#include <Wire.h>
#include "DFRobot_RGBLCD1602.h"
#include <cmath>

// --- Xiao ESP32-S3 I2C Pins ---
// !!! FROM YOUR CONFIRMED WORKING SETUP THAT SHOWED "Hello Xiao!" !!!
// !!! PLEASE VERIFY AND UPDATE THESE GPIO NUMBERS !!!
// Example: If SDA is on Xiao D4 (silkscreen) and SCL is on Xiao D5 (silkscreen)
const int I2C_SDA_PIN = 5; // Placeholder: GPIO6 (Xiao D4)
const int I2C_SCL_PIN = 6; // Placeholder: GPIO7 (Xiao D5)

// --- LCD I2C Address for RGB Controller (from DFRobot example & your scan) ---
const uint8_t LCD_RGB_ADDRESS = 0x60; // The DFRobot library uses this in the constructor

// --- LCD Object ---
// Using the constructor that takes (RGBAddr, lcdCols, lcdRows)
DFRobot_RGBLCD1602 lcd(LCD_RGB_ADDRESS, 16, 2);

// --- Thermistor Configuration ---
const int THERMISTOR_PIN = 2;             // ADC Pin for thermistor (D2 / GPIO2 on Xiao)
const float NOMINAL_RESISTANCE = 10000.0;
const float NOMINAL_TEMPERATURE = 25.0;
const float B_COEFFICIENT = 3950.0;
const float SERIES_RESISTOR = 10000.0;
const float V_IN = 3.3;

// --- ADC Reading Parameters ---
const int ADC_MAX = 4095;
const int NUM_SAMPLES = 10;
const int SAMPLE_DELAY_MS = 10;

// ... (includes and all constant definitions remain the same) ...
// !!! ENSURE I2C_SDA_PIN and I2C_SCL_PIN ARE 100% CORRECT FOR YOUR WIRING !!!
// Example: const int I2C_SDA_PIN = 6; const int I2C_SCL_PIN = 7;

void setup() {
  delay(1000); // Increased initial delay to 1 second for maximum power stability

  Serial.begin(115200);
  unsigned long serialStartTime = millis();
  while (!Serial && (millis() - serialStartTime < 3000)) { delay(10); }

  Serial.println("Thermistor + DFRobot LCD - AGGRESSIVE INIT TEST");
  // ... (Serial prints for pins) ...

  Serial.println("Attempting I2C Bus Re-initialization...");
  // No Wire.end() on ESP32 usually, begin just reconfigures
  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN); // First attempt to initialize I2C
  delay(200); // Give it a moment

  // Some suggest a second begin can sometimes help if the bus was stuck
  // Wire.end(); // Not typically available/needed for ESP32 Wire like this
  // Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN);
  // Serial.println("Second Wire.begin() called.");
  // delay(200);

  lcd.init();
  Serial.println("lcd.init() called (Attempt 1).");

  lcd.setPWM(lcd.REG_RED, 0);
  lcd.setPWM(lcd.REG_GREEN, 0);
  lcd.setPWM(lcd.REG_BLUE, 255);
  Serial.println("LCD Backlight set to Blue.");

  lcd.setCursor(0, 0);
  lcd.print("Temp Sensor:");
  lcd.setCursor(0, 1);
  lcd.print("Starting...");
  Serial.println("LCD Initial message displayed.");
  delay(1500);
}


void loop() {
  // --- Read Thermistor ---
  float totalAdcValue = 0;
  for (int i = 0; i < NUM_SAMPLES; i++) {
    totalAdcValue += analogRead(THERMISTOR_PIN);
    delay(SAMPLE_DELAY_MS);
  }
  float averageAdcValue = totalAdcValue / NUM_SAMPLES;
  float vOut = (averageAdcValue / ADC_MAX) * V_IN;
  float thermistorResistance;

  if (V_IN - vOut <= 1e-6) { thermistorResistance = 1e9; }
  else if (vOut <= 1e-6) { thermistorResistance = 1; }
  else { thermistorResistance = SERIES_RESISTOR * (vOut / (V_IN - vOut)); }

  // --- Calculate Temperature ---
  float temperatureCelsius = -999.0;
  if (thermistorResistance > 0 && NOMINAL_RESISTANCE > 0 && B_COEFFICIENT > 0) {
    float t0_kelvin = NOMINAL_TEMPERATURE + 273.15;
    float steinhart_val = thermistorResistance / NOMINAL_RESISTANCE;
    if (steinhart_val > 0) {
      steinhart_val = log(steinhart_val);
      steinhart_val /= B_COEFFICIENT;
      steinhart_val += (1.0 / t0_kelvin);
      if (abs(steinhart_val) > 1e-9) {
        temperatureCelsius = (1.0 / steinhart_val) - 273.15;
      }
    }
  }

  // --- Print to Serial Monitor (useful for debugging even standalone) ---
  Serial.print("Temp C: "); Serial.println(temperatureCelsius, 1);

  // --- Display on LCD ---
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Oven Temp:");

  lcd.setCursor(0, 1);
  if (temperatureCelsius > -273.0) {
    char tempStrC[7];
    dtostrf(temperatureCelsius, 5, 1, tempStrC); // Format for up to XXX.X
    lcd.print(tempStrC);
    lcd.print((char)223); // Degree symbol °
    lcd.print("C");

    // Optional: Change backlight with PWM based on temperature
    // (You can keep this simple or make it more complex)
    if (temperatureCelsius < 50) {
        lcd.setPWM(lcd.REG_BLUE, 255); // Cool = Blue
        lcd.setPWM(lcd.REG_GREEN, 0);
        lcd.setPWM(lcd.REG_RED, 0);
    } else if (temperatureCelsius < 150) {
        lcd.setPWM(lcd.REG_GREEN, 200); // Warm = Greenish/Yellowish
        lcd.setPWM(lcd.REG_BLUE, 50);
        lcd.setPWM(lcd.REG_RED, 150);
    } else { // Hot
        lcd.setPWM(lcd.REG_RED, 255);   // Hot = Red
        lcd.setPWM(lcd.REG_GREEN, 0);
        lcd.setPWM(lcd.REG_BLUE, 0);
    }

  } else {
    lcd.print("Sensor Err");
    lcd.setPWM(lcd.REG_RED, 255); // Error color
    lcd.setPWM(lcd.REG_GREEN, 0);
    lcd.setPWM(lcd.REG_BLUE, 0);
  }

  delay(2000);
}