#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <HX711_ADC.h>

// Pin definitions for HX711
const int HX711_dout = 4; // HX711 data pin
const int HX711_sck = 5;  // HX711 clock pin

// HX711 constructor
HX711_ADC LoadCell(HX711_dout, HX711_sck);

// OLED display settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_ADDR 0x3C  // OLED I2C address

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);  // Initialize OLED

// Calibration value for HX711
const int calVal_eepromAdress = 0;
unsigned long t = 0;

void setup() {
  Serial.begin(115200);  // Start serial communication
  delay(10);
  Serial.println("Starting...");

  // Initialize HX711 load cell
  LoadCell.begin();
  unsigned long stabilizingtime = 2000;
  boolean _tare = true;  // Tare the load cell
  LoadCell.start(stabilizingtime, _tare);
  
  if (LoadCell.getTareTimeoutFlag() || LoadCell.getSignalTimeoutFlag()) {
    Serial.println("Timeout, check MCU>HX711 wiring and pin designations");
    while (1);  // Wait forever if HX711 fails
  } else {
    LoadCell.setCalFactor(1.0);  // Calibration factor
    Serial.println("Startup is complete");
  }

  // Initialize OLED
  Wire.begin(21, 22);  // SDA, SCL pins for ESP32
  if (!display.begin(SSD1306_PAGEADDR, OLED_ADDR)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);  // Stay here if initialization fails
  }
  
  display.clearDisplay();  // Clear display buffer
  display.setTextSize(1);  // Set text size
  display.setTextColor(SSD1306_WHITE);  // Set text color
  display.setCursor(0, 0);  // Set cursor position

  calibrate();  // Start calibration procedure
}

void loop() {
  static boolean newDataReady = 0;
  const int serialPrintInterval = 0; // Print interval (increase to slow down output)

  // Check for new data from HX711
  if (LoadCell.update()) newDataReady = true;

  if (newDataReady) {
    if (millis() > t + serialPrintInterval) {
      float weight = LoadCell.getData();  // Get weight from load cell
      Serial.print("Load_cell output val: ");
      Serial.println(weight);
      
      // Convert weight to points
      int points = weightToPoints(weight);
      Serial.print("Converted points: ");
      Serial.println(points);

      // Display data on OLED
      display.clearDisplay();
      display.setCursor(0, 0);  // Reset cursor
      display.print("Weight: ");
      display.print(weight, 2);  // Display weight with 2 decimal places
      display.println(" kg");

      display.print("Points: ");
      display.println(points);  // Display converted points
      display.display();  // Update OLED display

      newDataReady = 0;
      t = millis();
    }
  }

  // Handle serial commands
  if (Serial.available() > 0) {
    char inByte = Serial.read();
    if (inByte == 't') LoadCell.tareNoDelay();  // Tare load cell
    else if (inByte == 'r') calibrate();  // Start calibration
    else if (inByte == 'c') changeSavedCalFactor();  // Edit calibration factor
  }

  // Check if last tare operation is complete
  if (LoadCell.getTareStatus() == true) {
    Serial.println("Tare complete");
  }
}

void calibrate() {
  Serial.println("***");
  Serial.println("Start calibration:");
  Serial.println("Place the load cell on a level stable surface.");
  Serial.println("Remove any load applied to the load cell.");
  Serial.println("Send 't' from serial monitor to set the tare offset.");

  boolean _resume = false;
  while (!_resume) {
    LoadCell.update();
    if (Serial.available() > 0) {
      char inByte = Serial.read();
      if (inByte == 't') LoadCell.tareNoDelay();
    }
    if (LoadCell.getTareStatus() == true) {
      Serial.println("Tare complete");
      _resume = true;
    }
  }

  Serial.println("Now, place your known mass on the load cell.");
  Serial.println("Then send the weight of this mass (i.e. 100.0) from serial monitor.");

  float known_mass = 0;
  _resume = false;
  while (!_resume) {
    LoadCell.update();
    if (Serial.available() > 0) {
      known_mass = Serial.parseFloat();
      if (known_mass != 0) {
        Serial.print("Known mass is: ");
        Serial.println(known_mass);
        _resume = true;
      }
    }
  }

  LoadCell.refreshDataSet();
  float newCalibrationValue = LoadCell.getNewCalibration(known_mass);

  Serial.print("New calibration value: ");
  Serial.println(newCalibrationValue);
  Serial.println("End calibration");
  Serial.println("***");
}

void changeSavedCalFactor() {
  float oldCalibrationValue = LoadCell.getCalFactor();
  boolean _resume = false;
  Serial.println("***");
  Serial.print("Current value is: ");
  Serial.println(oldCalibrationValue);
  Serial.println("Send new value from serial monitor.");

  float newCalibrationValue;
  while (!_resume) {
    if (Serial.available() > 0) {
      newCalibrationValue = Serial.parseFloat();
      if (newCalibrationValue != 0) {
        Serial.print("New calibration value: ");
        Serial.println(newCalibrationValue);
        LoadCell.setCalFactor(newCalibrationValue);
        _resume = true;
      }
    }
  }
}

int weightToPoints(float weight) {
  // Convert weight (kg) to points
  if (weight >= 0 && weight <= 100) {
    return (int)(weight * 10);  // Example: 1 kg = 10 points
  } else {
    return 0;  // Out of range
  }
}