#include "Click.h"
#include "MIDI.h"
#include "PCM.h"
#include "Timer.h"
#include "UI.h"
#include "config.h"
#include "log.h"

#include <chrono>
#include <cmath>
#include <cstdint>
#include <exception>
#include <iostream>
#include <limits>
#include <memory>
#include <stdexcept>

#include <stdio.h>
#include <sys/types.h>
#include <sys/time.h>
#include <time.h>
#include <signal.h>

#include <boost/signals2.hpp>

using namespace std::chrono_literals;
using namespace std::string_literals;

double diff_timespec(const struct timespec *time1, const struct timespec *time0) {
  return (time1->tv_sec - time0->tv_sec)
      + (time1->tv_nsec - time0->tv_nsec) / 1000000000.0;
}

bool run_flag = true;

void signal_handler(int) {
  run_flag = false;
  std::cout << "Signal received. Terminating." << std::endl;
}

int main(void)
{
  signal(SIGTERM, signal_handler);
  signal(SIGINT, signal_handler);

  try {
    //debug_cout.activate();
    log_cout.activate();
    log_cout.log_lines(log_lines);

    Config config;

    std::shared_ptr<ClockClick> clock_click = std::make_shared<ClockClick>();
    std::shared_ptr<NoteClick> note_click = std::make_shared<NoteClick>(config);
    std::shared_ptr<InternalClick> internal_click = std::make_shared<InternalClick>(config);

    MIDI midi;
    PCM pcm;
    UI ui(config);

    pcm.write();

    Timer timer_500ms(500ms, true);
    timer_500ms.start();

    Timer timer_10min(10min, true);
    timer_10min.start();

    // Main signals
    boost::signals2::signal<void()> signal_count_loops;

    //
    // Signal-Slot Connections:
    //
    midi.signal_note.connect([&](int channel, int note, uint64_t timestamp){note_click->receive_note(channel, note, timestamp);});
    note_click->signal_click.connect([&](){pcm.click();});
    note_click->signal_bpm.connect([&](int bpm){ui.slot_note_bpm(bpm);});
    clock_click->signal_bpm.connect([&](int bpm){ui.slot_clock_bpm(bpm);});
    midi.signal_active_sensing.connect([&](){ui.slot_active_sensing();});
    timer_500ms.elapsed.connect([&](){ui.draw();});
    signal_count_loops.connect([&](){ui.count_main_loops();});
    midi.signal_count_events.connect([&](){ui.count_midi_events();});
    timer_10min.elapsed.connect([&](){config.persist();});
    midi.signal_note.connect([&](int channel, int note, uint64_t timestamp){ui.slot_midi_note(channel, note, timestamp);});
    midi.signal_clock.connect([&](){clock_click->receive_clock();});

    midi.flush();

    while (run_flag) {
      debug_cout << "Main loop entered." << std::endl;
      signal_count_loops();

      fd_set read_set;
      FD_ZERO(&read_set);
      FD_SET(midi.fd(), &read_set);

#if 0
      // PCM fd almost always writeable: for single frames at high speed
      fd_set write_set;
      FD_ZERO(&write_set);
      FD_SET(pcm.fd(), &write_set);
#endif

      struct timeval timeout;
      timeout.tv_sec = 0;
      timeout.tv_usec = 20000;

      int result = select(FD_SETSIZE, &read_set, nullptr/*&write_set*/, nullptr, &timeout);
      if (result < 0) {
        throw std::runtime_error("select() failed");
      } else if (result == 0) {
        debug_cout << "select() timeout" << std::endl;
      }

      while (midi.event_ready())
      {
        //std::cout << "read..." << std::endl;
        auto event = midi.read();
        //std::cout << "process..." << std::endl;
        midi.process(event);
      }

      if (pcm.write_available()) {
        //std::cout << "DEBUG: WRITE" << std::endl;
        pcm.write();
      }

      // handle timers, TODO: make updates more efficient at scale
      timer_500ms.update();
      timer_10min.update();
    }
  } catch (const std::exception& ex) {
    std::cerr << "Error: " << ex.what() << std::endl;
  }
 
  return 0;
}