"""NMEA 2000 navigation data models.

Holds the live data received from PGN 127250/127251 (heading/ROT -- Sprint 3)
and the new PGN 129026/129284 (COG+SOG / XTE+waypoint -- Sprint 5).

All timestamps are float seconds (time.monotonic()).
NaN means the value has never been received.
"""

from __future__ import annotations

import math
import time
from dataclasses import dataclass, field


@dataclass
class HeadingData:
    """PGN 127250 + 127251 -- magnetic heading and rate of turn."""

    heading_deg: float = math.nan
    rot_dps: float = 0.0
    timestamp: float = field(default_factory=lambda: 0.0)
    max_age_s: float = 5.0

    def update(self, heading_deg: float, rot_dps: float) -> None:
        self.heading_deg = heading_deg
        self.rot_dps = rot_dps
        self.timestamp = time.monotonic()

    @property
    def is_valid(self) -> bool:
        if math.isnan(self.heading_deg):
            return False
        return (time.monotonic() - self.timestamp) < self.max_age_s

    @property
    def age_ms(self) -> int:
        return int((time.monotonic() - self.timestamp) * 1000)


@dataclass
class CogSogData:
    """PGN 129026 -- Course Over Ground (true) and Speed Over Ground.

    COG is in degrees true (0..360).
    SOG is in knots.
    """

    cog_deg: float = math.nan
    sog_kn: float = math.nan
    timestamp: float = field(default_factory=lambda: 0.0)
    max_age_s: float = 5.0

    def update(self, cog_deg: float, sog_kn: float) -> None:
        self.cog_deg = cog_deg % 360.0
        self.sog_kn = sog_kn
        self.timestamp = time.monotonic()

    @property
    def is_valid(self) -> bool:
        if math.isnan(self.cog_deg) or math.isnan(self.sog_kn):
            return False
        return (time.monotonic() - self.timestamp) < self.max_age_s

    @property
    def age_ms(self) -> int:
        return int((time.monotonic() - self.timestamp) * 1000)


@dataclass
class XteData:
    """PGN 129284 -- Cross Track Error and active waypoint.

    xte_m: distance off track in metres.
      Positive  → vessel is to starboard of the track line (steer port).
      Negative  → vessel is to port  of the track line (steer starboard).

    waypoint_name: free text from the chart plotter, empty if not available.
    dtw_m: distance to waypoint in metres (NaN if unknown).
    """

    xte_m: float = math.nan
    dtw_m: float = math.nan
    waypoint_name: str = ""
    timestamp: float = field(default_factory=lambda: 0.0)
    max_age_s: float = 5.0

    def update(
        self,
        xte_m: float,
        dtw_m: float = math.nan,
        waypoint_name: str = "",
    ) -> None:
        self.xte_m = xte_m
        self.dtw_m = dtw_m
        self.waypoint_name = waypoint_name
        self.timestamp = time.monotonic()

    @property
    def is_valid(self) -> bool:
        if math.isnan(self.xte_m):
            return False
        return (time.monotonic() - self.timestamp) < self.max_age_s

    @property
    def age_ms(self) -> int:
        return int((time.monotonic() - self.timestamp) * 1000)


@dataclass
class NmeaNavData:
    """Aggregated live navigation data used by the autopilot control loop."""

    heading: HeadingData = field(default_factory=HeadingData)
    cog_sog: CogSogData = field(default_factory=CogSogData)
    xte: XteData = field(default_factory=XteData)