#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

#include <Arduino.h>

//info capteur
#define LENG 31   //0x42 + 31 bytes equal to 32 bytes
unsigned char buf[LENG];

//pin ESP32 :
const int SetPin = 5;
const int redLED = 14;
const int yellowLED = 16;

//info bluetooth
BLECharacteristic *pCharacteristic;
bool deviceConnected = false;

//variables globales : 
std::string rxValue; 
float PM10 = 0;
float PM5 = 0;
float CO2 = 0;
int PM01Value=0;  
int PM2_5Value=0; 
int PM10Value=0;  

// UUIDs:
// https://www.uuidgenerator.net/
#define SERVICE_UUID           "6E400001-B5A3-F393-E0A9-E50E24DCCA9E"
#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;
      digitalWrite(redLED,HIGH);
    };

    void onDisconnect(BLEServer* pServer) {
      deviceConnected = false;
        digitalWrite(redLED,LOW);
    }
};

class MyCallbacks: public BLECharacteristicCallbacks {
    void onWrite(BLECharacteristic *pCharacteristic) {
      //std::string rxValue = pCharacteristic->getValue();
      rxValue = pCharacteristic->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("stop measure!");
        }
        else if (rxValue.find("B") != -1) {
          Serial.println("measure!");
        }
        Serial.println();
        Serial.println("*********");
      }
    }
};


void setup() {
  //bluetooth
  Serial.begin(9600);
  pinMode(yellowLED,OUTPUT);
  pinMode(SetPin, OUTPUT);
  pinMode(redLED,OUTPUT);
  
  //Création du device BLE
  BLEDevice::init("MyESP32");

  //Création du serveur BLE
  BLEServer *pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

  //Création du service BLE
  BLEService *pService = pServer->createService(SERVICE_UUID);

  //Création du BLE characteristic
  pCharacteristic = pService->createCharacteristic(
                      CHARACTERISTIC_UUID_TX,
                      BLECharacteristic::PROPERTY_NOTIFY
                    );
                      
  pCharacteristic->addDescriptor(new BLE2902());

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

  pCharacteristic->setCallbacks(new MyCallbacks());

  //Lancement du service
  pService->start();

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

void loop() 
{
  if (deviceConnected)
  {
    while(rxValue!="B")
    {
      delay(100);
    }
    digitalWrite(SetPin, HIGH);
    digitalWrite(yellowLED,HIGH);
    rxValue="A";
    delay(5000);

    
    //commence à lire quand il detecte 0x42
    if(Serial.find(0x42))
    {
      //récupération de la trame envoyée par le capteur 
      Serial.readBytes(buf,LENG);
      if(buf[0] == 0x4d)
      {
      if(checkValue(buf,LENG))
        {
        PM01Value=transmitPM01(buf);  //récupère le taux de PM1 dans la trame
        PM2_5Value=transmitPM2_5(buf);//récupère le taux de PM2.5 dans la trame
        PM10Value=transmitPM10(buf);  //récupère le taux de PM10 dans la trame
        Serial.println(PM10Value);
        }           
      } 
    }
    //on converti ces valeurs en string : 
    char txString[20];
    //de taille 4 car le capteur mesure entre 0 et 500 normalement.
    char PM10String[4];
    dtostrf(PM10Value, 3, 0, PM10String); //float_val, min_width:1, digits_after_decimal, char_buffer
    char PM5String[4];
    dtostrf(PM2_5Value, 3, 0, PM5String); 
    char CO2String[4];
    dtostrf(PM01Value, 3, 0, CO2String); 

    txString[0]=PM10String[0];
    txString[1]=PM10String[1];
    txString[2]=PM10String[2];
    txString[3]='-';
    txString[4]=PM5String[0];
    txString[5]=PM5String[1];
    txString[6]=PM5String[2];
    txString[7]='-';
    txString[8]=CO2String[0];
    txString[9]=CO2String[1];
    txString[10]=CO2String[2];
    txString[11]='-';

    pCharacteristic->setValue(txString);
    //envoie de la string
    pCharacteristic->notify(); 
    Serial.print("message envoyé : ");
    Serial.print(txString);
  }
  delay(100);
  digitalWrite(SetPin, LOW);
  digitalWrite(yellowLED,LOW);
}




//fonctions de gestion de la trame reçue par le capteur :
char checkValue(unsigned char *thebuf, char leng)
{  
  char receiveflag=0;
  int receiveSum=0;

  for(int i=0; i<(leng-2); i++){
  receiveSum=receiveSum+thebuf[i];
  }
  receiveSum=receiveSum + 0x42;
 
  if(receiveSum == ((thebuf[leng-2]<<8)+thebuf[leng-1]))  //check the serial data 
  {
    receiveSum = 0;
    receiveflag = 1;
  }
  return receiveflag;
}

int transmitPM01(unsigned char *thebuf)
{
  int PM01Val;
  PM01Val=((thebuf[3]<<8) + thebuf[4]);
  return PM01Val;
}

int transmitPM2_5(unsigned char *thebuf)
{
  int PM2_5Val;
  PM2_5Val=((thebuf[5]<<8) + thebuf[6]);
  return PM2_5Val;
}

int transmitPM10(unsigned char *thebuf)
{
  int PM10Val;
  PM10Val=((thebuf[7]<<8) + thebuf[8]); 
  return PM10Val;
}