"""
Flight service module for handling complex flight operations.
"""

from typing import List
from simulator.models.flight import Flight


def cancel_flight_cascade(flight: Flight) -> List[Flight]:
    """
    Cancel a flight and all subsequent flights that depend on it.

    Returns a list of all canceled flights (including the original).
    """
    canceled_flights = []

    def cancel_recursive(current_flight: Flight):
        """Recursively cancel flights that depend on the current flight."""
        if current_flight.canceled:
            return  # Already canceled

        # Mark flight as canceled
        current_flight.canceled = True
        current_flight.save(update_fields=["canceled"])
        canceled_flights.append(current_flight)

        # Find all flights that depart from this flight's destination
        # after this flight's arrival time
        dependent_flights = Flight.objects.filter(
            equipment=current_flight.equipment,
            origin=current_flight.destination,
            departure_time__gte=current_flight.arrival_time,
            canceled=False,
        ).order_by("departure_time")

        # Check if any of these flights actually depend on this flight
        for next_flight in dependent_flights:
            # Find what the previous non-canceled flight would be if we cancel current_flight
            previous_non_canceled = (
                Flight.objects.filter(
                    equipment=current_flight.equipment,
                    departure_time__lt=next_flight.departure_time,
                    canceled=False,
                )
                .exclude(pk=current_flight.pk)
                .exclude(pk=next_flight.pk)
            )

            # Find the one that arrives last
            latest_arrival = None
            previous_flight = None
            for pf in previous_non_canceled:
                if latest_arrival is None or pf.arrival_time > latest_arrival:
                    latest_arrival = pf.arrival_time
                    previous_flight = pf

            # Determine where the equipment would be
            if previous_flight:
                expected_location = previous_flight.destination
            else:
                expected_location = current_flight.equipment.base_location

            # If the next flight can't depart from its origin, cancel it
            if expected_location != next_flight.origin:
                cancel_recursive(next_flight)

    cancel_recursive(flight)
    return canceled_flights