#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/module_suspend_event.h>
#include <caf/events/power_event.h>

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

#include <caf/events/power_manager_event.h>

#include "module_lifecycle.h"
#include "usb_function_hook.h"
#include "usb_control_event.h"
#include "usb_state_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"

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,
};

enum usb_stack_state {
	USB_STACK_UNINITIALIZED = 0,
	USB_STACK_READY,
	USB_STACK_ENABLED,
};

enum usb_bus_state {
	USB_BUS_DISCONNECTED = 0,
	USB_BUS_POWERED,
	USB_BUS_ACTIVE,
	USB_BUS_SUSPENDED,
};

struct usb_owner_ctx {
	struct module_lifecycle_ctx lc;
	enum usb_stack_state stack;
	enum usb_bus_state bus;
};

static int do_init(void);
static int do_start(void);
static int do_stop(void);

/* Project exception: mode policy suspend/resume controls USB availability,
 * while global power events still map to standby lifecycle transitions.
 */
static const struct module_lifecycle_cfg lifecycle_cfg = {
	.mode = ML_MODE_SUSPEND,
	.stopped_state = MODULE_STATE_STANDBY,
};

static const struct module_lifecycle_ops lifecycle_ops = {
	.do_init = do_init,
	.do_start = do_start,
	.do_stop = do_stop,
};

static struct usb_owner_ctx usb_ctx = {
	.lc = {
		.state = LC_UNINIT,
		.cfg = &lifecycle_cfg,
		.ops = &lifecycle_ops,
	},
	.stack = USB_STACK_UNINITIALIZED,
	.bus = USB_BUS_DISCONNECTED,
};

static inline enum usb_state usb_public_state_get(void)
{
	if (!module_lifecycle_is_running(&usb_ctx.lc) ||
	    (usb_ctx.stack == USB_STACK_UNINITIALIZED)) {
		return USB_STATE_DISABLED;
	}

	switch (usb_ctx.bus) {
	case USB_BUS_DISCONNECTED:
		return USB_STATE_DISCONNECTED;
	case USB_BUS_POWERED:
		return USB_STATE_POWERED;
	case USB_BUS_ACTIVE:
		return USB_STATE_ACTIVE;
	case USB_BUS_SUSPENDED:
		return USB_STATE_SUSPENDED;
	default:
		return USB_STATE_DISABLED;
	}
}

static inline void usb_bus_set(enum usb_bus_state state)
{
	if (usb_ctx.bus == state) {
		return;
	}

	usb_ctx.bus = state;

	if (module_lifecycle_is_initialized(&usb_ctx.lc)) {
		submit_usb_state(usb_public_state_get());
	}
}

static void update_power_manager_restriction(bool vbus_present)
{
	power_manager_restrict(MODULE_IDX(MODULE),
			       vbus_present ? POWER_MANAGER_LEVEL_ALIVE :
					      POWER_MANAGER_LEVEL_SUSPENDED);
}

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);

	if (msg->type == USBD_MSG_CDC_ACM_CONTROL_LINE_STATE) {
		uint32_t dtr = 0U;
		int err = uart_line_ctrl_get(msg->dev, UART_LINE_CTRL_DTR, &dtr);

		if (err) {
			LOG_WRN("Failed to get CDC DTR (%d)", err);
		} else {
			submit_usb_control_cdc_line_state_event(msg->dev, dtr != 0U);
		}

		return;
	}

	if (msg->type == USBD_MSG_CDC_ACM_LINE_CODING) {
		uint32_t baudrate = 0U;
		uint8_t data_bits = 0U;
		uint8_t stop_bits = 0U;
		uint8_t parity = 0U;
		uint8_t flow_ctrl = 0U;
		int err;

		err = uart_line_ctrl_get(msg->dev, UART_LINE_CTRL_BAUD_RATE, &baudrate);
		if (err) {
			LOG_WRN("Failed to get CDC baudrate (%d)", err);
		}

#ifdef CONFIG_UART_USE_RUNTIME_CONFIGURE
		{
			struct uart_config cfg;

			err = uart_config_get(msg->dev, &cfg);
			if (err) {
				LOG_WRN("uart_config_get failed (%d)", err);
			} else {
				data_bits = (uint8_t)cfg.data_bits;
				stop_bits = (uint8_t)cfg.stop_bits;
				parity = (uint8_t)cfg.parity;
				flow_ctrl = (uint8_t)cfg.flow_ctrl;
			}
		}
#endif

		submit_usb_control_cdc_line_coding_event(msg->dev, baudrate,
						 data_bits, stop_bits,
						 parity, flow_ctrl);
		return;
	}

	switch (msg->type) {
	case USBD_MSG_VBUS_READY:
		update_power_manager_restriction(true);
		usb_bus_set(USB_BUS_POWERED);

		if (module_lifecycle_is_running(&usb_ctx.lc) &&
		    (usb_ctx.stack == USB_STACK_READY)) {
			int err = do_start();

			if (err) {
				LOG_ERR("USB start on VBUS ready failed (%d)", err);
			}
		}
		break;

	case USBD_MSG_VBUS_REMOVED:
		if (usb_ctx.stack == USB_STACK_ENABLED) {
			int err = do_stop();

			if (err) {
				LOG_ERR("USB stop on VBUS removed failed (%d)", err);
			}
		} else {
			update_power_manager_restriction(false);
		}

		if (usb_ctx.stack != USB_STACK_UNINITIALIZED) {
			usb_ctx.stack = USB_STACK_READY;
		}

		usb_bus_set(USB_BUS_DISCONNECTED);
		break;

	case USBD_MSG_CONFIGURATION:
		if (msg->status) {
			usb_bus_set(USB_BUS_ACTIVE);
		} else if (usb_ctx.stack == USB_STACK_ENABLED) {
			usb_bus_set(USB_BUS_POWERED);
		}
		break;

	case USBD_MSG_SUSPEND:
		if (usb_ctx.stack == USB_STACK_ENABLED) {
			usb_bus_set(USB_BUS_SUSPENDED);
		}
		break;

	case USBD_MSG_RESUME:
		if (usb_ctx.stack == USB_STACK_ENABLED) {
			usb_bus_set(USB_BUS_ACTIVE);
		}
		break;

	default:
		break;
	}
}

static int do_init(void)
{
	int err;

	usb_ctx.stack = USB_STACK_UNINITIALIZED;
	usb_ctx.bus = USB_BUS_DISCONNECTED;
	update_power_manager_restriction(false);

	STRUCT_SECTION_FOREACH(usb_function_hook, hook) {
		if (hook->pre_stack_init == NULL) {
			continue;
		}

		err = hook->pre_stack_init();
		if (err) {
			LOG_ERR("USB function hook %s failed (%d)", hook->name, err);
			return 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;
	}

	usb_ctx.stack = USB_STACK_READY;

	return 0;
}

static int do_start(void)
{
	int err;

	if (usb_ctx.stack == USB_STACK_ENABLED) {
		return 0;
	}

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

		usb_ctx.stack = USB_STACK_ENABLED;
		usb_ctx.bus = USB_BUS_POWERED;
		update_power_manager_restriction(true);
		return 0;
	}

	if (usb_ctx.bus == USB_BUS_DISCONNECTED) {
		return 0;
	}

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

	usb_ctx.stack = USB_STACK_ENABLED;
	update_power_manager_restriction(true);
	return 0;
}

static int do_stop(void)
{
	int err;

	if (usb_ctx.stack == USB_STACK_ENABLED) {
		err = usbd_disable(&blinky_usbd);
		if (err) {
			LOG_ERR("usbd_disable failed (%d)", err);
			return err;
		}
	}

	usb_ctx.stack = USB_STACK_READY;
	update_power_manager_restriction(false);
	return 0;
}

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 (module_set_lifecycle(&usb_ctx.lc, LC_RUNNING) == 0) {
		submit_usb_state(usb_public_state_get());
	}

	return false;
}

static bool handle_module_suspend_req_event(
	const struct module_suspend_req_event *event)
{
	if ((event->sink_module_id != MODULE_ID(MODULE)) ||
	    (usb_ctx.lc.state != LC_RUNNING)) {
		return false;
	}

	if (module_set_lifecycle(&usb_ctx.lc, LC_SUSPENDED) == 0) {
		submit_usb_state(usb_public_state_get());
	}

	return false;
}

static bool handle_module_resume_req_event(
	const struct module_resume_req_event *event)
{
	if ((event->sink_module_id != MODULE_ID(MODULE)) ||
	    (usb_ctx.lc.state != LC_SUSPENDED)) {
		return false;
	}

	if (module_set_lifecycle(&usb_ctx.lc, LC_RUNNING) == 0) {
		submit_usb_state(usb_public_state_get());
	}

	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_module_suspend_req_event(aeh)) {
		return handle_module_suspend_req_event(
			cast_module_suspend_req_event(aeh));
	}

	if (is_module_resume_req_event(aeh)) {
		return handle_module_resume_req_event(
			cast_module_resume_req_event(aeh));
	}

	if (is_power_down_event(aeh)) {
		if (module_lifecycle_is_initialized(&usb_ctx.lc)) {
			if (module_set_lifecycle(&usb_ctx.lc, LC_STOPPED) == 0) {
				submit_usb_state(usb_public_state_get());
			}
		}

		return false;
	}

	if (is_wake_up_event(aeh)) {
		if (module_lifecycle_is_initialized(&usb_ctx.lc)) {
			if (module_set_lifecycle(&usb_ctx.lc, LC_RUNNING) == 0) {
				submit_usb_state(usb_public_state_get());
			}
		}

		return false;
	}

	return false;
}

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