/*
    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 2017-2020 Telegram Systems LLP
*/
#include "validator-group.hpp"
#include "fabric.h"
#include "ton/ton-io.hpp"
#include "td/utils/overloaded.h"
#include "common/delay.h"
#include "ton/ton-tl.hpp"
#include "td/utils/Random.h"

namespace ton {

namespace validator {

void ValidatorGroup::generate_block_candidate(td::uint32 round_id, td::Promise<BlockCandidate> promise) {
  if (round_id > last_known_round_id_) {
    last_known_round_id_ = round_id;
  }
  if (!started_) {
    promise.set_error(td::Status::Error(ErrorCode::notready, "cannot collate block: group not started"));
    return;
  }
  if (lite_mode_) {
    send_collate_query(round_id, td::Timestamp::in(10.0), std::move(promise));
    return;
  }
  run_collate_query(shard_, min_masterchain_block_id_, prev_block_ids_,
                    Ed25519_PublicKey{local_id_full_.ed25519_value().raw()}, validator_set_, manager_,
                    td::Timestamp::in(10.0), std::move(promise));
}

void ValidatorGroup::validate_block_candidate(td::uint32 round_id, BlockCandidate block,
                                              td::Promise<UnixTime> promise) {
  if (round_id > last_known_round_id_) {
    last_known_round_id_ = round_id;
  }
  if (round_id < last_known_round_id_) {
    promise.set_error(td::Status::Error(ErrorCode::notready, "too old"));
    return;
  }

  if (approved_candidates_cache_round_ != round_id) {
    approved_candidates_cache_round_ = round_id;
    approved_candidates_cache_.clear();
  }
  auto next_block_id = create_next_block_id(block.id.root_hash, block.id.file_hash);
  block.id = next_block_id;

  CacheKey cache_key = block_to_cache_key(block);
  auto it = approved_candidates_cache_.find(cache_key);
  if (it != approved_candidates_cache_.end()) {
    promise.set_result(it->second);
    return;
  }

  auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), round_id, block = block.clone(),
                                       promise = std::move(promise)](td::Result<ValidateCandidateResult> R) mutable {
    if (R.is_error()) {
      auto S = R.move_as_error();
      if (S.code() != ErrorCode::timeout && S.code() != ErrorCode::notready) {
        LOG(ERROR) << "failed to validate candidate: " << S;
      }
      delay_action(
          [SelfId, round_id, block = std::move(block), promise = std::move(promise)]() mutable {
            td::actor::send_closure(SelfId, &ValidatorGroup::validate_block_candidate, round_id, std::move(block),
                                    std::move(promise));
          },
          td::Timestamp::in(0.1));
    } else {
      auto v = R.move_as_ok();
      v.visit(td::overloaded(
          [&](UnixTime ts) {
            td::actor::send_closure(SelfId, &ValidatorGroup::update_approve_cache, round_id, block_to_cache_key(block),
                                    ts);
            promise.set_result(ts);
          },
          [&](CandidateReject reject) {
            promise.set_error(
                td::Status::Error(ErrorCode::protoviolation, PSTRING() << "bad candidate: " << reject.reason));
          }));
    }
  });
  if (!started_) {
    P.set_error(td::Status::Error(ErrorCode::notready, "validator group not started"));
    return;
  }
  VLOG(VALIDATOR_DEBUG) << "validating block candidate " << next_block_id;
  run_validate_query(shard_, min_masterchain_block_id_, prev_block_ids_, std::move(block), validator_set_, manager_,
                     td::Timestamp::in(10.0), std::move(P), lite_mode_ ? ValidateMode::lite : 0);
}

void ValidatorGroup::update_approve_cache(td::uint32 round_id, CacheKey key, UnixTime value) {
  if (approved_candidates_cache_round_ != round_id) {
    return;
  }
  approved_candidates_cache_[key] = value;
}

void ValidatorGroup::accept_block_candidate(td::uint32 round_id, PublicKeyHash src, td::BufferSlice block_data,
                                            RootHash root_hash, FileHash file_hash,
                                            std::vector<BlockSignature> signatures,
                                            std::vector<BlockSignature> approve_signatures,
                                            validatorsession::ValidatorSessionStats stats,
                                            td::Promise<td::Unit> promise) {
  if (round_id >= last_known_round_id_) {
    last_known_round_id_ = round_id + 1;
  }
  auto sig_set = create_signature_set(std::move(signatures));
  validator_set_->check_signatures(root_hash, file_hash, sig_set).ensure();
  auto approve_sig_set = create_signature_set(std::move(approve_signatures));
  validator_set_->check_approve_signatures(root_hash, file_hash, approve_sig_set).ensure();

  if (!started_) {
    postponed_accept_.push_back(PostponedAccept{root_hash, file_hash, std::move(block_data), std::move(sig_set),
                                                std::move(approve_sig_set), std::move(stats), std::move(promise)});
    return;
  }
  auto next_block_id = create_next_block_id(root_hash, file_hash);
  td::actor::send_closure(manager_, &ValidatorManager::log_validator_session_stats, next_block_id, std::move(stats));
  auto block =
      block_data.size() > 0 ? create_block(next_block_id, std::move(block_data)).move_as_ok() : td::Ref<BlockData>{};
  accept_block_query(next_block_id, std::move(block), std::move(prev_block_ids_), std::move(sig_set),
                     std::move(approve_sig_set), src == local_id_, std::move(promise));
  prev_block_ids_ = std::vector<BlockIdExt>{next_block_id};
}

void ValidatorGroup::accept_block_query(BlockIdExt block_id, td::Ref<BlockData> block, std::vector<BlockIdExt> prev,
                                        td::Ref<BlockSignatureSet> sig_set, td::Ref<BlockSignatureSet> approve_sig_set,
                                        bool send_broadcast, td::Promise<td::Unit> promise, bool is_retry) {
  if (!is_retry) {
    td::actor::send_closure(manager_, &ValidatorManager::validated_new_block, block_id);
  }
  auto P = td::PromiseCreator::lambda([=, SelfId = actor_id(this),
                                       promise = std::move(promise)](td::Result<td::Unit> R) mutable {
    if (R.is_error()) {
      if (R.error().code() == ErrorCode::cancelled) {
        promise.set_value(td::Unit());
        return;
      }
      LOG_CHECK(R.error().code() == ErrorCode::timeout || R.error().code() == ErrorCode::notready) << R.move_as_error();
      td::actor::send_closure(SelfId, &ValidatorGroup::accept_block_query, block_id, std::move(block), std::move(prev),
                              std::move(sig_set), std::move(approve_sig_set), false, std::move(promise), true);
    } else {
      promise.set_value(R.move_as_ok());
    }
  });

  run_accept_block_query(block_id, std::move(block), std::move(prev), validator_set_, std::move(sig_set),
                         std::move(approve_sig_set), send_broadcast, shard_.is_masterchain() || !lite_mode_, manager_,
                         std::move(P));
}

void ValidatorGroup::skip_round(td::uint32 round_id) {
  if (round_id >= last_known_round_id_) {
    last_known_round_id_ = round_id + 1;
  }
}

void ValidatorGroup::get_approved_candidate(PublicKey source, RootHash root_hash, FileHash file_hash,
                                            FileHash collated_data_file_hash, td::Promise<BlockCandidate> promise) {
  BlockIdExt id = create_next_block_id(root_hash, file_hash);

  td::actor::send_closure(manager_, &ValidatorManager::get_block_candidate_from_db, source, id, collated_data_file_hash,
                          std::move(promise));
}

BlockId ValidatorGroup::create_next_block_id_simple() const {
  BlockSeqno seqno = 0;
  for (auto &p : prev_block_ids_) {
    if (seqno < p.id.seqno) {
      seqno = p.id.seqno;
    }
  }
  return BlockId{shard_.workchain, shard_.shard, seqno + 1};
}

BlockIdExt ValidatorGroup::create_next_block_id(RootHash root_hash, FileHash file_hash) const {
  return BlockIdExt{create_next_block_id_simple(), root_hash, file_hash};
}

std::unique_ptr<validatorsession::ValidatorSession::Callback> ValidatorGroup::make_validator_session_callback() {
  class Callback : public validatorsession::ValidatorSession::Callback {
   public:
    Callback(td::actor::ActorId<ValidatorGroup> id) : id_(id) {
    }
    void on_candidate(td::uint32 round, PublicKey source, validatorsession::ValidatorSessionRootHash root_hash,
                      td::BufferSlice data, td::BufferSlice collated_data,
                      td::Promise<validatorsession::ValidatorSession::CandidateDecision> promise) override {
      auto P = td::PromiseCreator::lambda([id = id_, promise = std::move(promise)](td::Result<td::uint32> R) mutable {
        if (R.is_ok()) {
          promise.set_value(validatorsession::ValidatorSession::CandidateDecision{R.move_as_ok()});
        } else {
          auto S = R.move_as_error();
          promise.set_value(
              validatorsession::ValidatorSession::CandidateDecision{S.message().c_str(), td::BufferSlice()});
        }
      });

      BlockCandidate candidate{Ed25519_PublicKey{source.ed25519_value().raw()},
                               BlockIdExt{0, 0, 0, root_hash, sha256_bits256(data.as_slice())},
                               sha256_bits256(collated_data.as_slice()), data.clone(), collated_data.clone()};

      td::actor::send_closure(id_, &ValidatorGroup::validate_block_candidate, round, std::move(candidate),
                              std::move(P));
    }
    void on_generate_slot(td::uint32 round, td::Promise<BlockCandidate> promise) override {
      td::actor::send_closure(id_, &ValidatorGroup::generate_block_candidate, round, std::move(promise));
    }
    void on_block_committed(td::uint32 round, PublicKey source, validatorsession::ValidatorSessionRootHash root_hash,
                            validatorsession::ValidatorSessionFileHash file_hash, td::BufferSlice data,
                            std::vector<std::pair<PublicKeyHash, td::BufferSlice>> signatures,
                            std::vector<std::pair<PublicKeyHash, td::BufferSlice>> approve_signatures,
                            validatorsession::ValidatorSessionStats stats) override {
      std::vector<BlockSignature> sigs;
      for (auto &sig : signatures) {
        sigs.emplace_back(BlockSignature{sig.first.bits256_value(), std::move(sig.second)});
      }
      std::vector<BlockSignature> approve_sigs;
      for (auto &sig : approve_signatures) {
        approve_sigs.emplace_back(BlockSignature{sig.first.bits256_value(), std::move(sig.second)});
      }
      auto P = td::PromiseCreator::lambda([](td::Result<td::Unit>) {});
      td::actor::send_closure(id_, &ValidatorGroup::accept_block_candidate, round, source.compute_short_id(),
                              std::move(data), root_hash, file_hash, std::move(sigs), std::move(approve_sigs),
                              std::move(stats), std::move(P));
    }
    void on_block_skipped(td::uint32 round) override {
      td::actor::send_closure(id_, &ValidatorGroup::skip_round, round);
    }
    void get_approved_candidate(PublicKey source, validatorsession::ValidatorSessionRootHash root_hash,
                                validatorsession::ValidatorSessionFileHash file_hash,
                                validatorsession::ValidatorSessionCollatedDataFileHash collated_data_file_hash,
                                td::Promise<BlockCandidate> promise) override {
      td::actor::send_closure(id_, &ValidatorGroup::get_approved_candidate, source, root_hash, file_hash,
                              collated_data_file_hash, std::move(promise));
    }

   private:
    td::actor::ActorId<ValidatorGroup> id_;
  };

  return std::make_unique<Callback>(actor_id(this));
}

void ValidatorGroup::create_session() {
  CHECK(!init_);
  init_ = true;
  std::vector<validatorsession::ValidatorSessionNode> vec;
  auto v = validator_set_->export_vector();
  bool found = false;
  for (auto &el : v) {
    validatorsession::ValidatorSessionNode n;
    n.pub_key = ValidatorFullId{el.key};
    n.weight = el.weight;
    if (el.addr.is_zero()) {
      n.adnl_id = adnl::AdnlNodeIdShort{n.pub_key.compute_short_id()};
    } else {
      n.adnl_id = adnl::AdnlNodeIdShort{el.addr};
    }
    if (n.pub_key.compute_short_id() == local_id_) {
      CHECK(!found);
      found = true;
      local_id_full_ = n.pub_key;
      local_adnl_id_ = n.adnl_id;
    }
    vec.emplace_back(std::move(n));
  }
  CHECK(found);

  if (!config_.new_catchain_ids) {
    session_ = validatorsession::ValidatorSession::create(session_id_, config_, local_id_, std::move(vec),
                                                          make_validator_session_callback(), keyring_, adnl_, rldp_,
                                                          overlays_, db_root_, "-", allow_unsafe_self_blocks_resync_);
  } else {
    session_ = validatorsession::ValidatorSession::create(
        session_id_, config_, local_id_, std::move(vec), make_validator_session_callback(), keyring_, adnl_, rldp_,
        overlays_, db_root_ + "/catchains/",
        PSTRING() << "." << shard_.workchain << "." << shard_.shard << "." << validator_set_->get_catchain_seqno()
                  << ".",
        allow_unsafe_self_blocks_resync_);
  }
  if (started_) {
    td::actor::send_closure(session_, &validatorsession::ValidatorSession::start);
  }

  td::actor::send_closure(rldp_, &rldp::Rldp::add_id, local_adnl_id_);
}

void ValidatorGroup::start(std::vector<BlockIdExt> prev, BlockIdExt min_masterchain_block_id) {
  prev_block_ids_ = prev;
  min_masterchain_block_id_ = min_masterchain_block_id;
  started_ = true;

  if (init_) {
    td::actor::send_closure(session_, &validatorsession::ValidatorSession::start);
  }

  for (auto &p : postponed_accept_) {
    auto next_block_id = create_next_block_id(p.root_hash, p.file_hash);
    td::actor::send_closure(manager_, &ValidatorManager::log_validator_session_stats, next_block_id,
                            std::move(p.stats));

    auto block =
        p.block.size() > 0 ? create_block(next_block_id, std::move(p.block)).move_as_ok() : td::Ref<BlockData>{};
    accept_block_query(next_block_id, std::move(block), std::move(prev_block_ids_), std::move(p.sigs),
                       std::move(p.approve_sigs), false, std::move(p.promise));
    prev_block_ids_ = std::vector<BlockIdExt>{next_block_id};
  }
  postponed_accept_.clear();
}

void ValidatorGroup::destroy() {
  if (!session_.empty()) {
    auto ses = session_.release();
    delay_action([ses]() mutable { td::actor::send_closure(ses, &validatorsession::ValidatorSession::destroy); },
                 td::Timestamp::in(10.0));
  }
  stop();
}

void ValidatorGroup::get_session_info(
    td::Promise<tl_object_ptr<ton_api::engine_validator_validatorSessionInfo>> promise) {
  if (session_.empty() || !started_) {
    promise.set_error(td::Status::Error(ErrorCode::notready, "session not started"));
  }
  auto P = td::PromiseCreator::lambda(
      [promise = std::move(promise), block_id = create_next_block_id_simple()](
          td::Result<tl_object_ptr<ton_api::engine_validator_validatorSessionInfo>> R) mutable {
        if (R.is_error()) {
          promise.set_error(R.move_as_error());
          return;
        }
        auto info = R.move_as_ok();
        info->current_block_ = create_tl_block_id_simple(block_id);
        promise.set_result(std::move(info));
      });
  td::actor::send_closure(session_, &validatorsession::ValidatorSession::get_session_info, std::move(P));
}

void ValidatorGroup::send_collate_query(td::uint32 round_id, td::Timestamp timeout,
                                        td::Promise<BlockCandidate> promise, unsigned max_retries) {
  if (round_id < last_known_round_id_) {
    promise.set_error(td::Status::Error("too old"));
    return;
  }
  adnl::AdnlNodeIdShort collator = adnl::AdnlNodeIdShort::zero();
  // TODO: some other way for storing and choosing collators for real network
  int cnt = 0;
  for (const CollatorNodeDescr& c : collator_set_) {
    if (shard_is_ancestor(shard_, c.shard) && td::Random::fast(0, cnt) == 0) {
      collator = adnl::AdnlNodeIdShort(c.adnl_id);
      ++cnt;
    }
  }
  if (collator.is_zero()) {
    promise.set_error(td::Status::Error(PSTRING() << "no collator for shard " << shard_.to_str()));
    return;
  }

  if (max_retries > 0) {
    promise = td::PromiseCreator::lambda(
        [=, SelfId = actor_id(this), promise = std::move(promise)](td::Result<BlockCandidate> R) mutable {
          if (R.is_ok()) {
            promise.set_result(R.move_as_ok());
          } else if (timeout && timeout.is_in_past()) {
            promise.set_result(R.move_as_error());
          } else {
            LOG(WARNING) << "collate query error, retrying: " << R.move_as_error();
            td::actor::send_closure(SelfId, &ValidatorGroup::send_collate_query, round_id, timeout, std::move(promise),
                                    max_retries - 1);
          }
        });
  }

  std::vector<tl_object_ptr<ton_api::tonNode_blockIdExt>> prev_blocks;
  for (const BlockIdExt &p : prev_block_ids_) {
    prev_blocks.push_back(create_tl_block_id(p));
  }
  td::BufferSlice query = create_serialize_tl_object<ton_api::collatorNode_generateBlock>(
      shard_.workchain, shard_.shard, create_tl_block_id(min_masterchain_block_id_), std::move(prev_blocks),
      local_id_full_.ed25519_value().raw());

  auto P = td::PromiseCreator::lambda(
      [SelfId = actor_id(this), round_id, promise = std::move(promise)](td::Result<td::BufferSlice> R) mutable {
        if (R.is_error()) {
          promise.set_error(R.move_as_error_prefix("rldp query failed: "));
          return;
        }
        td::actor::send_closure(SelfId, &ValidatorGroup::receive_collate_query_response, round_id, R.move_as_ok(),
                                std::move(promise));
      });
  LOG(INFO) << "collate query for " << create_next_block_id_simple().to_str() << ": send query to " << collator;
  size_t max_answer_size = config_.max_block_size + config_.max_collated_data_size + 256;
  td::Timestamp query_timeout = td::Timestamp::in(10.0);
  query_timeout.relax(timeout);
  td::actor::send_closure(rldp_, &rldp::Rldp::send_query_ex, local_adnl_id_, collator, "collatequery",
                          std::move(P), timeout, std::move(query), max_answer_size);
}

void ValidatorGroup::receive_collate_query_response(td::uint32 round_id, td::BufferSlice data,
                                                    td::Promise<BlockCandidate> promise) {
  if (round_id < last_known_round_id_) {
    promise.set_error(td::Status::Error("too old"));
    return;
  }
  TRY_RESULT_PROMISE(promise, f, fetch_tl_object<ton_api::collatorNode_GenerateBlockResult>(data, true));
  tl_object_ptr<ton_api::db_candidate> b;
  ton_api::downcast_call(*f, td::overloaded(
                                 [&](ton_api::collatorNode_generateBlockError &r) {
                                   td::Status error = td::Status::Error(r.code_, r.message_);
                                   promise.set_error(error.move_as_error_prefix("collate query: "));
                                 },
                                 [&](ton_api::collatorNode_generateBlockSuccess &r) { b = std::move(r.candidate_); }));
  if (!b) {
    return;
  }
  auto key = PublicKey{b->source_};
  if (!key.is_ed25519()) {
    promise.set_error(td::Status::Error("collate query: block candidate source mismatch"));
    return;
  }
  auto e_key = Ed25519_PublicKey{key.ed25519_value().raw()};
  if (e_key != Ed25519_PublicKey{local_id_full_.ed25519_value().raw()}) {
    promise.set_error(td::Status::Error("collate query: block candidate source mismatch"));
    return;
  }
  auto block_id = ton::create_block_id(b->id_);
  if (block_id.shard_full() != shard_) {
    promise.set_error(td::Status::Error("collate query: shard mismatch"));
    return;
  }
  auto collated_data_hash = td::sha256_bits256(b->collated_data_);
  BlockCandidate candidate(e_key, block_id, collated_data_hash, std::move(b->data_), std::move(b->collated_data_));

  auto P = td::PromiseCreator::lambda(
      [candidate = candidate.clone(), promise = std::move(promise)](td::Result<UnixTime> R) mutable {
        if (R.is_error()) {
          promise.set_error(R.move_as_error_prefix("validate received block error: "));
          return;
        }
        promise.set_result(std::move(candidate));
      });
  validate_block_candidate(round_id, std::move(candidate), std::move(P));
}

}  // namespace validator

}  // namespace ton