#include <Arduino.h>
#include <LiquidCrystal_I2C.h>

#define echoPin 18 // attach pin GPIO18 to pin Echo of AJ-SR04M
#define trigPin 5  // attach pin GPIO5 ESP32 to pin Trig of AJ-SR04M
#define sound_speed 0.0344 //sound speed in CM/uSeg                     
#define buzzerPin 13 // attach pin GPIO13 to Buzzer +VE

#define COLS 16 // Columns of LCD
#define ROWS 2 // Rows of LCD

//LiquidCrystal_I2C LCD = LiquidCrystal_I2C(0x27, COLS, ROWS);
LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x27, COLS, ROWS);

long duration; // Time taken for the pulse to reach the receiver
const float distanceEmpty= 180; // Max Critical Distance (180 cms), value clud change depends on of tank size
const float distanceFull= 35; // OverFull distance between sensor and minim water distance (cm). To check & Resize
const float range=distanceEmpty-distanceFull;
int demora;
char* status;

//variable to calc distance & percentage of tank
float distanceCM;
float percentage_measureCM;
float percen;


void displayLCD(const char* tankstatus, float distanceCalc, int percentageCalc)
{
  Serial.println("LCD Msg: " + String(tankstatus));
  Serial.println("LCD Distance cm: " + String(distanceCalc));
  Serial.println("LCD Percentage %: " + String(percentageCalc));

  lcd.clear(); //LCD Clear
  lcd.setCursor(0, 0);
  lcd.print(String(tankstatus) + String(percentageCalc)+"%");
  lcd.setCursor(0, 1);
  lcd.print("Dist.(cm):"+ String(distanceCalc));
}

void buzzerAlert(int demora, const char* status)
{
    Serial.println("Trigger Buzzer - demora: "+ String(demora)+ " / Tipo:" + String(status));

    if (status=="A")
    {
      tone(buzzerPin,587);
      delay(demora);
      noTone(buzzerPin);
    }
    else
    { //Tipo N
      tone(buzzerPin,640);
      delay(1000);
      noTone(buzzerPin);
    }
}

void start_measure()
{
  digitalWrite(trigPin, LOW); //Clears the trigPin
  delayMicroseconds(2); // keep the trigger "OFF"
  digitalWrite(trigPin, HIGH); // turn on the Trigger to generate pulse
  delayMicroseconds(10); // keep the trigger "ON" for 10 ms to generate pulse
  digitalWrite(trigPin, LOW); // Turn off the pulse trigger to stop pulse
}

void setup()
{
  pinMode(trigPin, OUTPUT); //sets trigPin as an Output
  pinMode(echoPin, INPUT);  //sets echoPin as an Input
  Serial.begin(115200); //starts the serial communication
  Serial.println("Distance measurement using AJ-SR04M");
 
  lcd.init();//LCD inicializing 
  lcd.backlight(); // Turn on the backlight

  displayLCD ("Starting measurement...",0,0); //Display Setup/Start
  delay(2000);

  lcd.setCursor(0,1);
  lcd.print("Start in 5..."); //You can write 16 Characters per line .
  delay(1000); //wait 3 sec
  lcd.setCursor(0,1);
  lcd.print("Start in 4..."); //You can write 16 Characters per line .
  delay(1000); //wait 3 sec
  lcd.setCursor(0,1);
  lcd.print("Start in 3..."); //You can write 16 Characters per line .
  delay(1000); //wait 3 sec
  lcd.setCursor(0,1);
  lcd.print("Start in 2..."); //You can write 16 Characters per line .
  delay(1000); //wait 3 sec
  lcd.setCursor(0,1);
  lcd.print("Start in 1..."); //You can write 16 Characters per line .
  delay(1000); //wait 3 sec

  // Buzzer test on Setup/Start
  buzzerAlert(1000,"N"); //Buzzer alert beep
}

void loop()
{
  
  start_measure(); // Start measure with AJ-SR04M, using trigPin

  // If pulse reached the receiver echoPin
  // become high Then pulseIn() returns the
  // time taken by the pulse to reach the receiver
  duration = pulseIn(echoPin, HIGH); //Reads the echoPin, returnd the sound wave travel time in uSeg
  distanceCM = duration * sound_speed / 2;
  
  // % Calc. value about distanceCM / distanceFull / range
  percentage_measureCM = ((distanceCM-distanceFull)/range)*100;
  Serial.println("===========================");
  Serial.println("Values");
  Serial.println("===========================");
  Serial.println("Tank %: " + String(percentage_measureCM));
  Serial.print("Distance: " + String(distanceCM));
  Serial.println(" cm");
  Serial.println("===========================");
  

if (distanceCM >= distanceEmpty)
 { //Tank Empty (LOW LIQUID)
    if (percentage_measureCM > 99) // Si super el Umbral Max
    {  percen = 0; // cuando es > 99, ponemos que el tanque esta vacio
    }
    displayLCD ("Empty! ", distanceCM, percen); // display LCD Empty tank!!
    buzzerAlert(3000, "A"); //Buzzer alert code
    Serial.println("Lectura :Empty - Wait 10 seg");
    delay(10000); //luego de una lectura correcta esperamos 10 seg para volver a leer
 }
else
 {if (distanceCM <= distanceFull)
    { //Tank Over Full
      displayLCD ("Full!", distanceCM, 100);
      buzzerAlert(3000, "A"); //Buzzer alert code
      Serial.println("Lectura :Empty - Wait 10 seg");
      delay(10000); //luego de una lectura correcta esperamos 10 seg para volver a leer
    }
  else
  { //Tank Normal
    displayLCD ("Tank:", distanceCM, (100-percentage_measureCM));
    Serial.println("Lectura :OK - Wait 60 seg");
    delay(60000); //luego de una lectura correcta esperamos 60 seg para volver a leer
  } 
 }
  
  //Delay ms to start loop again
  delay(100);
}