from django.db import models
from .carrier import Carrier
from .aircraft import Equipment
from .aerodrome import Aerodrome
from django.core.validators import MinValueValidator, MaxValueValidator


class Flight(models.Model):
    carrier = models.ForeignKey(
        Carrier, on_delete=models.CASCADE, related_name="flights"
    )
    equipment = models.ForeignKey(
        Equipment, on_delete=models.CASCADE, related_name="flights"
    )
    origin = models.ForeignKey(
        Aerodrome, on_delete=models.CASCADE, related_name="departures"
    )
    destination = models.ForeignKey(
        Aerodrome, on_delete=models.CASCADE, related_name="arrivals"
    )

    flight_number = models.PositiveIntegerField(
        validators=[MinValueValidator(1), MaxValueValidator(9999)]
    )
    departure_time = models.DateTimeField()
    arrival_time = models.DateTimeField()

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=["carrier", "flight_number"], name="unique_flight_per_carrier"
            )
        ]

    def __str__(self):
        return f"{self.carrier.icao}{self.flight_number} {self.origin.icao} > {self.destination.icao}"