/*
 * Copyright (c) 2020 Peter Johanson <peter@peterjohanson.com>
 *
 * SPDX-License-Identifier: MIT
 */

#define DT_DRV_COMPAT zmk_behavior_mod_tap

#include <device.h>
#include <drivers/behavior.h>
#include <logging/log.h>

#include <zmk/event-manager.h>
#include <zmk/events/keycode-state-changed.h>
#include <zmk/events/modifiers-state-changed.h>

LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);

struct behavior_mod_tap_config { };
struct behavior_mod_tap_data {
  u16_t pending_press_positions;
};

int behavior_mod_tap_listener(const struct zmk_event_header *eh)
{
  if (is_keycode_state_changed(eh)) {
    struct device *dev = device_get_binding(DT_INST_LABEL(0));
    const struct keycode_state_changed *ev = cast_keycode_state_changed(eh);
    if (ev->state) {
      struct behavior_mod_tap_data *data = dev->driver_data;
      data->pending_press_positions = 0;
    }
  }
  return 0;
}

ZMK_LISTENER(behavior_mod_tap, behavior_mod_tap_listener);
ZMK_SUBSCRIPTION(behavior_mod_tap, keycode_state_changed);

static int behavior_mod_tap_init(struct device *dev)
{
	return 0;
};


static int on_keymap_binding_pressed(struct device *dev, u32_t position, u32_t mods, u32_t keycode)
{
  struct behavior_mod_tap_data *data = dev->driver_data;
  LOG_DBG("mods: %d, keycode: %d", mods, keycode);
  WRITE_BIT(data->pending_press_positions, position, true);
  return ZMK_EVENT_RAISE(create_modifiers_state_changed(mods, true));
}

static int on_keymap_binding_released(struct device *dev, u32_t position, u32_t mods, u32_t keycode)
{
  struct behavior_mod_tap_data *data = dev->driver_data;
  LOG_DBG("mods: %d, keycode: %d", mods, keycode);
  
  ZMK_EVENT_RAISE(create_modifiers_state_changed(mods, false));
  k_msleep(10); // TODO: Better approach than k_msleep to avoid USB send failures? Retries in the USB endpoint layer?
  if (data->pending_press_positions & BIT(position)) {
    ZMK_EVENT_RAISE(create_keycode_state_changed(USAGE_KEYPAD, keycode, true));
    k_msleep(10);
    ZMK_EVENT_RAISE(create_keycode_state_changed(USAGE_KEYPAD, keycode, false));
  }

  return 0;
}

static const struct behavior_driver_api behavior_mod_tap_driver_api = {
  .binding_pressed = on_keymap_binding_pressed,
  .binding_released = on_keymap_binding_released,
};

static const struct behavior_mod_tap_config behavior_mod_tap_config = {};

static struct behavior_mod_tap_data behavior_mod_tap_data;

DEVICE_AND_API_INIT(behavior_mod_tap, DT_INST_LABEL(0), behavior_mod_tap_init,
                    &behavior_mod_tap_data,
                    &behavior_mod_tap_config,
                    APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,
                    &behavior_mod_tap_driver_api);