from __future__ import annotations

import logging
from collections import defaultdict
from dataclasses import dataclass, field
from datetime import timedelta
from typing import Dict, List, Optional, TYPE_CHECKING

from game.ato import Flight, FlightType
from game.ato.packagewaypoints import PackageWaypoints
from game.db import Database
from game.utils import Speed
from gen.flights.flightplan import FormationFlightPlan
from gen.flights.traveltime import TotEstimator

if TYPE_CHECKING:
    from game.theater import MissionTarget


@dataclass
class Package:
    """A mission package."""

    #: The mission target. Currently can be either a ControlPoint or a
    #: TheaterGroundObject (non-ControlPoint map objectives).
    target: MissionTarget

    _db: Database[Flight]

    #: The set of flights in the package.
    flights: List[Flight] = field(default_factory=list)

    delay: int = field(default=0)

    #: True if the package ToT should be reset to ASAP whenever the player makes
    #: a change. This is really a UI property rather than a game property, but
    #: we want it to persist in the save.
    auto_asap: bool = field(default=False)

    #: Desired TOT as an offset from mission start.
    time_over_target: timedelta = field(default=timedelta())

    waypoints: Optional[PackageWaypoints] = field(default=None)

    @property
    def has_players(self) -> bool:
        return any(flight.client_count for flight in self.flights)

    @property
    def formation_speed(self) -> Optional[Speed]:
        """The speed of the package when in formation.

        If none of the flights in the package will join a formation, this
        returns None. This is not uncommon, since only strike-like (strike,
        DEAD, anti-ship, BAI, etc.) flights and their escorts fly in formation.
        Others (CAP and CAS, currently) will coordinate in target timing but
        fly their own path to the target.
        """
        speeds = []
        for flight in self.flights:
            if isinstance(flight.flight_plan, FormationFlightPlan):
                speeds.append(flight.flight_plan.best_flight_formation_speed)
        if not speeds:
            return None
        return min(speeds)

    # TODO: Should depend on the type of escort.
    # SEAD might be able to leave before CAP.
    @property
    def escort_start_time(self) -> Optional[timedelta]:
        times = []
        for flight in self.flights:
            waypoint = flight.flight_plan.request_escort_at()
            if waypoint is None:
                continue
            tot = flight.flight_plan.tot_for_waypoint(waypoint)
            if tot is None:
                logging.error(
                    f"{flight} requested escort at {waypoint} but that "
                    "waypoint has no TOT. It may not be escorted."
                )
                continue
            times.append(tot)
        if times:
            return min(times)
        return None

    @property
    def escort_end_time(self) -> Optional[timedelta]:
        times = []
        for flight in self.flights:
            waypoint = flight.flight_plan.dismiss_escort_at()
            if waypoint is None:
                continue
            tot = flight.flight_plan.tot_for_waypoint(waypoint)
            if tot is None:
                tot = flight.flight_plan.depart_time_for_waypoint(waypoint)
            if tot is None:
                logging.error(
                    f"{flight} dismissed escort at {waypoint} but that "
                    "waypoint has no TOT or departure time. It may not be "
                    "escorted."
                )
                continue
            times.append(tot)
        if times:
            return max(times)
        return None

    @property
    def mission_departure_time(self) -> Optional[timedelta]:
        times = []
        for flight in self.flights:
            times.append(flight.flight_plan.mission_departure_time)
        if times:
            return max(times)
        return None

    def set_tot_asap(self) -> None:
        self.time_over_target = TotEstimator(self).earliest_tot()

    def add_flight(self, flight: Flight) -> None:
        """Adds a flight to the package."""
        self.flights.append(flight)
        self._db.add(flight.id, flight)

    def remove_flight(self, flight: Flight) -> None:
        """Removes a flight from the package."""
        self.flights.remove(flight)
        self._db.remove(flight.id)
        if not self.flights:
            self.waypoints = None

    @property
    def primary_task(self) -> Optional[FlightType]:
        if not self.flights:
            return None

        flight_counts: Dict[FlightType, int] = defaultdict(lambda: 0)
        for flight in self.flights:
            flight_counts[flight.flight_type] += 1

        # The package will contain a mix of mission types, but in general we can
        # determine the goal of the mission because some mission types are more
        # likely to be the main task than others. For example, a package with
        # only CAP flights is a CAP package, a flight with CAP and strike is a
        # strike package, a flight with CAP and DEAD is a DEAD package, and a
        # flight with strike and SEAD is an OCA/Strike package. This list defines the
        # priority order for package task names. The package's primary task will be the
        # first task in this list that matches a flight in the package.
        tasks_by_priority = [
            FlightType.CAS,
            FlightType.STRIKE,
            FlightType.ANTISHIP,
            FlightType.OCA_AIRCRAFT,
            FlightType.OCA_RUNWAY,
            FlightType.BAI,
            FlightType.DEAD,
            FlightType.TRANSPORT,
            FlightType.SEAD,
            FlightType.TARCAP,
            FlightType.BARCAP,
            FlightType.AEWC,
            FlightType.FERRY,
            FlightType.REFUELING,
            FlightType.SWEEP,
            FlightType.ESCORT,
        ]
        for task in tasks_by_priority:
            if flight_counts[task]:
                return task

        # If we get here, our task_priorities list above is incomplete. Log the
        # issue and return the type of *any* flight in the package.
        some_mission = next(iter(self.flights)).flight_type
        logging.warning(f"Unhandled mission type: {some_mission}")
        return some_mission

    @property
    def package_description(self) -> str:
        """Generates a package description based on flight composition."""
        task = self.primary_task
        if task is None:
            return "No mission"
        oca_strike_types = {FlightType.OCA_AIRCRAFT, FlightType.OCA_RUNWAY}
        if task in oca_strike_types:
            return "OCA Strike"
        return str(task)

    def __hash__(self) -> int:
        # TODO: Far from perfect. Number packages?
        return hash(self.target.name)