/* Copyright (c) 2012 Nordic Semiconductor. All Rights Reserved.
 *
 * The information contained herein is property of Nordic Semiconductor ASA.
 * Terms and conditions of usage are described in detail in NORDIC
 * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
 *
 * Licensees are granted free, non-transferable use of the information. NO
 * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
 * the file.
 */

/* Attention! 
*  To maintain compliance with Nordic Semiconductor ASA’s Bluetooth profile 
*  qualification listings, this section of source code must not be modified.
*/

#include "ble_gls.h"
#include <string.h>
#include "ble_srv_common.h"
#include "ble_racp.h"
#include "ble_gls_db.h"


#define OPERAND_FILTER_TYPE_SEQ_NUM     0x01                                     /**< Filter data using Sequence Number criteria. */
#define OPERAND_FILTER_TYPE_FACING_TIME 0x02                                     /**< Filter data using User Facing Time criteria. */
#define OPERAND_FILTER_TYPE_RFU_START   0x07                                     /**< Start of filter types reserved For Future Use range */
#define OPERAND_FILTER_TYPE_RFU_END     0xFF                                     /**< End of filter types reserved For Future Use range */

#define OPCODE_LENGTH 1                                                          /**< Length of opcode inside Glucose Measurement packet. */
#define HANDLE_LENGTH 2                                                          /**< Length of handle inside Glucose Measurement packet. */
#define MAX_GLM_LEN   (BLE_L2CAP_MTU_DEF - OPCODE_LENGTH - HANDLE_LENGTH)        /**< Maximum size of a transmitted Glucose Measurement. */

#define GLS_NACK_PROC_ALREADY_IN_PROGRESS   BLE_GATT_STATUS_ATTERR_APP_BEGIN + 0 /**< Reply when a requested procedure is already in progress. */
#define GLS_NACK_CCCD_IMPROPERLY_CONFIGURED BLE_GATT_STATUS_ATTERR_APP_BEGIN + 1 /**< Reply when the a s CCCD is improperly configured. */

/**@brief Glucose Service communication state. */
typedef enum
{
    STATE_NO_COMM,                                                     /**< The service is not in a communicating state. */
    STATE_RACP_PROC_ACTIVE,                                            /**< Processing requested data. */
    STATE_RACP_RESPONSE_PENDING,                                       /**< There is a RACP indication waiting to be sent. */
    STATE_RACP_RESPONSE_IND_VERIF                                      /**< Waiting for a verification of a RACP indication. */
} gls_state_t;

static gls_state_t      m_gls_state;                                   /**< Current communication state. */
static uint16_t         m_next_seq_num;                                /**< Sequence number of the next database record. */
static uint8_t          m_racp_proc_operator;                          /**< Operator of current request. */
static uint16_t         m_racp_proc_seq_num;                           /**< Sequence number of current request. */
static uint8_t          m_racp_proc_record_ndx;                        /**< Current record index. */
static uint8_t          m_racp_proc_records_reported;                  /**< Number of reported records. */
static uint8_t          m_racp_proc_records_reported_since_txcomplete; /**< Number of reported records since last TX_COMPLETE event. */
static ble_racp_value_t m_pending_racp_response;                       /**< RACP response to be sent. */
static uint8_t          m_pending_racp_response_operand[2];            /**< Operand of RACP response to be sent. */


/**@brief Function for setting the GLS communication state.
 *
 * @param[in] new_state  New communication state.
 */
static void state_set(gls_state_t new_state)
{
    m_gls_state = new_state;
}


/**@brief Function for setting the next sequence number by reading the last record in the data base.
 *
 * @return NRF_SUCCESS on successful initialization of service, otherwise an error code.
 */
static uint32_t next_sequence_number_set(void)
{
    uint16_t      num_records;
    ble_gls_rec_t rec;

    num_records = ble_gls_db_num_records_get();
    if (num_records > 0)
    {
        // Get last record
        uint32_t err_code = ble_gls_db_record_get(num_records - 1, &rec);
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }
        m_next_seq_num = rec.meas.sequence_number + 1;
    }
    else
    {
        m_next_seq_num = 0;
    }

    return NRF_SUCCESS;
}


/**@brief Function for encoding a Glucose measurement.
 *
 * @param[in]  p_meas            Measurement to be encoded.
 * @param[out] p_encoded_buffer  Pointer to buffer where the encoded measurement is to be stored.
 *
 * @return Size of encoded measurement.
 */
static uint8_t gls_meas_encode(const ble_gls_meas_t * p_meas, uint8_t * p_encoded_buffer)
{
    uint8_t len = 0;

    p_encoded_buffer[len++] = p_meas->flags;

    len += uint16_encode(p_meas->sequence_number, &p_encoded_buffer[len]);
    len += ble_date_time_encode(&p_meas->base_time, &p_encoded_buffer[len]);

    if (p_meas->flags & BLE_GLS_MEAS_FLAG_TIME_OFFSET)
    {
        len += uint16_encode(p_meas->time_offset, &p_encoded_buffer[len]);
    }

    if (p_meas->flags & BLE_GLS_MEAS_FLAG_CONC_TYPE_LOC)
    {
        uint16_t encoded_concentration;

        encoded_concentration = ((p_meas->glucose_concentration.exponent << 12) & 0xF000) |
                                ((p_meas->glucose_concentration.mantissa <<  0) & 0x0FFF);

        p_encoded_buffer[len++] = (uint8_t)(encoded_concentration);
        p_encoded_buffer[len++] = (uint8_t)(encoded_concentration >> 8);
        p_encoded_buffer[len++] = (p_meas->sample_location << 4) | (p_meas->type & 0x0F);
    }

    if (p_meas->flags & BLE_GLS_MEAS_FLAG_SENSOR_STATUS)
    {
        len += uint16_encode(p_meas->sensor_status_annunciation, &p_encoded_buffer[len]);
    }

    return len;
}


/**@brief Function for adding the characteristic for a glucose measurement.
 *
 * @param[in] p_gls  Service instance.
 *
 * @return NRF_SUCCESS if characteristic was successfully added, otherwise an error code.
 */
static uint32_t glucose_measurement_char_add(ble_gls_t * p_gls)
{
    ble_gatts_char_md_t char_md;
    ble_gatts_attr_md_t cccd_md;
    ble_gatts_attr_t    attr_char_value;
    ble_uuid_t          ble_uuid;
    ble_gatts_attr_md_t attr_md;
    ble_gls_rec_t       initial_gls_rec_value;
    uint8_t             encoded_gls_meas[MAX_GLM_LEN];
    uint8_t             num_recs;
    memset(&cccd_md, 0, sizeof(cccd_md));

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&cccd_md.write_perm);
    cccd_md.vloc = BLE_GATTS_VLOC_STACK;

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

    char_md.char_props.notify = 1;
    char_md.p_char_user_desc  = NULL;
    char_md.p_char_pf         = NULL;
    char_md.p_user_desc_md    = NULL;
    char_md.p_cccd_md         = &cccd_md;
    char_md.p_sccd_md         = NULL;

    BLE_UUID_BLE_ASSIGN(ble_uuid, BLE_UUID_GLUCOSE_MEASUREMENT_CHAR);
    memset(&attr_md, 0, sizeof(attr_md));

    BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.write_perm);

    attr_md.vloc    = BLE_GATTS_VLOC_STACK;
    attr_md.rd_auth = 0;
    attr_md.wr_auth = 0;
    attr_md.vlen    = 1;

    memset(&attr_char_value, 0, sizeof(attr_char_value));
    memset(&initial_gls_rec_value, 0, sizeof(initial_gls_rec_value));

    num_recs = ble_gls_db_num_records_get();
    if (num_recs > 0)
    {
        uint32_t err_code = ble_gls_db_record_get(num_recs - 1, &initial_gls_rec_value);
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }
    }

    attr_char_value.p_uuid    = &ble_uuid;
    attr_char_value.p_attr_md = &attr_md;
    attr_char_value.init_len  = gls_meas_encode(&initial_gls_rec_value.meas, encoded_gls_meas);
    attr_char_value.init_offs = 0;
    attr_char_value.max_len   = MAX_GLM_LEN;
    attr_char_value.p_value   = encoded_gls_meas;

    return sd_ble_gatts_characteristic_add(p_gls->service_handle,
                                           &char_md,
                                           &attr_char_value,
                                           &p_gls->glm_handles);
}


/**@brief Function for adding the characteristic for a glucose feature.
 *
 * @param[in] p_gls  Service instance.
 *
 * @return NRF_SUCCESS if characteristic was successfully added, otherwise an error code.
 */
static uint32_t glucose_feature_char_add(ble_gls_t * p_gls)
{
    ble_gatts_char_md_t char_md;
    ble_gatts_attr_t    attr_char_value;
    ble_uuid_t          ble_uuid;
    ble_gatts_attr_md_t attr_md;
    uint8_t             encoded_initial_feature[2];

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

    char_md.char_props.read  = 1;    
    char_md.p_char_user_desc = NULL;
    char_md.p_char_pf        = NULL;
    char_md.p_user_desc_md   = NULL;
    char_md.p_cccd_md        = NULL;
    char_md.p_sccd_md        = NULL;

    BLE_UUID_BLE_ASSIGN(ble_uuid, BLE_UUID_GLUCOSE_FEATURE_CHAR);

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

    BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&attr_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.write_perm);

    attr_md.vloc    = BLE_GATTS_VLOC_STACK;
    attr_md.rd_auth = 0;
    attr_md.wr_auth = 0;
    attr_md.vlen    = 0;

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

    encoded_initial_feature[0] = (uint8_t)(p_gls->feature);
    encoded_initial_feature[1] = (uint8_t)((p_gls->feature) >> 8);

    attr_char_value.p_uuid    = &ble_uuid;
    attr_char_value.p_attr_md = &attr_md;
    attr_char_value.init_len  = sizeof (uint16_t);
    attr_char_value.init_offs = 0;
    attr_char_value.max_len   = sizeof (uint16_t);
    attr_char_value.p_value   = encoded_initial_feature;

    return sd_ble_gatts_characteristic_add(p_gls->service_handle,
                                           &char_md,
                                           &attr_char_value,
                                           &p_gls->glf_handles);
}


/**@brief Function for adding the characteristic for a record access control point.
 *
 * @param[in] p_gls  Service instance.
 *
 * @return NRF_SUCCESS if characteristic was successfully added, otherwise an error code.
 */
static uint32_t record_access_control_point_char_add(ble_gls_t * p_gls)
{
    ble_gatts_char_md_t char_md;
    ble_gatts_attr_md_t cccd_md;
    ble_gatts_attr_t    attr_char_value;
    ble_uuid_t          ble_uuid;
    ble_gatts_attr_md_t attr_md;

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

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&cccd_md.write_perm);
    cccd_md.vloc = BLE_GATTS_VLOC_STACK;

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

    char_md.char_props.indicate = 1;
    char_md.char_props.write    = 1;
    char_md.p_char_user_desc    = NULL;
    char_md.p_char_pf           = NULL;
    char_md.p_user_desc_md      = NULL;
    char_md.p_cccd_md           = &cccd_md;
    char_md.p_sccd_md           = NULL;

    BLE_UUID_BLE_ASSIGN(ble_uuid, BLE_UUID_RECORD_ACCESS_CONTROL_POINT_CHAR);

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

    BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&attr_md.write_perm);

    attr_md.vloc    = BLE_GATTS_VLOC_STACK;
    attr_md.rd_auth = 0;
    attr_md.wr_auth = 1;
    attr_md.vlen    = 1;
    
    memset(&attr_char_value, 0, sizeof(attr_char_value));
    
    attr_char_value.p_uuid    = &ble_uuid;
    attr_char_value.p_attr_md = &attr_md;
    attr_char_value.init_len  = 0;
    attr_char_value.init_offs = 0;
    attr_char_value.max_len   = BLE_L2CAP_MTU_DEF;
    attr_char_value.p_value   = 0;

    return sd_ble_gatts_characteristic_add(p_gls->service_handle,
                                           &char_md,
                                           &attr_char_value,
                                           &p_gls->racp_handles);
}


uint32_t ble_gls_init(ble_gls_t * p_gls, const ble_gls_init_t * p_gls_init)
{
    uint32_t   err_code;
    ble_uuid_t ble_uuid;

    // Initialize data base
    err_code = ble_gls_db_init();
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    err_code = next_sequence_number_set();
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    // Initialize service structure
    p_gls->evt_handler          = p_gls_init->evt_handler;
    p_gls->error_handler        = p_gls_init->error_handler;
    p_gls->feature              = p_gls_init->feature;
    p_gls->is_context_supported = p_gls_init->is_context_supported;
    p_gls->conn_handle          = BLE_CONN_HANDLE_INVALID;


    // Initialize global variables
    state_set(STATE_NO_COMM);
    m_racp_proc_records_reported_since_txcomplete = 0;

    // Add service
    BLE_UUID_BLE_ASSIGN(ble_uuid, BLE_UUID_GLUCOSE_SERVICE);

    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &ble_uuid, &p_gls->service_handle);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    // Add glucose measurement characteristic
    err_code = glucose_measurement_char_add(p_gls);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    // Add glucose measurement feature characteristic
    err_code = glucose_feature_char_add(p_gls);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    // Add record control access point characteristic
    err_code = record_access_control_point_char_add(p_gls);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    return NRF_SUCCESS;
}


/**@brief Function for sending a response from the Record Access Control Point.
 *
 * @param[in] p_gls       Service instance.
 * @param[in] p_racp_val  RACP value to be sent.
 */
static void racp_send(ble_gls_t * p_gls, ble_racp_value_t * p_racp_val)
{
    uint32_t               err_code;
    uint8_t                encoded_resp[25];
    uint8_t                len;
    uint16_t               hvx_len;
    ble_gatts_hvx_params_t hvx_params;

    if (
        (m_gls_state != STATE_RACP_RESPONSE_PENDING)
        &&
        (m_racp_proc_records_reported_since_txcomplete > 0)
       )
    {
        state_set(STATE_RACP_RESPONSE_PENDING);
        return;
    }

    // Send indication
    len     = ble_racp_encode(p_racp_val, encoded_resp);
    hvx_len = len;

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

    hvx_params.handle = p_gls->racp_handles.value_handle;
    hvx_params.type   = BLE_GATT_HVX_INDICATION;
    hvx_params.offset = 0;
    hvx_params.p_len  = &hvx_len;
    hvx_params.p_data = encoded_resp;

    err_code = sd_ble_gatts_hvx(p_gls->conn_handle, &hvx_params);

    // Error handling
    if ((err_code == NRF_SUCCESS) && (hvx_len != len))
    {
        err_code = NRF_ERROR_DATA_SIZE;
    }
    switch (err_code)
    {
        case NRF_SUCCESS:
            // Wait for HVC event
            state_set(STATE_RACP_RESPONSE_IND_VERIF);
            break;

        case BLE_ERROR_NO_TX_BUFFERS:
            // Wait for TX_COMPLETE event to retry transmission
            state_set(STATE_RACP_RESPONSE_PENDING);
            break;

        case NRF_ERROR_INVALID_STATE:
            // Make sure state machine returns to the default state
            state_set(STATE_NO_COMM);
            break;

        default:
            // Report error to application
            if (p_gls->error_handler != NULL)
            {
                p_gls->error_handler(err_code);
            }

            // Make sure state machine returns to the default state
            state_set(STATE_NO_COMM);
            break;
    }
}


/**@brief Function for sending a RACP response containing a Response Code Op Code and a Response Code Value.
 *
 * @param[in] p_gls   Service instance.
 * @param[in] opcode  RACP Op Code.
 * @param[in] value   RACP Response Code Value.
 */
static void racp_response_code_send(ble_gls_t * p_gls, uint8_t opcode, uint8_t value)
{
    m_pending_racp_response.opcode      = RACP_OPCODE_RESPONSE_CODE;
    m_pending_racp_response.operator    = RACP_OPERATOR_NULL;
    m_pending_racp_response.operand_len = 2;
    m_pending_racp_response.p_operand   = m_pending_racp_response_operand;

    m_pending_racp_response_operand[0] = opcode;
    m_pending_racp_response_operand[1] = value;

    racp_send(p_gls, &m_pending_racp_response);
}


/**@brief Function for sending a glucose measurement/context.
 *
 * @param[in] p_gls  Service instance.
 * @param[in] p_rec  Measurement to be sent.
 *
 * @return NRF_SUCCESS on success, otherwise an error code.
 */
static uint32_t glucose_meas_send(ble_gls_t * p_gls, ble_gls_rec_t * p_rec)
{
    uint32_t               err_code;
    uint8_t                encoded_glm[MAX_GLM_LEN];
    uint16_t               len;
    uint16_t               hvx_len;
    ble_gatts_hvx_params_t hvx_params;

    len     = gls_meas_encode(&p_rec->meas, encoded_glm);
    hvx_len = len;

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

    hvx_params.handle = p_gls->glm_handles.value_handle;
    hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
    hvx_params.offset = 0;
    hvx_params.p_len  = &hvx_len;
    hvx_params.p_data = encoded_glm;

    err_code = sd_ble_gatts_hvx(p_gls->conn_handle, &hvx_params);
    if (err_code == NRF_SUCCESS)
    {
        if (hvx_len != len)
        {
            err_code = NRF_ERROR_DATA_SIZE;
        }
        else
        {
            // Measurement successfully sent
            m_racp_proc_records_reported++;
            m_racp_proc_records_reported_since_txcomplete++;
        }
    }

    return err_code;
}


/**@brief Function for responding to the ALL operation.
 *
 * @param[in] p_gls  Service instance.
 *
 * @return NRF_SUCCESS on success, otherwise an error code.
 */
static uint32_t racp_report_records_all(ble_gls_t * p_gls)
{
    uint16_t total_records = ble_gls_db_num_records_get();

    if (m_racp_proc_record_ndx >= total_records)
    {
        state_set(STATE_NO_COMM);
    }
    else
    {
        uint32_t      err_code;
        ble_gls_rec_t rec;

        err_code = ble_gls_db_record_get(m_racp_proc_record_ndx, &rec);
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }

        err_code = glucose_meas_send(p_gls, &rec);
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }
    }

    return NRF_SUCCESS;
}


/**@brief Function for responding to the FIRST or the LAST operation.
 *
 * @param[in] p_gls  Service instance.
 *
 * @return  NRF_SUCCESS on success, otherwise an error code.
 */
static uint32_t racp_report_records_first_last(ble_gls_t * p_gls)
{
    uint32_t      err_code;
    ble_gls_rec_t rec;
    uint16_t      total_records;

    total_records = ble_gls_db_num_records_get();

    if ((m_racp_proc_records_reported != 0) || (total_records == 0))
    {
        state_set(STATE_NO_COMM);
    }
    else
    {
        if (m_racp_proc_operator == RACP_OPERATOR_FIRST)
        {
            err_code = ble_gls_db_record_get(0, &rec);
            if (err_code != NRF_SUCCESS)
            {
                return err_code;
            }
        }
        else if (m_racp_proc_operator == RACP_OPERATOR_LAST)
        {
            err_code = ble_gls_db_record_get(total_records - 1, &rec);
            if (err_code != NRF_SUCCESS)
            {
                return err_code;
            }
        }

        err_code = glucose_meas_send(p_gls, &rec);
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }
    }

    return NRF_SUCCESS;
}


/**@brief Function for responding to the GREATER_OR_EQUAL operation.
 *
 * @param[in] p_gls  Service instance.
 *
 * @return NRF_SUCCESS on success, otherwise an error code.
 */
static uint32_t racp_report_records_greater_or_equal(ble_gls_t * p_gls)
{
    uint16_t total_records = ble_gls_db_num_records_get();

    while (m_racp_proc_record_ndx < total_records)
    {
        uint32_t      err_code;
        ble_gls_rec_t rec;

        err_code = ble_gls_db_record_get(m_racp_proc_record_ndx, &rec);
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }

        if (rec.meas.sequence_number >= m_racp_proc_seq_num)
        {
            err_code = glucose_meas_send(p_gls, &rec);
            if (err_code != NRF_SUCCESS)
            {
                return err_code;
            }
            break;
        }
        m_racp_proc_record_ndx++;
    }
    if (m_racp_proc_record_ndx == total_records)
    {
        state_set(STATE_NO_COMM);
    }

    return NRF_SUCCESS;
}


/**@brief Function for informing that the REPORT RECORDS procedure is completed.
 *
 * @param[in] p_gls  Service instance.
 */
static void racp_report_records_completed(ble_gls_t * p_gls)
{
    uint8_t resp_code_value;

    if (m_racp_proc_records_reported > 0)
    {
        resp_code_value = RACP_RESPONSE_SUCCESS;
    }
    else
    {
        resp_code_value = RACP_RESPONSE_NO_RECORDS_FOUND;
    }

    racp_response_code_send(p_gls, RACP_OPCODE_REPORT_RECS, resp_code_value);
}


/**@brief Function for the RACP report records procedure.
 *
 * @param[in] p_gls  Service instance.
 */
static void racp_report_records_procedure(ble_gls_t * p_gls)
{
    uint32_t err_code;

    while (m_gls_state == STATE_RACP_PROC_ACTIVE)
    {
        // Execute requested procedure
        switch (m_racp_proc_operator)
        {
            case RACP_OPERATOR_ALL:
                err_code = racp_report_records_all(p_gls);
                break;

            case RACP_OPERATOR_FIRST:
            case RACP_OPERATOR_LAST:
                err_code = racp_report_records_first_last(p_gls);
                break;

            case RACP_OPERATOR_GREATER_OR_EQUAL:
                err_code = racp_report_records_greater_or_equal(p_gls);
                break;

            default:
                // Report error to application
                if (p_gls->error_handler != NULL)
                {
                    p_gls->error_handler(NRF_ERROR_INTERNAL);
                }

                // Make sure state machine returns to the default state
                state_set(STATE_NO_COMM);
                return;
        }

        // Error handling
        switch (err_code)
        {
            case NRF_SUCCESS:
                if (m_gls_state == STATE_RACP_PROC_ACTIVE)
                {
                    m_racp_proc_record_ndx++;
                }
                else
                {
                    racp_report_records_completed(p_gls);
                }
                break;

            case BLE_ERROR_NO_TX_BUFFERS:
                // Wait for TX_COMPLETE event to resume transmission
                return;

            case NRF_ERROR_INVALID_STATE:
                // Notification is probably not enabled. Ignore request.
                state_set(STATE_NO_COMM);
                return;

            default:
                // Report error to application
                if (p_gls->error_handler != NULL)
                {
                    p_gls->error_handler(err_code);
                }

                // Make sure state machine returns to the default state
                state_set(STATE_NO_COMM);
                return;
        }
    }
}


/**@brief Function for testing if the received request is to be executed.
 *
 * @param[in]  p_racp_request   Request to be checked.
 * @param[out] p_response_code  Response code to be sent in case the request is rejected.
 *                              RACP_RESPONSE_RESERVED is returned if the received message is
 *                              to be rejected without sending a response.
 *
 * @return TRUE if the request is to be executed, FALSE if it is to be rejected.
 *         If it is to be rejected, p_response_code will contain the response code to be
 *         returned to the central.
 */
static bool is_request_to_be_executed(const ble_racp_value_t * p_racp_request,
                                      uint8_t                * p_response_code)
{
    *p_response_code = RACP_RESPONSE_RESERVED;

    if (p_racp_request->opcode == RACP_OPCODE_ABORT_OPERATION)
    {
        if (m_gls_state == STATE_RACP_PROC_ACTIVE)
        {
            if (p_racp_request->operator != RACP_OPERATOR_NULL)
            {
                *p_response_code = RACP_RESPONSE_INVALID_OPERATOR;
            }
            else if (p_racp_request->operand_len != 0)
            {
                *p_response_code = RACP_RESPONSE_INVALID_OPERAND;
            }
            else
            {
                *p_response_code = RACP_RESPONSE_SUCCESS;
            }
        }
        else
        {
            *p_response_code = RACP_RESPONSE_ABORT_FAILED;
        }
    }
    else if (m_gls_state != STATE_NO_COMM)
    {
        return false;
    }
    // Supported opcodes.
    else if ((p_racp_request->opcode == RACP_OPCODE_REPORT_RECS) ||
             (p_racp_request->opcode == RACP_OPCODE_REPORT_NUM_RECS))
    {
        switch (p_racp_request->operator)
        {
            // Operators WITHOUT a filter.
            case RACP_OPERATOR_ALL:
            case RACP_OPERATOR_FIRST:
            case RACP_OPERATOR_LAST:
                if (p_racp_request->operand_len != 0)
                {
                    *p_response_code = RACP_RESPONSE_INVALID_OPERAND;
                }
                break;

            // Operators WITH a filter.
            case RACP_OPERATOR_GREATER_OR_EQUAL:
                if (p_racp_request->p_operand[0] == OPERAND_FILTER_TYPE_SEQ_NUM)
                {
                    if (p_racp_request->operand_len != 3)
                    {
                        *p_response_code = RACP_RESPONSE_INVALID_OPERAND;
                    }
                }
                else if (p_racp_request->p_operand[0] == OPERAND_FILTER_TYPE_FACING_TIME)
                {
                    *p_response_code = RACP_RESPONSE_OPERAND_UNSUPPORTED;
                }
                else if (p_racp_request->p_operand[0] >= OPERAND_FILTER_TYPE_RFU_START)
                {
                    *p_response_code = RACP_RESPONSE_OPERAND_UNSUPPORTED;
                }
                else
                {
                    *p_response_code = RACP_RESPONSE_INVALID_OPERAND;
                }
                break;

            // Unsupported operators.
            case RACP_OPERATOR_LESS_OR_EQUAL:
            case RACP_OPERATOR_RANGE:
                *p_response_code = RACP_RESPONSE_OPERATOR_UNSUPPORTED;
                 break;

            // Invalid operators.
            case RACP_OPERATOR_NULL:
            default:
                if (p_racp_request->operator >= RACP_OPERATOR_RFU_START)
                {
                    *p_response_code = RACP_RESPONSE_OPERATOR_UNSUPPORTED;
                }
                else
                {
                    *p_response_code = RACP_RESPONSE_INVALID_OPERATOR;
                }
                break;
        }
    }
    // Unsupported opcodes,
    else if (p_racp_request->opcode == RACP_OPCODE_DELETE_RECS)
    {
        *p_response_code = RACP_RESPONSE_OPCODE_UNSUPPORTED;
    }
    // Unknown opcodes.
    else
    {
        *p_response_code = RACP_RESPONSE_OPCODE_UNSUPPORTED;
    }

    // NOTE: The computation of the return value will change slightly when deferred write has been
    //       implemented in the stack.
    return (*p_response_code == RACP_RESPONSE_RESERVED);
}


/**@brief Function for processing a REPORT RECORDS request.
 *
 * @param[in] p_gls           Service instance.
 * @param[in] p_racp_request  Request to be executed.
 */
static void report_records_request_execute(ble_gls_t * p_gls, ble_racp_value_t * p_racp_request)
{
    uint16_t seq_num = (p_racp_request->p_operand[2] << 8) | p_racp_request->p_operand[1];

    state_set(STATE_RACP_PROC_ACTIVE);

    m_racp_proc_record_ndx       = 0;
    m_racp_proc_operator         = p_racp_request->operator;
    m_racp_proc_records_reported = 0;
    m_racp_proc_seq_num          = seq_num;

    racp_report_records_procedure(p_gls);
}


/**@brief Function for processing a REPORT NUM RECORDS request.
 *
 * @param[in] p_gls           Service instance.
 * @param[in] p_racp_request  Request to be executed.
 */
static void report_num_records_request_execute(ble_gls_t * p_gls, ble_racp_value_t * p_racp_request)
{
    uint16_t total_records;
    uint16_t num_records;

    total_records = ble_gls_db_num_records_get();
    num_records   = 0;

    if (p_racp_request->operator == RACP_OPERATOR_ALL)
    {
        num_records = total_records;
    }
    else if (p_racp_request->operator == RACP_OPERATOR_GREATER_OR_EQUAL)
    {
        uint16_t seq_num;
        uint16_t i;

        seq_num = (p_racp_request->p_operand[2] << 8) | p_racp_request->p_operand[1];

        for (i = 0; i < total_records; i++)
        {
            uint32_t      err_code;
            ble_gls_rec_t rec;

            err_code = ble_gls_db_record_get(i, &rec);
            if (err_code != NRF_SUCCESS)
            {
                if (p_gls->error_handler != NULL)
                {
                    p_gls->error_handler(err_code);
                }
                return;
            }

            if (rec.meas.sequence_number >= seq_num)
            {
                num_records++;
            }
        }
    }
    else if ((p_racp_request->operator == RACP_OPERATOR_FIRST) ||
             (p_racp_request->operator == RACP_OPERATOR_LAST))
    {
        if (total_records > 0)
        {
            num_records = 1;
        }
    }

    m_pending_racp_response.opcode      = RACP_OPCODE_NUM_RECS_RESPONSE;
    m_pending_racp_response.operator    = RACP_OPERATOR_NULL;
    m_pending_racp_response.operand_len = sizeof(uint16_t);
    m_pending_racp_response.p_operand   = m_pending_racp_response_operand;

    m_pending_racp_response_operand[0] = num_records & 0xFF;
    m_pending_racp_response_operand[1] = num_records >> 8;

    racp_send(p_gls, &m_pending_racp_response);
}


/**@brief Function for checking if the CCCDs are configured.
 *
 * @param[in] p_gls                  Service instance.
 * @param[in] p_are_cccd_configured  boolean indicating if both cccds are configured
 */
uint32_t ble_gls_are_cccd_configured(ble_gls_t * p_gls, bool * p_are_cccd_configured)
{
    uint32_t err_code;
    uint8_t  cccd_value_buf[BLE_CCCD_VALUE_LEN];
    bool     is_glm_notif_enabled  = false;
    bool     is_racp_indic_enabled = false;
    ble_gatts_value_t gatts_value;

    // Initialize value struct.
    memset(&gatts_value, 0, sizeof(gatts_value));

    gatts_value.len     = BLE_CCCD_VALUE_LEN;
    gatts_value.offset  = 0;
    gatts_value.p_value = cccd_value_buf;

    err_code = sd_ble_gatts_value_get(p_gls->conn_handle,
                                      p_gls->glm_handles.cccd_handle,
                                      &gatts_value);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    is_glm_notif_enabled = ble_srv_is_notification_enabled(cccd_value_buf);

    err_code = sd_ble_gatts_value_get(p_gls->conn_handle,
                                      p_gls->racp_handles.cccd_handle,
                                      &gatts_value);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    is_racp_indic_enabled = ble_srv_is_indication_enabled(cccd_value_buf);
    if (is_racp_indic_enabled & is_glm_notif_enabled)
    {
        *p_are_cccd_configured = true;
    }
    else
    {
        *p_are_cccd_configured = false;
    }
    return NRF_SUCCESS;
}


/**@brief Function for handling a write event to the Record Access Control Point.
 *
 * @param[in] p_gls        Service instance.
 * @param[in] p_evt_write  WRITE event to be handled.
 */
static void on_racp_value_write(ble_gls_t * p_gls, ble_gatts_evt_write_t * p_evt_write)
{
    ble_racp_value_t                      racp_request;
    uint8_t                               response_code;
    ble_gatts_rw_authorize_reply_params_t auth_reply;
    bool                                  are_cccd_configured;
    uint32_t                              err_code;

    auth_reply.type = BLE_GATTS_AUTHORIZE_TYPE_WRITE;

    err_code = ble_gls_are_cccd_configured(p_gls, &are_cccd_configured);
    if (err_code != NRF_SUCCESS)
    {
        if (p_gls->error_handler != NULL)
        {
            p_gls->error_handler(err_code);
        }
        return;
    }

    if (!are_cccd_configured)
    {
        auth_reply.params.write.gatt_status = GLS_NACK_CCCD_IMPROPERLY_CONFIGURED;
        err_code                            = sd_ble_gatts_rw_authorize_reply(p_gls->conn_handle,
                                                                              &auth_reply);

        if (err_code != NRF_SUCCESS)
        {
            if (p_gls->error_handler != NULL)
            {
                p_gls->error_handler(err_code);
            }
        }
        return;
    }

    // Decode request.
    ble_racp_decode(p_evt_write->len, p_evt_write->data, &racp_request);

    // Check if request is to be executed.
    if (is_request_to_be_executed(&racp_request, &response_code))
    {
        auth_reply.params.write.gatt_status = BLE_GATT_STATUS_SUCCESS;
        err_code                            = sd_ble_gatts_rw_authorize_reply(p_gls->conn_handle,
                                                                              &auth_reply);

        if (err_code != NRF_SUCCESS)
        {
            if (p_gls->error_handler != NULL)
            {
                p_gls->error_handler(err_code);
            }
            return;
        }
        // Execute request.
        if (racp_request.opcode == RACP_OPCODE_REPORT_RECS)
        {
            report_records_request_execute(p_gls, &racp_request);
        }
        else if (racp_request.opcode == RACP_OPCODE_REPORT_NUM_RECS)
        {
            report_num_records_request_execute(p_gls, &racp_request);
        }
    }
    else if (response_code != RACP_RESPONSE_RESERVED)
    {
        auth_reply.params.write.gatt_status = BLE_GATT_STATUS_SUCCESS;
        err_code                            = sd_ble_gatts_rw_authorize_reply(p_gls->conn_handle,
                                                                              &auth_reply);

        if (err_code != NRF_SUCCESS)
        {
            if (p_gls->error_handler != NULL)
            {
                p_gls->error_handler(err_code);
            }
            return;
        }

        // Abort any running procedure.
        state_set(STATE_NO_COMM);

        // Respond with error code.
        racp_response_code_send(p_gls, racp_request.opcode, response_code);
    }
    else
    {
        auth_reply.params.write.gatt_status = GLS_NACK_PROC_ALREADY_IN_PROGRESS;
        err_code                            = sd_ble_gatts_rw_authorize_reply(p_gls->conn_handle,
                                                                              &auth_reply);

        if (err_code != NRF_SUCCESS)
        {
            if (p_gls->error_handler != NULL)
            {
                p_gls->error_handler(err_code);
            }
            return;
        }
    }
}


/**@brief Function for handling the Glucose measurement CCCD write event.
 *
 * @param[in] p_gls        Service instance.
 * @param[in] p_evt_write  WRITE event to be handled.
 */
static void on_glm_cccd_write(ble_gls_t * p_gls, ble_gatts_evt_write_t * p_evt_write)
{
    if (p_evt_write->len == 2)
    {
        // CCCD written, update notification state
        ble_gls_evt_t evt;

        if (ble_srv_is_notification_enabled(p_evt_write->data))
        {
            evt.evt_type = BLE_GLS_EVT_NOTIFICATION_ENABLED;
        }
        else
        {
            evt.evt_type = BLE_GLS_EVT_NOTIFICATION_DISABLED;
        }

        if (p_gls->evt_handler != NULL)
        {
            p_gls->evt_handler(p_gls, &evt);
        }
    }
}


/**@brief Function for handling the WRITE event.
 *
 * @details Handles WRITE events from the BLE stack.
 *
 * @param[in] p_gls      Glucose Service structure.
 * @param[in] p_ble_evt  Event received from the BLE stack.
 */
static void on_write(ble_gls_t * p_gls, ble_evt_t * p_ble_evt)
{
    ble_gatts_evt_write_t * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;

    if (p_evt_write->handle == p_gls->glm_handles.cccd_handle)
    {
        on_glm_cccd_write(p_gls, p_evt_write);
    }
    else if (p_evt_write->handle == p_gls->racp_handles.value_handle)
    {
        on_racp_value_write(p_gls, p_evt_write);
    }
}


/**@brief Function for handling the TX_COMPLETE event.
 *
 * @details Handles TX_COMPLETE events from the BLE stack.
 *
 * @param[in] p_gls      Glucose Service structure.
 * @param[in] p_ble_evt  Event received from the BLE stack.
 */
static void on_tx_complete(ble_gls_t * p_gls, ble_evt_t * p_ble_evt)
{
    m_racp_proc_records_reported_since_txcomplete = 0;

    if (m_gls_state == STATE_RACP_RESPONSE_PENDING)
    {
        racp_send(p_gls, &m_pending_racp_response);
    }
    else if (m_gls_state == STATE_RACP_PROC_ACTIVE)
    {
        racp_report_records_procedure(p_gls);
    }
}


/**@brief Function for handling the HVC event.
 *
 * @details Handles HVC events from the BLE stack.
 *
 * @param[in] p_gls      Glucose Service structure.
 * @param[in] p_ble_evt  Event received from the BLE stack.
 */
static void on_hvc(ble_gls_t * p_gls, ble_evt_t * p_ble_evt)
{
    ble_gatts_evt_hvc_t * p_hvc = &p_ble_evt->evt.gatts_evt.params.hvc;

    if (p_hvc->handle == p_gls->racp_handles.value_handle)
    {
        if (m_gls_state == STATE_RACP_RESPONSE_IND_VERIF)
        {
            // Indication has been acknowledged. Return to default state.
            state_set(STATE_NO_COMM);
        }
        else
        {
            // We did not expect this event in this state. Report error to application.
            if (p_gls->error_handler != NULL)
            {
                p_gls->error_handler(NRF_ERROR_INVALID_STATE);
            }
        }
    }
}


static void on_rw_authorize_request(ble_gls_t * p_gls, ble_gatts_evt_t * p_gatts_evt)
{
    ble_gatts_evt_rw_authorize_request_t * p_auth_req = &p_gatts_evt->params.authorize_request;
    if (p_auth_req->type == BLE_GATTS_AUTHORIZE_TYPE_WRITE)
    {
        if (   (p_gatts_evt->params.authorize_request.request.write.op
                != BLE_GATTS_OP_PREP_WRITE_REQ)
            && (p_gatts_evt->params.authorize_request.request.write.op
                != BLE_GATTS_OP_EXEC_WRITE_REQ_NOW)
            && (p_gatts_evt->params.authorize_request.request.write.op
                != BLE_GATTS_OP_EXEC_WRITE_REQ_CANCEL)
           )
        {
            if (p_auth_req->request.write.handle == p_gls->racp_handles.value_handle)
            {
                on_racp_value_write(p_gls, &p_auth_req->request.write);
            }
        }
    }
}

void ble_gls_on_ble_evt(ble_gls_t * p_gls, ble_evt_t * p_ble_evt)
{
    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            p_gls->conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
            state_set(STATE_NO_COMM);
            break;

        case BLE_GAP_EVT_DISCONNECTED:
            p_gls->conn_handle = BLE_CONN_HANDLE_INVALID;
            break;

        case BLE_GATTS_EVT_WRITE:
            on_write(p_gls, p_ble_evt);
            break;

        case BLE_EVT_TX_COMPLETE:
            on_tx_complete(p_gls, p_ble_evt);
            break;

        case BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST:
            on_rw_authorize_request(p_gls, &p_ble_evt->evt.gatts_evt);
            break;

        case BLE_GATTS_EVT_HVC:
            on_hvc(p_gls, p_ble_evt);
            break;

        default:
            // No implementation needed.
            break;
    }
}


uint32_t ble_gls_glucose_new_meas(ble_gls_t * p_gls, ble_gls_rec_t * p_rec)
{
    p_rec->meas.sequence_number = m_next_seq_num++;
    return ble_gls_db_record_add(p_rec);
}
