Ham-Router/aprs/parser.py at main · DjGreenKrk/Ham-Router · GitHub

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from __future__ import annotations

"""APRS text parser producing runtime events plus optional canonical metadata."""

import logging
import re
from datetime import UTC, datetime

from core.canonical import empty_canonical_event, iso_utc_now
from core.model import MessageEvent, PositionEvent, Source, build_raw_payload


log = logging.getLogger("aprs.parser")

APRS_FRAME_RE = re.compile(
    r"^(?P<src>[A-Z0-9\-]+)>(?P<dst>[^:]+):(?P<body>.+)$",
    re.IGNORECASE,
)
POSITION_RE = re.compile(
    r"^(?P<type>[!=])"
    r"(?P<lat_deg>\d{2})(?P<lat_min>\d{2}\.\d{2})(?P<lat_hemi>[NS])"
    r"(?P<symbol_table>.)"
    r"(?P<lon_deg>\d{3})(?P<lon_min>\d{2}\.\d{2})(?P<lon_hemi>[EW])"
    r"(?P<symbol>.)(?P<comment>.*)$"
)
OBJECT_RE = re.compile(
    r"^;"
    r"(?P<name>.{9})"
    r"(?P<alive>[*_])"
    r"(?P<day>\d{2})(?P<hour>\d{2})(?P<minute>\d{2})z"
    r"(?P<lat_deg>\d{2})(?P<lat_min>\d{2}\.\d{2})(?P<lat_hemi>[NS])"
    r"(?P<symbol_table>.)"
    r"(?P<lon_deg>\d{3})(?P<lon_min>\d{2}\.\d{2})(?P<lon_hemi>[EW])"
    r"(?P<symbol>.)(?P<comment>.*)$"
)
TACTICAL_NAME_RE = re.compile(r"^\[:(?P<tactical_name>[^\r\n]+)$")
TACTICAL_NAME_INLINE_RE = re.compile(r"\[:(?P<tactical_name>[^\r\n]+)\s*$")
MESSAGE_RE = re.compile(
    r"^:(?P<target>.{9}):(?P<message>[^\{]*?)(?:\{(?P<message_id>[^\s\{]+))?$"
)
ACK_MESSAGE_RE = re.compile(r"^ack(?P<ack_id>[A-Za-z0-9]+)$", re.IGNORECASE)
ENCRYPTED_MESSAGE_RE = re.compile(r"^\[(?P<method>[A-Za-z0-9]+),(?P<payload>.+)$")


class APRSParseError(ValueError):
    pass


def parse_aprs_event(
    frame: str,
    *,
    source: Source = Source.APRS,
    ingress_adapter: str | None = None,
    raw_context: dict[str, object] | None = None,
) -> PositionEvent | MessageEvent:
    """Parse an APRS frame into the runtime model."""
    canonical = parse_aprs_canonical(frame)
    event = canonical_to_aprs_event(
        canonical,
        source=source,
        ingress_adapter=ingress_adapter,
        raw_context=raw_context,
    )
    log.debug(
        "APRS canonical -> %s source=%s subtype=%s msg_id=%r",
        event.kind,
        event.id,
        canonical["meta"]["source_subtype"],
        canonical["meta"]["message_id"],
    )
    return event


def parse_aprs_frame(frame: str) -> PositionEvent | MessageEvent:
    return parse_aprs_event(frame)


def decode_aprs_frame(frame: str) -> PositionEvent | MessageEvent:
    """Operator-friendly alias for APRS RX decoding."""
    return parse_aprs_event(frame)


def parse_aprs_canonical(frame: str) -> dict[str, object]:
    frame = frame.strip()
    match = APRS_FRAME_RE.match(frame)
    if not match:
        raise APRSParseError(f"invalid APRS frame: {frame}")

    source_id = match.group("src").upper()
    destination = match.group("dst").strip()
    body = match.group("body").strip()

    if body.startswith(("!", "=")):
        canonical = _parse_position_canonical(
            source_id=source_id,
            destination=destination,
            body=body,
            frame=frame,
        )
        log.debug(
            "APRS canonical event created format=%s subtype=%s callsign=%s lat=%s lon=%s",
            canonical["meta"]["source_format"],
            canonical["meta"]["source_subtype"],
            canonical["identity"]["callsign"],
            canonical["position"]["lat"],
            canonical["position"]["lon"],
        )
        return canonical

    if body.startswith(";"):
        canonical = _parse_object_canonical(
            source_id=source_id,
            destination=destination,
            body=body,
            frame=frame,
        )
        log.debug(
            "APRS canonical event created format=%s subtype=%s object=%s lat=%s lon=%s",
            canonical["meta"]["source_format"],
            canonical["meta"]["source_subtype"],
            canonical["identity"]["callsign"],
            canonical["position"]["lat"],
            canonical["position"]["lon"],
        )
        return canonical

    if body.startswith(":"):
        canonical = _parse_message_canonical(
            source_id=source_id,
            destination=destination,
            body=body,
            frame=frame,
        )
        log.debug(
            "APRS canonical event created format=%s subtype=%s callsign=%s target=%s msg_id=%r",
            canonical["meta"]["source_format"],
            canonical["meta"]["source_subtype"],
            canonical["identity"]["callsign"],
            canonical["sartrack"]["receiver"],
            canonical["meta"]["message_id"],
        )
        return canonical

    raise APRSParseError(f"unsupported APRS body: {body}")


def canonical_to_aprs_event(
    canonical: dict[str, object],
    *,
    source: Source = Source.APRS,
    ingress_adapter: str | None = None,
    raw_context: dict[str, object] | None = None,
) -> PositionEvent | MessageEvent:
    identity = canonical["identity"]
    position = canonical["position"]
    text = canonical["text"]
    meta = canonical["meta"]
    source_id = identity["callsign"]
    if not source_id:
        raise APRSParseError("canonical APRS event missing source callsign")

    raw_payload = build_raw_payload(
        canonical=canonical,
        ingress_adapter=ingress_adapter,
        raw_context=raw_context,
    )

    if text["text"]:
        return MessageEvent(
            id=str(source_id),
            target=str(canonical["sartrack"]["receiver"]) if canonical["sartrack"]["receiver"] else None,
            message=str(text["text"]),
            message_id=str(meta["message_id"]) if meta["message_id"] else None,
            source=source,
            raw=raw_payload,
        )

    if position["lat"] is None or position["lon"] is None:
        raise APRSParseError("canonical APRS event missing coordinates")

    return PositionEvent(
        id=str(source_id),
        entity_kind="object" if str(meta["source_subtype"] or "") == "object" else "station",
        type=str(meta["source_subtype"] or "unit"),
        lat=float(position["lat"]),
        lon=float(position["lon"]),
        tactical_name=str(identity["short_name"]) if identity["short_name"] else None,
        message=str(text["comment"]) if text["comment"] else None,
        symbol_table=str(canonical["comms"]["symbol_table"]) if canonical["comms"]["symbol_table"] else None,
        symbol_code=str(canonical["comms"]["symbol_code"]) if canonical["comms"]["symbol_code"] else None,
        object_name=str(canonical["sartrack"]["custom"].get("object_name"))
        if isinstance(canonical["sartrack"]["custom"], dict) and canonical["sartrack"]["custom"].get("object_name")
        else None,
        owner_id=str(canonical["sartrack"]["custom"].get("owner_callsign"))
        if isinstance(canonical["sartrack"]["custom"], dict) and canonical["sartrack"]["custom"].get("owner_callsign")
        else None,
        source=source,
        raw=raw_payload,
    )


def _parse_position_canonical(
    *,
    source_id: str,
    destination: str,
    body: str,
    frame: str,
) -> dict[str, object]:
    match = POSITION_RE.match(body)
    if not match:
        raise APRSParseError(f"invalid APRS position body: {body}")

    lat = _parse_coordinate(
        degrees=match.group("lat_deg"),
        minutes=match.group("lat_min"),
        hemisphere=match.group("lat_hemi"),
    )
    lon = _parse_coordinate(
        degrees=match.group("lon_deg"),
        minutes=match.group("lon_min"),
        hemisphere=match.group("lon_hemi"),
    )
    raw_comment = match.group("comment").strip() or None
    comment, tactical_name = _normalize_position_comment(raw_comment)
    symbol_table = match.group("symbol_table")
    symbol_code = match.group("symbol")

    log.debug(
        "Parsed APRS position source=%s lat=%s lon=%s symbol=%s%s comment=%r tactical_name=%r",
        source_id,
        lat,
        lon,
        symbol_table,
        symbol_code,
        comment,
        tactical_name,
    )
    canonical = empty_canonical_event()
    canonical["meta"]["source_format"] = "aprs_text"
    canonical["meta"]["source_subtype"] = "position"
    canonical["meta"]["parser_version"] = 1
    canonical["meta"]["raw_message"] = frame
    canonical["meta"]["received_at_utc"] = iso_utc_now()
    canonical["identity"]["uid"] = source_id
    canonical["identity"]["callsign"] = source_id
    canonical["identity"]["short_name"] = tactical_name
    canonical["identity"]["object_type"] = "person"
    canonical["position"]["lat"] = lat
    canonical["position"]["lon"] = lon
    canonical["text"]["comment"] = comment
    canonical["comms"]["destination"] = destination
    canonical["comms"]["symbol_table"] = symbol_table
    canonical["comms"]["symbol_code"] = symbol_code
    canonical["sartrack"]["custom"] = {
        "frame": frame,
        "body": body,
        "packet_type": match.group("type"),
        "comment": raw_comment,
        "tactical_name": tactical_name,
    }
    return canonical


def _parse_message_canonical(
    *,
    source_id: str,
    destination: str,
    body: str,
    frame: str,
) -> dict[str, object]:
    match = MESSAGE_RE.match(body)
    if not match:
        raise APRSParseError(f"invalid APRS message body: {body}")

    target_id = match.group("target").strip() or None
    message = match.group("message").strip()
    message_id = (match.group("message_id") or "").strip() or None

    if not target_id:
        raise APRSParseError(f"missing APRS message target: {body}")
    if not message:
        raise APRSParseError(f"empty APRS message payload: {body}")

    message_subtype, message_meta = _classify_message_subtype(target_id=target_id, message=message)

    log.debug(
        "Parsed APRS message source=%s target=%s subtype=%s message=%r message_id=%r",
        source_id,
        target_id,
        message_subtype,
        message,
        message_id,
    )
    canonical = empty_canonical_event()
    canonical["meta"]["source_format"] = "aprs_text"
    canonical["meta"]["source_subtype"] = message_subtype
    canonical["meta"]["parser_version"] = 1
    canonical["meta"]["raw_message"] = frame
    canonical["meta"]["received_at_utc"] = iso_utc_now()
    canonical["meta"]["message_id"] = message_id
    canonical["identity"]["uid"] = source_id
    canonical["identity"]["callsign"] = source_id
    canonical["identity"]["object_type"] = "person"
    canonical["text"]["text"] = message
    canonical["comms"]["destination"] = destination
    canonical["sartrack"]["receiver"] = target_id
    canonical["sartrack"]["custom"] = {
        "frame": frame,
        "body": body,
        "packet_type": ":",
        **message_meta,
    }
    return canonical


def _parse_object_canonical(
    *,
    source_id: str,
    destination: str,
    body: str,
    frame: str,
) -> dict[str, object]:
    match = OBJECT_RE.match(body)
    if not match:
        raise APRSParseError(f"invalid APRS object body: {body}")

    object_name = match.group("name").strip() or source_id
    lat = _parse_coordinate(
        degrees=match.group("lat_deg"),
        minutes=match.group("lat_min"),
        hemisphere=match.group("lat_hemi"),
    )
    lon = _parse_coordinate(
        degrees=match.group("lon_deg"),
        minutes=match.group("lon_min"),
        hemisphere=match.group("lon_hemi"),
    )
    raw_comment = match.group("comment").strip() or None
    comment, tactical_name = _normalize_position_comment(raw_comment)
    symbol_table = match.group("symbol_table")
    symbol_code = match.group("symbol")
    object_timestamp_raw = f"{match.group('day')}{match.group('hour')}{match.group('minute')}z"
    object_timestamp_utc = _parse_object_timestamp_utc(
        day=match.group("day"),
        hour=match.group("hour"),
        minute=match.group("minute"),
    )

    log.debug(
        "Parsed APRS object source=%s object=%s object_time_raw=%s object_time_utc=%s lat=%s lon=%s symbol=%s%s comment=%r tactical_name=%r",
        source_id,
        object_name,
        object_timestamp_raw,
        object_timestamp_utc,
        lat,
        lon,
        symbol_table,
        symbol_code,
        comment,
        tactical_name,
    )
    canonical = empty_canonical_event()
    canonical["meta"]["source_format"] = "aprs_text"
    canonical["meta"]["source_subtype"] = "object"
    canonical["meta"]["parser_version"] = 1
    canonical["meta"]["raw_message"] = frame
    canonical["meta"]["received_at_utc"] = iso_utc_now()
    canonical["identity"]["uid"] = object_name
    canonical["identity"]["callsign"] = object_name
    canonical["identity"]["short_name"] = tactical_name or object_name
    canonical["identity"]["object_type"] = "unknown"
    canonical["position"]["lat"] = lat
    canonical["position"]["lon"] = lon
    canonical["position"]["timestamp_utc"] = object_timestamp_utc
    canonical["text"]["comment"] = comment
    canonical["comms"]["destination"] = destination
    canonical["comms"]["symbol_table"] = symbol_table
    canonical["comms"]["symbol_code"] = symbol_code
    canonical["sartrack"]["custom"] = {
        "frame": frame,
        "body": body,
        "packet_type": ";",
        "owner_callsign": source_id,
        "object_name": object_name,
        "alive": match.group("alive") == "*",
        "object_timestamp_raw": object_timestamp_raw,
        "object_timestamp_utc": object_timestamp_utc,
        "comment": raw_comment,
        "tactical_name": tactical_name,
        "symbol_table": symbol_table,
        "symbol_code": symbol_code,
    }
    return canonical


def _parse_coordinate(*, degrees: str, minutes: str, hemisphere: str) -> float:
    value = int(degrees) + (float(minutes) / 60.0)
    if hemisphere in {"S", "W"}:
        value *= -1
    return value


def _normalize_position_comment(comment: str | None) -> tuple[str | None, str | None]:
    if not comment:
        return None, None

    tactical_match = TACTICAL_NAME_RE.fullmatch(comment)
    if tactical_match:
        tactical_name = tactical_match.group("tactical_name").strip()
        return tactical_name, tactical_name

    tactical_inline_match = TACTICAL_NAME_INLINE_RE.search(comment)
    if tactical_inline_match:
        tactical_name = tactical_inline_match.group("tactical_name").strip()
        stripped = comment[: tactical_inline_match.start()].strip() or tactical_name
        return stripped, tactical_name

    return comment, None


def _classify_message_subtype(*, target_id: str, message: str) -> tuple[str, dict[str, str]]:
    target_upper = target_id.strip().upper()
    message_stripped = message.strip()
    message_upper = message_stripped.upper()

    ack_match = ACK_MESSAGE_RE.fullmatch(message_stripped)
    if ack_match:
        return "ack", {"ack_id": ack_match.group("ack_id")}

    encrypted_match = ENCRYPTED_MESSAGE_RE.match(message_stripped)
    if encrypted_match:
        return (
            "encrypted_message",
            {
                "encryption_method": encrypted_match.group("method"),
                "encrypted_payload": encrypted_match.group("payload"),
            },
        )

    if target_upper.startswith("BLN"):
        return "bulletin", {"bulletin_id": target_upper}

    if target_upper.startswith("TEAM") or target_upper in {"GRUPA", "GROUP", "ALL"}:
        return "group_message", {"group_id": target_upper}

    if message_upper.startswith("PING"):
        return "ping", {}

    if message_stripped.startswith("?"):
        return "query", {"query": message_stripped}

    if message_upper.startswith("!SARTRACK "):
        return "status_response", {"status_payload": message_stripped}

    return "private_message", {}


def _parse_object_timestamp_utc(*, day: str, hour: str, minute: str) -> str | None:
    try:
        now = datetime.now(UTC)
        candidate = datetime(
            year=now.year,
            month=now.month,
            day=int(day),
            hour=int(hour),
            minute=int(minute),
            tzinfo=UTC,
        )
    except ValueError:
        return None

    # If APRS object time lands implausibly far in the future, assume month rollover.
    if candidate.timestamp() - now.timestamp() > 36 * 3600:
        if now.month == 1:
            year = now.year - 1
            month = 12
        else:
            year = now.year
            month = now.month - 1
        try:
            candidate = datetime(
                year=year,
                month=month,
                day=int(day),
                hour=int(hour),
                minute=int(minute),
                tzinfo=UTC,
            )
        except ValueError:
            return None

    return candidate.replace(second=0, microsecond=0).isoformat().replace("+00:00", "Z")