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

#include <app_event_manager.h>

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

#include <zephyr/logging/log.h>
#include <zephyr/usb/usbd.h>

#include "usb_device_module.h"
#include "usb_device_state_event.h"
#include "usb_function_ready_event.h"
#include "usb_prepare_event.h"

LOG_MODULE_REGISTER(MODULE, LOG_LEVEL_INF);

#define USB_DEVICE_VID 0x1915
#define USB_DEVICE_PID 0x52F0
#define USB_DEVICE_MANUFACTURER "Atguigu"
#define USB_DEVICE_PRODUCT "WH Mini Keyboard"
#define USB_REQUIRED_FUNCTION_MASK (USB_FUNCTION_HID | USB_FUNCTION_CDC_ACM)

USBD_DEVICE_DEFINE(blinky_usbd, DEVICE_DT_GET(DT_NODELABEL(usbd)),
		   USB_DEVICE_VID, USB_DEVICE_PID);

USBD_DESC_LANG_DEFINE(blinky_lang);
USBD_DESC_MANUFACTURER_DEFINE(blinky_mfr, USB_DEVICE_MANUFACTURER);
USBD_DESC_PRODUCT_DEFINE(blinky_product, USB_DEVICE_PRODUCT);

USBD_DESC_CONFIG_DEFINE(blinky_fs_cfg_desc, "FS Configuration");
USBD_CONFIGURATION_DEFINE(blinky_fs_config, 0, 250, &blinky_fs_cfg_desc);

static const char *const class_blocklist[] = {
	NULL,
};

static bool initialized;
static bool running;
static bool prepare_broadcasted;
static bool usbd_initialized;
static bool usb_enabled;
static uint8_t ready_function_mask;
static enum usb_device_state device_state = USB_DEVICE_STATE_DISCONNECTED;

static void submit_usb_device_state_event(enum usb_device_state state)
{
	struct usb_device_state_event *event = new_usb_device_state_event();

	event->state = state;
	APP_EVENT_SUBMIT(event);
}

static void submit_usb_prepare_event(void)
{
	struct usb_prepare_event *event = new_usb_prepare_event();

	APP_EVENT_SUBMIT(event);
}

static void update_usb_device_state(enum usb_device_state state)
{
	if (device_state == state) {
		return;
	}

	device_state = state;
	submit_usb_device_state_event(state);
}

static int usb_descriptors_init(void)
{
	int err;

	err = usbd_add_descriptor(&blinky_usbd, &blinky_lang);
	if (err) {
		return err;
	}

	err = usbd_add_descriptor(&blinky_usbd, &blinky_mfr);
	if (err) {
		return err;
	}

	err = usbd_add_descriptor(&blinky_usbd, &blinky_product);
	if (err) {
		return err;
	}

	err = usbd_add_configuration(&blinky_usbd, USBD_SPEED_FS, &blinky_fs_config);
	if (err) {
		return err;
	}

	err = usbd_register_all_classes(&blinky_usbd, USBD_SPEED_FS, 1, class_blocklist);
	if (err) {
		return err;
	}

	usbd_device_set_code_triple(&blinky_usbd, USBD_SPEED_FS, 0, 0, 0);

	return 0;
}

static void usbd_msg_cb(struct usbd_context *const usbd_ctx,
			const struct usbd_msg *const msg)
{
	ARG_UNUSED(usbd_ctx);

	switch (msg->type) {
	case USBD_MSG_VBUS_READY:
		if (!usb_enabled) {
			int err = usbd_enable(&blinky_usbd);

			if (err) {
				LOG_ERR("usbd_enable failed (%d)", err);
			} else {
				usb_enabled = true;
				update_usb_device_state(USB_DEVICE_STATE_POWERED);
			}
		}
		break;

	case USBD_MSG_VBUS_REMOVED:
		if (usb_enabled) {
			int err = usbd_disable(&blinky_usbd);

			if (err) {
				LOG_ERR("usbd_disable failed (%d)", err);
			}
		}

		usb_enabled = false;
		update_usb_device_state(USB_DEVICE_STATE_DISCONNECTED);
		break;

	case USBD_MSG_CONFIGURATION:
		if (msg->status) {
			update_usb_device_state(USB_DEVICE_STATE_ACTIVE);
		} else if (usb_enabled) {
			update_usb_device_state(USB_DEVICE_STATE_POWERED);
		}
		break;

	case USBD_MSG_SUSPEND:
		if (usb_enabled) {
			update_usb_device_state(USB_DEVICE_STATE_SUSPENDED);
		}
		break;

	case USBD_MSG_RESUME:
		if (usb_enabled) {
			update_usb_device_state(USB_DEVICE_STATE_ACTIVE);
		}
		break;

	default:
		break;
	}
}

static int usb_stack_init(void)
{
	int err;

	err = usbd_msg_register_cb(&blinky_usbd, usbd_msg_cb);
	if (err) {
		LOG_ERR("usbd_msg_register_cb failed (%d)", err);
		return err;
	}

	err = usb_descriptors_init();
	if (err) {
		LOG_ERR("usb descriptor init failed (%d)", err);
		return err;
	}

	err = usbd_init(&blinky_usbd);
	if (err) {
		LOG_ERR("usbd_init failed (%d)", err);
		return err;
	}

	usbd_initialized = true;

	if (!usbd_can_detect_vbus(&blinky_usbd)) {
		err = usbd_enable(&blinky_usbd);
		if (err) {
			LOG_ERR("usbd_enable failed (%d)", err);
			return err;
		}

		usb_enabled = true;
		update_usb_device_state(USB_DEVICE_STATE_POWERED);
	}

	return 0;
}

static int module_init(void)
{
	device_state = USB_DEVICE_STATE_DISCONNECTED;
	usb_enabled = false;
	ready_function_mask = 0U;
	prepare_broadcasted = false;
	usbd_initialized = false;

	return 0;
}

static int module_start(void)
{
	if (running) {
		return 0;
	}

	running = true;

	if (usbd_initialized || prepare_broadcasted) {
		return 0;
	}

	ready_function_mask = 0U;
	prepare_broadcasted = true;
	submit_usb_prepare_event();

	return 0;
}

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

	running = false;
}

static bool handle_module_state_event(const struct module_state_event *event)
{
	if (!check_state(event, MODULE_ID(main), MODULE_STATE_READY)) {
		return false;
	}

	if (!initialized) {
		int err = module_init();

		if (err) {
			module_set_state(MODULE_STATE_ERROR);
			return false;
		}

		initialized = true;
	}

	if (!running) {
		int err = module_start();

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

	return false;
}

static bool handle_usb_function_ready_event(const struct usb_function_ready_event *event)
{
	int err;

	if (!running || !prepare_broadcasted || usbd_initialized) {
		return false;
	}

	ready_function_mask |= event->function_mask;

	if ((ready_function_mask & USB_REQUIRED_FUNCTION_MASK) !=
	    USB_REQUIRED_FUNCTION_MASK) {
		return false;
	}

	err = usb_stack_init();
	if (err) {
		module_set_state(MODULE_STATE_ERROR);
		return false;
	}

	module_set_state(MODULE_STATE_READY);
	return false;
}

static bool app_event_handler(const struct app_event_header *aeh)
{
	if (is_module_state_event(aeh)) {
		return handle_module_state_event(cast_module_state_event(aeh));
	}

	if (is_usb_function_ready_event(aeh)) {
		return handle_usb_function_ready_event(cast_usb_function_ready_event(aeh));
	}

	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 if (usbd_initialized) {
				module_set_state(MODULE_STATE_READY);
			}
		}

		return false;
	}

	return false;
}

APP_EVENT_LISTENER(MODULE, app_event_handler);
APP_EVENT_SUBSCRIBE(MODULE, module_state_event);
APP_EVENT_SUBSCRIBE(MODULE, usb_function_ready_event);
APP_EVENT_SUBSCRIBE_EARLY(MODULE, power_down_event);
APP_EVENT_SUBSCRIBE(MODULE, wake_up_event);