from __future__ import annotations

from collections.abc import Iterator
from typing import Any, Optional, TYPE_CHECKING

from dcs import Point
from shapely.ops import unary_union

from game.utils import dcs_to_shapely_point, meters

if TYPE_CHECKING:
    from game.theater import ConflictTheater, TheaterGroundObject
    from game.threatzones import ThreatPoly


class SamEngagementZones:
    def __init__(
        self,
        threat_zones: ThreatPoly,
        individual_zones: list[tuple[TheaterGroundObject[Any], ThreatPoly]],
    ) -> None:
        self.threat_zones = threat_zones
        self.individual_zones = individual_zones

    def covers(self, position: Point) -> bool:
        return self.threat_zones.intersects(dcs_to_shapely_point(position))

    def iter_threatening_sams(
        self, position: Point
    ) -> Iterator[TheaterGroundObject[Any]]:
        for tgo, zone in self.individual_zones:
            if zone.intersects(dcs_to_shapely_point(position)):
                yield tgo

    @classmethod
    def from_theater(cls, theater: ConflictTheater, player: bool) -> SamEngagementZones:
        commit_regions = []
        individual_zones = []
        for cp in theater.control_points_for(player):
            for tgo in cp.connected_objectives:
                if (region := cls.threat_region(tgo)) is not None:
                    commit_regions.append(region)
                    individual_zones.append((tgo, region))
        return SamEngagementZones(unary_union(commit_regions), individual_zones)

    @classmethod
    def threat_region(cls, tgo: TheaterGroundObject[Any]) -> Optional[ThreatPoly]:
        threat_range = tgo.max_threat_range()
        if threat_range <= meters(0):
            return None
        return dcs_to_shapely_point(tgo.position).buffer(threat_range.meters)