/** library to query measurements from peacefair PZEM-004 and PZEM-004T electricity meter
 *  @file
 *  @author King Kévin <kingkevin@cuvoodoo.info>
 *  @copyright SPDX-License-Identifier: GPL-3.0-or-later
 *  @date 2016-2020
 *  @note peripherals used: USART @ref sensor_pzem_usart, timer @ref sensor_pzem_timer
 */
#pragma once

/** a measurement response has been received */
extern volatile bool sensor_pzem_measurement_received;

/** measurements (and configurations) offered by electricity meter */
enum sensor_pzem_measurement_type_t {
	SENSOR_PZEM_VOLTAGE = 0,
	SENSOR_PZEM_CURRENT = 1,
	SENSOR_PZEM_POWER = 2,
	SENSOR_PZEM_ENERGY = 3,
//	SENSOR_PZEM_ADDRESS = 4, // this is a setting, not a measurement
//	SENSOR_PZEM_ALARM = 5, // this is a setting, not a measurement
	SENSOR_PZEM_MAX
};

/** measurement returned by electricity meter */
struct sensor_pzem_measurement_t {
	enum sensor_pzem_measurement_type_t type; /**< measurement type */
	bool valid; /**< is the measurement valid (e.g. format and checksum are correct) */
	/** possible measurement values */
	union measurement_t {
		float voltage; /**< measured voltage in volts */
		float current; /**< measured current in amperes */
		uint16_t power; /**< measured power in watts */
		uint32_t energy; /**< measured energy in watts/hour (24 bits) */
	} value; /**< measurement value */
};

/** setup peripherals to communicate with electricity meter */
void sensor_pzem_setup(void);
/** request measurement from electricity meter
 *  @param[in] address electricity meter device address
 *  @param[in] type measurement type to request
 */
void sensor_pzem_measurement_request(uint32_t address, enum sensor_pzem_measurement_type_t type);
/** decode received measurement
 *  @return decoded measurement (invalid if no new measurement has been received)
 */
struct sensor_pzem_measurement_t sensor_pzem_measurement_decode(void);