#pragma once

/**
 * humidity and temperature sensor
 * https://www.ttieurope.com/content/dam/tti-europe/manufacturers/te-connectivity/resources/ENG_DS_HPC199_6_A6.pdf 
 * 
 * this sensor seems to be a bit stubborn.. requiring active polling until it is finished
 * just waiting some time does not seem to work
 * 
 */
template <typename I2C> class HTU2x {
	
private:

	I2C& i2c;
	static constexpr const uint8_t ADDR = 0x40;
	static constexpr const char* NAME = "HTU2x";
	
	static constexpr const uint8_t CMD_QUERY_TEMP = 0xF3;
	static constexpr const uint8_t CMD_QUERY_HUMI = 0xF5;
	static constexpr const uint8_t CMD_READ_USER_REG = 0xE7;
	static constexpr const uint8_t CMD_SOFT_RESET = 0xFE;

	

public:

	HTU2x(I2C& i2c) : i2c(i2c) {
		
	}
			
	/** is the device present on the bus? */
	bool isPresent() {
		return i2c.query(ADDR);
	}
			
	struct Result {
		float temp;
		float humi;
		float humiComp;
	};
				
	/** trigger a single measurement */	
	Result singleMeasure() {
		
		uint8_t tmp[3];	// 2 bytes + checksum
		Result res;
		
		sendCMD(CMD_QUERY_TEMP);
		if (waitForStart()) {
			i2c.readBytes(tmp, 3);
			i2c.stop();
			uint16_t t = ((tmp[0]<<8)|(tmp[1]<<0)) & 0xFFFC;
			//printf("a: %d\n", t);
			res.temp = -46.85f + 175.72 * t / float(1<<16);
		}
		
		sendCMD(CMD_QUERY_HUMI);
		if (waitForStart()) {
			i2c.readBytes(tmp, 3);
			i2c.stop();
			uint16_t h = ((tmp[0]<<8)|(tmp[1]<<0)) & 0xFFFC;
			//printf("b: %d\n", h);
			res.humi = -6 + 125 * h / float(1<<16);
			res.humiComp = res.humi + (-0.15 * (25 - res.temp));
		}
		
		return res;
		
	}
	
private:
	
	bool waitForStart() {
		for (int i = 0; i < 1024; ++i) {
			if (i2c.startRead(ADDR)) {return true;}
		}
		return false;
	}
	
	void sendCMD(uint8_t cmd) {
		i2c.writeRaw(ADDR, 1, &cmd);
	}
	
	void readUserRegister() {
		
		i2c.writeRaw(ADDR, 1, &CMD_SOFT_RESET);
		
		vTaskDelay(100 / portTICK_PERIOD_MS);
		
		uint8_t val = 0xaa;
		i2c.readReg(ADDR, CMD_READ_USER_REG, 1, &val);
		
		printf("user: %d\n", val);
		
	}
		
	
};