#include <LiquidCrystal.h>
#include <Adafruit_NeoPixel.h>

volatile int flow_frequency; // Measures flow sensor pulses

// Calculated litres/hour

float vol = 0.0,l_minute;

unsigned char flowsensor = 2; // Sensor Input

unsigned long currentTime;

unsigned long cloopTime;

LiquidCrystal lcd(12, 11, 5, 4, 3, 9);

// Time
signed short seconds, minutes;

char timeline[16];

// LED ring
Adafruit_NeoPixel strip = Adafruit_NeoPixel(24, 13, NEO_GRB + NEO_KHZ800);

int nextLED = 40 - (40/24);
int nextLEDindex = 23;

// buzzer
const int buzzer = 9;

int nextTone = 1;

void flow () // Interrupt function
{

   flow_frequency++;

}

void setup()
{

   pinMode(flowsensor, INPUT);

   digitalWrite(flowsensor, HIGH); // Optional Internal Pull-Up

   Serial.begin(9600);

   lcd.begin(20, 4);

   attachInterrupt(digitalPinToInterrupt(flowsensor), flow, RISING); // Setup Interrupt

   lcd.clear();

   lcd.setCursor(0,0);

   lcd.print("Water Flow Meter");

   currentTime = millis();

   cloopTime = currentTime;

   // LED ring starts with all lights green
   strip.begin();
   strip.setBrightness(150); //adjust brightness here
   colorWipe(strip.Color(0, 255, 0), 50); // Green

   // buzzer
   pinMode(buzzer, OUTPUT);

}

// Fill the dots one after the other with a color
void colorWipe(uint32_t c, uint8_t wait) {
  for(uint16_t i=0; i<strip.numPixels(); i++) {

      strip.setPixelColor(i, c);
      strip.show();
      delay(wait);
  }
}

// Delete light after time goes: every 40/24 one gets deleted
void deleteLight(int index) {
  strip.setPixelColor(index, strip.Color(0,0,0));
  if (index == 12) {
    for (int i = 0; i < index; i++) {
      strip.setPixelColor(index, strip.Color(255,255,0));
    }
  }
  if (index == 6) {
    for (int i = 0; i < index; i++) {
      strip.setPixelColor(index, strip.Color(255,0,0));
    }
  }
  strip.show();
}

void loop ()
{

   currentTime = millis();

   // Every second, calculate and print litres/hour

   if(currentTime >= (cloopTime + 1000))
   {

    cloopTime = currentTime; // Updates cloopTime

    if(flow_frequency != 0){
      Serial.println(" flow rate = 1 ");
      // Pulse frequency (Hz) = 7.5Q, Q is flow rate in L/min.

      l_minute = (flow_frequency / 7.5); // (Pulse frequency x 60 min) / 7.5Q = flowrate in L/hour

      lcd.clear();

      lcd.setCursor(0,0);

      lcd.print("Water Flow Meter");

      lcd.setCursor(0,1);

      l_minute = l_minute/60;

      vol = vol +l_minute;

      lcd.print("Vol:");

      lcd.print(vol);

      lcd.print(" L");

      flow_frequency = 0; // Reset Counter

      Serial.print(l_minute, DEC); // Print litres/hour

      Serial.println(" L/Sec");

      seconds++;
      if (seconds == 60) {
        seconds = 0;
        minutes++;
      }

      lcd.setCursor(0,2);

      sprintf(timeline,"%0.2d min %0.2d sec", minutes, seconds);
      lcd.print("Time: ");
      lcd.print(timeline);

      // turn led off if necessary
      if (vol <= nextLED && nextLEDindex >= 0) {
        deleteLight(nextLEDindex);
        nextLED = nextLED - 40/24;
        nextLEDindex = nextLEDindex - 1;
      } 

      // if one liter spent, make sound
      if (vol >= nextTone) {
        tone(buzzer, 1000);
        nextTone++;
      }
      else {
        noTone(buzzer);
      }

    }

    else {
      Serial.println(" flow rate = 0 ");

      lcd.clear();

      lcd.setCursor(0,0);

      lcd.print("Water Flow Meter");

      lcd.setCursor(0,1);

      lcd.print("Vol:");

      lcd.print(vol);

      lcd.print(" L");

      seconds++;
      if (seconds == 60) {
        seconds = 0;
        minutes++;
      }

      sprintf(timeline,"%0.2d min %0.2d sec", minutes, seconds);
      lcd.setCursor(0, 2);
      lcd.print("Time: ");
      lcd.print(timeline);

    }

   }

}