make tickets assignable to users

core/tickets/models.py

@@ -1,6 +1,7 @@
 from django.db import models
 from django_softdelete.models import SoftDeleteModel
 
+from authentication.models import ExtendedUser
 from inventory.models import Event
 from django.db.models.signals import post_save, pre_save
 from django.dispatch import receiver
@@ -32,7 +33,6 @@ class IssueThread(SoftDeleteModel):
     id = models.AutoField(primary_key=True)
     uuid = models.CharField(max_length=255, unique=True, null=False, blank=False)
     name = models.CharField(max_length=255)
-    assigned_to = models.CharField(max_length=255, null=True)
     manually_created = models.BooleanField(default=False)
 
     def short_uuid(self):
@@ -51,10 +51,24 @@ class IssueThread(SoftDeleteModel):
             return
         self.state_changes.create(state=value)
 
+    @property
+    def assigned_to(self):
+        try:
+            return self.assignments.order_by('-timestamp').first().assigned_to
+        except AttributeError:
+            return None
+
+    @assigned_to.setter
+    def assigned_to(self, value):
+        if self.assigned_to == value:
+            return
+        self.assignments.create(assigned_to=value)
+
     class Meta:
         permissions = [
             ('send_mail', 'Can send mail'),
             ('add_issuethread_manual', 'Can add issue thread manually'),
+            ('assign_issuethread', 'Can assign issue thread'),
         ]
 
 
@@ -70,12 +84,6 @@ def create_issue_thread(sender, instance, created, **kwargs):
     if created:
         StateChange.objects.create(issue_thread=instance, state='pending_new')
 
-    class Meta:
-        permissions = [
-            ('send_mail', 'Can send mail'),
-            ('add_issuethread_manual', 'Can add issue thread manually'),
-        ]
-
 
 class Comment(models.Model):
     id = models.AutoField(primary_key=True)
@@ -89,3 +97,10 @@ class StateChange(models.Model):
     issue_thread = models.ForeignKey(IssueThread, on_delete=models.CASCADE, related_name='state_changes')
     state = models.CharField(max_length=255, choices=STATE_CHOICES, default='pending_new')
     timestamp = models.DateTimeField(auto_now_add=True)
+
+
+class Assignment(models.Model):
+    id = models.AutoField(primary_key=True)
+    issue_thread = models.ForeignKey(IssueThread, on_delete=models.CASCADE, related_name='assignments')
+    assigned_to = models.ForeignKey(ExtendedUser, on_delete=models.CASCADE, related_name='assigned_tickets')
+    timestamp = models.DateTimeField(auto_now_add=True)