diff --git a/core/models.py b/core/models.py
index 34795a5..3d6543e 100644
--- a/core/models.py
+++ b/core/models.py
@@ -1,4 +1,3 @@
-from cloudinary.models import CloudinaryField
 from datetime import timedelta
 from django.contrib.auth.models import AbstractUser
 from django.core.validators import FileExtensionValidator
@@ -6,6 +5,7 @@ from django.conf import settings
 from django.db import models
 from django.utils import timezone
 
+#User Model
 class User(AbstractUser):
     is_citizen = models.BooleanField(default=False)
     is_moderator = models.BooleanField(default=False)
@@ -33,6 +33,9 @@ class User(AbstractUser):
     is_banned = models.BooleanField(default=False)
     banned_until = models.DateTimeField(null=True, blank=True)
 
+    def __str__(self):
+        return self.username
+
     def ban(self, days=7):
         """Ban user for given number of days (default = 7)."""
         self.is_banned = True
@@ -45,16 +48,16 @@ class User(AbstractUser):
         self.banned_until = None
         self.save()
 
-    def is_currently_banned(self):
-        """Check if user is still banned (auto-unban if expired)."""
+    @property
+    def currently_banned(self):
         if self.is_banned and self.banned_until:
             if timezone.now() >= self.banned_until:
-                # Auto unban if ban expired
                 self.unban()
                 return False
             return True
         return False
-    
+
+#Department Model
 class Department(models.Model):
     name = models.CharField(max_length=100, unique=True)
     description = models.TextField(blank=True, null=True)
@@ -78,10 +81,17 @@ class Department(models.Model):
 
     class Meta:
         ordering = ["name"]
+        constraints = [
+            models.UniqueConstraint(
+                fields=["admin"],
+                name="unique_department_admin"
+            )
+        ]
 
     def __str__(self):
         return self.name
 
+#Issue Model
 class Issue(models.Model):
     STATUS_REPORTED = 'reported'
     STATUS_ACKNOWLEDGED = 'acknowledged'
@@ -117,10 +127,11 @@ class Issue(models.Model):
     latitude = models.FloatField(null=True, blank=True)
     longitude = models.FloatField(null=True, blank=True)
 
-    photo = CloudinaryField(
-        'images',
+    photo = models.ImageField(
+        upload_to="issues/",
         blank=True,
         null=True,
+        validators=[FileExtensionValidator(["jpg", "jpeg", "png", "webp"])]
     )
 
     status = models.CharField(
@@ -133,39 +144,56 @@ class Issue(models.Model):
     updated_at = models.DateTimeField(auto_now=True)
 
     class Meta:
-        ordering = ["-created_at"]  # 🔹 latest issues first by default
+        ordering = ["-created_at"]
+        indexes = [
+            models.Index(fields=["status"]),
+            models.Index(fields=["created_at"]),
+            models.Index(fields=["department"]),
+            models.Index(fields=["reporter"]),
+        ]
+
+
+  # 🔹 latest issues first by default
 
     def __str__(self):
         return f"{self.title} ({self.get_status_display()})"
 
     # 🔹 Helpers
     def vote_count(self):
-        return self.votes.count() if hasattr(self, "votes") else 0
+        return self.votes.count()
+
 
     def has_user_voted(self, user):
-        if user.is_authenticated and hasattr(self, "votes"):
+        if user.is_authenticated:
             return self.votes.filter(user=user).exists()
-        return 
+        return False
+
     
     def assign_to_department(self, department):
-        """Assign issue to a department and auto-update status to acknowledged"""
+        if self.department_id == department.id:
+            return
         self.department = department
         self.status = self.STATUS_ACKNOWLEDGED
         self.save()
-    
 
-    
+#Vote Model
 class Vote(models.Model):
     user = models.ForeignKey(User, on_delete=models.CASCADE)
     issue = models.ForeignKey(Issue, on_delete=models.CASCADE, related_name='votes')
     created_at = models.DateTimeField(auto_now_add=True)
 
     class Meta:
-        unique_together = ('user', 'issue')  # Prevent duplicate votes per user
+        constraints = [
+            models.UniqueConstraint(
+                fields=["user", "issue"],
+            name="unique_vote_per_user_issue"
+            )
+        ]
 
     def __str__(self):
         return f"{self.user.username} voted on {self.issue.title}"
 
+#Comment Model
 class Comment(models.Model):
     issue = models.ForeignKey(Issue, on_delete=models.CASCADE, related_name="comments")
     user = models.ForeignKey(User, on_delete=models.CASCADE)