#pragma once

#include "config.h"

#include <chrono>
#include <deque>
#include <utility>

#include <boost/signals2.hpp>

#include "Touchpad.h"
#include "Temperature.h"

using clock_type = std::chrono::high_resolution_clock;

struct IntervalCounter
{
public:
  IntervalCounter();
  int get_count_per_second();
  void count(uint64_t n = 1);

private:
  uint64_t m_count{};
  uint64_t m_count_checkpoint{};
  std::chrono::time_point<clock_type> m_checkpoint_timestamp{};
};

template<typename T>
class AgeOutValue
{
public:
  AgeOutValue(std::chrono::milliseconds timeout):
    m_timeout(timeout),
    m_checkpoint_timestamp(clock_type::now()),
    m_value{}
  {
  }

  bool is_current()
  {
    return clock_type::now() - m_checkpoint_timestamp < m_timeout;
  }

  // returns value, or 0 if aged-out
  T value()
  {
    T result{};

    if (is_current()) {
      result = m_value;
    }

    return result;
  }

  void update(const T& value)
  {
    m_value = value;
    m_checkpoint_timestamp = clock_type::now();
  }

  T& update()
  {
    m_checkpoint_timestamp = clock_type::now();
    return m_value;
  }

private:
  const std::chrono::milliseconds m_timeout;
  std::chrono::time_point<clock_type> m_checkpoint_timestamp{};
  T m_value;
};

class UI
{
public:

  UI(Config& config);

  void draw();

  void handle_input();

  bool key_available();

  // signals, from user input
  boost::signals2::signal<void(int)> signal_bpm;
  boost::signals2::signal<void(int, int)> signal_note_set_from_midi;
  boost::signals2::signal<void(int)> signal_mode;
  boost::signals2::signal<void(int)> signal_output;

  // slots
  void count_main_loops();
  void count_midi_events(size_t size);
  void count_midi_notes();
  void slot_active_sensing();
  void slot_midi_note(int channel, int note, uint64_t timestamp);
  void slot_note_bpm(int bpm);
  void slot_clock_bpm(int bpm);

private:
  Config& m_config;

  IntervalCounter m_main_loops;
  IntervalCounter m_midi_events;
  IntervalCounter m_midi_bytes;
  IntervalCounter m_midi_notes;

  std::chrono::time_point<clock_type> m_active_sensing_timestamp;

  uint64_t m_midi_timestamp;
  AgeOutValue<std::deque<std::pair<int,int>>> m_midi_monitor;

  AgeOutValue<int> m_note_bpm;
  AgeOutValue<int> m_clock_bpm;

  Touchpad m_touchpad;
  Temperature m_temperature;
};