venus/axiom-nmea/raymarine_nmea/nmea/sentences/wind.py

"""
Wind-related NMEA sentences.

MWV - Wind Speed and Angle
MWD - Wind Direction and Speed
"""

from typing import Optional

from ..sentence import NMEASentence


class MWVSentence(NMEASentence):
    """MWV - Wind Speed and Angle.

    Format:
        $IIMWV,A.A,R,S.S,U,A*CC

    Fields:
        1. Wind angle in degrees (0-360)
        2. Reference (R=Relative/Apparent, T=True)
        3. Wind speed
        4. Wind speed units (K=km/h, M=m/s, N=knots, S=statute mph)
        5. Status (A=valid, V=invalid)

    Example:
        $IIMWV,045.0,R,12.5,N,A*28

    Note:
        MWV can represent either apparent or true wind:
        - Relative (R): Wind angle relative to bow, clockwise
        - True (T): True wind direction relative to bow
    """

    talker_id = "II"
    sentence_type = "MWV"

    def __init__(
        self,
        angle: Optional[float] = None,
        reference: str = "R",
        speed: Optional[float] = None,
        speed_units: str = "N",
        status: str = "A",
    ):
        """Initialize MWV sentence.

        Args:
            angle: Wind angle in degrees (0-360)
            reference: R=Relative/Apparent, T=True
            speed: Wind speed
            speed_units: K=km/h, M=m/s, N=knots, S=mph
            status: A=valid, V=invalid
        """
        self.angle = angle
        self.reference = reference
        self.speed = speed
        self.speed_units = speed_units
        self.status = status

    def format_fields(self) -> Optional[str]:
        """Format MWV fields."""
        # Need at least angle or speed
        if self.angle is None and self.speed is None:
            return None

        angle_str = f"{self.angle:.1f}" if self.angle is not None else ""
        speed_str = f"{self.speed:.1f}" if self.speed is not None else ""

        return (
            f"{angle_str},"
            f"{self.reference},"
            f"{speed_str},"
            f"{self.speed_units},"
            f"{self.status}"
        )


class MWDSentence(NMEASentence):
    """MWD - Wind Direction and Speed.

    Format:
        $IIMWD,D.D,T,D.D,M,S.S,N,S.S,M*CC

    Fields:
        1. Wind direction (true) in degrees
        2. T = True
        3. Wind direction (magnetic) in degrees
        4. M = Magnetic
        5. Wind speed in knots
        6. N = Knots
        7. Wind speed in m/s
        8. M = Meters/second

    Example:
        $IIMWD,270.0,T,258.0,M,12.5,N,6.4,M*5A

    Note:
        MWD provides true wind direction (the direction FROM which wind blows),
        expressed as a compass bearing, not relative to the vessel.
    """

    talker_id = "II"
    sentence_type = "MWD"

    def __init__(
        self,
        direction_true: Optional[float] = None,
        direction_mag: Optional[float] = None,
        speed_kts: Optional[float] = None,
    ):
        """Initialize MWD sentence.

        Args:
            direction_true: True wind direction in degrees (from which wind blows)
            direction_mag: Magnetic wind direction in degrees
            speed_kts: Wind speed in knots
        """
        self.direction_true = direction_true
        self.direction_mag = direction_mag
        self.speed_kts = speed_kts

    def format_fields(self) -> Optional[str]:
        """Format MWD fields."""
        # Need at least direction or speed
        if self.direction_true is None and self.speed_kts is None:
            return None

        # Format directions
        dir_t_str = f"{self.direction_true:.1f}" if self.direction_true is not None else ""
        dir_m_str = f"{self.direction_mag:.1f}" if self.direction_mag is not None else ""

        # Format speeds
        if self.speed_kts is not None:
            spd_kts_str = f"{self.speed_kts:.1f}"
            spd_ms = self.speed_kts / 1.94384449
            spd_ms_str = f"{spd_ms:.1f}"
        else:
            spd_kts_str = ""
            spd_ms_str = ""

        return (
            f"{dir_t_str},T,"
            f"{dir_m_str},M,"
            f"{spd_kts_str},N,"
            f"{spd_ms_str},M"
        )