/*
    This file is part of TON Blockchain Library.

    TON Blockchain Library is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    TON Blockchain Library 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.

    Copyright 2017-2019 Telegram Systems LLP
*/
#include "td/utils/Random.h"

#include "adnl/utils.hpp"
#include "dht/dht.h"

#include "overlay.hpp"
#include "auto/tl/ton_api.hpp"

#include "keys/encryptor.h"

namespace ton {

namespace overlay {

td::actor::ActorOwn<Overlay> Overlay::create(td::actor::ActorId<keyring::Keyring> keyring,
                                             td::actor::ActorId<adnl::Adnl> adnl,
                                             td::actor::ActorId<OverlayManager> manager,
                                             td::actor::ActorId<dht::Dht> dht_node, adnl::AdnlNodeIdShort local_id,
                                             OverlayIdFull overlay_id, std::unique_ptr<Overlays::Callback> callback,
                                             OverlayPrivacyRules rules) {
  auto R = td::actor::create_actor<OverlayImpl>("overlay", keyring, adnl, manager, dht_node, local_id,
                                                std::move(overlay_id), true, std::vector<adnl::AdnlNodeIdShort>(),
                                                std::move(callback), std::move(rules));
  return td::actor::ActorOwn<Overlay>(std::move(R));
}

td::actor::ActorOwn<Overlay> Overlay::create(td::actor::ActorId<keyring::Keyring> keyring,
                                             td::actor::ActorId<adnl::Adnl> adnl,
                                             td::actor::ActorId<OverlayManager> manager,
                                             td::actor::ActorId<dht::Dht> dht_node, adnl::AdnlNodeIdShort local_id,
                                             OverlayIdFull overlay_id, std::vector<adnl::AdnlNodeIdShort> nodes,
                                             std::unique_ptr<Overlays::Callback> callback, OverlayPrivacyRules rules) {
  auto R =
      td::actor::create_actor<OverlayImpl>("overlay", keyring, adnl, manager, dht_node, local_id, std::move(overlay_id),
                                           false, std::move(nodes), std::move(callback), std::move(rules));
  return td::actor::ActorOwn<Overlay>(std::move(R));
}

OverlayImpl::OverlayImpl(td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
                         td::actor::ActorId<OverlayManager> manager, td::actor::ActorId<dht::Dht> dht_node,
                         adnl::AdnlNodeIdShort local_id, OverlayIdFull overlay_id, bool pub,
                         std::vector<adnl::AdnlNodeIdShort> nodes, std::unique_ptr<Overlays::Callback> callback,
                         OverlayPrivacyRules rules)
    : keyring_(keyring)
    , adnl_(adnl)
    , manager_(manager)
    , dht_node_(dht_node)
    , local_id_(local_id)
    , id_full_(std::move(overlay_id))
    , callback_(std::move(callback))
    , public_(pub)
    , rules_(std::move(rules)) {
  overlay_id_ = id_full_.compute_short_id();

  VLOG(OVERLAY_INFO) << this << ": creating " << (public_ ? "public" : "private");

  for (auto &node : nodes) {
    CHECK(!public_);
    auto X = OverlayNode{node, overlay_id_};
    do_add_peer(std::move(X));
  }

  update_neighbours(static_cast<td::uint32>(nodes.size()));
}

void OverlayImpl::process_query(adnl::AdnlNodeIdShort src, ton_api::overlay_getRandomPeers &query,
                                td::Promise<td::BufferSlice> promise) {
  if (public_) {
    VLOG(OVERLAY_DEBUG) << this << ": received " << query.peers_->nodes_.size() << " nodes from " << src
                        << " in getRandomPeers query";
    std::vector<OverlayNode> nodes;
    for (auto &n : query.peers_->nodes_) {
      auto N = OverlayNode::create(n);
      if (N.is_ok()) {
        nodes.emplace_back(N.move_as_ok());
      }
    }
    add_peers(std::move(nodes));
    send_random_peers(src, std::move(promise));
  } else {
    VLOG(OVERLAY_WARNING) << this << ": DROPPING getRandomPeers query from " << src << " in private overlay";
    promise.set_error(td::Status::Error(ErrorCode::protoviolation, "overlay is private"));
  }
}

void OverlayImpl::process_query(adnl::AdnlNodeIdShort src, ton_api::overlay_getBroadcast &query,
                                td::Promise<td::BufferSlice> promise) {
  auto it = broadcasts_.find(query.hash_);
  if (it == broadcasts_.end()) {
    VLOG(OVERLAY_NOTICE) << this << ": received getBroadcastQuery(" << query.hash_ << ") from " << src
                         << " but broadcast is unknown";
    promise.set_value(create_serialize_tl_object<ton_api::overlay_broadcastNotFound>());
    return;
  }
  if (delivered_broadcasts_.find(query.hash_) != delivered_broadcasts_.end()) {
    VLOG(OVERLAY_DEBUG) << this << ": received getBroadcastQuery(" << query.hash_ << ") from " << src
                        << " but broadcast already deleted";
    promise.set_value(create_serialize_tl_object<ton_api::overlay_broadcastNotFound>());
    return;
  }

  VLOG(OVERLAY_DEBUG) << this << ": received getBroadcastQuery(" << query.hash_ << ") from " << src
                      << " sending broadcast";
  promise.set_value(it->second->serialize());
}

void OverlayImpl::process_query(adnl::AdnlNodeIdShort src, ton_api::overlay_getBroadcastList &query,
                                td::Promise<td::BufferSlice> promise) {
  VLOG(OVERLAY_WARNING) << this << ": DROPPING getBroadcastList query";
  promise.set_error(td::Status::Error(ErrorCode::protoviolation, "dropping get broadcast list query"));
}

/*void OverlayImpl::process_query(adnl::AdnlNodeIdShort src, adnl::AdnlQueryId query_id, ton_api::overlay_customQuery &query) {
  callback_->receive_query(src, query_id, id_, std::move(query.data_));
}
*/

void OverlayImpl::receive_query(adnl::AdnlNodeIdShort src, td::BufferSlice data, td::Promise<td::BufferSlice> promise) {
  if (!public_) {
    auto P = peers_.get(src);
    if (P == nullptr) {
      VLOG(OVERLAY_WARNING) << this << ": received query in private overlay from unknown source " << src;
      promise.set_error(td::Status::Error(ErrorCode::protoviolation, "overlay is private"));
      return;
    }
  }
  auto R = fetch_tl_object<ton_api::Function>(data.clone(), true);

  if (R.is_error()) {
    // allow custom query to be here
    callback_->receive_query(src, overlay_id_, std::move(data), std::move(promise));
    return;
  }

  auto Q = R.move_as_ok();

  VLOG(OVERLAY_EXTRA_DEBUG) << this << "query from " << src << ": " << ton_api::to_string(Q);

  ton_api::downcast_call(*Q.get(), [&](auto &object) { this->process_query(src, object, std::move(promise)); });
}

td::Status OverlayImpl::process_broadcast(adnl::AdnlNodeIdShort message_from,
                                          tl_object_ptr<ton_api::overlay_broadcast> bcast) {
  return BroadcastSimple::create(this, std::move(bcast));
}

td::Status OverlayImpl::process_broadcast(adnl::AdnlNodeIdShort message_from,
                                          tl_object_ptr<ton_api::overlay_broadcastFec> b) {
  return OverlayFecBroadcastPart::create(this, std::move(b));
}

td::Status OverlayImpl::process_broadcast(adnl::AdnlNodeIdShort message_from,
                                          tl_object_ptr<ton_api::overlay_broadcastFecShort> b) {
  return OverlayFecBroadcastPart::create(this, std::move(b));
}

td::Status OverlayImpl::process_broadcast(adnl::AdnlNodeIdShort message_from,
                                          tl_object_ptr<ton_api::overlay_broadcastNotFound> bcast) {
  return td::Status::Error(ErrorCode::protoviolation,
                           PSTRING() << "received strange message broadcastNotFound from " << message_from);
}

td::Status OverlayImpl::process_broadcast(adnl::AdnlNodeIdShort message_from,
                                          tl_object_ptr<ton_api::overlay_fec_received> msg) {
  auto it = fec_broadcasts_.find(msg->hash_);
  if (it != fec_broadcasts_.end()) {
    VLOG(OVERLAY_DEBUG) << this << ": received fec opt-out message from " << message_from << " for broadcast "
                        << msg->hash_;
    it->second->add_received(message_from);
  } else {
    VLOG(OVERLAY_DEBUG) << this << ": received fec opt-out message from " << message_from << " for unknown broadcast "
                        << msg->hash_;
  }
  return td::Status::OK();
}

td::Status OverlayImpl::process_broadcast(adnl::AdnlNodeIdShort message_from,
                                          tl_object_ptr<ton_api::overlay_fec_completed> msg) {
  auto it = fec_broadcasts_.find(msg->hash_);
  if (it != fec_broadcasts_.end()) {
    VLOG(OVERLAY_DEBUG) << this << ": received fec completed message from " << message_from << " for broadcast "
                        << msg->hash_;
    it->second->add_completed(message_from);
  } else {
    VLOG(OVERLAY_DEBUG) << this << ": received fec completed message from " << message_from << " for unknown broadcast "
                        << msg->hash_;
  }
  return td::Status::OK();
}

td::Status OverlayImpl::process_broadcast(adnl::AdnlNodeIdShort message_from,
                                          tl_object_ptr<ton_api::overlay_unicast> msg) {
  VLOG(OVERLAY_DEBUG) << this << ": received unicast from " << message_from;
  callback_->receive_message(message_from, overlay_id_, std::move(msg->data_));
  return td::Status::OK();
}

void OverlayImpl::receive_message(adnl::AdnlNodeIdShort src, td::BufferSlice data) {
  if (!public_) {
    if (peers_.get(src) == nullptr) {
      VLOG(OVERLAY_WARNING) << this << ": received query in private overlay from unknown source " << src;
      return;
    }
  }
  auto X = fetch_tl_object<ton_api::overlay_Broadcast>(data.clone(), true);
  if (X.is_error()) {
    VLOG(OVERLAY_DEBUG) << this << ": received custom message";
    callback_->receive_message(src, overlay_id_, std::move(data));
    return;
  }
  auto Q = X.move_as_ok();
  ton_api::downcast_call(*Q.get(), [Self = this, &Q, &src](auto &object) {
    Self->process_broadcast(src, move_tl_object_as<std::remove_reference_t<decltype(object)>>(Q));
  });
}

void OverlayImpl::alarm() {
  bcast_gc();
  if (public_) {
    if (peers_.size() > 0) {
      auto P = get_random_peer();
      if (P) {
        send_random_peers(P->get_id(), {});
      }
    }
    if (next_dht_query_.is_in_past()) {
      auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<dht::DhtValue> res) {
        td::actor::send_closure(SelfId, &OverlayImpl::receive_dht_nodes, std::move(res), true);
      });
      td::actor::send_closure(dht_node_, &dht::Dht::get_value, dht::DhtKey{overlay_id_.pubkey_hash(), "nodes", 0},
                              std::move(P));
      next_dht_query_ = td::Timestamp::in(td::Random::fast(60.0, 100.0));
    }
    if (update_db_at_.is_in_past()) {
      if (peers_.size() > 0) {
        std::vector<OverlayNode> vec;
        for (td::uint32 i = 0; i < 20; i++) {
          vec.push_back(get_random_peer()->get());
        }
        td::actor::send_closure(manager_, &OverlayManager::save_to_db, local_id_, overlay_id_, std::move(vec));
      }
      update_db_at_ = td::Timestamp::in(60.0);
    }

    alarm_timestamp() = td::Timestamp::in(1.0);
  } else {
    update_neighbours(0);
    alarm_timestamp() = td::Timestamp::in(60.0 + td::Random::fast(0, 100) * 0.6);
  }
}

void OverlayImpl::receive_dht_nodes(td::Result<dht::DhtValue> res, bool dummy) {
  CHECK(public_);
  if (res.is_ok()) {
    auto v = res.move_as_ok();
    auto R = fetch_tl_object<ton_api::overlay_nodes>(v.value().clone(), true);
    if (R.is_ok()) {
      auto r = R.move_as_ok();
      VLOG(OVERLAY_INFO) << this << ": received " << r->nodes_.size() << " nodes from overlay";
      VLOG(OVERLAY_EXTRA_DEBUG) << this << ": nodes: " << ton_api::to_string(r);
      std::vector<OverlayNode> nodes;
      for (auto &n : r->nodes_) {
        auto N = OverlayNode::create(n);
        if (N.is_ok()) {
          nodes.emplace_back(N.move_as_ok());
        }
      }
      add_peers(std::move(nodes));
    } else {
      VLOG(OVERLAY_WARNING) << this << ": incorrect value in DHT for overlay nodes: " << R.move_as_error();
    }
  } else {
    VLOG(OVERLAY_NOTICE) << this << ": can not get value from DHT: " << res.move_as_error();
  }

  VLOG(OVERLAY_INFO) << this << ": adding self node to DHT overlay's nodes";
  auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), oid = print_id()](td::Result<OverlayNode> R) {
    if (R.is_error()) {
      LOG(ERROR) << oid << "cannot get self node";
      return;
    }
    td::actor::send_closure(SelfId, &OverlayImpl::update_dht_nodes, R.move_as_ok());
  });
  get_self_node(std::move(P));
}

void OverlayImpl::update_dht_nodes(OverlayNode node) {
  if (!public_) {
    return;
  }

  auto nodes = create_tl_object<ton_api::overlay_nodes>(std::vector<tl_object_ptr<ton_api::overlay_node>>());
  nodes->nodes_.emplace_back(node.tl());

  dht::DhtKey dht_key{overlay_id_.pubkey_hash(), "nodes", 0};
  auto update_rule = dht::DhtUpdateRuleOverlayNodes::create();
  dht::DhtKeyDescription dht_key_descr(std::move(dht_key), id_full_.pubkey(), update_rule.move_as_ok(),
                                       td::BufferSlice());
  dht_key_descr.check().ensure();
  dht::DhtValue value{std::move(dht_key_descr), serialize_tl_object(nodes, true),
                      static_cast<td::uint32>(td::Clocks::system() + 3600), td::BufferSlice()};
  value.check().ensure();

  auto P = td::PromiseCreator::lambda([oid = print_id()](td::Result<td::Unit> res) {
    if (res.is_error()) {
      VLOG(OVERLAY_NOTICE) << oid << ": error storing to DHT: " << res.move_as_error();
    }
  });

  td::actor::send_closure(dht_node_, &dht::Dht::set_value, std::move(value), std::move(P));
}

void OverlayImpl::bcast_gc() {
  while (broadcasts_.size() > max_data_bcasts()) {
    auto bcast = BroadcastSimple::from_list_node(bcast_data_lru_.get());
    CHECK(bcast);
    auto hash = bcast->get_hash();
    broadcasts_.erase(hash);
    if (delivered_broadcasts_.insert(hash).second) {
      bcast_lru_.push(hash);
    }
  }
  while (fec_broadcasts_.size() > 0) {
    auto bcast = BroadcastFec::from_list_node(bcast_fec_lru_.prev);
    CHECK(bcast);
    if (bcast->get_date() > td::Clocks::system() - 60) {
      break;
    }
    auto hash = bcast->get_hash();
    CHECK(fec_broadcasts_.count(hash) == 1);
    fec_broadcasts_.erase(hash);
    if (delivered_broadcasts_.insert(hash).second) {
      bcast_lru_.push(hash);
    }
  }
  while (bcast_lru_.size() > max_bcasts()) {
    auto Id = bcast_lru_.front();
    bcast_lru_.pop();
    CHECK(delivered_broadcasts_.erase(Id));
  }
  CHECK(delivered_broadcasts_.size() == bcast_lru_.size());
}

void OverlayImpl::send_message_to_neighbours(td::BufferSlice data) {
  for (auto &n : neighbours_) {
    td::actor::send_closure(manager_, &OverlayManager::send_message, n, local_id_, overlay_id_, data.clone());
  }
}

void OverlayImpl::send_broadcast(PublicKeyHash send_as, td::uint32 flags, td::BufferSlice data) {
  auto S = BroadcastSimple::create_new(actor_id(this), keyring_, send_as, std::move(data), flags);
  if (S.is_error()) {
    LOG(WARNING) << "failed to send broadcast: " << S;
  }
}

void OverlayImpl::send_broadcast_fec(PublicKeyHash send_as, td::uint32 flags, td::BufferSlice data) {
  OverlayOutboundFecBroadcast::create(std::move(data), flags, actor_id(this), send_as);
}

void OverlayImpl::print(td::StringBuilder &sb) {
  sb << this;
}

td::Status OverlayImpl::check_date(td::uint32 date) {
  auto n = td::Clocks::system();
  if (date < n - 20) {
    return td::Status::Error(ErrorCode::notready, "too old broadcast");
  }
  if (date > n + 20) {
    return td::Status::Error(ErrorCode::notready, "too new broadcast");
  }
  return td::Status::OK();
}

td::Status OverlayImpl::check_source_eligible(PublicKey source, const Certificate *cert, td::uint32 size) {
  if (size == 0) {
    return td::Status::Error(ErrorCode::protoviolation, "empty broadcast");
  }
  auto short_id = source.compute_short_id();

  auto r = rules_.max_size(source.compute_short_id());
  if (r >= size) {
    return td::Status::OK();
  }
  if (!cert) {
    return td::Status::Error(ErrorCode::protoviolation, "source is not eligible");
  }
  TRY_STATUS(cert->check(short_id, overlay_id_, static_cast<td::int32>(td::Clocks::system()), size));
  auto issuer_short = cert->issuer_hash();
  if (rules_.max_size(issuer_short) < size) {
    return td::Status::Error(ErrorCode::protoviolation, "bad certificate");
  }
  return td::Status::OK();
}

td::Status OverlayImpl::check_delivered(BroadcastHash hash) {
  if (delivered_broadcasts_.count(hash) == 1 || broadcasts_.count(hash) == 1) {
    return td::Status::Error(ErrorCode::notready, "duplicate broadcast");
  } else {
    return td::Status::OK();
  }
}

BroadcastFec *OverlayImpl::get_fec_broadcast(BroadcastHash hash) {
  auto it = fec_broadcasts_.find(hash);
  if (it == fec_broadcasts_.end()) {
    return nullptr;
  } else {
    return it->second.get();
  }
}

void OverlayImpl::register_fec_broadcast(std::unique_ptr<BroadcastFec> bcast) {
  auto hash = bcast->get_hash();
  bcast_fec_lru_.put(bcast.get());
  fec_broadcasts_.emplace(hash, std::move(bcast));
  bcast_gc();
}

void OverlayImpl::get_self_node(td::Promise<OverlayNode> promise) {
  OverlayNode s{local_id_, overlay_id_};
  auto to_sign = s.to_sign();
  auto P = td::PromiseCreator::lambda([oid = print_id(), s = std::move(s), promise = std::move(promise)](
                                          td::Result<std::pair<td::BufferSlice, PublicKey>> R) mutable {
    if (R.is_error()) {
      auto S = R.move_as_error();
      LOG(ERROR) << oid << ": failed to get self node: " << S;
      promise.set_error(std::move(S));
      return;
    }
    auto V = R.move_as_ok();
    s.update_signature(std::move(V.first));
    s.update_adnl_id(adnl::AdnlNodeIdFull{V.second});
    promise.set_value(std::move(s));
  });

  td::actor::send_closure(keyring_, &keyring::Keyring::sign_add_get_public_key, local_id_.pubkey_hash(),
                          std::move(to_sign), std::move(P));
}

void OverlayImpl::send_new_fec_broadcast_part(PublicKeyHash local_id, Overlay::BroadcastDataHash data_hash,
                                              td::uint32 size, td::uint32 flags, td::BufferSlice part, td::uint32 seqno,
                                              fec::FecType fec_type, td::uint32 date) {
  auto S = OverlayFecBroadcastPart::create_new(this, actor_id(this), local_id, data_hash, size, flags, std::move(part),
                                               seqno, std::move(fec_type), date);
  if (S.is_error() && S.code() != ErrorCode::notready) {
    LOG(WARNING) << "failed to send broadcast part: " << S;
  }
}

void OverlayImpl::deliver_broadcast(PublicKeyHash source, td::BufferSlice data) {
  callback_->receive_broadcast(source, overlay_id_, std::move(data));
}

void OverlayImpl::failed_to_create_fec_broadcast(td::Status reason) {
  if (reason.code() == ErrorCode::notready) {
    LOG(DEBUG) << "failed to receive fec broadcast: " << reason;
  } else {
    LOG(WARNING) << "failed to receive fec broadcast: " << reason;
  }
}

void OverlayImpl::created_fec_broadcast(PublicKeyHash local_id, std::unique_ptr<OverlayFecBroadcastPart> bcast) {
  bcast->update_overlay(this);
  auto S = bcast->run();
  if (S.is_error() && S.code() != ErrorCode::notready) {
    LOG(WARNING) << "failed to send fec broadcast: " << S;
  }
}

void OverlayImpl::failed_to_create_simple_broadcast(td::Status reason) {
  if (reason.code() == ErrorCode::notready) {
    LOG(DEBUG) << "failed to send simple broadcast: " << reason;
  } else {
    LOG(WARNING) << "failed to send simple broadcast: " << reason;
  }
}

void OverlayImpl::created_simple_broadcast(std::unique_ptr<BroadcastSimple> bcast) {
  bcast->update_overlay(this);
  auto S = bcast->run();
  register_simple_broadcast(std::move(bcast));
  if (S.is_error() && S.code() != ErrorCode::notready) {
    LOG(WARNING) << "failed to receive fec broadcast: " << S;
  }
}

void OverlayImpl::register_simple_broadcast(std::unique_ptr<BroadcastSimple> bcast) {
  auto hash = bcast->get_hash();
  bcast_data_lru_.put(bcast.get());
  broadcasts_.emplace(hash, std::move(bcast));
  bcast_gc();
}

td::Result<Encryptor *> OverlayImpl::get_encryptor(PublicKey source) {
  auto short_id = source.compute_short_id();
  auto it = encryptor_map_.find(short_id);
  if (it != encryptor_map_.end()) {
    return it->second->get();
  }
  TRY_RESULT(e, source.create_encryptor());
  auto res = e.get();
  auto cache = std::make_unique<CachedEncryptor>(short_id, std::move(e));
  encryptor_lru_.put(cache.get());
  encryptor_map_.emplace(short_id, std::move(cache));
  while (encryptor_map_.size() > max_encryptors()) {
    auto x = CachedEncryptor::from_list_node(encryptor_lru_.get());
    auto id = x->id();
    encryptor_map_.erase(id);
  }
  return res;
}

std::shared_ptr<Certificate> OverlayImpl::get_certificate(PublicKeyHash source) {
  auto it = certs_.find(source);
  return (it == certs_.end()) ? nullptr : it->second;
}

void OverlayImpl::set_privacy_rules(OverlayPrivacyRules rules) {
  rules_ = std::move(rules);
}

}  // namespace overlay

}  // namespace ton