feat: Add Segment events for CheckoutIntent state transitions

Track state changes in CheckoutIntent lifecycle by emitting
appropriate Segment analytics events on transitions

Author: zwidekalanga

enterprise_access/apps/customer_billing/apps.py

@@ -6,3 +6,6 @@
 class CustomerBillingConfig(AppConfig):
     default_auto_field = 'django.db.models.BigAutoField'
     name = 'enterprise_access.apps.customer_billing'
+
+    def ready(self):
+        import enterprise_access.apps.customer_billing.signals  # noqa

enterprise_access/apps/customer_billing/constants.py

@@ -73,6 +73,12 @@ class CheckoutIntentState(StrEnum):
     ERRORED_PROVISIONING = 'errored_provisioning'
     EXPIRED = 'expired'
 
+class CheckoutIntentSegmentEvents:
+    """
+    Segment events for CheckoutIntent lifecycle tracking.
+    """
+    LIFECYCLE_EVENT = 'edx.server.enterprise-access.checkout-intent.lifecycle.event'
+
 
 ALLOWED_CHECKOUT_INTENT_STATE_TRANSITIONS = {
     CheckoutIntentState.CREATED: [

enterprise_access/apps/customer_billing/signals.py

@@ -0,0 +1,39 @@
+from django.db.models.signals import post_save, pre_save
+from django.dispatch import receiver
+
+from enterprise_access.apps.api.serializers import CheckoutIntentReadOnlySerializer
+from enterprise_access.apps.customer_billing.constants import (
+    CheckoutIntentSegmentEvents,
+)
+from enterprise_access.apps.customer_billing.models import CheckoutIntent
+from enterprise_access.apps.track.segment import track_event
+
+
+@receiver(pre_save, sender=CheckoutIntent)
+def capture_previous_state(sender, instance, **kwargs):
+    """Capture the previous state before saving."""
+    if instance.pk:  # Only for updates, not creation
+        try:
+            instance._previous_state = CheckoutIntent.objects.get(pk=instance.pk).state
+        except CheckoutIntent.DoesNotExist:
+            instance._previous_state = None
+    else:
+        instance._previous_state = None
+
+
+@receiver(post_save, sender=CheckoutIntent)
+def track_checkout_intent_changes(sender, instance, created, **kwargs):
+    """Automatically track events after save."""
+    previous_state = None if created else getattr(instance, '_previous_state', None)
+
+    # Only track if it's a creation or if the state actually changed
+    if created or (previous_state is not None and previous_state != instance.state):
+        properties = CheckoutIntentReadOnlySerializer(instance).data
+        properties["previous_state"] = previous_state
+        properties["new_state"] = instance.state
+
+        track_event(
+            lms_user_id=str(instance.user.id),
+            event_name=CheckoutIntentSegmentEvents.LIFECYCLE_EVENT,
+            properties=properties,
+        )