added flight mechanics

simulator/models/flight.py

@@ -3,6 +3,10 @@ from .carrier import Carrier
 from .aircraft import Equipment
 from .aerodrome import Aerodrome
 from django.core.validators import MinValueValidator, MaxValueValidator
+from simulator.utils import haversine_nm
+from datetime import timedelta
+from django.core.exceptions import ValidationError
+from django.utils import timezone
 
 
 class Flight(models.Model):
@@ -23,7 +27,6 @@ class Flight(models.Model):
         validators=[MinValueValidator(1), MaxValueValidator(9999)]
     )
     departure_time = models.DateTimeField()
-    arrival_time = models.DateTimeField()
 
     class Meta:
         constraints = [
@@ -34,3 +37,44 @@ class Flight(models.Model):
 
     def __str__(self):
         return f"{self.carrier.icao}{self.flight_number} {self.origin.icao} > {self.destination.icao}"
+
+    @property
+    def distance_nm(self) -> float:
+        return haversine_nm(
+            self.origin.latitude,
+            self.origin.longitude,
+            self.destination.latitude,
+            self.destination.longitude,
+        )
+
+    @property
+    def duration(self) -> timedelta:
+        speed = self.equipment.model.cruise_speed_kt  # knots = nm/hr
+        hours = self.distance_nm / speed
+        return timedelta(hours=hours)
+
+    @property
+    def arrival_time(self):
+        return self.departure_time + self.duration
+
+    def clean(self):
+        overlapping = Flight.objects.filter(
+            equipment=self.equipment,
+            departure_time__lt=self.arrival_time,
+            arrival_time__gt=self.departure_time,
+        ).exclude(pk=self.pk)
+
+        if overlapping.exists():
+            raise ValidationError(
+                f"{self.equipment} is already assigned to another flight in this timeframe."
+            )
+
+    @property
+    def status(self):
+        now = timezone.now()
+        if now < self.departure_time:
+            return "Scheduled"
+        elif self.departure_time <= now < self.arrival_time:
+            return "In-Flight"
+        else:
+            return "Arrived"