#include <Wire.h>

#define I2C_ADDR 0x04

// I2C Communication (Taken from Groove sensor, hoping to use the same library on client side)
#define CMD_ADC_NH3             1     // NH3 channel
#define CMD_ADC_CO              2     // CO channel
#define CMD_ADC_NO2             3     // NO2 channel
#define CMD_ADC_ALL             4     // All channels
#define CMD_CHANGE_I2C          5     // I2C address change
#define CMD_READ_EEPROM         6     // Read stored data from EEPROM as unsigned int
#define CMD_SET_R0_ADC          7     // Set R0 ADC value
#define CMD_GET_R0_ADC          8     // Get R0 ADC value
#define CMD_GET_R0_ADC_DEFAULT  9     // Get factory R0 ADC value
#define CMD_CONTROL_LED         10    // Control LED (no LED on my board, but Groove supports is, so ... meh!)
#define CMD_CONTROL_PWR         11    // Heater control

// EEPROM Addresses (Match Groove addresses)
#define EEPROM_INIT_DONE        0
#define EEPROM_DEFAULT_ADC_NH3  2
#define EEPROM_DEFAULT_ADC_CO   4
#define EEPROM_DEFAULT_ADC_NO2  6
#define EEPROM_ADC_NH3          8
#define EEPROM_ADC_CO           10
#define EEPROM_ADC_NO2          12
#define EEPROM_I2C_ADDR         20


void setup() {
  Serial.begin(115200);
  // Connect to sensor through wire lib directly
  Wire.begin();

  // Check version
  Wire.beginTransmission(I2C_ADDR);
  Wire.write(CMD_READ_EEPROM);
  Wire.write(EEPROM_INIT_DONE);
  Wire.endTransmission();
  uint8_t returned = Wire.requestFrom(I2C_ADDR, 2);
  if (returned == 2 && Wire.available() == 2) {
    uint8_t msb = Wire.read();
    uint8_t lsb = Wire.read();
    Serial.print("Init data: ");
    Serial.println((msb << 8) | lsb);
  } else {
    Serial.println("ERROR 1234: Unexpected data!");
  }

  // Activate Heater
  Wire.beginTransmission(I2C_ADDR);
  Wire.write(CMD_CONTROL_PWR);
  Wire.write(1);
  Wire.endTransmission();
}

void loop() {
  // Grab all data
  Wire.beginTransmission(I2C_ADDR);
  Wire.write(CMD_ADC_ALL);
  Wire.endTransmission();
  delayMicroseconds(50);
  uint8_t ret = Wire.requestFrom(I2C_ADDR, 6);
  if (ret == 6 && Wire.available() == 6) {
    uint16_t data[3];
    for (uint8_t i = 0; i < 3; ++i) {
      uint8_t msb = Wire.read();
      uint8_t lsb = Wire.read();
      data[i] = (msb << 8) | lsb; 
    }
    Serial.print(data[0]);
    Serial.print("\t");
    Serial.print(data[1]);
    Serial.print("\t");
    Serial.println(data[2]);
  } else {
    Serial.print("Request error! - Returned bytes: ");
    Serial.println(ret);
  }

  delay(50);
}