some fields validation and model cleaning

containers/models.py

@@ -1,11 +1,13 @@
-
+from django.core.exceptions import ValidationError
 from django.db import models
+
+from common.fields import ContainerNumberField
 from common.models import LinesModel, ContainerTypeModel
 # from payments.models import ContainerTariffPeriod, AdditionalFees
 
 # Create your models here.
 class Container(models.Model):
-    number = models.CharField(max_length=11)
+    number = ContainerNumberField(max_length=11)
     line = models.ForeignKey(
         LinesModel,
         on_delete=models.CASCADE,
@@ -25,7 +27,7 @@ class Container(models.Model):
     receive_vehicle = models.CharField(max_length=100, blank=True, null=True)
     damages = models.TextField(blank=True, null=True)
     heavy_damaged = models.BooleanField(default=False)
-    position = models.CharField(max_length=100, blank=True, null=True)
+    position = models.CharField(max_length=7, blank=True, null=True)
     swept = models.BooleanField(default=False)
     swept_on = models.DateTimeField(blank=True, null=True)
     swept_by = models.ForeignKey(
@@ -67,6 +69,11 @@ class Container(models.Model):
     )
     expedition_vehicle = models.CharField(max_length=100, blank=True, null=True)
 
+    def clean(self):
+        if Container.objects.filter(number=self.number, expedited=False).exclude(id=self.id).exists():
+            raise ValidationError(f'Container with number {self.number} already exists in the depot.!')
+        if self.heavy_damaged and not self.damages.strip():
+            raise ValidationError('Heavy damaged containers must have damages specified.')
 
 
 class ContainerHistory(Container):