#include <Wire.h>


#define flowsensor 2          // Interrupt pin 2
#define statusLed LED_BUILTIN // Built in LED
#define prssensor A0          // Pressure Sensor Input Pin A0
#define outPulse 8            // L/min Pulse Output Pin D8

int number = 0;

//  Setup Flowmeter
volatile unsigned long flowPulseCount = 0; // Counts flow sensor pulses unsigned 
unsigned long flowPulseCount_prev = 0; // Previous Counts of flow sensor

float l_sec = 0;      // Calculated litres/sec
float litres = 0;     // Calculated litres
float rem_litres = 0; // Remaining Litres left over from output pulse 

const float calFactor = 1.00; // flow calibration factor

//  Setup Pressure
float prs_bar = 0.0;      // Calculated pressure kPa
float low = 204;    //  Scaling values
float high = 1023;

unsigned long currentTime; 
unsigned long cloopTime;

// Create Data length for I2C based on 2 Floats being sent
byte data[sizeof(float) * 2];
int dataLength = sizeof(data);


void setup() {
  
  // Start Serial Monitor
  Serial.begin(9600);
  Serial.println("Starting Up....");

  // Start i2C
  Wire.begin(10);                // join i2c bus with address #10
  Wire.onRequest(requestEvent); // register event

  //Set IO
  //pinMode(flowsensor, INPUT);
  pinMode(prssensor, INPUT);
  pinMode(statusLed, OUTPUT);
  pinMode(outPulse, OUTPUT);
   
  attachInterrupt(digitalPinToInterrupt(flowsensor), flow, RISING); // Setup Interrupt
   
  currentTime = millis();
  cloopTime = currentTime;

}

void loop() {

  currentTime = millis();
  

  // Set Pulsed Output Low to start
  digitalWrite(outPulse, LOW);

  // Every second, calculate litres/second
  if(currentTime >= (cloopTime + 1000))
  {
      cloopTime = currentTime; // Updates cloopTime
      unsigned long flowPulseCount_now = flowPulseCount;
      unsigned long flow_frequency = flowPulseCount_now - flowPulseCount_prev;
      
      // Flash StatusLed to show loop running, can be removed
      flashStatusLed(1); 

      

      //  Get Flow Reading
      //  Pulse frequency (Hz) = 4.8Q, Q is flow rate in L/min.
      l_sec = (flow_frequency / 4.8 / 60) * calFactor; // (Pulse frequency x 100) / 4.8Q x Cal factor = flowrate in L/sec 2dp
     
      //  Get Pressure Reading
      prs_bar = map(analogRead(prssensor), low, high, 0, 1000); // Scale pressure raw to 0 - 10.00 bar

      // Update Flow
      float flow = l_sec;

      Serial.print("Flow : ");
      Serial.print(flow, 1);
      Serial.print("L  ");

      // Update Pressure
      float pressure = prs_bar;

      Serial.print("Pres.: ");
      Serial.print(pressure/100, 2);
      Serial.print("bar  ");

      float freq = flow_frequency;

      Serial.print(freq,0);
      Serial.println("#  ");

      flowPulseCount_prev = flowPulseCount_now; // Update previous count for next calculation

      // Calculate and accumulate volume to get 
      litres += l_sec;

      // Generate a pulse if 1 liter or more has been accumulated
      


  if (flowPulseCount > 4294967200) {
    flowPulseCount = 0;
  }
  // Create Data Array with updated values for I2C
  setupDataArray();

  }

if (litres >= 1.00){
          int numPulses = (int)(litres); // Calculate the number of pulses to send
          for (int i = 0; i < numPulses; i++) {
            digitalWrite(outPulse, HIGH);
            delay(5);
            digitalWrite(outPulse, LOW); // Output pulse every 1 l/min
            delay(1000/numPulses -5);
          }
        litres -= numPulses; // Subtract the number of pulses sent from the accumulated liters
      
      
  }
}
void setupDataArray() {
  *((float*)data) = l_sec; // copy flow to first 4 bytes of data
  *((float*)(data + sizeof(float))) = prs_bar; // copy pressure to second 4 bytes of data
  Serial.print(data[0]);
  Serial.print(" ");
  Serial.print(data[1]);
  Serial.print(" ");
  Serial.print(data[2]);
  Serial.print(" ");
  Serial.print(data[3]);
  Serial.print("   ");
  Serial.print(data[4]);
  Serial.print(" ");
  Serial.print(data[5]);
  Serial.print(" ");
  Serial.print(data[6]);
  Serial.print(" ");
  Serial.println(data[7]);
}

void flow() // Interrupt function - count pulses from flowmeter
{
   flowPulseCount++;
}

void flashStatusLed(int count) {
  for (int i = 0; i < count; i++) {
    digitalWrite(statusLed, HIGH);
    delay(100);
    digitalWrite(statusLed, LOW);
    delay(10);
  }
}

void requestEvent() {
  Wire.write(data, dataLength); // respond 
  
}