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

#include <app_event_manager.h>

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

#include <caf/events/ble_common_event.h>
#include <bluetooth/services/hids.h>
#include <zephyr/logging/log.h>

#include "hid_led_event.h"
#include "hid_channel_state_event.h"
#include "hid_report_sent_event.h"
#include "hid_tx_report_event.h"
#include "keyboard_core.h"
#include "module_lifecycle.h"
#include "set_protocol_event.h"

LOG_MODULE_REGISTER(MODULE, LOG_LEVEL_INF);

#define BLE_HID_KEYS_REPORT_ID 0x01
#define BLE_HID_CONSUMER_REPORT_ID 0x02
#define BLE_HID_KEYS_REPORT_IDX 0
#define BLE_HID_CONSUMER_REPORT_IDX 1
#define BLE_HID_KEYS_LED_REPORT_SIZE 1U
#define BASE_USB_HID_SPEC_VERSION 0x0101

struct in_flight_report {
	bool active;
	enum keyboard_report_type report_type;
	uint16_t sequence;
};

BT_HIDS_DEF(hids_obj,
	    KEYBOARD_NKRO_REPORT_SIZE,
	    KEYBOARD_CONSUMER_REPORT_SIZE,
	    BLE_HID_KEYS_LED_REPORT_SIZE);

struct ble_hid_module_ctx {
	struct module_lifecycle_ctx lc;
	struct bt_conn *active_conn;
	struct in_flight_report in_flight;
	enum keyboard_protocol_mode protocol_mode;
	bool secured;
	bool keyboard_report_notify_enabled;
	bool consumer_report_notify_enabled;
	bool boot_keyboard_notify_enabled;
};

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

static const struct module_lifecycle_cfg lifecycle_cfg = {
	.mode = ML_MODE_NONE,
	.stopped_state = MODULE_STATE_OFF,
};

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

static struct ble_hid_module_ctx ctx = {
	.lc = {
		.state = LC_UNINIT,
		.cfg = &lifecycle_cfg,
		.ops = &lifecycle_ops,
	},
	.protocol_mode = KEYBOARD_PROTOCOL_MODE_REPORT,
};

static const uint8_t hid_report_desc[] = {
	0x05, 0x01,             /* Usage Page (Generic Desktop) */
	0x09, 0x06,             /* Usage (Keyboard) */
	0xA1, 0x01,             /* Collection (Application) */
	0x85, BLE_HID_KEYS_REPORT_ID,
	0x05, 0x07,             /* Usage Page (Keyboard/Keypad) */
	0x19, 0xE0,             /* Usage Minimum (0xE0) */
	0x29, 0xE7,             /* Usage Maximum (0xE7) */
	0x15, 0x00,             /* Logical Minimum (0) */
	0x25, 0x01,             /* Logical Maximum (1) */
	0x75, 0x01,             /* Report Size (1) */
	0x95, 0x08,             /* Report Count (8) */
	0x81, 0x02,             /* Input (Data,Var,Abs) */
	0x05, 0x07,             /* Usage Page (Keyboard/Keypad) */
	0x19, 0x00,             /* Usage Minimum (0x00) */
	0x2A, 0xDF, 0x00,       /* Usage Maximum (0x00DF) */
	0x15, 0x00,             /* Logical Minimum (0) */
	0x25, 0x01,             /* Logical Maximum (1) */
	0x75, 0x01,             /* Report Size (1) */
	0x96, 0xE0, 0x00,       /* Report Count (224) */
	0x81, 0x02,             /* Input (Data,Var,Abs) */
	0x85, BLE_HID_KEYS_REPORT_ID,
	0x05, 0x08,             /* Usage Page (LEDs) */
	0x19, 0x01,             /* Usage Minimum (1) */
	0x29, 0x05,             /* Usage Maximum (5) */
	0x15, 0x00,             /* Logical Minimum (0) */
	0x25, 0x01,             /* Logical Maximum (1) */
	0x75, 0x01,             /* Report Size (1) */
	0x95, 0x05,             /* Report Count (5) */
	0x91, 0x02,             /* Output (Data,Var,Abs) */
	0x75, 0x03,             /* Report Size (3) */
	0x95, 0x01,             /* Report Count (1) */
	0x91, 0x01,             /* Output (Const,Array,Abs) */
	0xC0,                   /* End Collection */
	0x05, 0x0C,             /* Usage Page (Consumer) */
	0x09, 0x01,             /* Usage (Consumer Control) */
	0xA1, 0x01,             /* Collection (Application) */
	0x85, BLE_HID_CONSUMER_REPORT_ID,
	0x15, 0x00,             /* Logical Minimum (0) */
	0x26, 0xFF, 0x03,       /* Logical Maximum (1023) */
	0x19, 0x00,             /* Usage Minimum (0) */
	0x2A, 0xFF, 0x03,       /* Usage Maximum (1023) */
	0x75, 0x10,             /* Report Size (16) */
	0x95, 0x01,             /* Report Count (1) */
	0x81, 0x00,             /* Input (Data,Array,Abs) */
	0xC0                    /* End Collection */
};

static void submit_ble_transport_state_event(void)
{
	bool ready = module_lifecycle_is_running(&ctx.lc) &&
		     ctx.secured && (ctx.active_conn != NULL);
	uint8_t report_ready_bm = 0U;

	if (ready && ((ctx.protocol_mode == KEYBOARD_PROTOCOL_MODE_BOOT) ?
			      ctx.boot_keyboard_notify_enabled :
			      ctx.keyboard_report_notify_enabled)) {
		report_ready_bm |= BIT(KEYBOARD_REPORT_TYPE_KEYS);
	}

	if (ready && (ctx.protocol_mode == KEYBOARD_PROTOCOL_MODE_REPORT) &&
	    ctx.consumer_report_notify_enabled) {
		report_ready_bm |= BIT(KEYBOARD_REPORT_TYPE_CONSUMER);
	}

	submit_hid_channel_state_event(
		HID_SEND_CH_BLE_SHARED,
		report_ready_bm,
		ctx.protocol_mode);
}

static void input_report_notify_handler(uint8_t report_id, enum bt_hids_notify_evt evt)
{
	bool enabled = (evt == BT_HIDS_CCCD_EVT_NOTIFY_ENABLED);

	if (report_id == BLE_HID_KEYS_REPORT_ID) {
		ctx.keyboard_report_notify_enabled = enabled;
	} else if (report_id == BLE_HID_CONSUMER_REPORT_ID) {
		ctx.consumer_report_notify_enabled = enabled;
	}

	submit_ble_transport_state_event();
}

static void boot_keyboard_notify_handler(enum bt_hids_notify_evt evt)
{
	ctx.boot_keyboard_notify_enabled = (evt == BT_HIDS_CCCD_EVT_NOTIFY_ENABLED);
	submit_ble_transport_state_event();
}

static void hid_report_complete_cb(struct bt_conn *conn, void *user_data)
{
	ARG_UNUSED(conn);
	ARG_UNUSED(user_data);

	if (!ctx.in_flight.active) {
		return;
	}

	submit_hid_report_sent_event(HID_SEND_CH_BLE_SHARED,
				     ctx.in_flight.report_type,
				     ctx.in_flight.sequence, false);
	ctx.in_flight.active = false;
}

static void keyboard_led_report_common(struct bt_hids_rep *rep, bool write)
{
	if (!write || (rep->data == NULL) || (rep->size < BLE_HID_KEYS_LED_REPORT_SIZE)) {
		return;
	}

	submit_hid_led_event(HID_TRANSPORT_BLE, rep->data[0]);
}

static void keyboard_led_report_handler(struct bt_hids_rep *rep,
					struct bt_conn *conn,
					bool write)
{
	ARG_UNUSED(conn);

	keyboard_led_report_common(rep, write);
}

static void boot_keyboard_led_report_handler(struct bt_hids_rep *rep,
					     struct bt_conn *conn,
					     bool write)
{
	ARG_UNUSED(conn);

	keyboard_led_report_common(rep, write);
}

static void pm_evt_handler(enum bt_hids_pm_evt evt, struct bt_conn *conn)
{
	ARG_UNUSED(conn);

	switch (evt) {
	case BT_HIDS_PM_EVT_BOOT_MODE_ENTERED:
		ctx.protocol_mode = KEYBOARD_PROTOCOL_MODE_BOOT;
		break;

	case BT_HIDS_PM_EVT_REPORT_MODE_ENTERED:
		ctx.protocol_mode = KEYBOARD_PROTOCOL_MODE_REPORT;
		break;

	default:
		return;
	}

	submit_set_protocol_event(HID_TRANSPORT_BLE, ctx.protocol_mode);
	submit_ble_transport_state_event();
}

static int do_init(void)
{
	struct bt_hids_init_param hids_init_param = { 0 };
	struct bt_hids_inp_rep *input_report;
	struct bt_hids_outp_feat_rep *output_report;

	hids_init_param.info.bcd_hid = BASE_USB_HID_SPEC_VERSION;
	hids_init_param.info.b_country_code = 0x00;
	hids_init_param.info.flags = BT_HIDS_REMOTE_WAKE | BT_HIDS_NORMALLY_CONNECTABLE;
	hids_init_param.rep_map.data = hid_report_desc;
	hids_init_param.rep_map.size = sizeof(hid_report_desc);
	hids_init_param.pm_evt_handler = pm_evt_handler;
	hids_init_param.is_kb = true;
	hids_init_param.boot_kb_notif_handler = boot_keyboard_notify_handler;
	hids_init_param.boot_kb_outp_rep_handler = boot_keyboard_led_report_handler;

	input_report = &hids_init_param.inp_rep_group_init.reports[BLE_HID_KEYS_REPORT_IDX];
	input_report->id = BLE_HID_KEYS_REPORT_ID;
	input_report->size = KEYBOARD_NKRO_REPORT_SIZE;
	input_report->handler_ext = input_report_notify_handler;
	hids_init_param.inp_rep_group_init.cnt++;

	input_report = &hids_init_param.inp_rep_group_init.reports[BLE_HID_CONSUMER_REPORT_IDX];
	input_report->id = BLE_HID_CONSUMER_REPORT_ID;
	input_report->size = KEYBOARD_CONSUMER_REPORT_SIZE;
	input_report->handler_ext = input_report_notify_handler;
	hids_init_param.inp_rep_group_init.cnt++;

	output_report = &hids_init_param.outp_rep_group_init.reports[0];
	output_report->id = BLE_HID_KEYS_REPORT_ID;
	output_report->size = BLE_HID_KEYS_LED_REPORT_SIZE;
	output_report->handler = keyboard_led_report_handler;
	hids_init_param.outp_rep_group_init.cnt = 1U;

	return bt_hids_init(&hids_obj, &hids_init_param);
}

static int do_start(void)
{
	if (module_lifecycle_is_running(&ctx.lc)) {
		return 0;
	}

	submit_ble_transport_state_event();

	return 0;
}

static int do_stop(void)
{
	if (!module_lifecycle_is_running(&ctx.lc)) {
		return 0;
	}

	ctx.in_flight.active = false;
	submit_ble_transport_state_event();

	return 0;
}

static void reset_connection_state(void)
{
	ctx.active_conn = NULL;
	ctx.secured = false;
	ctx.keyboard_report_notify_enabled = false;
	ctx.consumer_report_notify_enabled = false;
	ctx.boot_keyboard_notify_enabled = false;
	ctx.protocol_mode = KEYBOARD_PROTOCOL_MODE_REPORT;
	ctx.in_flight.active = false;
}

static bool handle_ble_peer_event(const struct ble_peer_event *event)
{
	int err;

	switch (event->state) {
	case PEER_STATE_CONNECTED:
		if (ctx.active_conn != NULL) {
			return false;
		}

		ctx.active_conn = event->id;
		ctx.protocol_mode = KEYBOARD_PROTOCOL_MODE_REPORT;
		submit_set_protocol_event(HID_TRANSPORT_BLE, ctx.protocol_mode);
		err = bt_hids_connected(&hids_obj, event->id);
		if (err) {
			LOG_ERR("bt_hids_connected failed (%d)", err);
		}
		submit_ble_transport_state_event();
		return false;

	case PEER_STATE_SECURED:
		if (ctx.active_conn != event->id) {
			return false;
		}

		ctx.secured = true;
		submit_ble_transport_state_event();
		return false;

	case PEER_STATE_DISCONNECTED:
		if (ctx.active_conn != event->id) {
			return false;
		}

		err = bt_hids_disconnected(&hids_obj, event->id);
		if (err) {
			LOG_WRN("bt_hids_disconnected failed (%d)", err);
		}

		reset_connection_state();
		submit_ble_transport_state_event();
		return false;

	default:
		return false;
	}
}

static bool handle_hid_tx_report_event(const struct hid_tx_report_event *event)
{
	int err;

	if (!module_lifecycle_is_running(&ctx.lc) ||
	    (event->channel != HID_SEND_CH_BLE_SHARED) ||
	    ctx.in_flight.active) {
		return false;
	}

	if ((ctx.active_conn == NULL) || !ctx.secured) {
		return false;
	}

	if (event->report_type == KEYBOARD_REPORT_TYPE_KEYS) {
		if (event->protocol_mode != ctx.protocol_mode) {
			LOG_WRN("Drop BLE keys report due to protocol mismatch");
			return false;
		}

		ctx.in_flight.active = true;
		ctx.in_flight.report_type = event->report_type;
		ctx.in_flight.sequence = event->sequence;

		if (ctx.protocol_mode == KEYBOARD_PROTOCOL_MODE_BOOT) {
			err = bt_hids_boot_kb_inp_rep_send(&hids_obj,
							 ctx.active_conn,
							 event->dyndata.data,
							 (uint8_t)event->dyndata.size,
							 hid_report_complete_cb);
		} else {
			err = bt_hids_inp_rep_send(&hids_obj,
						    ctx.active_conn,
						    BLE_HID_KEYS_REPORT_IDX,
						    event->dyndata.data,
						    (uint8_t)event->dyndata.size,
						    hid_report_complete_cb);
		}

		if (err) {
			ctx.in_flight.active = false;
			LOG_WRN("BLE keyboard report submit failed (%d)", err);
			submit_hid_report_sent_event(HID_SEND_CH_BLE_SHARED,
						     KEYBOARD_REPORT_TYPE_KEYS,
						     event->sequence, true);
		}

		return false;
	}

	if (event->report_type == KEYBOARD_REPORT_TYPE_CONSUMER) {
		if (ctx.protocol_mode != KEYBOARD_PROTOCOL_MODE_REPORT) {
			LOG_WRN("Drop BLE consumer report in boot mode");
			return false;
		}

		ctx.in_flight.active = true;
		ctx.in_flight.report_type = event->report_type;
		ctx.in_flight.sequence = event->sequence;

		err = bt_hids_inp_rep_send(&hids_obj,
					    ctx.active_conn,
					    BLE_HID_CONSUMER_REPORT_IDX,
					    event->dyndata.data,
					    (uint8_t)event->dyndata.size,
					    hid_report_complete_cb);
		if (err) {
			ctx.in_flight.active = false;
			LOG_WRN("BLE consumer report submit failed (%d)", err);
			submit_hid_report_sent_event(HID_SEND_CH_BLE_SHARED,
						     KEYBOARD_REPORT_TYPE_CONSUMER,
						     event->sequence, true);
		}
	}

	return false;
}

static bool app_event_handler(const struct app_event_header *aeh)
{
	if (is_hid_tx_report_event(aeh)) {
		return handle_hid_tx_report_event(cast_hid_tx_report_event(aeh));
	}

	if (is_ble_peer_event(aeh)) {
		return handle_ble_peer_event(cast_ble_peer_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)) {
			(void)module_set_lifecycle(&ctx.lc, LC_RUNNING);
		}

		return false;
	}

	return false;
}

APP_EVENT_LISTENER(MODULE, app_event_handler);
APP_EVENT_SUBSCRIBE_EARLY(MODULE, module_state_event);
APP_EVENT_SUBSCRIBE(MODULE, hid_tx_report_event);
APP_EVENT_SUBSCRIBE_EARLY(MODULE, ble_peer_event);