/*

Copyright (c) 2015-2021, Arvid Norberg

Copyright (c) 2016-2017, 2020, Alden Torres

Copyright (c) 2017-2018, Steven Siloti

All rights reserved.

Redistribution and use in source and binary forms, with or without

modification, are permitted provided that the following conditions

are met:

    * Redistributions of source code must retain the above copyright

      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above copyright

      notice, this list of conditions and the following disclaimer in

      the documentation and/or other materials provided with the distribution.

    * Neither the name of the author nor the names of its

      contributors may be used to endorse or promote products derived

      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

POSSIBILITY OF SUCH DAMAGE.

*/

#include "libtorrent/config.hpp"

#include "libtorrent/announce_entry.hpp"

#include "libtorrent/string_util.hpp" // for is_space

#include "libtorrent/aux_/time.hpp"

#include "libtorrent/aux_/session_settings.hpp"

#include "libtorrent/aux_/listen_socket_handle.hpp"

#include "libtorrent/aux_/announce_entry.hpp"

namespace libtorrent {

  namespace {

    // wait at least 5 seconds before retrying a failed tracker

    seconds32 constexpr tracker_retry_delay_min{ 5 };

    // never wait more than 60 minutes to retry a tracker

    minutes32 constexpr tracker_retry_delay_max{ 60 };

  }

TORRENT_VERSION_NAMESPACE_2

  announce_infohash::announce_infohash()

    : fails(0)

    , updating(false)

    , start_sent(false)

    , complete_sent(false)

    , triggered_manually(false)

  {}

  announce_entry::announce_entry(string_view u)

    : url(u.to_string())

    , source(0)

    , verified(false)

#if TORRENT_ABI_VERSION == 1

    , fails(0)

    , send_stats(false)

    , start_sent(false)

    , complete_sent(false)

    , triggered_manually(false)

    , updating(false)

#endif

  {}

  announce_entry::announce_entry()

    : source(0)

    , verified(false)

#if TORRENT_ABI_VERSION == 1

    , fails(0)

    , send_stats(false)

    , start_sent(false)

    , complete_sent(false)

    , triggered_manually(false)

    , updating(false)

#endif

  {}

  announce_entry::~announce_entry() = default;

  announce_entry::announce_entry(announce_entry const&) = default;

  announce_entry& announce_entry::operator=(announce_entry const&) & = default;

  announce_endpoint::announce_endpoint() = default;

#if TORRENT_ABI_VERSION <= 2

  void announce_infohash::reset()

  {

    start_sent = false;

    next_announce = time_point32::min();

    min_announce = time_point32::min();

  }

  void announce_infohash::failed(int const backoff_ratio, seconds32 const retry_interval)

  {

    // fails is only 7 bits

    if (fails < (1 << 7) - 1) ++fails;

    // the exponential back-off ends up being:

    // 7, 15, 27, 45, 95, 127, 165, ... seconds

    // with the default tracker_backoff of 250

    int const fail_square = int(fails) * int(fails);

    seconds32 const delay = std::max(retry_interval

      , std::min(duration_cast<seconds32>(tracker_retry_delay_max)

        , tracker_retry_delay_min

          + fail_square * tracker_retry_delay_min * backoff_ratio / 100

      ));

    TORRENT_ASSERT(delay <= tracker_retry_delay_max);

    if (!is_working()) next_announce = aux::time_now32() + delay;

    updating = false;

  }

  bool announce_infohash::can_announce(time_point now, bool is_seed, std::uint8_t fail_limit) const

  {

    TORRENT_ASSERT(next_announce <= now + tracker_retry_delay_max);

    // if we're a seed and we haven't sent a completed

    // event, we need to let this announce through

    bool const need_send_complete = is_seed && !complete_sent;

    // add some slack here for rounding errors

    return now + seconds(1) >= next_announce

      && (now >= min_announce || need_send_complete)

      && (fails < fail_limit || fail_limit == 0)

      && !updating;

  }

  void announce_endpoint::reset()

  {

    for (auto& ih : info_hashes)

      ih.reset();

    start_sent = false;

    next_announce = time_point32::min();

    min_announce = time_point32::min();

  }

  void announce_entry::reset()

  {

    for (auto& aep : endpoints)

      aep.reset();

  }

  bool announce_endpoint::can_announce(time_point now, bool is_seed, std::uint8_t fail_limit) const

  {

    return std::any_of(std::begin(info_hashes), std::end(info_hashes)

      , [&](announce_infohash const& ih) { return ih.can_announce(now, is_seed, fail_limit); });

  }

  bool announce_endpoint::is_working() const

  {

    return std::any_of(std::begin(info_hashes), std::end(info_hashes)

      , [](announce_infohash const& ih) { return ih.is_working(); });

  }

  void announce_entry::trim()

  {

    while (!url.empty() && is_space(url[0]))

      url.erase(url.begin());

  }

#endif

#if TORRENT_ABI_VERSION == 1

  bool announce_entry::can_announce(time_point now, bool is_seed) const

  {

    return std::any_of(endpoints.begin(), endpoints.end()

      , [&](announce_endpoint const& aep) { return aep.can_announce(now, is_seed, fail_limit); });

  }

  bool announce_entry::is_working() const

  {

    return std::any_of(endpoints.begin(), endpoints.end()

      , [](announce_endpoint const& aep) { return aep.is_working(); });

  }

#endif

TORRENT_VERSION_NAMESPACE_2_END

namespace aux {

  announce_infohash::announce_infohash()

    : fails(0)

    , updating(false)

    , start_sent(false)

    , complete_sent(false)

    , triggered_manually(false)

  {}

  announce_endpoint::announce_endpoint(aux::listen_socket_handle const& s, bool const completed)

    : local_endpoint(s ? s.get_local_endpoint() : tcp::endpoint())

    , enabled(true)

    , socket(s)

  {

    TORRENT_UNUSED(completed);

  }

  announce_entry::announce_entry(string_view u)

    : url(u.to_string())

    , source(0)

    , verified(false)

  {}

  announce_entry::announce_entry(lt::announce_entry const& ae)

    : url(ae.url)

    , trackerid(ae.trackerid)

    , tier(ae.tier)

    , fail_limit(ae.fail_limit)

    , source(ae.source)

    , verified(false)

  {

    if (source == 0) source = lt::announce_entry::source_client;

  }

  announce_entry::announce_entry()

    : source(0)

    , verified(false)

  {}

  announce_entry::~announce_entry() = default;

  announce_entry::announce_entry(announce_entry const&) = default;

  announce_entry& announce_entry::operator=(announce_entry const&) & = default;

  void announce_infohash::reset()

  {

    start_sent = false;

    next_announce = time_point32::min();

    min_announce = time_point32::min();

  }

  void announce_infohash::failed(int const backoff_ratio, seconds32 const retry_interval)

  {

    // fails is only 7 bits

    if (fails < (1 << 7) - 1) ++fails;

    // the exponential back-off ends up being:

    // 7, 15, 27, 45, 95, 127, 165, ... seconds

    // with the default tracker_backoff of 250

    int const fail_square = int(fails) * int(fails);

    seconds32 const delay = std::max(retry_interval

      , std::min(duration_cast<seconds32>(tracker_retry_delay_max)

        , tracker_retry_delay_min

          + fail_square * tracker_retry_delay_min * backoff_ratio / 100

      ));

    if (!is_working()) next_announce = aux::time_now32() + delay;

    updating = false;

  }

  bool announce_infohash::can_announce(time_point now, bool is_seed, std::uint8_t fail_limit) const

  {

    // if we're a seed and we haven't sent a completed

    // event, we need to let this announce through

    bool const need_send_complete = is_seed && !complete_sent;

    // add some slack here for rounding errors

    return now  + seconds(1) >= next_announce

      && (now >= min_announce || need_send_complete)

      && (fails < fail_limit || fail_limit == 0)

      && !updating;

  }

  void announce_endpoint::reset()

  {

    for (auto& ih : info_hashes)

      ih.reset();

  }

  void announce_entry::reset()

  {

    for (auto& aep : endpoints)

      aep.reset();

  }

  announce_endpoint* announce_entry::find_endpoint(aux::listen_socket_handle const& s)

  {

    auto aep = std::find_if(endpoints.begin(), endpoints.end()

      , [&](aux::announce_endpoint const& a) { return a.socket == s; });

    if (aep != endpoints.end()) return &*aep;

    else return nullptr;

  }

} // aux

} // libtorrent