#include "Touchpad.h"

#include <filesystem>
#include <fmt/format.h>
#include <sys/poll.h>
#include <fcntl.h>

#include "log.h"

namespace fs = std::filesystem;

namespace {
  fs::path eventfile_from_index(int i)
  {
    fs::path result{"/dev/input/event"};
    result += fs::path{std::to_string(i)};
    return result;
  }

  libevdev* get_evdev(int& result_fd)
  {
    for (int i = 0; ; ++i) {
      fs::path filename = eventfile_from_index(i);
      if (!fs::exists(filename)) {
        log_cout << "Warning: No suitable evdev device found.\n";
        return nullptr;
      }

      int fd = open(filename.string().c_str(), O_RDONLY | O_NONBLOCK);
      if (fd < 0) {
        log_cout << fmt::format("Warning: evdev open() failed for {}", filename.string()) << std::endl;
        continue;
      }
      libevdev* result{};
      int rc = libevdev_new_from_fd(fd, &result);
      if (rc < 0) {
        log_cout << fmt::format("Warning: Failed to init libevdev ({})\n", strerror(-rc));
        continue;
      }

      if (!libevdev_has_event_type(result, EV_REL) ||
        !libevdev_has_event_code(result, EV_KEY, BTN_LEFT) ||
        !libevdev_has_event_code(result, EV_KEY, BTN_RIGHT))
      {
        // Not the correct device
        continue;
      }
      log_cout << fmt::format("evdev using: Input device name: \"{}\"\n", libevdev_get_name(result));
      log_cout << fmt::format("evdev using: Input device ID: bus {:x} vendor {:x} product {:x}\n",
        libevdev_get_id_bustype(result),
        libevdev_get_id_vendor(result),
        libevdev_get_id_product(result));
      result_fd = fd;
      return result;
    }
  }

  void free_evdev(libevdev* evdev, int fd)
  {
    if (evdev) {
      libevdev_free(evdev);
      close(fd);
    }
  }
}

Touchpad::Touchpad(): m_fd{}, m_dev{}, m_valid{}, m_ev{}
{
  m_dev = get_evdev(m_fd);
  if (m_dev != nullptr) {
    m_valid = true;
  }
}

Touchpad::~Touchpad()
{
  free_evdev(m_dev, m_fd);
}

bool Touchpad::is_valid()
{
  return m_valid;
}

bool Touchpad::event_available()
{
  if (!m_valid) {
    return false;
  }

  if (m_ev.has_value()) {
    return true;
  }

  input_event ev{};
  int rc = libevdev_next_event(m_dev, LIBEVDEV_READ_FLAG_NORMAL, &ev);
  if (rc != 0) {
    return false;
  }
  log_cout << fmt::format("Event: {} {} {}\n",
                       libevdev_event_type_get_name(ev.type),
                       libevdev_event_code_get_name(ev.type, ev.code),
                       ev.value);

  m_ev = ev;

  return true;
}

input_event Touchpad::get_event()
{
  if (m_ev.has_value()) {
    input_event result = *m_ev;
    m_ev.reset();
    return result;
  }

  input_event ev{};
  int rc = libevdev_next_event(m_dev, LIBEVDEV_READ_FLAG_NORMAL, &ev);
  if (rc != 0) {
    throw std::runtime_error("Touchpad::get_event() couldn't read event");
  }
  log_cout << fmt::format("Event: {} {} {}\n",
                       libevdev_event_type_get_name(ev.type),
                       libevdev_event_code_get_name(ev.type, ev.code),
                       ev.value);
  return ev;
}

bool Touchpad::event_is_button1(const input_event& ev)
{
  return ev.type == EV_KEY && ev.code == BTN_LEFT && ev.value == 0; // Press down
}

bool Touchpad::event_is_button2(const input_event& ev)
{
  return ev.type == EV_KEY && ev.code == BTN_RIGHT && ev.value == 0; // Press down
}