from dataclasses import dataclass

from edge.tracking import Track
from edge.events import Event, EventType, severity_for
from edge.detectors.fall import FallDetector
from edge.detectors.immobility import ImmobilityWatchdog
from edge.detectors.ghost import GhostIncidentDetector
from edge.detectors.zone import ZoneIntrusionDetector
from edge.detectors.occupancy import OccupancyWatchdog, OccupancyConfig


@dataclass
class EngineConfig:
    camera_id: str = "cam"
    cooldown_s: float = 30.0


_OCCUPANCY_TYPES = {"lone_worker": EventType.LONE_WORKER,
                    "overcapacity": EventType.OVERCAPACITY,
                    "overstay": EventType.OVERSTAY}


class EventEngine:
    def __init__(self, fall: FallDetector, immobility: ImmobilityWatchdog,
                 ghost: GhostIncidentDetector, zone: ZoneIntrusionDetector,
                 cfg: EngineConfig, occupancy: OccupancyWatchdog | None = None):
        self.fall = fall
        self.immobility = immobility
        self.ghost = ghost
        self.zone = zone
        # Keyword-with-default so the existing 5-arg constructors (runtime, tests) keep working.
        self.occupancy = occupancy if occupancy is not None else OccupancyWatchdog(OccupancyConfig())
        self.cfg = cfg
        self._last_emit: dict[tuple, float] = {}

    def _allow(self, key: tuple, now: float) -> bool:
        last = self._last_emit.get(key)
        if last is not None and now - last < self.cfg.cooldown_s:
            return False
        self._last_emit[key] = now
        return True

    def forget(self, track_id: int) -> None:
        """트랙 소실 시 하위 감지기 + dedup 캐시의 트랙별 상태를 정리 (24/7 장치 메모리 누수 방지)."""
        self.fall.forget(track_id)
        self.immobility.forget(track_id)
        self.zone.forget(track_id)
        self.occupancy.forget(track_id)
        self._last_emit = {k: v for k, v in self._last_emit.items()
                           if not (len(k) >= 2 and k[1] == track_id)}

    def _mk(self, etype: EventType, occurred_at: float, track_id=None, zone_id=None,
            metrics=None, spatial=None) -> Event:
        m = metrics or {}
        duration_s = m.get("immobility_s") or m.get("waited_s") or m.get("dwell_s") \
            or m.get("alone_s") or 0.0
        return Event(etype, severity_for(etype), self.cfg.camera_id, track_id,
                     zone_id, occurred_at, duration_s, m, spatial)

    def process(self, active_tracks: list[Track], lost_tracks: list[Track],
                now: float, frame_wh=None, wall_now: float | None = None) -> list[Event]:
        # `now` is a MONOTONIC clock (never jumps): it drives every detector timer, hysteresis,
        # and cooldown, so an NTP step cannot instantly satisfy immobile_s / expire all tracks /
        # reset a genuine immobility countdown. `wall_now` is real wall-clock time, used ONLY to
        # stamp Event.occurred_at (the server correlates and retains by wall time). Defaults to
        # `now` so single-clock callers (unit tests) keep their existing occurred_at behavior.
        occurred_at = wall_now if wall_now is not None else now
        events: list[Event] = []
        self.ghost.on_lost(lost_tracks, now)

        for tr in active_tracks:
            # frame_wh lets the zone detector normalize the foot to the dashboard's 0..1 zone
            # space (see ZoneIntrusionDetector._foot). run_once supplies the live frame size.
            zone_hits = self.zone.update(tr, now, frame_wh)
            in_zone = bool(self.zone.active_zone_ids(tr.track_id))
            # 발 좌표(0..1)를 트랙 이벤트 전부에 부착 — 서버 히트맵의 원료. 존 감지기가 이미
            # 계산하는 좌표계를 그대로 재사용해 존 폴리곤과 같은 공간에 놓인다.
            foot = self.zone._foot(tr, frame_wh)

            sig, meta = self.fall.update(tr, now)
            state = self.fall._states.get(tr.track_id)
            self.ghost.note_state(tr.track_id, state.name if state else "STANDING")
            if sig == "fall" and self._allow((EventType.FALL, tr.track_id), now):
                events.append(self._mk(EventType.FALL, occurred_at, tr.track_id,
                                       metrics=meta, spatial=foot))
            elif sig == "no_motion" and self._allow((EventType.NO_MOTION, tr.track_id), now):
                events.append(self._mk(EventType.NO_MOTION, occurred_at, tr.track_id,
                                       metrics=meta, spatial=foot))
            elif sig == "near_fall" and self._allow((EventType.NEAR_FALL, tr.track_id), now):
                # 니어미스(FALLING까지 갔다 확정 전 회복): 알람용이 아니라 히트맵/통계 재료.
                events.append(self._mk(EventType.NEAR_FALL, occurred_at, tr.track_id,
                                       metrics=meta, spatial=foot))

            fired, imeta = self.immobility.update(tr, now, in_danger_zone=in_zone)
            if fired and self._allow((EventType.IMMOBILITY, tr.track_id), now):
                events.append(self._mk(EventType.IMMOBILITY, occurred_at, tr.track_id,
                                       metrics=imeta, spatial=foot))

            for hit in zone_hits:
                # 협착(pinch) is the highest-danger zone (machinery entrapment) and must emit
                # PINCH/HIGH — the old `restricted else WARNING` silently downgraded it. The
                # dashboard offers exactly these three levels (see zones.php).
                etype = {"pinch": EventType.PINCH,
                         "restricted": EventType.ZONE_RESTRICTED}.get(
                             hit["level"], EventType.ZONE_WARNING)
                if self._allow((etype, tr.track_id, hit["zone_id"]), now):
                    events.append(self._mk(etype, occurred_at, tr.track_id,
                                           zone_id=hit["zone_id"], spatial=foot))

        # 존 규칙(2인 1조 · 정원 · 체류): 위 per-track 루프에서 zone.update가 갱신한 멤버십을
        # 존별 인원으로 뒤집어 감시자에 넘긴다. stale 트랙은 run_once가 이미 걸러냈으므로
        # 여기 인원수는 이번 틱에 실제로 검출된 사람만 센다.
        zone_tracks: dict[str, set[int]] = {}
        for tr in active_tracks:
            for zid in self.zone.active_zone_ids(tr.track_id):
                zone_tracks.setdefault(zid, set()).add(tr.track_id)
        for o in self.occupancy.update(self.zone.zones, zone_tracks, now):
            etype = _OCCUPANCY_TYPES[o["kind"]]
            # 쿨다운 키에 zone_id 포함: 존 A의 위반이 존 B의 발보를 막지 않는다. track_id가
            # None인 존 단위 이벤트의 키는 forget()이 지우지 못하지만, 존 수에 비례하는
            # 소량이라 누수로 보지 않는다 (ghost와 달리 키 공간이 유한).
            if self._allow((etype, o["track_id"], o["zone_id"]), now):
                events.append(self._mk(etype, occurred_at, track_id=o["track_id"],
                                       zone_id=o["zone_id"], metrics=o["metrics"]))

        for g in self.ghost.update(active_tracks, now):
            # No _allow cooldown for GHOST: ghost.update pops each incident from its candidates as it
            # emits, and track ids are never reused, so a given track fires GHOST at most once ever.
            # Routing it through _allow would only insert a permanent (GHOST, track_id) dedup key for
            # a track that was already forgotten reappear_s ago — a slow 24/7 memory leak that
            # forget() can never reclaim (the track never appears in lost_tracks again).
            # Ghost's loss point is camera-native pixels (bbox centre at loss time). Normalize to
            # the same 0..1 space every other event's spatial uses so the heatmap can overlay them;
            # frame_wh=None (unit tests) keeps raw coords, matching the zone detector's convention.
            gs = g["spatial"]
            if frame_wh and gs is not None:
                w, h = frame_wh
                if w > 0 and h > 0:
                    gs = (gs[0] / w, gs[1] / h)
            events.append(self._mk(EventType.GHOST, occurred_at, track_id=g["track_id"],
                                   spatial=gs,
                                   metrics={"last_state": g["last_state"],
                                            "waited_s": g["waited_s"]}))

        # ghost.on_lost already consumed lost tracks' state above, so forgetting here is safe.
        for tr in lost_tracks:
            self.forget(tr.track_id)
        return events