from __future__ import annotations

from collections.abc import Iterator
from dataclasses import dataclass
from datetime import timedelta
from typing import TYPE_CHECKING, Type

from ._common_ctld import generate_random_ctld_point
from game.theater.missiontarget import MissionTarget
from game.utils import feet
from .ibuilder import IBuilder
from .planningerror import PlanningError
from .standard import StandardFlightPlan, StandardLayout
from .waypointbuilder import WaypointBuilder
from ...theater.interfaces.CTLD import CTLD

if TYPE_CHECKING:
    from ..flightwaypoint import FlightWaypoint
    from dcs import Point


@dataclass(frozen=True)
class AirliftLayout(StandardLayout):
    nav_to_pickup: list[FlightWaypoint]
    # There will not be a pickup waypoint when the pickup airfield is the departure
    # airfield for cargo planes, as the cargo is pre-loaded. Helicopters will still pick
    # up the cargo near the airfield.
    pickup: FlightWaypoint | None
    # pickup_zone will be used for player flights to create the CTLD stuff
    ctld_pickup_zone: FlightWaypoint | None
    nav_to_drop_off: list[FlightWaypoint]
    # There will not be a drop-off waypoint when the drop-off airfield and the arrival
    # airfield is the same for a cargo plane, as planes will land to unload and we don't
    # want a double landing. Helicopters will still drop their cargo near the airfield
    # before landing.
    drop_off: FlightWaypoint | None
    # drop_off_zone will be used for player flights to create the CTLD stuff
    ctld_drop_off_zone: FlightWaypoint | None
    nav_to_home: list[FlightWaypoint]

    def iter_waypoints(self) -> Iterator[FlightWaypoint]:
        yield self.departure
        yield from self.nav_to_pickup
        if self.pickup is not None:
            yield self.pickup
        if self.ctld_pickup_zone is not None:
            yield self.ctld_pickup_zone
        yield from self.nav_to_drop_off
        if self.drop_off is not None:
            yield self.drop_off
        if self.ctld_drop_off_zone is not None:
            yield self.ctld_drop_off_zone
        yield from self.nav_to_home
        yield self.arrival
        if self.divert is not None:
            yield self.divert
        yield self.bullseye


class AirliftFlightPlan(StandardFlightPlan[AirliftLayout]):
    @staticmethod
    def builder_type() -> Type[Builder]:
        return Builder

    @property
    def tot_waypoint(self) -> FlightWaypoint:
        # The TOT is the time that the cargo will be dropped off. If the drop-off
        # location is the arrival airfield and this is not a helicopter flight, there
        # will not be a separate drop-off waypoint; the arrival landing waypoint is the
        # drop-off waypoint.
        return self.layout.drop_off or self.layout.arrival

    def tot_for_waypoint(self, waypoint: FlightWaypoint) -> timedelta | None:
        # TOT planning isn't really useful for transports. They're behind the front
        # lines so no need to wait for escorts or for other missions to complete.
        return None

    def depart_time_for_waypoint(self, waypoint: FlightWaypoint) -> timedelta | None:
        return None

    @property
    def mission_departure_time(self) -> timedelta:
        return self.package.time_over_target


class Builder(IBuilder[AirliftFlightPlan, AirliftLayout]):
    def layout(self) -> AirliftLayout:
        cargo = self.flight.cargo
        if cargo is None:
            raise PlanningError(
                "Cannot plan transport mission for flight with no cargo."
            )

        altitude = feet(1500)
        altitude_is_agl = True

        builder = WaypointBuilder(self.flight, self.coalition)

        pickup = None
        drop_off = None
        pickup_zone = None
        drop_off_zone = None

        if cargo.origin != self.flight.departure:
            pickup = builder.cargo_stop(cargo.origin)
        if cargo.next_stop != self.flight.arrival:
            drop_off = builder.cargo_stop(cargo.next_stop)

        if self.flight.is_helo:
            # Create CTLD Zones for Helo flights
            pickup_zone = builder.pickup_zone(
                MissionTarget("Pickup Zone", self._generate_ctld_pickup())
            )
            drop_off_zone = builder.dropoff_zone(
                MissionTarget("Dropoff zone", self._generate_ctld_dropoff())
            )
            # Show the zone waypoints only to the player
            pickup_zone.only_for_player = True
            drop_off_zone.only_for_player = True

        nav_to_pickup = builder.nav_path(
            self.flight.departure.position,
            cargo.origin.position,
            altitude,
            altitude_is_agl,
        )

        return AirliftLayout(
            departure=builder.takeoff(self.flight.departure),
            nav_to_pickup=nav_to_pickup,
            pickup=pickup,
            ctld_pickup_zone=pickup_zone,
            nav_to_drop_off=builder.nav_path(
                cargo.origin.position,
                cargo.next_stop.position,
                altitude,
                altitude_is_agl,
            ),
            drop_off=drop_off,
            ctld_drop_off_zone=drop_off_zone,
            nav_to_home=builder.nav_path(
                cargo.origin.position,
                self.flight.arrival.position,
                altitude,
                altitude_is_agl,
            ),
            arrival=builder.land(self.flight.arrival),
            divert=builder.divert(self.flight.divert),
            bullseye=builder.bullseye(),
        )

    def build(self) -> AirliftFlightPlan:
        return AirliftFlightPlan(self.flight, self.layout())

    def _generate_ctld_pickup(self) -> Point:
        cargo = self.flight.cargo
        if cargo and cargo.origin and isinstance(cargo.origin, CTLD):
            return generate_random_ctld_point(cargo.origin)
        raise RuntimeError("Could not generate CTLD pickup")

    def _generate_ctld_dropoff(self) -> Point:
        cargo = self.flight.cargo
        if cargo and cargo.transport and isinstance(cargo.transport.destination, CTLD):
            return generate_random_ctld_point(cargo.transport.destination)
        raise RuntimeError("Could not generate CTLD dropoff")