#include <stdint.h>
#include <string.h>
#include "kernel.h"
#include "nordic_common.h"
#include "nrf.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_params.h"
#include "nrf_sdh.h"
#include "nrf_sdh_soc.h"
#include "nrf_sdh_ble.h"
#include "nrf_sdh_rtos.h"
#include "nrf_ble_gatt.h"
#include "nrf_ble_qwr.h"
#include "app_timer.h"
#include "ble_nus.h"
#include "ble_dis.h"
#include "ble_bas.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#define APP_BLE_CONN_CFG_TAG            1                                           /**< A tag identifying the SoftDevice BLE configuration. */

#define DEVICE_NAME                     "Nordic_UART"                               /**< Name of device. Will be included in the advertising data. */
#define NUS_SERVICE_UUID_TYPE           BLE_UUID_TYPE_VENDOR_BEGIN                  /**< UUID type for the Nordic UART Service (vendor specific). */

#define APP_BLE_OBSERVER_PRIO           3                                           /**< Application's BLE observer priority. You shouldn't need to modify this value. */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(20, UNIT_1_25_MS)             /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(75, UNIT_1_25_MS)             /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */
#define SLAVE_LATENCY                   0                                           /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */
#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                       /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                      /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */

#define DEAD_BEEF                       0xDEADBEEF                                  /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */

NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
NRF_BLE_QWR_DEF(m_qwr);                                                             /**< Context for the Queued Write module.*/
BLE_ADVERTISING_DEF(m_advertising);                                                 /**< Advertising module instance. */
BLE_BAS_DEF(m_bas);
BLE_NUS_DEF(m_nus, NRF_SDH_BLE_TOTAL_LINK_COUNT);                                   /**< BLE NUS service instance. */

static uint16_t   m_conn_handle          = BLE_CONN_HANDLE_INVALID;                 /**< Handle of the current connection. */
static uint16_t   m_ble_nus_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - 3;            /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */
static ble_uuid_t m_adv_uuids[]          =                                          /**< Universally unique service identifier. */
{
	{BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}
};

static void nrf_qwr_error_handler(uint32_t nrf_error)
{
	NRF_LOG_INFO("%s: nrf_error=%d", __func__, nrf_error);
}

static void conn_params_error_handler(uint32_t nrf_error)
{
	NRF_LOG_INFO("%s: nrf_error=%d", __func__, nrf_error);
}

/**@brief Function for the GAP initialization.
 *
 * @details This function will set up all the necessary GAP (Generic Access Profile) parameters of
 *          the device. It also sets the permissions and appearance.
 */
static void gap_params_init(void)
{
	uint32_t                err_code;
	ble_gap_conn_params_t   gap_conn_params;
	ble_gap_conn_sec_mode_t sec_mode;

	BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);
	err_code = sd_ble_gap_device_name_set(&sec_mode,(const uint8_t *)DEVICE_NAME, strlen(DEVICE_NAME));
	APP_ERROR_CHECK(err_code);

	memset(&gap_conn_params, 0, sizeof(gap_conn_params));
	gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;
	gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;
	gap_conn_params.slave_latency     = SLAVE_LATENCY;
	gap_conn_params.conn_sup_timeout  = CONN_SUP_TIMEOUT;

	err_code = sd_ble_gap_ppcp_set(&gap_conn_params);
	APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling the data from the Nordic UART Service.
 *
 * @details This function will process the data received from the Nordic UART BLE Service and send
 *          it to the UART module.
 *
 * @param[in] p_evt       Nordic UART Service event.
 */
static void nus_data_handler(ble_nus_evt_t * p_evt)
{
	if (p_evt->type == BLE_NUS_EVT_RX_DATA)
	{
		NRF_LOG_INFO("Received data from BLE NUS:");
		NRF_LOG_HEXDUMP_INFO(p_evt->params.rx_data.p_data, p_evt->params.rx_data.length);
	}
}

/**@brief Function for initializing services that will be used by the application.
 */
static void services_init(void)
{
	char               str[32];
	uint32_t           err_code;
	ble_nus_init_t     nus_init;
	ble_dis_init_t     dis_init;
	ble_bas_init_t     bas_init;
	nrf_ble_qwr_init_t qwr_init = {0};

	// Initialize Queued Write Module.
	qwr_init.error_handler = nrf_qwr_error_handler;

	err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);
	APP_ERROR_CHECK(err_code);

	// Initialize NUS.
	memset(&nus_init, 0, sizeof(nus_init));

	nus_init.data_handler = nus_data_handler;

	err_code = ble_nus_init(&m_nus, &nus_init);
	APP_ERROR_CHECK(err_code);
	
	memset(&dis_init, 0, sizeof(dis_init));
	sprintf(str, "%08X", kernel_version());
	ble_srv_ascii_to_utf8(&dis_init.sw_rev_str, str);
	ble_srv_ascii_to_utf8(&dis_init.model_num_str, "klite");
	ble_srv_ascii_to_utf8(&dis_init.manufact_name_str, "kernev@foxmail.com");
	dis_init.dis_char_rd_sec = SEC_OPEN;
	err_code = ble_dis_init(&dis_init);
	APP_ERROR_CHECK(err_code);
	
	memset(&bas_init, 0, sizeof(bas_init));
	bas_init.bl_rd_sec        = SEC_OPEN;
	bas_init.bl_cccd_wr_sec   = SEC_OPEN;
	bas_init.bl_report_rd_sec = SEC_OPEN;
	bas_init.evt_handler          = NULL;
	bas_init.support_notification = true;
	bas_init.p_report_ref         = NULL;
	bas_init.initial_batt_level   = 100;
	err_code = ble_bas_init(&m_bas, &bas_init);
	APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling an event from the Connection Parameters Module.
 *
 * @details This function will be called for all events in the Connection Parameters Module
 *          which are passed to the application.
 *
 * @note All this function does is to disconnect. This could have been done by simply setting
 *       the disconnect_on_fail config parameter, but instead we use the event handler
 *       mechanism to demonstrate its use.
 *
 * @param[in] p_evt  Event received from the Connection Parameters Module.
 */
static void on_conn_params_evt(ble_conn_params_evt_t * p_evt)
{
	uint32_t err_code;

	if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED)
	{
		err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
		APP_ERROR_CHECK(err_code);
	}
}

/**@brief Function for initializing the Connection Parameters module.
 */
static void conn_params_init(void)
{
	uint32_t               err_code;
	ble_conn_params_init_t cp_init;

	memset(&cp_init, 0, sizeof(cp_init));

	cp_init.p_conn_params                  = NULL;
	cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
	cp_init.next_conn_params_update_delay  = NEXT_CONN_PARAMS_UPDATE_DELAY;
	cp_init.max_conn_params_update_count   = MAX_CONN_PARAMS_UPDATE_COUNT;
	cp_init.start_on_notify_cccd_handle    = BLE_GATT_HANDLE_INVALID;
	cp_init.disconnect_on_fail             = false;
	cp_init.evt_handler                    = on_conn_params_evt;
	cp_init.error_handler                  = conn_params_error_handler;

	err_code = ble_conn_params_init(&cp_init);
	APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling advertising events.
 *
 * @details This function will be called for advertising events which are passed to the application.
 *
 * @param[in] ble_adv_evt  Advertising event.
 */
static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
{
	switch (ble_adv_evt)
	{
		case BLE_ADV_EVT_FAST:
			break;
		case BLE_ADV_EVT_IDLE:
			break;
		default:
			break;
	}
}

/**@brief Function for handling BLE events.
 *
 * @param[in]   p_ble_evt   Bluetooth stack event.
 * @param[in]   p_context   Unused.
 */
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
	uint32_t err_code;
	NRF_LOG_INFO("%s: %X", __func__,p_ble_evt->header.evt_id);
	switch (p_ble_evt->header.evt_id)
	{
		case BLE_GAP_EVT_CONNECTED:
			NRF_LOG_INFO("Connected");
			m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
			err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
			APP_ERROR_CHECK(err_code);
			break;

		case BLE_GAP_EVT_DISCONNECTED:
			NRF_LOG_INFO("Disconnected");
			m_conn_handle = BLE_CONN_HANDLE_INVALID;
			break;

		case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
		{
			NRF_LOG_INFO("PHY update request.");
			ble_gap_phys_t const phys =
			{
				.rx_phys = BLE_GAP_PHY_AUTO,
				.tx_phys = BLE_GAP_PHY_AUTO,
			};
			err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
			APP_ERROR_CHECK(err_code);
		} break;

		case BLE_GAP_EVT_SEC_PARAMS_REQUEST:
			// Pairing not supported
			err_code = sd_ble_gap_sec_params_reply(m_conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL);
			APP_ERROR_CHECK(err_code);
			break;

		case BLE_GATTS_EVT_SYS_ATTR_MISSING:
			// No system attributes have been stored.
			err_code = sd_ble_gatts_sys_attr_set(m_conn_handle, NULL, 0, 0);
			APP_ERROR_CHECK(err_code);
			break;

		case BLE_GATTC_EVT_TIMEOUT:
			// Disconnect on GATT Client timeout event.
			err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
			APP_ERROR_CHECK(err_code);
			break;

		case BLE_GATTS_EVT_TIMEOUT:
			// Disconnect on GATT Server timeout event.
			err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
			APP_ERROR_CHECK(err_code);
			break;

		default:
			// No implementation needed.
			NRF_LOG_INFO("Ignore event");
			break;
	}
}


/**@brief Function for the SoftDevice initialization.
 *
 * @details This function initializes the SoftDevice and the BLE event interrupt.
 */
static void ble_stack_init(void)
{
	ret_code_t err_code;

	err_code = nrf_sdh_enable_request();
	APP_ERROR_CHECK(err_code);

	// Configure the BLE stack using the default settings.
	// Fetch the start address of the application RAM.
	uint32_t ram_start = 0;
	err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
	APP_ERROR_CHECK(err_code);

	// Enable BLE stack.
	err_code = nrf_sdh_ble_enable(&ram_start);
	APP_ERROR_CHECK(err_code);

	// Register a handler for BLE events.
	NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL);
}


/**@brief Function for handling events from the GATT library. */
static void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
	if ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
	{
		m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
		NRF_LOG_INFO("Data len is set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
	}
	NRF_LOG_INFO("ATT MTU exchange completed. central 0x%x peripheral 0x%x", p_gatt->att_mtu_desired_central, p_gatt->att_mtu_desired_periph);
}


/**@brief Function for initializing the GATT library. */
static void gatt_init(void)
{
	ret_code_t err_code;

	err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
	APP_ERROR_CHECK(err_code);

	err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
	APP_ERROR_CHECK(err_code);
}

/**@brief Function for initializing the Advertising functionality.
 */
static void advertising_init(void)
{
	uint32_t               err_code;
	ble_advertising_init_t init;

	memset(&init, 0, sizeof(init));
	init.advdata.name_type          = BLE_ADVDATA_FULL_NAME;
	init.advdata.include_appearance = false;
	init.advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;

	init.srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
	init.srdata.uuids_complete.p_uuids  = m_adv_uuids;

	init.config.ble_adv_fast_enabled  = true;
	init.config.ble_adv_fast_interval = 512;  /* x0.625ms = 320ms */
	init.config.ble_adv_fast_timeout  = 0;
	init.evt_handler = on_adv_evt;

	err_code = ble_advertising_init(&m_advertising, &init);
	APP_ERROR_CHECK(err_code);

	ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}


/**@brief Function for initializing the nrf log module.
 */
static void app_log_init(void)
{
	NRF_LOG_INIT(NULL);
	NRF_LOG_DEFAULT_BACKENDS_INIT();
}

/**@brief Function for starting advertising. */
static void advertising_start(void)
{
	ret_code_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
	APP_ERROR_CHECK(err_code);
}

static void bas_update_timer(void *arg)
{
	static uint8_t level;
	level = (level + 1) % 100;
	NRF_LOG_INFO("Update battery level: %d", level);
	ble_bas_battery_level_update(&m_bas, level, BLE_CONN_HANDLE_ALL);
}

static void bas_update_init(void)
{
	APP_TIMER_DEF(bas_timer);
	app_timer_create(&bas_timer, APP_TIMER_MODE_REPEATED, bas_update_timer);
	app_timer_start(bas_timer, 3000, NULL);
}

void app_init(void)
{
	app_log_init();
	app_timer_init();
	ble_stack_init();
	gap_params_init();
	gatt_init();
	services_init();
	advertising_init();
	conn_params_init();
	advertising_start();
	nrf_sdh_rtos_init();
	NRF_LOG_INFO("Debug logging for UART over RTT started.");
	bas_update_init();
}