From 7b760362173f5e0cc798e0d48996ab3f8db6d7be Mon Sep 17 00:00:00 2001
From: Joshua Laymon <joshlaymon@icloud.com>
Date: Sun, 31 Aug 2025 13:01:02 +0000
Subject: [PATCH] Add web/core/models_audit.py

---
 web/core/models_audit.py | 121 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 web/core/models_audit.py

diff --git a/web/core/models_audit.py b/web/core/models_audit.py
new file mode 100644
index 0000000..43b3ba1
--- /dev/null
+++ b/web/core/models_audit.py
@@ -0,0 +1,121 @@
+from django.db import models
+from django.utils import timezone
+from django.dispatch import receiver
+from django.db.models.signals import pre_save, post_save, post_delete
+from django.forms.models import model_to_dict
+from django.apps import apps
+
+class AuditLog(models.Model):
+    ACTION_CREATE = "create"
+    ACTION_UPDATE = "update"
+    ACTION_DELETE = "delete"
+    ACTIONS = [
+        (ACTION_CREATE, "Created"),
+        (ACTION_UPDATE, "Updated"),
+        (ACTION_DELETE, "Deleted"),
+    ]
+
+    entry_id = models.IntegerField(db_index=True)
+    action = models.CharField(max_length=10, choices=ACTIONS, db_index=True)
+    username = models.CharField(max_length=255, blank=True, default="")
+    timestamp = models.DateTimeField(default=timezone.now, db_index=True)
+    # For updates: {"field": ["old","new"], ...}
+    # For creates: {"__created__": {<field>: <value>, ...}}
+    # For deletes: {"__deleted__": {<field>: <value>, ...}}
+    changes = models.JSONField(null=True, blank=True)
+
+    class Meta:
+        ordering = ["-timestamp"]
+        indexes = [
+            models.Index(fields=["timestamp"]),
+            models.Index(fields=["action"]),
+            models.Index(fields=["entry_id"]),
+        ]
+
+    def __str__(self):
+        return f"{self.timestamp:%Y-%m-%d %H:%M:%S} {self.action} #{self.entry_id} by {self.username or '-'}"
+
+# ---- helpers for diffs ----
+
+Entry = apps.get_model("core", "Entry")  # avoids circular import
+
+def _tracked_field_names():
+    names = []
+    for f in Entry._meta.get_fields():
+        if getattr(f, "many_to_many", False):
+            continue
+        if not getattr(f, "concrete", False):
+            continue
+        if getattr(f, "primary_key", False):
+            continue
+        if getattr(f, "editable", True) is False:
+            continue
+        names.append(f.name)
+    return names
+
+_TRACKED = _tracked_field_names()
+
+def _serialize_entry(obj):
+    d = model_to_dict(obj, fields=_TRACKED)
+    for k, v in d.items():
+        d[k] = "" if v is None else str(v)
+    return d
+
+# ---- get current username from middleware ----
+from .middleware import get_current_username  # you’ll add this in step 2
+
+# ---- signals ----
+
+@receiver(pre_save, sender=Entry)
+def _audit_entry_pre_save(sender, instance, **kwargs):
+    # For updates, stash old snapshot on the instance
+    if instance.pk:
+        try:
+            existing = Entry.objects.get(pk=instance.pk)
+            instance.__audit_old__ = _serialize_entry(existing)
+        except Entry.DoesNotExist:
+            instance.__audit_old__ = None
+    else:
+        instance.__audit_old__ = None
+
+@receiver(post_save, sender=Entry)
+def _audit_entry_save(sender, instance, created, **kwargs):
+    from .models_audit import AuditLog
+    if created:
+        AuditLog.objects.create(
+            entry_id=instance.id,
+            action=AuditLog.ACTION_CREATE,
+            username=get_current_username(),
+            changes={"__created__": _serialize_entry(instance)},
+        )
+    else:
+        old = getattr(instance, "__audit_old__", None)
+        new = _serialize_entry(instance)
+        if old is None:
+            changes = {"__created__": new}
+            action = AuditLog.ACTION_CREATE
+        else:
+            diffs = {}
+            for field in _TRACKED:
+                ov = old.get(field, "")
+                nv = new.get(field, "")
+                if ov != nv:
+                    diffs[field] = [ov, nv]
+            changes = diffs or None
+            action = AuditLog.ACTION_UPDATE
+        AuditLog.objects.create(
+            entry_id=instance.id,
+            action=action,
+            username=get_current_username(),
+            changes=changes,
+        )
+
+@receiver(post_delete, sender=Entry)
+def _audit_entry_delete(sender, instance, **kwargs):
+    from .models_audit import AuditLog
+    AuditLog.objects.create(
+        entry_id=instance.id,
+        action=AuditLog.ACTION_DELETE,
+        username=get_current_username(),
+        changes={"__deleted__": _serialize_entry(instance)},
+    )
\ No newline at end of file