text: /* mbed Microcontroller Library
   * Copyright (c) 2006-2015 ARM Limited
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <events/mbed_events.h>
  #include <mbed.h>
  #include "ble/BLE.h"
  #include "ble/DiscoveredCharacteristic.h"
  #include "ble/DiscoveredService.h"
  
  DigitalOut alivenessLED(LED1, 1);
  static DiscoveredCharacteristic ledCharacteristic;
  static bool triggerLedCharacteristic;
  static const char PEER_NAME[] = "LED";
  
  static EventQueue eventQueue(/* event count */ 16 * EVENTS_EVENT_SIZE);
  
  void periodicCallback(void) {
      alivenessLED = !alivenessLED; /* Do blinky on LED1 while we're waiting for BLE events */
  }
  
  void advertisementCallback(const Gap::AdvertisementCallbackParams_t *params) {
      // parse the advertising payload, looking for data type COMPLETE_LOCAL_NAME
      // The advertising payload is a collection of key/value records where
      // byte 0: length of the record excluding this byte
      // byte 1: The key, it is the type of the data
      // byte [2..N] The value. N is equal to byte0 - 1
      for (uint8_t i = 0; i < params->advertisingDataLen; ++i) {
  
          const uint8_t record_length = params->advertisingData[i];
          if (record_length == 0) {
              continue;
          }
          const uint8_t type = params->advertisingData[i + 1];
          const uint8_t* value = params->advertisingData + i + 2;
          const uint8_t value_length = record_length - 1;
  
          if(type == GapAdvertisingData::COMPLETE_LOCAL_NAME) {
              if ((value_length == sizeof(PEER_NAME)) && (memcmp(value, PEER_NAME, value_length) == 0)) {
                  printf(
                      "adv peerAddr[%02x %02x %02x %02x %02x %02x] rssi %d, isScanResponse %u, AdvertisementType %u\r\n",
                      params->peerAddr[5], params->peerAddr[4], params->peerAddr[3], params->peerAddr[2],
                      params->peerAddr[1], params->peerAddr[0], params->rssi, params->isScanResponse, params->type
                  );
                  BLE::Instance().gap().connect(params->peerAddr, Gap::ADDR_TYPE_RANDOM_STATIC, NULL, NULL);
                  break;
              }
          }
          i += record_length;
      }
  }
  
  void serviceDiscoveryCallback(const DiscoveredService *service) {
      if (service->getUUID().shortOrLong() == UUID::UUID_TYPE_SHORT) {
          printf("S UUID-%x attrs[%u %u]\r\n", service->getUUID().getShortUUID(), service->getStartHandle(), service->getEndHandle());
      } else {
          printf("S UUID-");
          const uint8_t *longUUIDBytes = service->getUUID().getBaseUUID();
          for (unsigned i = 0; i < UUID::LENGTH_OF_LONG_UUID; i++) {
              printf("%02x", longUUIDBytes[i]);
          }
          printf(" attrs[%u %u]\r\n", service->getStartHandle(), service->getEndHandle());
      }
  }
  
  void updateLedCharacteristic(void) {
      if (!BLE::Instance().gattClient().isServiceDiscoveryActive()) {
          ledCharacteristic.read();
      }
  }
  
  void characteristicDiscoveryCallback(const DiscoveredCharacteristic *characteristicP) {
      printf("  C UUID-%x valueAttr[%u] props[%x]\r\n", characteristicP->getUUID().getShortUUID(), characteristicP->getValueHandle(), (uint8_t)characteristicP->getProperties().broadcast());
      if (characteristicP->getUUID().getShortUUID() == 0xa001) { /* !ALERT! Alter this filter to suit your device. */
          ledCharacteristic        = *characteristicP;
          triggerLedCharacteristic = true;
      }
  }
  
  void discoveryTerminationCallback(Gap::Handle_t connectionHandle) {
      printf("terminated SD for handle %u\r\n", connectionHandle);
      if (triggerLedCharacteristic) {
          triggerLedCharacteristic = false;
          eventQueue.call(updateLedCharacteristic);
      }
  }
  
  void connectionCallback(const Gap::ConnectionCallbackParams_t *params) {
      if (params->role == Gap::CENTRAL) {
          BLE &ble = BLE::Instance();
          ble.gattClient().onServiceDiscoveryTermination(discoveryTerminationCallback);
          ble.gattClient().launchServiceDiscovery(params->handle, serviceDiscoveryCallback, characteristicDiscoveryCallback, 0xa000, 0xa001);
      }
  }
  
  void triggerToggledWrite(const GattReadCallbackParams *response) {
      if (response->handle == ledCharacteristic.getValueHandle()) {
          printf("triggerToggledWrite: handle %u, offset %u, len %u\r\n", response->handle, response->offset, response->len);
          for (unsigned index = 0; index < response->len; index++) {
              printf("%c[%02x]", response->data[index], response->data[index]);
          }
          printf("\r\n");
  
          uint8_t toggledValue = response->data[0] ^ 0x1;
          ledCharacteristic.write(1, &toggledValue);
      }
  }
  
  void triggerRead(const GattWriteCallbackParams *response) {
      if (response->handle == ledCharacteristic.getValueHandle()) {
          ledCharacteristic.read();
      }
  }
  
  void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *) {
      printf("disconnected\r\n");
      /* Start scanning and try to connect again */
      BLE::Instance().gap().startScan(advertisementCallback);
  }
  
  void onBleInitError(BLE &ble, ble_error_t error)
  {
     /* Initialization error handling should go here */
  }
  
  void printMacAddress()
  {
      /* Print out device MAC address to the console*/
      Gap::AddressType_t addr_type;
      Gap::Address_t address;
      BLE::Instance().gap().getAddress(&addr_type, address);
      printf("DEVICE MAC ADDRESS: ");
      for (int i = 5; i >= 1; i--){
          printf("%02x:", address[i]);
      }
      printf("%02x\r\n", address[0]);
  }
  
  void bleInitComplete(BLE::InitializationCompleteCallbackContext *params)
  {
      BLE&        ble   = params->ble;
      ble_error_t error = params->error;
  
      if (error != BLE_ERROR_NONE) {
          /* In case of error, forward the error handling to onBleInitError */
          onBleInitError(ble, error);
          return;
      }
  
      /* Ensure that it is the default instance of BLE */
      if (ble.getInstanceID() != BLE::DEFAULT_INSTANCE) {
          return;
      }
  
      ble.gap().onDisconnection(disconnectionCallback);
      ble.gap().onConnection(connectionCallback);
  
      ble.gattClient().onDataRead(triggerToggledWrite);
      ble.gattClient().onDataWrite(triggerRead);
  
      // scan interval: 400ms and scan window: 400ms.
      // Every 400ms the device will scan for 400ms
      // This means that the device will scan continuously.
      ble.gap().setScanParams(400, 400);
      ble.gap().startScan(advertisementCallback);
  
      printMacAddress();
  }
  
  void scheduleBleEventsProcessing(BLE::OnEventsToProcessCallbackContext* context) {
      BLE &ble = BLE::Instance();
      eventQueue.call(Callback<void()>(&ble, &BLE::processEvents));
  }
  
  int main()
  {
      triggerLedCharacteristic = false;
      eventQueue.call_every(500, periodicCallback);
  
      BLE &ble = BLE::Instance();
      ble.onEventsToProcess(scheduleBleEventsProcessing);
      ble.init(bleInitComplete);
  
      eventQueue.dispatch_forever();
  
      return 0;
  }
  