//
// 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 "td/actor/actor.h"
#include "td/actor/ConcurrentScheduler.h"

#include "td/utils/SliceBuilder.h"
#include "td/utils/tests.h"

namespace {

class PowerWorker final : public td::Actor {
 public:
  class Callback {
   public:
    Callback() = default;
    Callback(const Callback &) = delete;
    Callback &operator=(const Callback &) = delete;
    Callback(Callback &&) = delete;
    Callback &operator=(Callback &&) = delete;
    virtual ~Callback() = default;
    virtual void on_ready(int query, int res) = 0;
    virtual void on_closed() = 0;
  };
  void set_callback(td::unique_ptr<Callback> callback) {
    callback_ = std::move(callback);
  }
  void task(td::uint32 x, td::uint32 p) {
    td::uint32 res = 1;
    for (td::uint32 i = 0; i < p; i++) {
      res *= x;
    }
    callback_->on_ready(x, res);
  }
  void close() {
    callback_->on_closed();
    stop();
  }

 private:
  td::unique_ptr<Callback> callback_;
};

class Manager final : public td::Actor {
 public:
  Manager(int queries_n, int query_size, td::vector<td::ActorId<PowerWorker>> workers)
      : workers_(std::move(workers))
      , ref_cnt_(static_cast<int>(workers_.size()))
      , left_query_(queries_n)
      , query_size_(query_size) {
  }

  class Callback final : public PowerWorker::Callback {
   public:
    Callback(td::ActorId<Manager> actor_id, int worker_id) : actor_id_(actor_id), worker_id_(worker_id) {
    }
    void on_ready(int query, int result) final {
      td::send_closure(actor_id_, &Manager::on_ready, worker_id_, query, result);
    }
    void on_closed() final {
      td::send_closure_later(actor_id_, &Manager::on_closed, worker_id_);
    }

   private:
    td::ActorId<Manager> actor_id_;
    int worker_id_;
  };

  void start_up() final {
    int i = 0;
    for (auto &worker : workers_) {
      ref_cnt_++;
      td::send_closure_later(worker, &PowerWorker::set_callback, td::make_unique<Callback>(actor_id(this), i));
      i++;
      td::send_closure_later(worker, &PowerWorker::task, 3, query_size_);
      left_query_--;
    }
  }

  void on_ready(int worker_id, int query, int res) {
    ref_cnt_--;
    if (left_query_ == 0) {
      td::send_closure(workers_[worker_id], &PowerWorker::close);
    } else {
      ref_cnt_++;
      td::send_closure(workers_[worker_id], &PowerWorker::task, 3, query_size_);
      left_query_--;
    }
  }

  void on_closed(int worker_id) {
    ref_cnt_--;
    if (ref_cnt_ == 0) {
      td::Scheduler::instance()->finish();
      stop();
    }
  }

 private:
  td::vector<td::ActorId<PowerWorker>> workers_;
  int ref_cnt_;
  int left_query_;
  int query_size_;
};

static void test_workers(int threads_n, int workers_n, int queries_n, int query_size) {
  td::ConcurrentScheduler sched;
  sched.init(threads_n);

  td::vector<td::ActorId<PowerWorker>> workers;
  for (int i = 0; i < workers_n; i++) {
    int thread_id = threads_n ? i % (threads_n - 1) + 2 : 0;
    workers.push_back(sched.create_actor_unsafe<PowerWorker>(thread_id, PSLICE() << "worker" << i).release());
  }
  sched.create_actor_unsafe<Manager>(threads_n ? 1 : 0, "Manager", queries_n, query_size, std::move(workers)).release();

  sched.start();
  while (sched.run_main(10)) {
    // empty
  }
  sched.finish();

  // sched.test_one_thread_run();
}
}  // namespace

TEST(Actors, workers_big_query_one_thread) {
  test_workers(0, 10, 1000, 300000);
}

TEST(Actors, workers_big_query_two_threads) {
  test_workers(2, 10, 1000, 300000);
}

TEST(Actors, workers_big_query_nine_threads) {
  test_workers(9, 10, 1000, 300000);
}

TEST(Actors, workers_small_query_one_thread) {
  test_workers(0, 10, 1000000, 1);
}

TEST(Actors, workers_small_query_two_threads) {
  test_workers(2, 10, 1000000, 1);
}

TEST(Actors, workers_small_query_nine_threads) {
  test_workers(9, 10, 1000000, 1);
}