/*
    Video: https://www.youtube.com/watch?v=oCMOYS71NIU
    Based on Neil Kolban example for IDF: https://github.com/nkolban/esp32-snippets/blob/master/cpp_utils/tests/BLE%20Tests/SampleNotify.cpp
    inspired by Evandro Copercini
    Update and Ported to Arduino ESP32 by Joel Stéphane Loic Ngando in 2022    

   Create a BLE server that, once we receive a connection, will send periodic notifications.
   The service advertises itself as: 6E400001-B5A3-F393-E0A9-E50E24DCCA9E
   Has a characteristic of: 6E400002-B5A3-F393-E0A9-E50E24DCCA9E - used for receiving data with "WRITE" 
   Has a characteristic of: 6E400003-B5A3-F393-E0A9-E50E24DCCA9E - used to send data with  "NOTIFY"

   The design of creating the BLE server is:
   1. Create a BLE Server
   2. Create a BLE Service
   3. Create a BLE Characteristic on the Service
   4. Create a BLE Descriptor on the characteristic
   5. Start the service.
   6. Start advertising.

   In this example rxValue is the data received (only accessible inside that function).
   And txValue is the data to be sent, in this example just a byte incremented every second. 
*/
#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

BLECharacteristic *pCharacteristicTx;
BLECharacteristic *pCharacteristicRx;
bool deviceConnected = false;
float txValue = 0;
const int readPin =4; // Use GPIO number. See ESP32 board pinouts
const int LED = 2; // Could be different depending on the dev board. I used the DOIT ESP32 dev board.
std::string rxValue ="";
#define TdsSensorPin 27
#define VREF 3.3              // analog reference voltage(Volt) of the ADC
#define SCOUNT  30            // sum of sample point
float niveau_Chlore;
int analogBuffer[SCOUNT];     // store the analog value in the array, read from ADC
int analogBufferTemp[SCOUNT];
int analogBufferIndex = 0;
int copyIndex = 0;
float idealTds;
float averageVoltage = 0;
float tdsValue = 0;
float temperature = 25;       // current temperature for compensation

//std::string rxValue; // Could also make this a global var to access it in loop()

// See the following for generating UUIDs:
// https://www.uuidgenerator.net/

#define SERVICE_UUID           "6E400001-B5A3-F393-E0A9-E50E24DCCA9E" // UART service UUID
#define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"
#define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"

class MyServerCallbacks: public BLEServerCallbacks {
    void onConnect(BLEServer* pServer) {
      deviceConnected = true;
    };

    void onDisconnect(BLEServer* pServer) {
      deviceConnected = false;
    }
};

class MyCallbacks: public BLECharacteristicCallbacks {
    void onWrite(BLECharacteristic *pCharacteristicRx) {
       rxValue = pCharacteristicRx->getValue();

      if (rxValue.length() > 0) {
        Serial.println("*********");
        Serial.print("Received Value: ");

        for (int i = 0; i < rxValue.length(); i++) {
          Serial.print(rxValue[i]);
        }

        //Serial.println();

        // Do stuff based on the command received from the app
        if (rxValue.find("A") != -1) { 
          Serial.println("Turning ON!");
          digitalWrite(LED, HIGH);
        }
        else if (rxValue.find("B") != -1) {
          Serial.println("Turning OFF!");
          digitalWrite(LED, LOW);
        }

        Serial.println();
        Serial.println("*********");
      }
    }
};
// median filtering algorithm
int getMedianNum(int bArray[], int iFilterLen){
  int bTab[iFilterLen];
  for (byte i = 0; i<iFilterLen; i++)
  bTab[i] = bArray[i];
  int i, j, bTemp;
  for (j = 0; j < iFilterLen - 1; j++) {
    for (i = 0; i < iFilterLen - j - 1; i++) {
      if (bTab[i] > bTab[i + 1]) {
        bTemp = bTab[i];
        bTab[i] = bTab[i + 1];
        bTab[i + 1] = bTemp;
      }
    }
  }
  if ((iFilterLen & 1) > 0){
    bTemp = bTab[(iFilterLen - 1) / 2];
  }
  else {
    bTemp = (bTab[iFilterLen / 2] + bTab[iFilterLen / 2 - 1]) / 2;
  }
  return bTemp;
}

void setup() {
  Serial.begin(115200);
  pinMode(TdsSensorPin,INPUT);

  pinMode(LED, OUTPUT);

  // Create the BLE Device
  BLEDevice::init("ESP32 UART Test"); // Give it a name

  // Create the BLE Server
  BLEServer *pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

  // Create the BLE Service
  BLEService *pService = pServer->createService(SERVICE_UUID);

  // Create a BLE Characteristic
  pCharacteristicTx = pService->createCharacteristic(
                      CHARACTERISTIC_UUID_TX,
                      BLECharacteristic::PROPERTY_NOTIFY
                    );
                      
  pCharacteristicTx->addDescriptor(new BLE2902());

  BLECharacteristic *pCharacteristicRx = pService->createCharacteristic(
                                         CHARACTERISTIC_UUID_RX,
                                         BLECharacteristic::PROPERTY_WRITE
                                       );

  pCharacteristicRx->setCallbacks(new MyCallbacks());

  // Start the service
  pService->start();

  // Start advertising
  pServer->getAdvertising()->start();
  Serial.println("Waiting a client connection to notify...");
}

void loop() {
  
  
  String readString="";
  bool isCodingFun = true;
  txValue = analogRead(readPin);

  niveau_Chlore = analogRead(15);
  idealTds= 180;
  if (niveau_Chlore < 1020) { digitalWrite(13, LOW); } // éteint la LED
  else {digitalWrite(13, HIGH); }
  if (niveau_Chlore < 820) { digitalWrite(12, LOW); } // éteint la LED
  else {digitalWrite(12, HIGH); }
  if (niveau_Chlore < 620) { digitalWrite(11, LOW); } // éteint la LED
  else {digitalWrite(11, HIGH); }

  static unsigned long analogSampleTimepoint = millis();
  if(millis()-analogSampleTimepoint > 40U){     //every 40 milliseconds,read the analog value from the ADC
    analogSampleTimepoint = millis();
    analogBuffer[analogBufferIndex] = analogRead(TdsSensorPin);    //read the analog value and store into the buffer
    analogBufferIndex++;
    if(analogBufferIndex == SCOUNT){ 
      analogBufferIndex = 0;
    }
  }
  if (rxValue.find("GetPHinfo") != std::string::npos) {
    //Cast string to std::string du to the function setvalue()
    String stringOne = String(niveau_Chlore, DEC); 
  std::string stdStr(stringOne.c_str(), stringOne.length());
  pCharacteristicTx->setValue(stdStr); // Sending message provied by the controller
  pCharacteristicTx->notify(); // Send the value to the app!
     isCodingFun = false;
     rxValue="";
     
  }
  
  while(Serial.available() && deviceConnected) //all the time there is something to read
{
  //read the input
    delay(50);  //waste some time to allow characters to arrive
    char c=Serial.read(); //read a character
    readString+=c;  //add it to a String
    isCodingFun = false;
}
if(isCodingFun==false)
{
  //Cast string to std::string du to the function setvalue()
 /* std::string stdStr(readString.c_str(), readString.length());
  pCharacteristicTx->setValue(stdStr); // Sending message provied by the controller
  pCharacteristicTx->notify(); // Send the value to the app!
  Serial.print("*** Sent Value: ");
  Serial.println(readString);
  Serial.println(" ***");
  Serial.println();*/
}
 
    
  
  delay(1000);
}