#include <Wire.h>

// Default I2C Address for T6713 is 0x15 (decimal 21)
#define T6713_ADDR 0x15
#define I2C_SCL_PIN 20  // Change to your SCL pin
#define I2C_SDA_PIN 6  // Change to your SDA pin

#include <bme68xLibrary.h>
#ifndef BME68X_I2C_ADDR
  #define BME68X_I2C_ADDR 0x76 // Change to 0x77 if sensor not found
#endif
Bme68x bme;

void setup() {
  Serial.begin(115200);
  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN); // Join I2C bus

  Serial.println("Initializing Sensors...");

  // 1. Initialize BME680
  bme.begin(BME68X_I2C_ADDR, Wire);
  if(bme.checkStatus()) {
    Serial.println("BME680 Error: " + bme.statusString());
    if (bme.checkStatus() == BME68X_ERROR) {
      Serial.println("Check wiring or I2C address (0x76 vs 0x77)");
      while(1); // Halt if BME fails
    }
  }
  Serial.println("BME680 Found!");

  // Configure BME680 for "Forced Mode" (On-Demand)
  bme.setTPH(); // Set default oversampling for Temp, Pres, Hum
  
  // Configure Heater for Gas Measurement (300°C for 100ms)
  bme.setHeaterProf(300, 100);

  Serial.println("Sensors Ready. Starting Loop...");
  delay(2000); // Let sensor warm up
}




void loop() {
  Serial.println("-----------------------------");
  
  // --- Read T6713 (CO2) ---
  int co2 = readT6713();
  if (co2 >= 0) {
    Serial.print("T6713  | CO2: "); Serial.print(co2); Serial.println(" ppm");
  } else {
    Serial.println("T6713  | Read Error");
  }

  // --- Read BME680 (Temp, Hum, Pres, Gas) ---
  bme68xData data;
  bme.setOpMode(BME68X_FORCED_MODE); // Trigger measurement
  
  // Wait for measurement to complete (depends on heater duration)
  delay(bme.getMeasDur(BME68X_FORCED_MODE) / 1000 + 50); 

  if (bme.fetchData()) {
    bme.getData(data);
    Serial.print("BME680 | Temp: "); Serial.print(data.temperature); Serial.println(" C");
    Serial.print("BME680 | Hum:  "); Serial.print(data.humidity); Serial.println(" %");
    Serial.print("BME680 | Pres: "); Serial.print(data.pressure / 100.0); Serial.println(" hPa");
    Serial.print("BME680 | Gas:  "); Serial.print(data.gas_resistance / 1000.0); Serial.println(" kOhm");
  } else {
    Serial.println("BME680 | Failed to fetch data");
  }

  // Wait 5 seconds before next cycle
  delay(5000);
}

// Helper function for T6713
int readT6713() {
  Wire.beginTransmission(T6713_ADDR);
  Wire.write(0x04); // Function: Read Input Registers
  Wire.write(0x13); // Address High
  Wire.write(0x8B); // Address Low
  Wire.write(0x00); 
  Wire.write(0x01); // Length (1 register)
  if (Wire.endTransmission() != 0) return -1;

  delay(10); // Processing delay

  Wire.requestFrom(T6713_ADDR, 4);
  if (Wire.available() == 4) {
    Wire.read(); Wire.read(); // Skip Func & Len
    byte high = Wire.read();
    byte low = Wire.read();
    return (high << 8) | low;
  }
  return -1;
}