/*

Copyright (c) 2006, Daniel Wallin

Copyright (c) 2006, 2008-2010, 2013-2017, 2019, Arvid Norberg

Copyright (c) 2015, Thomas Yuan

Copyright (c) 2016-2017, Alden Torres

Copyright (c) 2017, Pavel Pimenov

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/kademlia/find_data.hpp>

#include <libtorrent/kademlia/node.hpp>

#include <libtorrent/kademlia/dht_observer.hpp>

#include <libtorrent/io.hpp>

#include <libtorrent/socket.hpp>

#include <libtorrent/socket_io.hpp>

#ifndef TORRENT_DISABLE_LOGGING

#include <libtorrent/hex.hpp> // to_hex

#endif

namespace libtorrent { namespace dht {

void find_data_observer::reply(msg const& m)

{

  bdecode_node const r = m.message.dict_find_dict("r");

  if (!r)

  {

#ifndef TORRENT_DISABLE_LOGGING

    get_observer()->log(dht_logger::traversal, "[%u] missing response dict"

      , algorithm()->id());

#endif

    timeout();

    return;

  }

  bdecode_node const id = r.dict_find_string("id");

  if (!id || id.string_length() != 20)

  {

#ifndef TORRENT_DISABLE_LOGGING

    get_observer()->log(dht_logger::traversal, "[%u] invalid id in response"

      , algorithm()->id());

#endif

    timeout();

    return;

  }

  bdecode_node const token = r.dict_find_string("token");

  if (token)

  {

    static_cast<find_data*>(algorithm())->got_write_token(

      node_id(id.string_ptr()), token.string_value().to_string());

  }

  traversal_observer::reply(m);

  done();

}

find_data::find_data(

  node& dht_node

  , node_id const& target

  , nodes_callback ncallback)

  : traversal_algorithm(dht_node, target)

  , m_nodes_callback(std::move(ncallback))

  , m_done(false)

{

}

void find_data::start()

{

  // if the user didn't add seed-nodes manually, grab k (bucket size)

  // nodes from routing table.

  if (m_results.empty())

  {

    std::vector<node_entry> const nodes = m_node.m_table.find_node(

      target(), routing_table::include_failed);

    for (auto const& n : nodes)

    {

      add_entry(n.id, n.ep(), observer::flag_initial);

    }

  }

  traversal_algorithm::start();

}

void find_data::got_write_token(node_id const& n, std::string write_token)

{

#ifndef TORRENT_DISABLE_LOGGING

  auto logger = get_node().observer();

  if (logger != nullptr && logger->should_log(dht_logger::traversal))

  {

    logger->log(dht_logger::traversal

      , "[%u] adding write token '%s' under id '%s'"

      , id(), aux::to_hex(write_token).c_str()

      , aux::to_hex(n).c_str());

  }

#endif

  m_write_tokens[n] = std::move(write_token);

}

observer_ptr find_data::new_observer(udp::endpoint const& ep

  , node_id const& id)

{

  auto o = m_node.m_rpc.allocate_observer<find_data_observer>(self(), ep, id);

#if TORRENT_USE_ASSERTS

  if (o) o->m_in_constructor = false;

#endif

  return o;

}

char const* find_data::name() const { return "find_data"; }

void find_data::done()

{

  m_done = true;

#ifndef TORRENT_DISABLE_LOGGING

  auto logger = get_node().observer();

  if (logger != nullptr)

  {

    logger->log(dht_logger::traversal, "[%u] %s DONE"

      , id(), name());

  }

#endif

  std::vector<std::pair<node_entry, std::string>> results;

  int num_results = m_node.m_table.bucket_size();

  for (auto i = m_results.begin()

    , end(m_results.end()); i != end && num_results > 0; ++i)

  {

    observer_ptr const& o = *i;

    if (!(o->flags & observer::flag_alive))

    {

#ifndef TORRENT_DISABLE_LOGGING

      if (logger != nullptr && logger->should_log(dht_logger::traversal))

      {

        logger->log(dht_logger::traversal, "[%u] not alive: %s"

          , id(), print_endpoint(o->target_ep()).c_str());

      }

#endif

      continue;

    }

    auto j = m_write_tokens.find(o->id());

    if (j == m_write_tokens.end())

    {

#ifndef TORRENT_DISABLE_LOGGING

      if (logger != nullptr && logger->should_log(dht_logger::traversal))

      {

        logger->log(dht_logger::traversal, "[%u] no write token: %s"

          , id(), print_endpoint(o->target_ep()).c_str());

      }

#endif

      continue;

    }

    results.emplace_back(node_entry(o->id(), o->target_ep()), j->second);

#ifndef TORRENT_DISABLE_LOGGING

    if (logger != nullptr && logger->should_log(dht_logger::traversal))

    {

      logger->log(dht_logger::traversal, "[%u] %s"

        , id(), print_endpoint(o->target_ep()).c_str());

    }

#endif

    --num_results;

  }

  if (m_nodes_callback) m_nodes_callback(results);

  traversal_algorithm::done();

}

} } // namespace libtorrent::dht