//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2021
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "telegram-bot-api/ClientManager.h"

#include "telegram-bot-api/Client.h"
#include "telegram-bot-api/ClientParameters.h"
#include "telegram-bot-api/WebhookActor.h"

#include "td/telegram/ClientActor.h"
#include "td/telegram/td_api.h"

#include "td/db/binlog/Binlog.h"
#include "td/db/binlog/ConcurrentBinlog.h"
#include "td/db/BinlogKeyValue.h"
#include "td/db/DbKey.h"
#include "td/db/TQueue.h"

#include "td/net/HttpFile.h"

#include "td/actor/MultiPromise.h"

#include "td/utils/common.h"
#include "td/utils/format.h"
#include "td/utils/logging.h"
#include "td/utils/misc.h"
#include "td/utils/Parser.h"
#include "td/utils/port/IPAddress.h"
#include "td/utils/port/Stat.h"
#include "td/utils/Slice.h"
#include "td/utils/SliceBuilder.h"
#include "td/utils/StackAllocator.h"
#include "td/utils/StringBuilder.h"
#include "td/utils/Time.h"

#include <algorithm>
#include <tuple>

namespace telegram_bot_api {

void ClientManager::close(td::Promise<td::Unit> &&promise) {
  close_promises_.push_back(std::move(promise));
  if (close_flag_) {
    return;
  }

  close_flag_ = true;
  auto ids = clients_.ids();
  for (auto id : ids) {
    auto *client_info = clients_.get(id);
    CHECK(client_info);
    send_closure(client_info->client_, &Client::close);
  }
  if (ids.empty()) {
    close_db();
  }
}

void ClientManager::send(PromisedQueryPtr query) {
  if (close_flag_) {
    // automatically send 429
    return;
  }

  td::string token = query->token().str();
  if (token[0] == '0' || token.size() > 80u || token.find('/') != td::string::npos ||
      token.find(':') == td::string::npos) {
    return fail_query(401, "Unauthorized: invalid token specified", std::move(query));
  }
  auto r_user_id = td::to_integer_safe<td::int64>(query->token().substr(0, token.find(':')));
  if (r_user_id.is_error() || !token_range_(r_user_id.ok())) {
    return fail_query(421, "Misdirected Request: unallowed token specified", std::move(query));
  }
  auto user_id = r_user_id.ok();
  if (user_id <= 0 || user_id >= (static_cast<td::int64>(1) << 54)) {
    return fail_query(401, "Unauthorized: invalid token specified", std::move(query));
  }

  if (query->is_test_dc()) {
    token += "/test";
  }

  auto id_it = token_to_id_.find(token);
  if (id_it == token_to_id_.end()) {
    td::string ip_address;
    if (query->peer_address().is_valid() && !query->peer_address().is_reserved()) {  // external connection
      ip_address = query->peer_address().get_ip_str().str();
    } else {
      // invalid peer address or connection from the local network
      ip_address = query->get_header("x-real-ip").str();
    }
    if (!ip_address.empty()) {
      td::IPAddress tmp;
      tmp.init_host_port(ip_address, 0).ignore();
      tmp.clear_ipv6_interface();
      if (tmp.is_valid()) {
        ip_address = tmp.get_ip_str().str();
      }
    }
    LOG(DEBUG) << "Receive incoming query for new bot " << token << " from " << query->peer_address();
    if (!ip_address.empty()) {
      LOG(DEBUG) << "Check Client creation flood control for IP address " << ip_address;
      auto res = flood_controls_.emplace(std::move(ip_address), td::FloodControlFast());
      auto &flood_control = res.first->second;
      if (res.second) {
        flood_control.add_limit(60, 20);        // 20 in a minute
        flood_control.add_limit(60 * 60, 600);  // 600 in an hour
      }
      auto now = static_cast<td::uint32>(td::Time::now());
      td::uint32 wakeup_at = flood_control.get_wakeup_at();
      if (wakeup_at > now) {
        LOG(INFO) << "Failed to create Client from IP address " << ip_address;
        return query->set_retry_after_error(static_cast<int>(wakeup_at - now) + 1);
      }
      flood_control.add_event(static_cast<td::int32>(now));
    }
    auto tqueue_id = get_tqueue_id(user_id, query->is_test_dc());
    if (active_client_count_.count(tqueue_id) != 0) {
      // return query->set_retry_after_error(1);
    }

    auto id =
        clients_.create(ClientInfo{BotStatActor(stat_.actor_id(&stat_)), token, tqueue_id, td::ActorOwn<Client>()});
    auto *client_info = clients_.get(id);
    client_info->client_ = td::create_actor<Client>(PSLICE() << "Client/" << token, actor_shared(this, id),
                                                    query->token().str(), query->is_test_dc(), tqueue_id, parameters_,
                                                    client_info->stat_.actor_id(&client_info->stat_));

    auto method = query->method();
    if (method != "deletewebhook" && method != "setwebhook") {
      auto bot_token_with_dc = PSTRING() << query->token() << (query->is_test_dc() ? ":T" : "");
      auto webhook_info = parameters_->shared_data_->webhook_db_->get(bot_token_with_dc);
      if (!webhook_info.empty()) {
        send_closure(client_info->client_, &Client::send,
                     get_webhook_restore_query(bot_token_with_dc, webhook_info, parameters_->shared_data_));
      }
    }

    std::tie(id_it, std::ignore) = token_to_id_.emplace(token, id);
  }
  send_closure(clients_.get(id_it->second)->client_, &Client::send,
               std::move(query));  // will send 429 if the client is already closed
}

void ClientManager::get_stats(td::Promise<td::BufferSlice> promise,
                              td::vector<std::pair<td::string, td::string>> args) {
  if (close_flag_) {
    promise.set_value(td::BufferSlice("Closing"));
    return;
  }
  size_t buf_size = 1 << 14;
  auto buf = td::StackAllocator::alloc(buf_size);
  td::StringBuilder sb(buf.as_slice());

  td::Slice id_filter;
  int new_verbosity_level = -1;
  td::string tag;
  for (auto &arg : args) {
    if (arg.first == "id") {
      id_filter = arg.second;
    }
    if (arg.first == "v") {
      auto r_new_verbosity_level = td::to_integer_safe<int>(arg.second);
      if (r_new_verbosity_level.is_ok()) {
        new_verbosity_level = r_new_verbosity_level.ok();
      }
    }
    if (arg.first == "tag") {
      tag = arg.second;
    }
  }
  if (new_verbosity_level > 0) {
    if (tag.empty()) {
      parameters_->shared_data_->next_verbosity_level_ = new_verbosity_level;
    } else {
      td::ClientActor::execute(td::td_api::make_object<td::td_api::setLogTagVerbosityLevel>(tag, new_verbosity_level));
    }
  }

  auto now = td::Time::now();
  td::int32 active_bot_count = 0;
  td::vector<std::pair<td::int64, td::uint64>> top_bot_ids;
  size_t max_bots = 50;
  for (auto id : clients_.ids()) {
    auto *client_info = clients_.get(id);
    CHECK(client_info);

    if (client_info->stat_.is_active(now)) {
      active_bot_count++;
    }

    if (!td::begins_with(client_info->token_, id_filter)) {
      continue;
    }

    auto score = static_cast<td::int64>(client_info->stat_.get_score(now) * -1e9);
    if (score == 0 && top_bot_ids.size() >= max_bots) {
      continue;
    }
    top_bot_ids.emplace_back(score, id);
  }
  if (top_bot_ids.size() < max_bots) {
    max_bots = top_bot_ids.size();
  }
  std::partial_sort(top_bot_ids.begin(), top_bot_ids.begin() + max_bots, top_bot_ids.end());
  top_bot_ids.resize(max_bots);

  sb << stat_.get_description() << '\n';
  if (id_filter.empty()) {
    sb << "uptime\t" << now - parameters_->start_time_ << '\n';
    sb << "bot_count\t" << clients_.size() << '\n';
    sb << "active_bot_count\t" << active_bot_count << '\n';
    auto r_mem_stat = td::mem_stat();
    if (r_mem_stat.is_ok()) {
      auto mem_stat = r_mem_stat.move_as_ok();
      sb << "rss\t" << td::format::as_size(mem_stat.resident_size_) << '\n';
      sb << "vm\t" << td::format::as_size(mem_stat.virtual_size_) << '\n';
      sb << "rss_peak\t" << td::format::as_size(mem_stat.resident_size_peak_) << '\n';
      sb << "vm_peak\t" << td::format::as_size(mem_stat.virtual_size_peak_) << '\n';
    } else {
      LOG(INFO) << "Failed to get memory statistics: " << r_mem_stat.error();
    }

    ServerCpuStat::update(td::Time::now());
    auto cpu_stats = ServerCpuStat::instance().as_vector(td::Time::now());
    for (auto &stat : cpu_stats) {
      sb << stat.key_ << "\t" << stat.value_ << '\n';
    }

    sb << "buffer_memory\t" << td::format::as_size(td::BufferAllocator::get_buffer_mem()) << '\n';
    sb << "active_webhook_connections\t" << WebhookActor::get_total_connections_count() << '\n';
    sb << "active_requests\t" << parameters_->shared_data_->query_count_.load(std::memory_order_relaxed) << '\n';
    sb << "active_network_queries\t" << td::get_pending_network_query_count(*parameters_->net_query_stats_) << '\n';
    auto stats = stat_.as_vector(now);
    for (auto &stat : stats) {
      sb << stat.key_ << "\t" << stat.value_ << '\n';
    }
  }

  for (auto top_bot_id : top_bot_ids) {
    auto *client_info = clients_.get(top_bot_id.second);
    CHECK(client_info);

    auto bot_info = client_info->client_.get_actor_unsafe()->get_bot_info();
    auto active_request_count = client_info->stat_.get_active_request_count();
    auto active_file_upload_bytes = client_info->stat_.get_active_file_upload_bytes();
    sb << '\n';
    sb << "id\t" << bot_info.id_ << '\n';
    sb << "uptime\t" << now - bot_info.start_time_ << '\n';
    sb << "token\t" << bot_info.token_ << '\n';
    sb << "username\t" << bot_info.username_ << '\n';
    if (active_request_count != 0) {
      sb << "active_request_count\t" << active_request_count << '\n';
    }
    if (active_file_upload_bytes != 0) {
      sb << "active_file_upload_bytes\t" << active_file_upload_bytes << '\n';
    }
    if (!bot_info.webhook_.empty()) {
      sb << "webhook\t" << bot_info.webhook_ << '\n';
      if (bot_info.has_webhook_certificate_) {
        sb << "has_custom_certificate\t" << bot_info.has_webhook_certificate_ << '\n';
      }
      if (bot_info.webhook_max_connections_ != parameters_->default_max_webhook_connections_) {
        sb << "webhook_max_connections\t" << bot_info.webhook_max_connections_ << '\n';
      }
    }
    sb << "head_update_id\t" << bot_info.head_update_id_ << '\n';
    if (bot_info.pending_update_count_ != 0) {
      sb << "tail_update_id\t" << bot_info.tail_update_id_ << '\n';
      sb << "pending_update_count\t" << bot_info.pending_update_count_ << '\n';
    }

    auto stats = client_info->stat_.as_vector(now);
    for (auto &stat : stats) {
      if (stat.key_ == "update_count" || stat.key_ == "request_count") {
        sb << stat.key_ << "/sec\t" << stat.value_ << '\n';
      }
    }

    if (sb.is_error()) {
      break;
    }
  }
  // ignore sb overflow
  promise.set_value(td::BufferSlice(sb.as_cslice()));
}

td::int64 ClientManager::get_tqueue_id(td::int64 user_id, bool is_test_dc) {
  return user_id + (static_cast<td::int64>(is_test_dc) << 54);
}

void ClientManager::start_up() {
  //NB: the same scheduler as for database in Td
  auto scheduler_id = 1;

  // init tqueue
  {
    auto load_start_time = td::Time::now();
    auto tqueue_binlog = td::make_unique<td::TQueueBinlog<td::Binlog>>();
    auto binlog = td::make_unique<td::Binlog>();
    auto tqueue = td::TQueue::create();
    td::vector<td::uint64> failed_to_replay_log_event_ids;
    td::int64 loaded_event_count = 0;
    binlog
        ->init(parameters_->working_directory_ + "tqueue.binlog",
               [&](const td::BinlogEvent &event) {
                 if (tqueue_binlog->replay(event, *tqueue).is_error()) {
                   failed_to_replay_log_event_ids.push_back(event.id_);
                 } else {
                   loaded_event_count++;
                 }
               })
        .ensure();
    tqueue_binlog.reset();

    if (!failed_to_replay_log_event_ids.empty()) {
      LOG(ERROR) << "Failed to replay " << failed_to_replay_log_event_ids.size() << " TQueue events";
      for (auto &log_event_id : failed_to_replay_log_event_ids) {
        binlog->erase(log_event_id);
      }
    }

    auto concurrent_binlog = std::make_shared<td::ConcurrentBinlog>(std::move(binlog), scheduler_id);
    auto concurrent_tqueue_binlog = td::make_unique<td::TQueueBinlog<td::BinlogInterface>>();
    concurrent_tqueue_binlog->set_binlog(std::move(concurrent_binlog));
    tqueue->set_callback(std::move(concurrent_tqueue_binlog));

    parameters_->shared_data_->tqueue_ = std::move(tqueue);

    LOG(WARNING) << "Loaded " << loaded_event_count << " TQueue events in " << (td::Time::now() - load_start_time)
                 << " seconds";
  }

  // init webhook_db
  auto concurrent_webhook_db = td::make_unique<td::BinlogKeyValue<td::ConcurrentBinlog>>();
  auto status = concurrent_webhook_db->init(parameters_->working_directory_ + "webhooks_db.binlog", td::DbKey::empty(),
                                            scheduler_id);
  LOG_IF(FATAL, status.is_error()) << "Can't open webhooks_db.binlog " << status.error();
  parameters_->shared_data_->webhook_db_ = std::move(concurrent_webhook_db);

  auto &webhook_db = *parameters_->shared_data_->webhook_db_;
  for (auto key_value : webhook_db.get_all()) {
    if (!token_range_(td::to_integer<td::uint64>(key_value.first))) {
      LOG(WARNING) << "DROP WEBHOOK: " << key_value.first << " ---> " << key_value.second;
      webhook_db.erase(key_value.first);
      continue;
    }

    auto query = get_webhook_restore_query(key_value.first, key_value.second, parameters_->shared_data_);
    send_closure_later(actor_id(this), &ClientManager::send, std::move(query));
  }

  // launch watchdog
  watchdog_id_ = td::create_actor_on_scheduler<Watchdog>(
      "ManagerWatchdog", td::Scheduler::instance()->sched_count() - 3, td::this_thread::get_id(), WATCHDOG_TIMEOUT);
  set_timeout_in(600.0);
}

PromisedQueryPtr ClientManager::get_webhook_restore_query(td::Slice token, td::Slice webhook_info,
                                                          std::shared_ptr<SharedData> shared_data) {
  // create Query with empty promise
  td::vector<td::BufferSlice> containers;
  auto add_string = [&containers](td::Slice str) {
    containers.emplace_back(str);
    return containers.back().as_slice();
  };

  token = add_string(token);

  LOG(WARNING) << "WEBHOOK: " << token << " ---> " << webhook_info;

  bool is_test_dc = false;
  if (td::ends_with(token, ":T")) {
    token.remove_suffix(2);
    is_test_dc = true;
  }

  td::ConstParser parser{webhook_info};
  td::vector<std::pair<td::MutableSlice, td::MutableSlice>> args;
  if (parser.try_skip("cert/")) {
    args.emplace_back(add_string("certificate"), add_string("previous"));
  }

  if (parser.try_skip("#maxc")) {
    args.emplace_back(add_string("max_connections"), add_string(parser.read_till('/')));
    parser.skip('/');
  }

  if (parser.try_skip("#ip")) {
    args.emplace_back(add_string("ip_address"), add_string(parser.read_till('/')));
    parser.skip('/');
  }

  if (parser.try_skip("#fix_ip")) {
    args.emplace_back(add_string("fix_ip_address"), add_string("1"));
    parser.skip('/');
  }

  if (parser.try_skip("#secret")) {
    args.emplace_back(add_string("secret_token"), add_string(parser.read_till('/')));
    parser.skip('/');
  }

  if (parser.try_skip("#allow")) {
    args.emplace_back(add_string("allowed_updates"), add_string(parser.read_till('/')));
    parser.skip('/');
  }

  args.emplace_back(add_string("url"), add_string(parser.read_all()));

  const auto method = add_string("setwebhook");
  auto query = td::make_unique<Query>(std::move(containers), token, is_test_dc, method, std::move(args),
                                      td::vector<std::pair<td::MutableSlice, td::MutableSlice>>(),
                                      td::vector<td::HttpFile>(), std::move(shared_data), td::IPAddress(), true);
  return PromisedQueryPtr(query.release(), PromiseDeleter(td::Promise<td::unique_ptr<Query>>()));
}

void ClientManager::raw_event(const td::Event::Raw &event) {
  auto id = get_link_token();
  auto *info = clients_.get(id);
  CHECK(info != nullptr);
  CHECK(info->tqueue_id_ != 0);
  auto &value = active_client_count_[info->tqueue_id_];
  if (event.ptr != nullptr) {
    value++;
  } else {
    CHECK(value > 0);
    if (--value == 0) {
      active_client_count_.erase(info->tqueue_id_);
    }
  }
}

void ClientManager::timeout_expired() {
  send_closure(watchdog_id_, &Watchdog::kick);
  set_timeout_in(WATCHDOG_TIMEOUT / 2);
}

void ClientManager::hangup_shared() {
  auto id = get_link_token();
  auto *info = clients_.get(id);
  CHECK(info != nullptr);
  info->client_.release();
  token_to_id_.erase(info->token_);
  clients_.erase(id);

  if (close_flag_ && clients_.empty()) {
    CHECK(active_client_count_.empty());
    close_db();
  }
}

void ClientManager::close_db() {
  LOG(WARNING) << "Closing databases";
  td::MultiPromiseActorSafe mpas("close binlogs");
  mpas.add_promise(td::PromiseCreator::lambda(
      [actor_id = actor_id(this)](td::Unit) { send_closure(actor_id, &ClientManager::finish_close); }));
  mpas.set_ignore_errors(true);

  auto lock = mpas.get_promise();
  parameters_->shared_data_->tqueue_->close(mpas.get_promise());
  parameters_->shared_data_->webhook_db_->close(mpas.get_promise());
  lock.set_value(td::Unit());
}

void ClientManager::finish_close() {
  LOG(WARNING) << "Stop ClientManager";
  watchdog_id_.reset();
  auto promises = std::move(close_promises_);
  for (auto &promise : promises) {
    promise.set_value(td::Unit());
  }
  stop();
}

constexpr double ClientManager::WATCHDOG_TIMEOUT;

}  // namespace telegram_bot_api