/**@brief     Function for handling characteristic discovery response.
 *
 * @param[in] p_db_discovery    Pointer to the DB Discovery structure.
 * @param[in] p_ble_gattc_evt   Pointer to the GATT Client event.
 */
static void on_characteristic_discovery_rsp(ble_db_discovery_t       * p_db_discovery,
                                            ble_gattc_evt_t    const * p_ble_gattc_evt)
{
    uint32_t            err_code;
    ble_gatt_db_srv_t * p_srv_being_discovered;
    bool                perform_desc_discov = false;

    if (p_ble_gattc_evt->conn_handle != p_db_discovery->conn_handle)
    {
        return;
    }

    p_srv_being_discovered = &(p_db_discovery->services[p_db_discovery->curr_srv_ind]);

    if (p_ble_gattc_evt->gatt_status == BLE_GATT_STATUS_SUCCESS)
    {
        ble_gattc_evt_char_disc_rsp_t const * p_char_disc_rsp_evt;

        p_char_disc_rsp_evt = &(p_ble_gattc_evt->params.char_disc_rsp);

        // Find out the number of characteristics that were previously discovered (in earlier
        // characteristic discovery responses, if any).
        uint8_t num_chars_prev_disc = p_srv_being_discovered->char_count;

        // Find out the number of characteristics that are currently discovered (in the
        // characteristic discovery response being handled).
        uint8_t num_chars_curr_disc = p_char_disc_rsp_evt->count;

        // Check if the total number of discovered characteristics are supported by this module.
        if ((num_chars_prev_disc + num_chars_curr_disc) <= BLE_GATT_DB_MAX_CHARS)
        {
            // Update the characteristics count.
            p_srv_being_discovered->char_count += num_chars_curr_disc;
            NRF_LOG_WARNING("%s(): Update the characteristics count = %d.", __FUNCTION__, p_srv_being_discovered->char_count)
        }
        else
        {
            // The number of characteristics discovered at the peer is more than the supported
            // maximum. This module will store only the characteristics found up to this point.
            p_srv_being_discovered->char_count = BLE_GATT_DB_MAX_CHARS;
            NRF_LOG_WARNING("Not enough space for characteristics associated with "
                            "service 0x%04X !", p_srv_being_discovered->srv_uuid.uuid);
            NRF_LOG_WARNING("Increase BLE_GATT_DB_MAX_CHARS to be able to store more "
                            "characteristics for each service!");
        }

        uint32_t i;
        uint32_t j;

        for (i = num_chars_prev_disc, j = 0; i < p_srv_being_discovered->char_count; i++, j++)
        {
            NRF_LOG_WARNING("%s (): char[%d] UUID: 0x%04X.", __FUNCTION__, i, p_ble_gattc_evt->params.char_disc_rsp.chars[j].uuid.uuid);
            p_srv_being_discovered->charateristics[i].characteristic =
                p_char_disc_rsp_evt->chars[j];

            p_srv_being_discovered->charateristics[i].cccd_handle       = BLE_GATT_HANDLE_INVALID;
            p_srv_being_discovered->charateristics[i].ext_prop_handle   = BLE_GATT_HANDLE_INVALID;
            p_srv_being_discovered->charateristics[i].user_desc_handle  = BLE_GATT_HANDLE_INVALID;
            p_srv_being_discovered->charateristics[i].report_ref_handle = BLE_GATT_HANDLE_INVALID;
        }

        ble_gattc_char_t * p_last_known_char;

        p_last_known_char = &(p_srv_being_discovered->charateristics[i - 1].characteristic);

        // If no more characteristic discovery is required, or if the maximum number of supported
        // characteristic per service has been reached, descriptor discovery will be performed.
        if (   !is_char_discovery_reqd(p_db_discovery, p_last_known_char)
            || (p_srv_being_discovered->char_count == BLE_GATT_DB_MAX_CHARS))
        {
            perform_desc_discov = true;
        }
        else
        {
            // Update the current characteristic index.
            p_db_discovery->curr_char_ind = p_srv_being_discovered->char_count;

            // Perform another round of characteristic discovery.
            err_code = characteristics_discover(p_db_discovery, p_ble_gattc_evt->conn_handle);

            if (err_code != NRF_SUCCESS)
            {
                p_db_discovery->discovery_in_progress = false;

                discovery_error_evt_trigger(p_db_discovery, err_code, p_ble_gattc_evt->conn_handle);

                m_pending_user_evts[0].evt.evt_type    = BLE_DB_DISCOVERY_AVAILABLE;
                m_pending_user_evts[0].evt.conn_handle = p_ble_gattc_evt->conn_handle;

                return;
            }
        }
    }
    else
    {
        // The previous characteristic discovery resulted in no characteristics.
        // descriptor discovery should be performed.
        perform_desc_discov = true;
    }

    if (perform_desc_discov)
    {
        bool raise_discov_complete;

        p_db_discovery->curr_char_ind = 0;

        err_code = descriptors_discover(p_db_discovery,
                                        &raise_discov_complete,
                                        p_ble_gattc_evt->conn_handle);

        if (err_code != NRF_SUCCESS)
        {
            p_db_discovery->discovery_in_progress = false;

            discovery_error_evt_trigger(p_db_discovery, err_code, p_ble_gattc_evt->conn_handle);

            m_pending_user_evts[0].evt.evt_type    = BLE_DB_DISCOVERY_AVAILABLE;
            m_pending_user_evts[0].evt.conn_handle = p_ble_gattc_evt->conn_handle;

            return;
        }
        if (raise_discov_complete)
        {
            // No more characteristics and descriptors need to be discovered. Discovery is complete.
            // Send a discovery complete event to the user application.
            NRF_LOG_DEBUG("Discovery of service with UUID 0x%x completed with success"
                          " on connection handle 0x%x.",
                          p_srv_being_discovered->srv_uuid.uuid,
                          p_ble_gattc_evt->conn_handle);

            discovery_complete_evt_trigger(p_db_discovery, true, p_ble_gattc_evt->conn_handle);
            on_srv_disc_completion(p_db_discovery, p_ble_gattc_evt->conn_handle);
        }
    }
}