libscd 0.5.1

pub use crate::internal::scd4x::I2C_ADDRESS;

use crate::error::Error;
use crate::measurement::Measurement;
use crate::synchronous::i2c::{i2c_read, i2c_write};
use embedded_hal::delay::DelayNs;
use embedded_hal::i2c::I2c;

use crate::internal::scd4x::{
    decode_frc_status, decode_has_data_ready, decode_measurement, decode_sensor_variant,
    decode_serial_number, decode_temperature_offset, encode_temperature_offset, Command,
    AMBIENT_PRESSURE_RANGE_HPA, GET_AMBIENT_PRESSURE, GET_AUTOMATIC_SELF_CALIBRATION_ENABLED,
    GET_AUTOMATIC_SELF_CALIBRATION_TARGET, GET_DATA_READY_STATUS, GET_SENSOR_ALTITUDE,
    GET_SENSOR_VARIANT, GET_SERIAL_NUMBER, GET_TEMPERATURE_OFFSET, MAX_ALTITUDE,
    PERFORM_FACTORY_RESET, PERFORM_FORCED_RECALIBRATION, PERFORM_SELF_TEST, PERSIST_SETTINGS,
    READ_MEASUREMENT, REINIT, SET_AMBIENT_PRESSURE, SET_AUTOMATIC_SELF_CALIBRATION_ENABLED,
    SET_AUTOMATIC_SELF_CALIBRATION_TARGET, SET_SENSOR_ALTITUDE, SET_TEMPERATURE_OFFSET,
    START_LOW_POWER_PERIODIC_MEASUREMENT, START_PERIODIC_MEASUREMENT, STOP_PERIODIC_MEASUREMENT,
};

#[cfg(feature = "scd41")]
use crate::internal::scd4x::{
    GET_AUTOMATIC_SELF_CALIBRATION_INITIAL_PERIOD, GET_AUTOMATIC_SELF_CALIBRATION_STANDARD_PERIOD,
    MEASURE_SINGLE_SHOT, MEASURE_SINGLE_SHOT_RHT_ONLY, POWER_DOWN,
    SET_AUTOMATIC_SELF_CALIBRATION_INITIAL_PERIOD, SET_AUTOMATIC_SELF_CALIBRATION_STANDARD_PERIOD,
    WAKE_UP,
};
use crate::SensorVariant;

/// Driver implementation for the SCD4x family of CO2 sensors. This driver is
/// compatible with both SCD40 and SCD41 devices.
///
/// Some operations are available only for SCD41 devices. They need to be
/// enabled via the `scd41` feature flag.
pub struct Scd4x<I2C, D> {
    i2c: I2C,
    delay: D,
    measurement_started: bool,
}

impl<I2C, D, E> Scd4x<I2C, D>
where
    I2C: I2c<Error = E>,
    D: DelayNs,
{
    /// Create a new sensor using the provided I2C bus and delay implementation
    pub fn new(i2c: I2C, delay: D) -> Self {
        Self {
            i2c,
            delay,
            measurement_started: false,
        }
    }

    /// Release the I2C bus held by this sensor
    pub fn release(self) -> I2C {
        self.i2c
    }

    fn check_is_command_allowed(&self, cmd: Command) -> Result<(), Error<E>> {
        if self.measurement_started & !cmd.allowed_while_running {
            return Err(Error::NotAllowed);
        }

        Ok(())
    }

    fn read_response(&mut self, read_buf: &mut [u8]) -> Result<(), Error<E>> {
        i2c_read(&mut self.i2c, I2C_ADDRESS, read_buf)
    }

    fn write_command(&mut self, cmd: Command) -> Result<(), Error<E>> {
        self.check_is_command_allowed(cmd)?;

        let buf = cmd.prepare();
        i2c_write(&mut self.i2c, I2C_ADDRESS, &buf)?;
        self.delay.delay_ms(cmd.exec_time as u32);

        Ok(())
    }

    fn write_command_with_data(&mut self, cmd: Command, data: u16) -> Result<(), Error<E>> {
        self.check_is_command_allowed(cmd)?;

        let buf = cmd.prepare_with_data(data);
        i2c_write(&mut self.i2c, I2C_ADDRESS, &buf)?;
        self.delay.delay_ms(cmd.exec_time as u32);

        Ok(())
    }

    fn command_with_response(&mut self, cmd: Command, read_buf: &mut [u8]) -> Result<(), Error<E>> {
        self.write_command(cmd)?;
        self.read_response(read_buf)
    }

    fn command_with_data_and_response(
        &mut self,
        cmd: Command,
        data: u16,
        read_buf: &mut [u8],
    ) -> Result<(), Error<E>> {
        self.write_command_with_data(cmd, data)?;
        self.read_response(read_buf)
    }

    /// Start periodic measurement mode. The default signal update interval
    /// is 5 seconds.
    pub fn start_periodic_measurement(&mut self) -> Result<(), Error<E>> {
        self.write_command(START_PERIODIC_MEASUREMENT)?;
        self.measurement_started = true;
        Ok(())
    }

    /// Stop periodic measurement mode to change the sensor configuration or
    /// to save power.
    ///
    /// Note that the sensor will only respond to other commands 500 ms after
    /// the `stop_periodic_measurement()` command has been issued.
    pub fn stop_periodic_measurement(&mut self) -> Result<(), Error<E>> {
        self.write_command(STOP_PERIODIC_MEASUREMENT)?;
        self.measurement_started = false;
        Ok(())
    }

    /// Start low power periodic measurement mode, signal update interval
    /// is approximately 30 seconds.
    pub fn start_low_power_periodic_measurement(&mut self) -> Result<(), Error<E>> {
        self.write_command(START_LOW_POWER_PERIODIC_MEASUREMENT)
    }

    /// Check if there is a measurement data ready to be read
    pub fn data_ready(&mut self) -> Result<bool, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_DATA_READY_STATUS, &mut buf)?;
        Ok(decode_has_data_ready(buf))
    }

    /// Read sensor output.
    ///
    /// The measurement data can only be read out  once per signal update
    /// interval as the buffer is emptied upon read-out. If no data is
    /// available in the buffer, the sensor returns a NACK. To avoid a
    /// NACK response, the `data_ready()` method can be issued to check
    /// data status.
    pub fn read_measurement(&mut self) -> Result<Measurement, Error<E>> {
        let mut buf = [0; 9];
        self.command_with_response(READ_MEASUREMENT, &mut buf)?;
        Ok(decode_measurement(buf))
    }

    /// Configure the temperature offset
    pub fn set_temperature_offset(&mut self, offset: f32) -> Result<(), Error<E>> {
        let value = encode_temperature_offset(offset)?;
        self.write_command_with_data(SET_TEMPERATURE_OFFSET, value)
    }

    /// Retrieve the configured temperature offset
    pub fn get_temperature_offset(&mut self) -> Result<f32, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_TEMPERATURE_OFFSET, &mut buf)?;
        Ok(decode_temperature_offset(buf))
    }

    /// Reading and writing the sensor altitude must be done while the SCD4x
    /// is in idle mode. Typically, the sensor altitude is set once after
    /// device installation. To save the setting to the EEPROM, the
    /// `persist_settings()` (see Section 3.9.1) command must be issued.
    ///
    /// The default sensor altitude value is set to 0 meters above sea level.
    /// Valid input values are between 0 – 3_000 m.
    pub fn set_sensor_altitude(&mut self, altitude: u16) -> Result<(), Error<E>> {
        if altitude > MAX_ALTITUDE {
            return Err(Error::InvalidInput);
        }

        self.write_command_with_data(SET_SENSOR_ALTITUDE, altitude)
    }

    /// The `get_sensor_altitude()` command can be sent while the SCD4x
    /// is in idle mode to read out the previously saved sensor altitude
    /// value set by the `set_sensor_altitude()` command.
    pub fn get_sensor_altitude(&mut self) -> Result<u16, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_SENSOR_ALTITUDE, &mut buf)?;

        Ok(u16::from_be_bytes([buf[0], buf[1]]))
    }

    /// The `set_ambient_pressure()` command can be sent during periodic
    /// measurements to enable continuous pressure compensation. Note that
    /// setting an ambient pressure overrides any pressure compensation
    /// based on a previously set sensor altitude. Use of this command is
    /// highly recommended for applications experiencing significant ambient
    /// pressure changes to ensure sensor accuracy. Valid input values are
    /// between 700-1200 HPa. The default value is 1013 HPa.
    pub fn set_ambient_pressure(&mut self, pressure: u16) -> Result<(), Error<E>> {
        if !AMBIENT_PRESSURE_RANGE_HPA.contains(&pressure) {
            return Err(Error::InvalidInput);
        }

        self.write_command_with_data(SET_AMBIENT_PRESSURE, pressure)
    }

    /// The `get_ambient_pressure` command can be sent during periodic
    /// measurements to read out the previously  saved ambient pressure value
    /// set by the `set_ambient_pressure` command.
    pub fn get_ambient_pressure(&mut self) -> Result<u16, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_AMBIENT_PRESSURE, &mut buf)?;

        Ok(u16::from_be_bytes([buf[0], buf[1]]))
    }

    /// Set the current state (enabled / disabled) of the ASC. By default,
    /// ASC is enabled. To save the setting to the EEPROM, the
    /// `persist_settings()` (see Section 3.9.1) command must be issued.
    pub fn enable_automatic_self_calibration(&mut self, enabled: bool) -> Result<(), Error<E>> {
        self.write_command_with_data(SET_AUTOMATIC_SELF_CALIBRATION_ENABLED, enabled as u16)
    }

    /// Check if the automatic self calibration algorithm is enabled
    pub fn get_automatic_self_calibration(&mut self) -> Result<bool, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_AUTOMATIC_SELF_CALIBRATION_ENABLED, &mut buf)?;

        let raw_status = u16::from_be_bytes([buf[0], buf[1]]);
        Ok(raw_status != 0)
    }

    /// The `set_automatic_self_calibration_target()` command can be sent when
    /// the SCD4x is in idle mode. It sets the value of the ASC baseline target.
    /// This is the lower-bound background CO2 concentration the sensor is exposed
    /// to regularly. The default value is 400.
    pub fn set_automatic_self_calibration_target(&mut self, ppm_co2: u16) -> Result<(), Error<E>> {
        self.write_command_with_data(SET_AUTOMATIC_SELF_CALIBRATION_TARGET, ppm_co2)
    }

    /// The `get_automatic_self_calibration_target()` command can be sent when
    /// the SCD4x is in idle mode. It gets the value of the ASC baseline target.
    pub fn get_automatic_self_calibration_target(&mut self) -> Result<u16, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_AUTOMATIC_SELF_CALIBRATION_TARGET, &mut buf)?;

        Ok(u16::from_be_bytes([buf[0], buf[1]]))
    }

    /// The `perform_forced_recalibration()` command can be sent when the SCD4x
    /// is in idle mode after having been in operation for at least 3 minutes in
    /// an environment with a homogenous and constant CO2 concentration that is
    /// already known.
    ///
    /// `ppm_co2` refers to the current CO2 level.
    ///
    /// An `Ok(None)` value indicates that the FRC has failed, because
    /// the sensor was not operated before sending the command.
    ///
    /// An `Ok(Some(_))` value indicates that the FRC was applied. It contains
    /// the magnitude of the correction
    pub fn perform_forced_recalibration(&mut self, ppm_co2: u16) -> Result<Option<i16>, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_data_and_response(PERFORM_FORCED_RECALIBRATION, ppm_co2, &mut buf)?;
        Ok(decode_frc_status(buf))
    }

    /// Configuration settings such as the temperature offset, sensor altitude
    /// and the ASC enabled/disabled parameters are by default stored in the
    /// volatile memory (RAM) only and will be lost after a power-cycle.
    /// The `persist_settings()` command  stores the current configuration in
    /// the EEPROM of the SCD4x, ensuring the settings persist across
    /// power-cycling. To avoid unnecessary wear of the EEPROM,
    /// the `persist_settings()` command should only be sent when persistence
    /// is required and if actual changes to the configuration have been made.
    pub fn persists_settings(&mut self) -> Result<(), Error<E>> {
        self.write_command(PERSIST_SETTINGS)
    }

    /// Reading out the serial number can be used to identify the chip
    /// and to verify the presence of the sensor.
    pub fn serial_number(&mut self) -> Result<u64, Error<E>> {
        let mut buf = [0; 9];
        self.command_with_response(GET_SERIAL_NUMBER, &mut buf)?;
        Ok(decode_serial_number(buf))
    }

    // Read out the sensor variant (scd40, scd41, scd43)
    pub fn sensor_variant(&mut self) -> Result<Option<SensorVariant>, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_SENSOR_VARIANT, &mut buf)?;
        Ok(decode_sensor_variant(buf))
    }

    /// The `perform_self_test()` command can be used as an end-of-line
    /// test to check the sensor functionality.
    pub fn perform_self_test(&mut self) -> Result<bool, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(PERFORM_SELF_TEST, &mut buf)?;

        let status = u16::from_be_bytes([buf[0], buf[1]]);
        Ok(status == 0)
    }

    /// The perform_factory_reset command resets all configuration
    /// settings stored in the EEPROM and erases the FRC and ASC
    /// algorithm history.
    pub fn perform_factory_reset(&mut self) -> Result<(), Error<E>> {
        self.write_command(PERFORM_FACTORY_RESET)
    }

    /// The reinit command reinitializes the sensor by reloading user
    /// settings from EEPROM.
    ///
    /// Before sending the reinit command, the`stop_periodic_measurement()`
    /// command must be issued. If the reinit command does not trigger the
    /// desired re-initialization, a power-cycle should be applied to
    /// the SCD4x.
    pub fn reinit(&mut self) -> Result<(), Error<E>> {
        self.write_command(REINIT)
    }

    /// On-demand measurement of CO2 concentration, relative humidity and
    /// temperature. The sensor output is read out by using the
    /// `read_measurement()` command (Section 3.5.2).
    #[cfg(feature = "scd41")]
    pub fn measure_single_shot(&mut self) -> Result<(), Error<E>> {
        self.write_command(MEASURE_SINGLE_SHOT)
    }

    /// On-demand measurement of relative humidity and temperature only.
    /// The sensor output is read out by using the `read_measurement()`
    /// command (Section 3.5.2). CO2 output is returned as 0 ppm.
    #[cfg(feature = "scd41")]
    pub fn measure_single_shot_rht_only(&mut self) -> Result<(), Error<E>> {
        self.write_command(MEASURE_SINGLE_SHOT_RHT_ONLY)
    }

    /// Put the sensor from idle to sleep to reduce current consumption.
    /// Can be used to power down when operating the sensor in
    /// power-cycled single shot mode.
    #[cfg(feature = "scd41")]
    pub fn power_down(&mut self) -> Result<(), Error<E>> {
        self.write_command(POWER_DOWN)
    }

    /// Wake up the sensor from sleep mode into idle mode. Note that the
    /// SCD4x does not acknowledge the `wake_up()` command. The sensor
    /// idle state after wake up can be verified by reading out the
    /// serial number (Section 3.9.2).
    #[cfg(feature = "scd41")]
    pub fn wake_up(&mut self) -> Result<(), Error<E>> {
        self.write_command(WAKE_UP)
    }

    #[cfg(feature = "scd41")]
    pub fn set_automatic_self_calibration_initial_period(
        &mut self,
        hours: u16,
    ) -> Result<(), Error<E>> {
        self.write_command_with_data(SET_AUTOMATIC_SELF_CALIBRATION_INITIAL_PERIOD, hours)
    }

    #[cfg(feature = "scd41")]
    pub fn get_automatic_self_calibration_initial_period(&mut self) -> Result<u16, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_AUTOMATIC_SELF_CALIBRATION_INITIAL_PERIOD, &mut buf)?;

        Ok(u16::from_be_bytes([buf[0], buf[1]]))
    }

    #[cfg(feature = "scd41")]
    pub fn set_automatic_self_calibration_standard_period(
        &mut self,
        hours: u16,
    ) -> Result<(), Error<E>> {
        self.write_command_with_data(SET_AUTOMATIC_SELF_CALIBRATION_STANDARD_PERIOD, hours)
    }

    #[cfg(feature = "scd41")]
    pub fn get_automatic_self_calibration_standard_period(&mut self) -> Result<u16, Error<E>> {
        let mut buf = [0; 3];
        self.command_with_response(GET_AUTOMATIC_SELF_CALIBRATION_STANDARD_PERIOD, &mut buf)?;

        Ok(u16::from_be_bytes([buf[0], buf[1]]))
    }
}