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

#include <app_event_manager.h>

#define MODULE display_module
#include <caf/events/module_state_event.h>
#include <caf/events/power_event.h>

#include <lvgl_zephyr.h>
#include <zephyr/device.h>
#include <zephyr/drivers/display.h>
#include <zephyr/drivers/led.h>
#include <zephyr/logging/log.h>

#include "bat_state_event.h"
#include "hid_led_event.h"
#include "mode_switch_event.h"
#include "theme_color.h"
#include "ui/ui_main.h"

LOG_MODULE_REGISTER(MODULE, LOG_LEVEL_INF);

BUILD_ASSERT(DT_HAS_CHOSEN(zephyr_display), "Missing zephyr,display chosen node");
BUILD_ASSERT(DT_NODE_HAS_STATUS(DT_ALIAS(backlight), okay),
	     "Missing backlight alias");

static const struct device *const display_dev =
	DEVICE_DT_GET(DT_CHOSEN(zephyr_display));
static const struct device *const backlight_dev =
	DEVICE_DT_GET(DT_PARENT(DT_ALIAS(backlight)));
static const uint32_t backlight_idx = DT_NODE_CHILD_IDX(DT_ALIAS(backlight));
static struct ui_main_model ui_model = {
	.theme_color = LV_COLOR_MAKE(BLINKY_THEME_DEFAULT_R,
				    BLINKY_THEME_DEFAULT_G,
				    BLINKY_THEME_DEFAULT_B),
	.inactive_border_color = LV_COLOR_MAKE(0x3A, 0x44, 0x52),
	.mode = MODE_SWITCH_BLE,
};
static bool initialized;
static bool running;
static bool lvgl_initialized;

static int backlight_set(bool on)
{
	if (on) {
		return led_on(backlight_dev, backlight_idx);
	}

	return led_off(backlight_dev, backlight_idx);
}

static int module_init(void)
{
	int err;

	LOG_INF("Display init on %s", display_dev->name);

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

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

	err = backlight_set(false);
	if (err) {
		LOG_ERR("Backlight off failed (%d)", err);
		return err;
	}

	return 0;
}

static int module_start(void)
{
	int err;

	if (running) {
		return 0;
	}

	if (!lvgl_initialized) {
		err = lvgl_init();
		if (err) {
			LOG_ERR("lvgl_init failed (%d)", err);
			return err;
		}

		lvgl_initialized = true;

		lvgl_lock();
		ui_main_init(&ui_model, "WH Mini", "Hello World");
		lvgl_unlock();
	}

	err = backlight_set(true);
	if (err) {
		LOG_ERR("Backlight enable failed (%d)", err);
		return err;
	}

	err = display_blanking_off(display_dev);
	if (err) {
		LOG_ERR("display_blanking_off failed (%d)", err);
		(void)backlight_set(false);
		return err;
	}

	running = true;
	LOG_INF("LVGL display started");

	return 0;
}

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

	(void)display_blanking_on(display_dev);
	(void)backlight_set(false);
	running = false;
	LOG_INF("LVGL display paused");
}

static void refresh_ui(void)
{
	if (!lvgl_initialized) {
		return;
	}

	lvgl_lock();
	ui_main_refresh_all(&ui_model, "WH Mini", "Hello World");
	lvgl_unlock();
}

static bool app_event_handler(const struct app_event_header *aeh)
{
	if (is_bat_state_event(aeh)) {
		const struct bat_state_event *event = cast_bat_state_event(aeh);

		ui_model.battery_level = event->soc;
		ui_model.charging = event->charging;
		ui_model.full = event->full;
		refresh_ui();
		return false;
	}

	if (is_mode_switch_event(aeh)) {
		const struct mode_switch_event *event = cast_mode_switch_event(aeh);

		ui_model.mode = event->mode;
		refresh_ui();
		return false;
	}

	if (is_hid_led_event(aeh)) {
		const struct hid_led_event *event = cast_hid_led_event(aeh);

		ui_model.led_mask = event->led_bm;
		refresh_ui();
		return false;
	}

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

		if (check_state(event, MODULE_ID(main), MODULE_STATE_READY)) {
			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(MODULE, bat_state_event);
APP_EVENT_SUBSCRIBE(MODULE, hid_led_event);
APP_EVENT_SUBSCRIBE(MODULE, module_state_event);
APP_EVENT_SUBSCRIBE(MODULE, mode_switch_event);
APP_EVENT_SUBSCRIBE_EARLY(MODULE, power_down_event);
APP_EVENT_SUBSCRIBE(MODULE, wake_up_event);