Created and activated the booking integrity ExecPlan, then implemented staff availability, overlap prevention, and duration validation with backend tests.

Added a staff availability model and migration, a booking validation service, and serializer enforcement.

backend/apps/salons/admin.py

@@ -1,9 +1,10 @@
 from django.contrib import admin
 
-from apps.salons.models import Review, Salon, SalonPhoto, Service, StaffProfile
+from apps.salons.models import Review, Salon, SalonPhoto, Service, StaffAvailability, StaffProfile
 
 admin.site.register(Salon)
 admin.site.register(SalonPhoto)
 admin.site.register(Service)
 admin.site.register(StaffProfile)
+admin.site.register(StaffAvailability)
 admin.site.register(Review)

backend/apps/salons/migrations/0002_staffavailability.py

@@ -0,0 +1,45 @@
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("salons", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="StaffAvailability",
+            fields=[
+                ("id", models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name="ID")),
+                (
+                    "day_of_week",
+                    models.PositiveSmallIntegerField(
+                        choices=[
+                            (0, "Monday"),
+                            (1, "Tuesday"),
+                            (2, "Wednesday"),
+                            (3, "Thursday"),
+                            (4, "Friday"),
+                            (5, "Saturday"),
+                            (6, "Sunday"),
+                        ]
+                    ),
+                ),
+                ("start_time", models.TimeField()),
+                ("end_time", models.TimeField()),
+                ("is_active", models.BooleanField(default=True)),
+                (
+                    "staff",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="availability",
+                        to="salons.staffprofile",
+                    ),
+                ),
+            ],
+            options={
+                "ordering": ["staff_id", "day_of_week", "start_time"],
+            },
+        ),
+    ]

backend/apps/salons/models.py

@@ -59,6 +59,34 @@ class StaffProfile(models.Model):
         return f"{self.user.email} - {self.salon.name}"
 
 
+class StaffAvailability(models.Model):
+    DAY_CHOICES = [
+        (0, "Monday"),
+        (1, "Tuesday"),
+        (2, "Wednesday"),
+        (3, "Thursday"),
+        (4, "Friday"),
+        (5, "Saturday"),
+        (6, "Sunday"),
+    ]
+
+    staff = models.ForeignKey(
+        StaffProfile,
+        on_delete=models.CASCADE,
+        related_name="availability",
+    )
+    day_of_week = models.PositiveSmallIntegerField(choices=DAY_CHOICES)
+    start_time = models.TimeField()
+    end_time = models.TimeField()
+    is_active = models.BooleanField(default=True)
+
+    class Meta:
+        ordering = ["staff_id", "day_of_week", "start_time"]
+
+    def __str__(self):
+        return f"{self.staff.user.email} {self.get_day_of_week_display()} {self.start_time}-{self.end_time}"
+
+
 class Review(models.Model):
     salon = models.ForeignKey(Salon, on_delete=models.CASCADE, related_name="reviews")
     customer = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="reviews")