#define BTSTACK_FILE__ "gatt_heart_rate_client.c"

#include <inttypes.h>

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "btstack.h"

static void handle_gatt_client_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);

static void gatt_heart_rate_client_request_to_send(void);

typedef enum {

APP_STATE_IDLE,

APP_STATE_W4_SCAN_RESULT,

APP_STATE_W4_CONNECT,

APP_STATE_W2_QUERY_SERVICE,

APP_STATE_W4_SERVICE_RESULT,

APP_STATE_W2_QUERY_HEART_RATE_MEASUREMENT_CHARACTERISTIC,

APP_STATE_W4_HEART_RATE_MEASUREMENT_CHARACTERISTIC,

APP_STATE_W2_ENABLE_NOTIFICATIONS,

APP_STATE_W4_ENABLE_NOTIFICATIONS_COMPLETE,

APP_STATE_W2_QUERY_SENSOR_LOCATION_CHARACTERISTIC,

APP_STATE_W4_SENSOR_LOCATION_CHARACTERISTIC,

APP_STATE_W2_QUERY_SENSOR_LOCATION,

APP_STATE_W4_SENSOR_LOCATION,

APP_STATE_CONNECTED

} app_state_t;

static const char * sensor_contact_string[] = {

"not supported",

"not supported",

"no/poor contact",

"good contact"

};

static bd_addr_t cmdline_addr;

static int cmdline_addr_found = 0;

static bd_addr_t le_streamer_addr;

static bd_addr_type_t le_streamer_addr_type;

static hci_con_handle_t connection_handle;

static btstack_context_callback_registration_t heart_rate_service_gatt_query_request;

static gatt_client_service_t heart_rate_service;

static gatt_client_characteristic_t body_sensor_location_characteristic;

static gatt_client_characteristic_t heart_rate_measurement_characteristic;

static uint8_t body_sensor_location;

static gatt_client_notification_t notification_listener;

static int listener_registered;

static app_state_t state = APP_STATE_IDLE;

static btstack_packet_callback_registration_t hci_event_callback_registration;

static int advertisement_report_contains_uuid16(uint16_t uuid16, uint8_t * advertisement_report){

// get advertisement from report event

const uint8_t * adv_data = gap_event_advertising_report_get_data(advertisement_report);

uint8_t adv_len = gap_event_advertising_report_get_data_length(advertisement_report);

// iterate over advertisement data

ad_context_t context;

int found = 0;

for (ad_iterator_init(&context, adv_len, adv_data) ; ad_iterator_has_more(&context) ; ad_iterator_next(&context)){

uint8_t data_type = ad_iterator_get_data_type(&context);

uint8_t data_size = ad_iterator_get_data_len(&context);

const uint8_t * data = ad_iterator_get_data(&context);

int i;

switch (data_type){

case BLUETOOTH_DATA_TYPE_INCOMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS:

case BLUETOOTH_DATA_TYPE_COMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS:

// compare common prefix

for (i=0; i<data_size;i+=2){

if (little_endian_read_16(data, i) == uuid16) {

found = 1;

break;

}

}

break;

default:

break;

}

}

return found;

}

static void handle_gatt_client_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){

UNUSED(packet_type);

UNUSED(channel);

UNUSED(size);

uint16_t heart_rate;

uint8_t sensor_contact;

uint8_t att_status;

switch(state){

case APP_STATE_W4_SERVICE_RESULT:

switch(hci_event_packet_get_type(packet)){

case GATT_EVENT_SERVICE_QUERY_RESULT:

// store service (we expect only one)

gatt_event_service_query_result_get_service(packet, &heart_rate_service);

break;

case GATT_EVENT_QUERY_COMPLETE:

att_status = gatt_event_query_complete_get_att_status(packet);

if (att_status != ATT_ERROR_SUCCESS){

printf("SERVICE_QUERY_RESULT - ATT Error 0x%02x.\n", att_status);

gap_disconnect(connection_handle);

break;

}

state = APP_STATE_W2_QUERY_HEART_RATE_MEASUREMENT_CHARACTERISTIC;

gatt_heart_rate_client_request_to_send();

break;

default:

break;

}

break;

case APP_STATE_W4_HEART_RATE_MEASUREMENT_CHARACTERISTIC:

switch(hci_event_packet_get_type(packet)){

case GATT_EVENT_CHARACTERISTIC_QUERY_RESULT:

gatt_event_characteristic_query_result_get_characteristic(packet, &heart_rate_measurement_characteristic);

break;

case GATT_EVENT_QUERY_COMPLETE:

att_status = gatt_event_query_complete_get_att_status(packet);

if (att_status != ATT_ERROR_SUCCESS){

printf("CHARACTERISTIC_QUERY_RESULT - ATT Error 0x%02x.\n", att_status);

gap_disconnect(connection_handle);

break;

}

// register handler for notifications

listener_registered = 1;

gatt_client_listen_for_characteristic_value_updates(&notification_listener, handle_gatt_client_event, connection_handle, &heart_rate_measurement_characteristic);

// enable notifications

printf("Enable Notify on Heart Rate Measurements characteristic.\n");

state = APP_STATE_W2_ENABLE_NOTIFICATIONS;

gatt_heart_rate_client_request_to_send();

break;

default:

break;

}

break;

case APP_STATE_W4_ENABLE_NOTIFICATIONS_COMPLETE:

switch(hci_event_packet_get_type(packet)){

case GATT_EVENT_QUERY_COMPLETE:

printf("Notifications enabled, ATT status 0x%02x\n", gatt_event_query_complete_get_att_status(packet));

state = APP_STATE_W2_QUERY_SENSOR_LOCATION_CHARACTERISTIC;

gatt_heart_rate_client_request_to_send();

break;

default:

break;

}

break;

case APP_STATE_W4_SENSOR_LOCATION_CHARACTERISTIC:

switch(hci_event_packet_get_type(packet)){

case GATT_EVENT_CHARACTERISTIC_QUERY_RESULT:

gatt_event_characteristic_query_result_get_characteristic(packet, &body_sensor_location_characteristic);

break;

case GATT_EVENT_QUERY_COMPLETE:

if (gatt_event_query_complete_get_att_status(packet) != ATT_ERROR_SUCCESS){

printf("CHARACTERISTIC_QUERY_RESULT - ATT Error 0x%02x.\n", packet[4]);

state = APP_STATE_CONNECTED;

break;

}

if (body_sensor_location_characteristic.value_handle == 0){

printf("Sensor Location characteristic not available.\n");

state = APP_STATE_CONNECTED;

break;

}

state = APP_STATE_W2_QUERY_SENSOR_LOCATION;

gatt_heart_rate_client_request_to_send();

break;

default:

break;

}

break;

case APP_STATE_W4_SENSOR_LOCATION:

switch(hci_event_packet_get_type(packet)){

case GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT:

body_sensor_location = gatt_event_characteristic_value_query_result_get_value(packet)[0];

printf("Sensor Location: %u\n", body_sensor_location);

break;

case GATT_EVENT_QUERY_COMPLETE:

state = APP_STATE_CONNECTED;

break;

default:

break;

}

break;

case APP_STATE_CONNECTED:

switch(hci_event_packet_get_type(packet)){

case GATT_EVENT_NOTIFICATION:

if (gatt_event_notification_get_value(packet)[0] & 1){

heart_rate = little_endian_read_16(gatt_event_notification_get_value(packet), 1);

} else {

heart_rate = gatt_event_notification_get_value(packet)[1];

}

sensor_contact = (gatt_event_notification_get_value(packet)[0] >> 1) & 3;

printf("Heart Rate: %3u, Sensor Contact: %s\n", heart_rate, sensor_contact_string[sensor_contact]);

break;

case GATT_EVENT_QUERY_COMPLETE:

break;

case GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE:

break;

default:

break;

}

break;

default:

break;

}

}

static void gatt_heart_rate_client_start(void){

if (cmdline_addr_found){

printf("Connect to %s\n", bd_addr_to_str(cmdline_addr));

state = APP_STATE_W4_CONNECT;

gap_connect(cmdline_addr, 0);

} else {

printf("Start scanning!\n");

state = APP_STATE_W4_SCAN_RESULT;

gap_set_scan_parameters(0,0x0030, 0x0030);

gap_start_scan();

}

}

static void gatt_heart_rate_client_send_next_query(void * context){

UNUSED(context);

switch (state){

case APP_STATE_W2_QUERY_SERVICE:

state = APP_STATE_W4_SERVICE_RESULT;

printf("Search for Heart Rate MService.\n");

gatt_client_discover_primary_services_by_uuid16(handle_gatt_client_event, connection_handle, ORG_BLUETOOTH_SERVICE_HEART_RATE);

break;

case APP_STATE_W2_QUERY_HEART_RATE_MEASUREMENT_CHARACTERISTIC:

state = APP_STATE_W4_HEART_RATE_MEASUREMENT_CHARACTERISTIC;

printf("Search for Heart Rate Measurement characteristic.\n");

gatt_client_discover_characteristics_for_service_by_uuid16(handle_gatt_client_event, connection_handle, &heart_rate_service, ORG_BLUETOOTH_CHARACTERISTIC_HEART_RATE_MEASUREMENT);

break;

case APP_STATE_W2_ENABLE_NOTIFICATIONS:

printf("Enable Notify on Heart Rate Measurements characteristic.\n");

state = APP_STATE_W4_ENABLE_NOTIFICATIONS_COMPLETE;

gatt_client_write_client_characteristic_configuration(handle_gatt_client_event, connection_handle,

&heart_rate_measurement_characteristic, GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION);

break;

case APP_STATE_W2_QUERY_SENSOR_LOCATION_CHARACTERISTIC:

state = APP_STATE_W4_SENSOR_LOCATION_CHARACTERISTIC;

printf("Search for Sensor Location characteristic.\n");

gatt_client_discover_characteristics_for_service_by_uuid16(handle_gatt_client_event, connection_handle, &heart_rate_service, ORG_BLUETOOTH_CHARACTERISTIC_BODY_SENSOR_LOCATION);

break;

case APP_STATE_W2_QUERY_SENSOR_LOCATION:

printf("Read Body Sensor Location.\n");

state = APP_STATE_W4_SENSOR_LOCATION;

gatt_client_read_value_of_characteristic(handle_gatt_client_event, connection_handle, &body_sensor_location_characteristic);

break;

default:

btstack_assert(false);

break;

}

}

static void gatt_heart_rate_client_request_to_send(void){

heart_rate_service_gatt_query_request.callback = &gatt_heart_rate_client_send_next_query;

gatt_client_request_to_send_gatt_query(&heart_rate_service_gatt_query_request, connection_handle);

}

static void hci_event_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){

UNUSED(channel);

UNUSED(size);

if (packet_type != HCI_EVENT_PACKET) return;

uint16_t conn_interval;

uint8_t event = hci_event_packet_get_type(packet);

switch (event) {

case BTSTACK_EVENT_STATE:

// BTstack activated, get started

if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING) {

gatt_heart_rate_client_start();

}

break;

case GAP_EVENT_ADVERTISING_REPORT:

if (state != APP_STATE_W4_SCAN_RESULT) return;

// check name in advertisement

if (!advertisement_report_contains_uuid16(ORG_BLUETOOTH_SERVICE_HEART_RATE, packet)) return;

// store address and type

gap_event_advertising_report_get_address(packet, le_streamer_addr);

le_streamer_addr_type = gap_event_advertising_report_get_address_type(packet);

// stop scanning, and connect to the device

state = APP_STATE_W4_CONNECT;

gap_stop_scan();

printf("Stop scan. Connect to device with addr %s.\n", bd_addr_to_str(le_streamer_addr));

gap_connect(le_streamer_addr,le_streamer_addr_type);

break;

case HCI_EVENT_META_GAP:

// wait for connection complete

if (hci_event_gap_meta_get_subevent_code(packet) != GAP_SUBEVENT_LE_CONNECTION_COMPLETE) break;

if (state != APP_STATE_W4_CONNECT) return;

connection_handle = gap_subevent_le_connection_complete_get_connection_handle(packet);

// print connection parameters (without using float operations)

conn_interval = gap_subevent_le_connection_complete_get_conn_interval(packet);

printf("Connection Interval: %u.%02u ms\n", conn_interval * 125 / 100, 25 * (conn_interval & 3));

printf("Connection Latency: %u\n", gap_subevent_le_connection_complete_get_conn_latency(packet));

// initialize gatt client context with handle, and add it to the list of active clients

// query primary services

printf("Search for Heart Rate service.\n");

state = APP_STATE_W2_QUERY_SERVICE;

gatt_heart_rate_client_request_to_send();

break;

case HCI_EVENT_DISCONNECTION_COMPLETE:

// unregister listener

connection_handle = HCI_CON_HANDLE_INVALID;

if (listener_registered){

listener_registered = 0;

gatt_client_stop_listening_for_characteristic_value_updates(&notification_listener);

}

if (cmdline_addr_found){

printf("Disconnected %s\n", bd_addr_to_str(cmdline_addr));

return;

}

printf("Disconnected %s\n", bd_addr_to_str(le_streamer_addr));

gatt_heart_rate_client_start();

break;

default:

break;

}

}

#ifdef HAVE_BTSTACK_STDIN

static void usage(const char *name){

fprintf(stderr, "Usage: %s [-a|--address aa:bb:cc:dd:ee:ff]\n", name);

fprintf(stderr, "If no argument is provided, GATT Heart Rate Client will start scanning and connect to a device that advertises the heart rate UUID.\n");

fprintf(stderr, "To connect to a specific device use argument [-a].\n\n");

}

int btstack_main(int argc, const char * argv[]);

int btstack_main(int argc, const char * argv[]){

#ifdef HAVE_BTSTACK_STDIN

int arg;

cmdline_addr_found = 0;

for (arg = 1; arg < argc; arg++) {

if(!strcmp(argv[arg], "-a") || !strcmp(argv[arg], "--address")){

if (arg + 1 < argc) {

arg++;

cmdline_addr_found = sscanf_bd_addr(argv[arg], cmdline_addr);

}

if (!cmdline_addr_found) {

usage(argv[0]);

return 1;

}

}

}

if (!cmdline_addr_found) {

fprintf(stderr, "No specific address specified or found; start scanning for heart rate UUID advertiser.\n");

}

(void)argc;

(void)argv;

l2cap_init();

gatt_client_init();

sm_init();

sm_set_io_capabilities(IO_CAPABILITY_NO_INPUT_NO_OUTPUT);

hci_event_callback_registration.callback = &hci_event_handler;

hci_add_event_handler(&hci_event_callback_registration);

// turn on!

hci_power_control(HCI_POWER_ON);

return 0;

}