#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Set the LCD address to 0x27 or 0x3F depending on your module
LiquidCrystal_I2C lcd(0x27, 16, 2); // 16 columns and 2 rows


// Custom bar characters (levels 1 to 5)
byte bar0[8] = { B11111, B10001, B10001, B10001, B10001, B10001, B10001, B11111  };
byte bar1[8] = { B10000, B10000, B10000, B10000, B10000, B10000, B10000, B10000 };
byte bar2[8] = { B11000, B11000, B11000, B11000, B11000, B11000, B11000, B11000 };
byte bar3[8] = { B11100, B11100, B11100, B11100, B11100, B11100, B11100, B11100 };
byte bar4[8] = { B11110, B11110, B11110, B11110, B11110, B11110, B11110, B11110 };
byte bar5[8] = { B11111, B11111, B11111, B11111, B11111, B11111, B11111, B11111 };

const int turbidityPin = A0;

int getAverageReading(int pin, int samples = 10) {
  long sum = 0;
  for (int i = 0; i < samples; i++) {
    sum += analogRead(pin);
    delay(10);  // small delay between samples
  }
  return sum / samples;
}


void setup() {
  lcd.init();               // Initialize the LCD
  lcd.backlight();           // Turn on the backlight
  lcd.setCursor(0, 0);       // Set cursor to column 0, row 0
  lcd.print("Hello, World!");
  lcd.setCursor(0, 1);       // Set cursor to column 0, row 1
  lcd.print("I2C LCD Test");
  Serial.begin(9600);

  // Create custom bar characters
  lcd.createChar(0, bar0);
  lcd.createChar(1, bar1);
  lcd.createChar(2, bar2);
  lcd.createChar(3, bar3);
  lcd.createChar(4, bar4);
  lcd.createChar(5, bar5);
}

void loop() {
  int sensorValue = getAverageReading(turbidityPin);
  float voltage = sensorValue * (5.0 / 1023.0);
  // float turbidity = -1120.4 * sq(voltage) + 5742.3 * voltage - 4352.9;
  float turbidity = map(sensorValue, 1023, 500, 0, 300);

  // Clamp negative NTU to 0
  if (turbidity < 0) turbidity = 0;

  // Interpret water status
  String status;
  if (turbidity < 1) status = "Very Clear";
  else if (turbidity < 5) status = "Clear";
  else if (turbidity < 10) status = "Slightly Muddy";
  else if (turbidity < 50) status = "Muddy";
  else if (turbidity < 100) status = "Very Muddy";
  else status = "Extremely Turbid";

  // Display NTU
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("NTU: ");
  lcd.print(turbidity, 1);  // 1 decimal place

  // Draw bar graph (0–10 scale mapped to blocks)
  int level;
  if (turbidity < 1) level = 0;
  else if (turbidity < 5) level = 1;
  else if (turbidity < 10) level = 2;
  else if (turbidity < 50) level = 3;
  else if (turbidity < 100) level = 4;
  else level = 5;  // for very turbid, max bars

  int bars = level;
  lcd.setCursor(11, 0);
  for (int i = 0; i < 10; i++) {
    if (i < bars)
      lcd.write(byte(5));  // full block
    else
      lcd.write(byte(0));  // empty block
  }

  // Display status on line 2
  lcd.setCursor(0, 1);
  lcd.print(status.substring(0, 16));  // Fit in 16 characters

  // Serial Monitor Output
  Serial.print("Sensor Value: ");
  Serial.print(sensorValue);
  Serial.print("  | Voltage: ");
  Serial.print(voltage, 3);  // 3 decimal places
  Serial.print(" V  | Turbidity: ");
  Serial.print(turbidity, 2); // 2 decimal places
  Serial.println(" NTU");
  delay(1000);
}