text: /**
   * Copyright (c) 2012 - 2021, Nordic Semiconductor ASA
   *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without modification,
   * are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form, except as embedded into a Nordic
   *    Semiconductor ASA integrated circuit in a product or a software update for
   *    such product, must reproduce the above copyright notice, this list of
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   *
   * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
   *    contributors may be used to endorse or promote products derived from this
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   *
   * 4. This software, with or without modification, must only be used with a
   *    Nordic Semiconductor ASA integrated circuit.
   *
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   *    engineered, decompiled, modified and/or disassembled.
   *
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   */
  /* Attention!
   * To maintain compliance with Nordic Semiconductor ASA's Bluetooth profile
   * qualification listings, this section of source code must not be modified.
   */
  #include "sdk_common.h"
  #if NRF_MODULE_ENABLED(BLE_HRS)
  #include "ble_hrs.h"
  #include <string.h>
  #include "ble_srv_common.h"
  
  
  #define OPCODE_LENGTH 1                                                              /**< Length of opcode inside Heart Rate Measurement packet. */
  #define HANDLE_LENGTH 2                                                              /**< Length of handle inside Heart Rate Measurement packet. */
  #define MAX_HRM_LEN      (NRF_SDH_BLE_GATT_MAX_MTU_SIZE - OPCODE_LENGTH - HANDLE_LENGTH) /**< Maximum size of a transmitted Heart Rate Measurement. */
  
  #define INITIAL_VALUE_HRM                       0                                    /**< Initial Heart Rate Measurement value. */
  
  // Heart Rate Measurement flag bits
  #define HRM_FLAG_MASK_HR_VALUE_16BIT            (0x01 << 0)                           /**< Heart Rate Value Format bit. */
  #define HRM_FLAG_MASK_SENSOR_CONTACT_DETECTED   (0x01 << 1)                           /**< Sensor Contact Detected bit. */
  #define HRM_FLAG_MASK_SENSOR_CONTACT_SUPPORTED  (0x01 << 2)                           /**< Sensor Contact Supported bit. */
  #define HRM_FLAG_MASK_EXPENDED_ENERGY_INCLUDED  (0x01 << 3)                           /**< Energy Expended Status bit. Feature Not Supported */
  #define HRM_FLAG_MASK_RR_INTERVAL_INCLUDED      (0x01 << 4)                           /**< RR-Interval bit. */
  
  
  /**@brief Function for handling the Connect event.
   *
   * @param[in]   p_hrs       Heart Rate Service structure.
   * @param[in]   p_ble_evt   Event received from the BLE stack.
   */
  static void on_connect(ble_hrs_t * p_hrs, ble_evt_t const * p_ble_evt)
  {
      p_hrs->conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
  }
  
  
  /**@brief Function for handling the Disconnect event.
   *
   * @param[in]   p_hrs       Heart Rate Service structure.
   * @param[in]   p_ble_evt   Event received from the BLE stack.
   */
  static void on_disconnect(ble_hrs_t * p_hrs, ble_evt_t const * p_ble_evt)
  {
      UNUSED_PARAMETER(p_ble_evt);
      p_hrs->conn_handle = BLE_CONN_HANDLE_INVALID;
  }
  
  
  /**@brief Function for handling write events to the Heart Rate Measurement characteristic.
   *
   * @param[in]   p_hrs         Heart Rate Service structure.
   * @param[in]   p_evt_write   Write event received from the BLE stack.
   */
  static void on_hrm_cccd_write(ble_hrs_t * p_hrs, ble_gatts_evt_write_t const * p_evt_write)
  {
      if (p_evt_write->len == 2)
      {
          // CCCD written, update notification state
          if (p_hrs->evt_handler != NULL)
          {
              ble_hrs_evt_t evt;
  
              if (ble_srv_is_notification_enabled(p_evt_write->data))
              {
                  evt.evt_type = BLE_HRS_EVT_NOTIFICATION_ENABLED;
              }
              else
              {
                  evt.evt_type = BLE_HRS_EVT_NOTIFICATION_DISABLED;
              }
  
              p_hrs->evt_handler(p_hrs, &evt);
          }
      }
  }
  
  
  /**@brief Function for handling the Write event.
   *
   * @param[in]   p_hrs       Heart Rate Service structure.
   * @param[in]   p_ble_evt   Event received from the BLE stack.
   */
  static void on_write(ble_hrs_t * p_hrs, ble_evt_t const * p_ble_evt)
  {
      ble_gatts_evt_write_t const * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
  
      if (p_evt_write->handle == p_hrs->hrm_handles.cccd_handle)
      {
          on_hrm_cccd_write(p_hrs, p_evt_write);
      }
  }
  
  
  void ble_hrs_on_ble_evt(ble_evt_t const * p_ble_evt, void * p_context)
  {
      ble_hrs_t * p_hrs = (ble_hrs_t *) p_context;
  
      switch (p_ble_evt->header.evt_id)
      {
          case BLE_GAP_EVT_CONNECTED:
              on_connect(p_hrs, p_ble_evt);
              break;
  
          case BLE_GAP_EVT_DISCONNECTED:
              on_disconnect(p_hrs, p_ble_evt);
              break;
  
          case BLE_GATTS_EVT_WRITE:
              on_write(p_hrs, p_ble_evt);
              break;
  
          default:
              // No implementation needed.
              break;
      }
  }
  
  
  /**@brief Function for encoding a Heart Rate Measurement.
   *
   * @param[in]   p_hrs              Heart Rate Service structure.
   * @param[in]   heart_rate         Measurement to be encoded.
   * @param[out]  p_encoded_buffer   Buffer where the encoded data will be written.
   *
   * @return      Size of encoded data.
   */
  static uint8_t hrm_encode(ble_hrs_t * p_hrs, uint16_t heart_rate, uint8_t * p_encoded_buffer)
  {
      uint8_t flags = 0;
      uint8_t len   = 1;
      int     i;
  
      // Set sensor contact related flags
      if (p_hrs->is_sensor_contact_supported)
      {
          flags |= HRM_FLAG_MASK_SENSOR_CONTACT_SUPPORTED;
      }
      if (p_hrs->is_sensor_contact_detected)
      {
          flags |= HRM_FLAG_MASK_SENSOR_CONTACT_DETECTED;
      }
  
      // Encode heart rate measurement
      if (heart_rate > 0xff)
      {
          flags |= HRM_FLAG_MASK_HR_VALUE_16BIT;
          len   += uint16_encode(heart_rate, &p_encoded_buffer[len]);
      }
      else
      {
          p_encoded_buffer[len++] = (uint8_t)heart_rate;
      }
  
      // Encode rr_interval values
      if (p_hrs->rr_interval_count > 0)
      {
          flags |= HRM_FLAG_MASK_RR_INTERVAL_INCLUDED;
      }
      for (i = 0; i < p_hrs->rr_interval_count; i++)
      {
          if (len + sizeof(uint16_t) > p_hrs->max_hrm_len)
          {
              // Not all stored rr_interval values can fit into the encoded hrm,
              // move the remaining values to the start of the buffer.
              memmove(&p_hrs->rr_interval[0],
                      &p_hrs->rr_interval[i],
                      (p_hrs->rr_interval_count - i) * sizeof(uint16_t));
              break;
          }
          len += uint16_encode(p_hrs->rr_interval[i], &p_encoded_buffer[len]);
      }
      p_hrs->rr_interval_count -= i;
  
      // Add flags
      p_encoded_buffer[0] = flags;
  
      return len;
  }
  
  
  uint32_t ble_hrs_init(ble_hrs_t * p_hrs, const ble_hrs_init_t * p_hrs_init)
  {
      uint32_t              err_code;
      ble_uuid_t            ble_uuid;
      ble_add_char_params_t add_char_params;
      uint8_t               encoded_initial_hrm[MAX_HRM_LEN];
  
      // Initialize service structure
      p_hrs->evt_handler                 = p_hrs_init->evt_handler;
      p_hrs->is_sensor_contact_supported = p_hrs_init->is_sensor_contact_supported;
      p_hrs->conn_handle                 = BLE_CONN_HANDLE_INVALID;
      p_hrs->is_sensor_contact_detected  = false;
      p_hrs->rr_interval_count           = 0;
      p_hrs->max_hrm_len                 = MAX_HRM_LEN;
  
      // Add service
      BLE_UUID_BLE_ASSIGN(ble_uuid, BLE_UUID_HEART_RATE_SERVICE);
  
      err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
                                          &ble_uuid,
                                          &p_hrs->service_handle);
  
      if (err_code != NRF_SUCCESS)
      {
          return err_code;
      }
  
      // Add heart rate measurement characteristic
      memset(&add_char_params, 0, sizeof(add_char_params));
  
      add_char_params.uuid              = BLE_UUID_HEART_RATE_MEASUREMENT_CHAR;
      add_char_params.max_len           = MAX_HRM_LEN;
      add_char_params.init_len          = hrm_encode(p_hrs, INITIAL_VALUE_HRM, encoded_initial_hrm);
      add_char_params.p_init_value      = encoded_initial_hrm;
      add_char_params.is_var_len        = true;
      add_char_params.char_props.notify = 1;
      add_char_params.cccd_write_access = p_hrs_init->hrm_cccd_wr_sec;
  
      err_code = characteristic_add(p_hrs->service_handle, &add_char_params, &(p_hrs->hrm_handles));
      if (err_code != NRF_SUCCESS)
      {
          return err_code;
      }
  
      if (p_hrs_init->p_body_sensor_location != NULL)
      {
          // Add body sensor location characteristic
          memset(&add_char_params, 0, sizeof(add_char_params));
  
          add_char_params.uuid            = BLE_UUID_BODY_SENSOR_LOCATION_CHAR;
          add_char_params.max_len         = sizeof(uint8_t);
          add_char_params.init_len        = sizeof(uint8_t);
          add_char_params.p_init_value    = p_hrs_init->p_body_sensor_location;
          add_char_params.char_props.read = 1;
          add_char_params.read_access     = p_hrs_init->bsl_rd_sec;
  
          err_code = characteristic_add(p_hrs->service_handle, &add_char_params, &(p_hrs->bsl_handles));
          if (err_code != NRF_SUCCESS)
          {
              return err_code;
          }
      }
  
      return NRF_SUCCESS;
  }
  
  
  uint32_t ble_hrs_heart_rate_measurement_send(ble_hrs_t * p_hrs, uint16_t heart_rate)
  {
      uint32_t err_code;
  
      // Send value if connected and notifying
      if (p_hrs->conn_handle != BLE_CONN_HANDLE_INVALID)
      {
          uint8_t                encoded_hrm[MAX_HRM_LEN];
          uint16_t               len;
          uint16_t               hvx_len;
          ble_gatts_hvx_params_t hvx_params;
  
          len     = hrm_encode(p_hrs, heart_rate, encoded_hrm);
          hvx_len = len;
  
          memset(&hvx_params, 0, sizeof(hvx_params));
  
          hvx_params.handle = p_hrs->hrm_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_hrm;
  
          err_code = sd_ble_gatts_hvx(p_hrs->conn_handle, &hvx_params);
          if ((err_code == NRF_SUCCESS) && (hvx_len != len))
          {
              err_code = NRF_ERROR_DATA_SIZE;
          }
      }
      else
      {
          err_code = NRF_ERROR_INVALID_STATE;
      }
  
      return err_code;
  }
  
  
  void ble_hrs_rr_interval_add(ble_hrs_t * p_hrs, uint16_t rr_interval)
  {
      if (p_hrs->rr_interval_count == BLE_HRS_MAX_BUFFERED_RR_INTERVALS)
      {
          // The rr_interval buffer is full, delete the oldest value
          memmove(&p_hrs->rr_interval[0],
                  &p_hrs->rr_interval[1],
                  (BLE_HRS_MAX_BUFFERED_RR_INTERVALS - 1) * sizeof(uint16_t));
          p_hrs->rr_interval_count--;
      }
  
      // Add new value
      p_hrs->rr_interval[p_hrs->rr_interval_count++] = rr_interval;
  }
  
  
  bool ble_hrs_rr_interval_buffer_is_full(ble_hrs_t * p_hrs)
  {
      return (p_hrs->rr_interval_count == BLE_HRS_MAX_BUFFERED_RR_INTERVALS);
  }
  
  
  uint32_t ble_hrs_sensor_contact_supported_set(ble_hrs_t * p_hrs, bool is_sensor_contact_supported)
  {
      // Check if we are connected to peer
      if (p_hrs->conn_handle == BLE_CONN_HANDLE_INVALID)
      {
          p_hrs->is_sensor_contact_supported = is_sensor_contact_supported;
          return NRF_SUCCESS;
      }
      else
      {
          return NRF_ERROR_INVALID_STATE;
      }
  }
  
  
  void ble_hrs_sensor_contact_detected_update(ble_hrs_t * p_hrs, bool is_sensor_contact_detected)
  {
      p_hrs->is_sensor_contact_detected = is_sensor_contact_detected;
  }
  
  
  uint32_t ble_hrs_body_sensor_location_set(ble_hrs_t * p_hrs, uint8_t body_sensor_location)
  {
      ble_gatts_value_t gatts_value;
  
      // Initialize value struct.
      memset(&gatts_value, 0, sizeof(gatts_value));
  
      gatts_value.len     = sizeof(uint8_t);
      gatts_value.offset  = 0;
      gatts_value.p_value = &body_sensor_location;
  
      return sd_ble_gatts_value_set(p_hrs->conn_handle, p_hrs->bsl_handles.value_handle, &gatts_value);
  }
  
  
  void ble_hrs_on_gatt_evt(ble_hrs_t * p_hrs, nrf_ble_gatt_evt_t const * p_gatt_evt)
  {
      if (    (p_hrs->conn_handle == p_gatt_evt->conn_handle)
          &&  (p_gatt_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
      {
          p_hrs->max_hrm_len = p_gatt_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
      }
  }
  #endif // NRF_MODULE_ENABLED(BLE_HRS)
  