStrerror(errNum).c_str()));
    }
  }
}

bool KqueueEventPoll::good() const { return kqfd_ != -1; }

void KqueueEventPoll::poll(const struct timeval& tv)
{
  struct timespec timeout = {tv.tv_sec, tv.tv_usec * 1000};
  int res;
  while ((res = kevent(kqfd_, kqEvents_.get(), 0, kqEvents_.get(),
                       kqEventsSize_, &timeout)) == -1 &&
         errno == EINTR)
    ;
  if (res > 0) {
    for (int i = 0; i < res; ++i) {
      KSocketEntry* p = reinterpret_cast<KSocketEntry*>(kqEvents_[i].udata);
      int events = 0;
      int filter = kqEvents_[i].filter;
      if (filter == EVFILT_READ) {
        events = KqueueEventPoll::IEV_READ;
      }
      else if (filter == EVFILT_WRITE) {
        events = KqueueEventPoll::IEV_WRITE;
      }
      p->processEvents(events);
    }
  }
  else if (res == -1) {
    int errNum = errno;
    A2_LOG_INFO(fmt("kevent error: %s", util::safeStrerror(errNum).c_str()));
  }
#ifdef ENABLE_ASYNC_DNS
  // It turns out that we have to call ares_process_fd before ares's
  // own timeout and ares may create new sockets or closes socket in
  // their API. So we call ares_process_fd for all ares_channel and
  // re-register their sockets.
  for (auto& r : nameResolverEntries_) {
    auto& ent = r.second;
    ent.processTimeout();
    ent.removeSocketEvents(this);
    ent.addSocketEvents(this);
  }
#endif // ENABLE_ASYNC_DNS

  // TODO timeout of name resolver is determined in Command(AbstractCommand,
  // DHTEntryPoint...Command)
}

namespace {
int translateEvents(EventPoll::EventType events)
{
  int newEvents = 0;
  if (EventPoll::EVENT_READ & events) {
    newEvents |= KqueueEventPoll::IEV_READ;
  }
  if (EventPoll::EVENT_WRITE & events) {
    newEvents |= KqueueEventPoll::IEV_WRITE;
  }
  return newEvents;
}
} // namespace

bool KqueueEventPoll::addEvents(sock_t socket,
                                const KqueueEventPoll::KEvent& event)
{
  auto i = socketEntries_.lower_bound(socket);
  int r = 0;
  struct timespec zeroTimeout = {0, 0};
  struct kevent changelist[2];
  size_t n;
  if (i != std::end(socketEntries_) && (*i).first == socket) {
    auto& socketEntry = (*i).second;
    event.addSelf(&socketEntry);
    n = socketEntry.getEvents(changelist);
  }
  else {
    i = socketEntries_.insert(i, std::make_pair(socket, KSocketEntry(socket)));
    auto& socketEntry = (*i).second;
    if (socketEntries_.size() > kqEventsSize_) {
      kqEventsSize_ *= 2;
      kqEvents_ = make_unique<struct kevent[]>(kqEventsSize_);
    }
    event.addSelf(&socketEntry);
    n = socketEntry.getEvents(changelist);
  }
  r = kevent(kqfd_, changelist, n, changelist, 0, &zeroTimeout);
  int errNum = errno;
  if (r == -1) {
    A2_LOG_DEBUG(fmt("Failed to add socket event %d:%s", socket,
                     util::safeStrerror(errNum).c_str()));
    return false;
  }
  else {
    return true;
  }
}

bool KqueueEventPoll::addEvents(sock_t socket, Command* command,
                                EventPoll::EventType events)
{
  int kqEvents = translateEvents(events);
  return addEvents(socket, KCommandEvent(command, kqEvents));
}

#ifdef ENABLE_ASYNC_DNS
bool KqueueEventPoll::addEvents(sock_t socket, Command* command, int events,
                                const std::shared_ptr<AsyncNameResolver>& rs)
{
  return addEvents(socket, KADNSEvent(rs, command, socket, events));
}
#endif // ENABLE_ASYNC_DNS

bool KqueueEventPoll::deleteEvents(sock_t socket,
                                   const KqueueEventPoll::KEvent& event)
{
  auto i = socketEntries_.find(socket);
  if (i == std::end(socketEntries_)) {
    A2_LOG_DEBUG(fmt("Socket %d is not found in SocketEntries.", socket));
    return false;
  }

  auto& socketEntry = (*i).second;
  event.removeSelf(&socketEntry);
  int r = 0;
  struct timespec zeroTimeout = {0, 0};
  struct kevent changelist[2];
  size_t n = socketEntry.getEvents(changelist);
  r = kevent(kqfd_, changelist, n, changelist, 0, &zeroTimeout);
  int errNum = errno;
  if (socketEntry.eventEmpty()) {
    socketEntries_.erase(i);
  }
  if (r == -1) {
    A2_LOG_DEBUG(fmt("Failed to delete socket event:%s",
                     util::safeStrerror(errNum).c_str()));
    return false;
  }
  else {
    return true;
  }
}

#ifdef ENABLE_ASYNC_DNS
bool KqueueEventPoll::deleteEvents(sock_t socket, Command* command,
                                   const std::shared_ptr<AsyncNameResolver>& rs)
{
  return deleteEvents(socket, KADNSEvent(rs, command, socket, 0));
}
#endif // ENABLE_ASYNC_DNS

bool KqueueEventPoll::deleteEvents(sock_t socket, Command* command,
                                   EventPoll::EventType events)
{
  int kqEvents = translateEvents(events);
  return deleteEvents(socket, KCommandEvent(command, kqEvents));
}

#ifdef ENABLE_ASYNC_DNS
bool KqueueEventPoll::addNameResolver(
    const std::shared_ptr<AsyncNameResolver>& resolver, Command* command)
{
  auto key = std::make_pair(resolver.get(), command);
  auto itr = nameResolverEntries_.lower_bound(key);

  if (itr != std::end(nameResolverEntries_) && (*itr).first == key) {
    return false;
  }

  itr = nameResolverEntries_.insert(
      itr, std::make_pair(key, KAsyncNameResolverEntry(resolver, command)));
  (*itr).second.addSocketEvents(this);
  return true;
}

bool KqueueEventPoll::deleteNameResolver(
    const std::shared_ptr<AsyncNameResolver>& resolver, Command* command)
{
  auto key = std::make_pair(resolver.get(), command);
  auto itr = nameResolverEntries_.find(key);
  if (itr == std::end(nameResolverEntries_)) {
    return false;
  }

  (*itr).second.removeSocketEvents(this);
  nameResolverEntries_.erase(itr);
  return true;
}
#endif // ENABLE_ASYNC_DNS

} // namespace aria2