#ifndef SENS_INA_3221
#define SENS_INA_3221

/** 3-Channel i2c volt/ampere sensor */

template <typename I2C> class INA3221 {
	
private:

	I2C& i2c;
	static constexpr const uint8_t ADDR = 0b1000000;
	static constexpr const char* NAME = "INA3221";
	
	static constexpr const uint8_t REG_CFG = 0x00;
	
	static constexpr const uint8_t REG_CH1_VS = 0x01;	// shunt voltage
	static constexpr const uint8_t REG_CH1_VB = 0x02;	// bus voltage
	
	static constexpr const uint8_t REG_CH2_VS = 0x03;
	static constexpr const uint8_t REG_CH2_VB = 0x04;
	
	static constexpr const uint8_t REG_CH3_VS = 0x05;
	static constexpr const uint8_t REG_CH3_VB = 0x06;

public:

	struct Channel {
		int16_t vShunt;
		int16_t vBus;
	};
	struct Voltages {
		Channel ch1;
		Channel ch2;
		Channel ch3;
	};

public:

	INA3221(I2C& i2c) : i2c(i2c) {
		
	}
	
	/** get the current config */
	uint16_t getConfig() {
		uint16_t res = 0;
		i2c.readReg(ADDR, REG_CFG, 2, (uint8_t*)&res); 
		return res;
	}
	
	/** read all 6 voltages (3 channels, each shunt and bus) */
	Voltages getVoltages() {
		
		uint8_t buf[2];
		Voltages res;
		
		i2c.readReg(ADDR, REG_CH1_VS, sizeof(buf), buf);
		res.ch1.vShunt =	getVoltage(buf);
		i2c.readReg(ADDR, REG_CH1_VB, sizeof(buf), buf);
		res.ch1.vBus =		getVoltage(buf);
		
		i2c.readReg(ADDR, REG_CH2_VS, sizeof(buf), buf);
		res.ch2.vShunt =	getVoltage(buf);
		i2c.readReg(ADDR, REG_CH2_VB, sizeof(buf), buf);
		res.ch2.vBus =		getVoltage(buf);
		
		i2c.readReg(ADDR, REG_CH3_VS, sizeof(buf), buf);
		res.ch3.vShunt =	getVoltage(buf);
		i2c.readReg(ADDR, REG_CH3_VB, sizeof(buf), buf);
		res.ch3.vBus =		getVoltage(buf);
		
		return res;
	}
	
	/** is an INA3221 present on the bus? */
	bool isPresent() {
		return i2c.query(ADDR);
	}
	
private:

	/** convert to bytes into a mV reading */
	int16_t getVoltage(const uint8_t* buf) {
		return ((buf[0] << 8) | (buf[1] << 0));	// the lowest 3 bits are always zero. no shift required!
	}
	
};


#endif // SENS_INA_3221