BLESerial.cpp

// Copyright (C) 2024, Mark Qvist

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

#include "Boards.h"

#if PLATFORM != PLATFORM_NRF52
#if HAS_BLE

#include "BLESerial.h"

uint32_t bt_passkey_callback();
void bt_passkey_notify_callback(uint32_t passkey);
bool bt_security_request_callback();
void bt_authentication_complete_callback(esp_ble_auth_cmpl_t auth_result);
bool bt_confirm_pin_callback(uint32_t pin);
void bt_connect_callback(BLEServer *server);
void bt_disconnect_callback(BLEServer *server);
bool bt_client_authenticated();

uint32_t BLESerial::onPassKeyRequest() { return bt_passkey_callback(); }
void BLESerial::onPassKeyNotify(uint32_t passkey) { bt_passkey_notify_callback(passkey); }
bool BLESerial::onSecurityRequest() { return bt_security_request_callback(); }
void BLESerial::onAuthenticationComplete(esp_ble_auth_cmpl_t auth_result) { bt_authentication_complete_callback(auth_result); }
void BLESerial::onConnect(BLEServer *server) { bt_connect_callback(server); }
void BLESerial::onDisconnect(BLEServer *server) { bt_disconnect_callback(server); ble_server->startAdvertising(); }
bool BLESerial::onConfirmPIN(uint32_t pin) { return bt_confirm_pin_callback(pin); };
bool BLESerial::connected() { return ble_server->getConnectedCount() > 0; }

int BLESerial::read() {
  int result = this->rx_buffer.pop();
  if (result == '\n') { this->numAvailableLines--; }
  return result;
}

size_t BLESerial::readBytes(uint8_t *buffer, size_t bufferSize) {
  int i = 0;
  while (i < bufferSize && available()) { buffer[i] = (uint8_t)this->rx_buffer.pop(); i++; }
  return i;
}

int BLESerial::peek() {
  if (this->rx_buffer.getLength() == 0) return -1;
  return this->rx_buffer.get(0);
}

int BLESerial::available() { return this->rx_buffer.getLength(); }

size_t BLESerial::print(const char *str) {
  if (ble_server->getConnectedCount() <= 0) return 0;
  size_t written = 0; for (size_t i = 0; str[i] != '\0'; i++)  { written += this->write(str[i]); }
  flush();

  return written;
}

size_t BLESerial::write(const uint8_t *buffer, size_t bufferSize) {
  if (ble_server->getConnectedCount() <= 0) { return 0; } else {
    size_t written = 0; for (int i = 0; i < bufferSize; i++) { written += this->write(buffer[i]); }
    flush();

    return written;
  }
}

size_t BLESerial::write(uint8_t byte) {
  if (bt_client_authenticated()) {
    if (ble_server->getConnectedCount() <= 0) { return 0; } else {
      this->transmitBuffer[this->transmitBufferLength] = byte;
      this->transmitBufferLength++;
      if (this->transmitBufferLength == maxTransferSize) { flush(); }
      return 1;
    }
  } else {
    return 0;
  }
}

void BLESerial::flush() {
  if (this->transmitBufferLength > 0) {
    TxCharacteristic->setValue(this->transmitBuffer, this->transmitBufferLength);
    this->transmitBufferLength = 0;
    this->lastFlushTime = millis();
    TxCharacteristic->notify(true);
  }
}

void BLESerial::begin(const char *name) {
  ConnectedDeviceCount = 0;
  BLEDevice::init(name);

  esp_ble_tx_power_set(ESP_BLE_PWR_TYPE_DEFAULT, ESP_PWR_LVL_P9); 
  esp_ble_tx_power_set(ESP_BLE_PWR_TYPE_ADV, ESP_PWR_LVL_P9);
  esp_ble_tx_power_set(ESP_BLE_PWR_TYPE_SCAN ,ESP_PWR_LVL_P9);

  ble_server = BLEDevice::createServer();
  ble_server->setCallbacks(this);
  BLEDevice::setEncryptionLevel(ESP_BLE_SEC_ENCRYPT_MITM);
  BLEDevice::setSecurityCallbacks(this);

  SetupSerialService();

  ble_adv = BLEDevice::getAdvertising();
  ble_adv->addServiceUUID(BLE_SERIAL_SERVICE_UUID);
  ble_adv->setMinPreferred(0x20);
  ble_adv->setMaxPreferred(0x40);
  ble_adv->setScanResponse(true);
  ble_adv->start();
}

void BLESerial::end() { BLEDevice::deinit(); }

void BLESerial::onWrite(BLECharacteristic *characteristic) {
  if (characteristic->getUUID().toString() == BLE_RX_UUID) {
    auto value = characteristic->getValue();
    for (int i = 0; i < value.length(); i++) { rx_buffer.push(value[i]); }
  }
}

void BLESerial::SetupSerialService() {
  SerialService = ble_server->createService(BLE_SERIAL_SERVICE_UUID);

  RxCharacteristic = SerialService->createCharacteristic(BLE_RX_UUID, BLECharacteristic::PROPERTY_WRITE);
  RxCharacteristic->setAccessPermissions(ESP_GATT_PERM_WRITE_ENC_MITM);
  RxCharacteristic->addDescriptor(new BLE2902());
  RxCharacteristic->setWriteProperty(true);
  RxCharacteristic->setCallbacks(this);

  TxCharacteristic = SerialService->createCharacteristic(BLE_TX_UUID, BLECharacteristic::PROPERTY_NOTIFY);
  TxCharacteristic->setAccessPermissions(ESP_GATT_PERM_READ_ENC_MITM);
  TxCharacteristic->addDescriptor(new BLE2902());
  TxCharacteristic->setNotifyProperty(true);
  TxCharacteristic->setReadProperty(true);

  SerialService->start();
}

BLESerial::BLESerial() { }

#endif
#endif