#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Arduino.h>
#include "HX711.h"
#include "soc/rtc.h"
#include "HX711.h"
#include <Pushbutton.h>


#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

const int trigPin = 5;
const int echoPin = 18;
const float tankHeight = 71.12; // Height of the liquid tank in centimeters
const float tankRadius = 17.78; // Radius of the liquid tank in centimeters
const float emptyThreshold = 1.0; // Distance threshold below which the tank is considered empty
const float maxDistance = 65.0;
const float pi = 3.14159265359; // Maximum distance to measure in centimeters

//define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701

const int LOADCELL_DOUT_PIN = 16;
const int LOADCELL_SCK_PIN = 4;

HX711 scale;
int reading;
int lastReading;
//REPLACE WITH YOUR CALIBRATION FACTOR
#define CALIBRATION_FACTOR -471.497

//OLED Display
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)

//Button
#define BUTTON_PIN 19
Pushbutton button(BUTTON_PIN);

long duration;
float distanceCm;
float distanceInch;

void setup() {
  Serial.begin(115200);
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  delay(500);
  display.clearDisplay();

  //rtc_clk_cpu_freq_set(RTC_CPU_FREQ_80M);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  delay(2000);
  display.clearDisplay();
  display.setTextColor(WHITE);
  
  Serial.println("Initializing the scale");
  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);

  scale.set_scale(CALIBRATION_FACTOR);   // this value is obtained by calibrating the scale with known weights; see the README for details
  scale.tare();               // reset the scale to 0

  display.setTextSize(2);
  display.setTextColor(WHITE);


  Serial.println("Setup done");
}

void loop() {

  // Wait a bit before scanning again
  delay(5000);
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  
  // Calculate the distance
  distanceCm = duration * SOUND_SPEED/2;

  if (distanceCm > 0 && distanceCm < tankHeight) { // Check if the distance is out of range
    float volume = pi * tankRadius * tankRadius * (100 - distanceCm);
    Serial.print(distanceCm);
    Serial.println(" cm");
    Serial.print(volume);
    Serial.println(" liters");
    delay(1000); // Wait for one second before taking the next measurement
    return; // Exit the loop without calculating volume
  } else {
    Serial.println("Out of range");
  }
  
  // Prints the distance in the Serial Monitor
  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);

  display.clearDisplay();
  display.setCursor(0, 5);
  //Display distance in cm
  
  display.print(distanceCm);
  display.print(" cm");
  float volume = pi * tankRadius * tankRadius * (100 - distanceCm);
  display.print(volume);
  display.println(" liters");
  delay(1000); // Wait for one second before taking the next measurement
  //return; // Exit the loop without calculating volume
  display.print("Out of range");
  //display.print(distanceCm);
  //display.print(" cm");
  
  // Display distance in inches
  /* display.print(distanceInch);
  display.print(" in");*/

  if (button.getSingleDebouncedPress()){
    Serial.print("tare...");
    scale.tare();
  }
  
  if (scale.wait_ready_timeout(200)) {
    reading = round(scale.get_units());
    Serial.print("Weight: ");
    Serial.println(reading);
    if (reading != lastReading){
      display.print(reading);  
    }
    lastReading = reading;
  }
  else {
    Serial.println("HX711 not found.");
  }
  display.display();

  delay(500);  
}