#include <errno.h>
#include <stdbool.h>
#include <string.h>

#include <app_event_manager.h>

#define MODULE led_strip_module
#include <caf/events/button_event.h>
#include <caf/events/module_state_event.h>
#include <caf/events/power_event.h>
#include <caf/key_id.h>

#include <zephyr/device.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/led_strip.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>

#include "led_effect/led_effect.h"
#include "led_strip_en_event.h"
#include "theme_rgb_update_event.h"
#include "theme_color.h"

LOG_MODULE_REGISTER(MODULE, LOG_LEVEL_INF);

#define LED_STRIP_NODE DT_CHOSEN(zephyr_led_strip)
#define LED_STRIP_NUM_PIXELS DT_PROP(LED_STRIP_NODE, chain_length)
#define LED_STRIP_TICK_INTERVAL K_MSEC(20)

BUILD_ASSERT(DT_NODE_HAS_STATUS(LED_STRIP_NODE, okay),
	     "Missing zephyr,led-strip chosen node");
BUILD_ASSERT(DT_NODE_HAS_PROP(LED_STRIP_NODE, supply_gpios),
	     "Missing supply-gpios on zephyr,led-strip node");
BUILD_ASSERT(LED_STRIP_NUM_PIXELS == 17U,
	     "LED strip key map expects 17 pixels");

static const struct device *const strip = DEVICE_DT_GET(LED_STRIP_NODE);
static const struct gpio_dt_spec strip_en =
	GPIO_DT_SPEC_GET(LED_STRIP_NODE, supply_gpios);

static const struct led_key_map led_key_map[] = {
	{ KEY_ID(0, 1), 0U },
	{ KEY_ID(1, 1), 1U },
	{ KEY_ID(2, 1), 2U },
	{ KEY_ID(3, 1), 3U },
	{ KEY_ID(0, 2), 4U },
	{ KEY_ID(1, 2), 5U },
	{ KEY_ID(2, 2), 6U },
	{ KEY_ID(0, 3), 7U },
	{ KEY_ID(1, 3), 8U },
	{ KEY_ID(2, 3), 9U },
	{ KEY_ID(3, 3), 10U },
	{ KEY_ID(0, 4), 11U },
	{ KEY_ID(1, 4), 12U },
	{ KEY_ID(2, 4), 13U },
	{ KEY_ID(0, 5), 14U },
	{ KEY_ID(1, 5), 15U },
	{ KEY_ID(3, 5), 16U },
};

static const struct led_effect_config effect_cfg = {
	.key_map = led_key_map,
	.key_map_len = ARRAY_SIZE(led_key_map),
	.pixel_count = LED_STRIP_NUM_PIXELS,
	.default_brightness = 0xFFU,
};

static struct led_rgb pixels[LED_STRIP_NUM_PIXELS];
static struct k_work_delayable effect_work;
static struct led_effect *effect;
static struct theme_rgb current_theme = {
	.r = BLINKY_THEME_DEFAULT_R,
	.g = BLINKY_THEME_DEFAULT_G,
	.b = BLINKY_THEME_DEFAULT_B,
};
static bool initialized;
static bool running;
static bool enabled = true;

static void clear_pixels(void)
{
	memset(pixels, 0, sizeof(pixels));
}

static int submit_frame(void)
{
	int err;

	err = led_strip_update_rgb(strip, pixels, ARRAY_SIZE(pixels));
	if (err) {
		LOG_WRN("led_strip_update_rgb failed (%d)", err);
	}

	return err;
}

static int set_strip_power(bool on)
{
	int err;

	err = gpio_pin_set_dt(&strip_en, on ? 1 : 0);
	if (err) {
		LOG_WRN("LED strip EN set failed (%d)", err);
	}

	return err;
}

static int refresh_idle_frame(void)
{
	clear_pixels();
	return submit_frame();
}

static void stop_effect_work(void)
{
	k_work_cancel_delayable(&effect_work);
}

static void schedule_effect_tick(k_timeout_t delay)
{
	k_work_reschedule(&effect_work, delay);
}

static int enable_strip_output(void)
{
	int err;

	err = set_strip_power(true);
	if (err) {
		return err;
	}

	return refresh_idle_frame();
}

static void disable_strip_output(void)
{
	stop_effect_work();
	clear_pixels();
	(void)submit_frame();
	(void)set_strip_power(false);
}

static void effect_work_handler(struct k_work *work)
{
	bool keep_running;

	ARG_UNUSED(work);

	if (!running || !enabled || (effect == NULL)) {
		return;
	}

	keep_running = effect->ops->tick(effect, k_ticks_to_ms_floor32(
						 LED_STRIP_TICK_INTERVAL.ticks),
					 pixels, ARRAY_SIZE(pixels));
	(void)submit_frame();

	if (keep_running) {
		schedule_effect_tick(LED_STRIP_TICK_INTERVAL);
	}
}

static int module_init(void)
{
	int err;

	if (!device_is_ready(strip)) {
		LOG_ERR("LED strip device %s not ready", strip->name);
		return -ENODEV;
	}

	if (!gpio_is_ready_dt(&strip_en)) {
		LOG_ERR("LED strip supply GPIO not ready");
		return -ENODEV;
	}

	err = gpio_pin_configure_dt(&strip_en, GPIO_OUTPUT_INACTIVE);
	if (err) {
		LOG_ERR("Failed to configure LED strip supply GPIO (%d)", err);
		return err;
	}

	k_work_init_delayable(&effect_work, effect_work_handler);
	clear_pixels();

	effect = led_effect_get_mutable(LED_EFFECT_ID_KEY_FADE);
	if ((effect == NULL) || (effect->ops == NULL)) {
		LOG_ERR("LED effect not available");
		return -ENOENT;
	}

	err = effect->ops->init(effect, &effect_cfg);
	if (err) {
		LOG_ERR("LED effect init failed (%d)", err);
		return err;
	}

	effect->ops->set_theme(effect, &current_theme);

	LOG_INF("LED strip ready len:%u", (uint32_t)led_strip_length(strip));
	return 0;
}

static int module_start(void)
{
	int err;

	if (running) {
		return 0;
	}

	running = true;

	if (!enabled) {
		return 0;
	}

	err = enable_strip_output();
	if (err) {
		running = false;
	}

	return err;
}

static void module_pause(void)
{
	if (!running) {
		return;
	}

	if ((effect != NULL) && (effect->ops != NULL)) {
		effect->ops->reset(effect);
	}

	disable_strip_output();
	running = false;
}

static bool handle_button_event(const struct button_event *event)
{
	if (!running || !enabled || (effect == NULL) || !event->pressed) {
		return false;
	}

	effect->ops->on_key_press(effect, event->key_id);
	schedule_effect_tick(K_NO_WAIT);

	return false;
}

static bool handle_led_strip_en_event(const struct led_strip_en_event *event)
{
	enabled = event->enabled;

	if (!running) {
		return false;
	}

	if (enabled) {
		int err = enable_strip_output();

		if (err) {
			module_set_state(MODULE_STATE_ERROR);
			return false;
		}
	} else {
		if ((effect != NULL) && (effect->ops != NULL)) {
			effect->ops->reset(effect);
		}

		disable_strip_output();
	}

	return false;
}

static bool handle_theme_rgb_update_event(const struct theme_rgb_update_event *event)
{
	current_theme = event->theme;

	if ((effect != NULL) && (effect->ops != NULL)) {
		effect->ops->set_theme(effect, &current_theme);
	}

	if (running && enabled && (effect != NULL) && effect->ops->is_active(effect)) {
		schedule_effect_tick(K_NO_WAIT);
	}

	return false;
}

static bool app_event_handler(const struct app_event_header *aeh)
{
	if (is_button_event(aeh)) {
		return handle_button_event(cast_button_event(aeh));
	}

	if (is_led_strip_en_event(aeh)) {
		return handle_led_strip_en_event(cast_led_strip_en_event(aeh));
	}

	if (is_theme_rgb_update_event(aeh)) {
		return handle_theme_rgb_update_event(cast_theme_rgb_update_event(aeh));
	}

	if (is_module_state_event(aeh)) {
		const struct module_state_event *event = cast_module_state_event(aeh);

		if (check_state(event, MODULE_ID(main), MODULE_STATE_READY)) {
			int err;

			if (!initialized) {
				err = module_init();
				if (err) {
					module_set_state(MODULE_STATE_ERROR);
					return false;
				}

				initialized = true;
			}

			err = module_start();
			if (err) {
				module_set_state(MODULE_STATE_ERROR);
			} else {
				module_set_state(MODULE_STATE_READY);
			}
		}

		return false;
	}

	if (is_power_down_event(aeh)) {
		if (initialized) {
			module_pause();
			module_set_state(MODULE_STATE_STANDBY);
		}

		return false;
	}

	if (is_wake_up_event(aeh)) {
		if (initialized) {
			int err = module_start();

			if (err) {
				module_set_state(MODULE_STATE_ERROR);
			} else {
				module_set_state(MODULE_STATE_READY);
			}
		}

		return false;
	}

	return false;
}

APP_EVENT_LISTENER(MODULE, app_event_handler);
APP_EVENT_SUBSCRIBE_EARLY(MODULE, button_event);
APP_EVENT_SUBSCRIBE(MODULE, led_strip_en_event);
APP_EVENT_SUBSCRIBE(MODULE, module_state_event);
APP_EVENT_SUBSCRIBE(MODULE, theme_rgb_update_event);
APP_EVENT_SUBSCRIBE_EARLY(MODULE, power_down_event);
APP_EVENT_SUBSCRIBE(MODULE, wake_up_event);