/*
 * threads_actor.hpp
 *
 *  Created on: Jun 11, 2021
 *      Author: erki
 */

#ifndef SKULLC_THREADS_ACTOR_HPP_
#define SKULLC_THREADS_ACTOR_HPP_

#include <cmsis_os.h>
#include <freertos_os2.h>
#include <queue.h>

#include <type_traits>
#include <variant>

#include "threads_primitivethread.hpp"
#include "threads_signal.hpp"
#include "threads_timer.hpp"
#include "threads_actor_thread.hpp"

namespace Threads
{

class IActor
{
public:
  IActor() = delete;
  IActor(ActorThread* thread)
  {
    moveToThread(thread);
  }

  virtual ~IActor()
  { }

  virtual void init()
  { }

  virtual void doWork() = 0;
  virtual bool hasWork() = 0;

  void moveToThread(ActorThread* thread)
  {
    assert(thread);

    if (thread_)
      thread_->removeActor_(this);

    thread->acceptActor_(this);
    thread_ = thread;
  }

protected:
  ActorThread* thread_ = nullptr;
};

template<typename CRTP, typename... Ts>
class Actor : public IActor
{
public:
  using value_type = std::variant<Ts...>;

  static_assert(std::is_default_constructible_v<value_type>, "Ts must be default constructible.");
  static_assert(std::is_trivially_copyable_v<value_type>, "Ts must be trivially copyable.");

  Actor(const std::uint32_t queue_size, ActorThread* thread)
      : IActor(thread),
        msg_queue_(xQueueCreate(queue_size, sizeof(value_type))), signal_(this)
  {
    assert(msg_queue_);
  }

  virtual ~Actor() {}

  void doWork() override
  {
    value_type data{};

    const BaseType_t got = xQueueReceive(msg_queue_, &data, 0);

    if (got == pdTRUE)
    {
      std::visit(Visitor_{this}, data);
    }
  }

  bool hasWork() override
  {
    return uxQueueMessagesWaiting(msg_queue_) > 0;
  }

  template<typename T>
  struct Signal : Signallable<T>
  {
    using parent = Actor<CRTP, Ts...>;

    static_assert(std::is_convertible_v<T, parent::value_type>, "value_type cannot be constructed from T.");

    explicit Signal(parent* q)
        : q_(q)
    {}

    void emit(const T& data) override
    {
      parent::value_type to_send = data;
      xQueueSend(q_->msg_queue_, &to_send, 0);
    }

    BaseType_t emitFromIsr(const T& data) override
    {
      parent::value_type to_send = data;
      BaseType_t was_awoken = pdFALSE;

      xQueueSendFromISR(q_->msg_queue_, &to_send, &was_awoken);

      return was_awoken;
    }

  private:
    parent* q_;
  };

  template<typename U>
  Signal<U> getSignal()
  {
    static_assert(std::is_convertible_v<U, value_type>, "value_type cannot be constructed from U.");

    return Signal<U>(this);
  }

  Signallable<value_type>* getStaticSignal()
  {
    return &signal_;
  }

private:
  QueueHandle_t msg_queue_;

  struct Visitor_
  {
    using parent = Actor<CRTP, Ts...>;
    parent* q;

    Visitor_(parent* q)
        : q(q)
    {}

    template<typename U>
    void operator()(const U& u)
    {
      CRTP* s = static_cast<CRTP*>(q);
      s->onSignal(u);
    }
  };

  Signal<value_type> signal_;
};

template<typename CRTP>
class Actor<CRTP, void> : public IActor
{
public:
  using value_type = void;

  Actor(const std::uint32_t queue_size, ActorThread* thread)
      : IActor(thread),
        msg_queue_(xQueueCreate(queue_size, sizeof(int))), signal_(*this)
  {
    assert(msg_queue_);
  }

  virtual ~Actor() {}

  void doWork() override
  {
    int data{};

    const BaseType_t got = xQueueReceive(msg_queue_, &data, 0);

    if (got == pdTRUE)
    {
      auto* crtp = static_cast<CRTP*>(this);
      crtp->onSignal();
    }
  }

  bool hasWork() override
  {
    return uxQueueMessagesWaiting(msg_queue_) > 0;
  }

  Signallable<value_type>* getSignal()
  {
    return &signal_;
  }

private:
  QueueHandle_t msg_queue_;

  friend struct Signal_;

  struct Signal_ : Signallable<value_type>
  {
    using parent = Actor<CRTP, void>;
    parent& q;

    explicit Signal_(parent& q)
        : q(q)
    {}

    void emit() override
    {
      const int data = 0;

      xQueueSend(q.msg_queue_, &data, 0);
    }

    BaseType_t emitFromIsr() override
    {
      const int data = 0;

      BaseType_t was_awoken = pdFALSE;
      xQueueSendFromISR(q.msg_queue_, &data, &was_awoken);

      return was_awoken;
    }
  };

  Signal_ signal_;
};

}// namespace Threads


#endif /* SKULLC_THREADS_ACTOR_HPP_ */