From 388ff1846159eeac0f3b68aa445418564d97b520 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=BE=9D=E7=91=AA=E8=B2=93?= <imacat@mail.imacat.idv.tw>
Date: Mon, 24 Aug 2020 22:52:58 +0800
Subject: [PATCH] Split BaseModel into RandomPkModel and StampedModel.

---
 accounting/models.py | 13 +++++++------
 mia_core/models.py   | 29 +++++++++++++++++++++++------
 mia_core/views.py    |  4 ++--
 3 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/accounting/models.py b/accounting/models.py
index d48b05d..08ed4d1 100644
--- a/accounting/models.py
+++ b/accounting/models.py
@@ -24,14 +24,15 @@ from decimal import Decimal
 from typing import Dict, List, Optional, Mapping
 
 from dirtyfields import DirtyFieldsMixin
-from django.db import models, transaction
+from django.db import models
 from django.db.models import Q, Max
 from django.http import HttpRequest
 
-from mia_core.models import BaseModel, L10nModel, LocalizedModel
+from mia_core.models import L10nModel, LocalizedModel, StampedModel, \
+    RandomPkModel
 
 
-class Account(DirtyFieldsMixin, LocalizedModel, BaseModel):
+class Account(DirtyFieldsMixin, LocalizedModel, StampedModel, RandomPkModel):
     """An account."""
     parent = models.ForeignKey(
         "self", on_delete=models.PROTECT, null=True,
@@ -108,13 +109,13 @@ class Account(DirtyFieldsMixin, LocalizedModel, BaseModel):
         self._is_in_use = value
 
 
-class AccountL10n(DirtyFieldsMixin, L10nModel, BaseModel):
+class AccountL10n(DirtyFieldsMixin, L10nModel, StampedModel, RandomPkModel):
     """The localization content of an account."""
     master = models.ForeignKey(
         Account, on_delete=models.CASCADE, related_name="l10n_set")
 
 
-class Transaction(DirtyFieldsMixin, BaseModel):
+class Transaction(DirtyFieldsMixin, StampedModel, RandomPkModel):
     """An accounting transaction."""
     date = models.DateField()
     ord = models.PositiveSmallIntegerField(default=1)
@@ -422,7 +423,7 @@ class Transaction(DirtyFieldsMixin, BaseModel):
             return "transfer"
 
 
-class Record(DirtyFieldsMixin, BaseModel):
+class Record(DirtyFieldsMixin, StampedModel, RandomPkModel):
     """An accounting record."""
     transaction = models.ForeignKey(
         Transaction, on_delete=models.CASCADE)
diff --git a/mia_core/models.py b/mia_core/models.py
index b5fd035..bc5d4fc 100644
--- a/mia_core/models.py
+++ b/mia_core/models.py
@@ -22,15 +22,30 @@ from typing import Any, Dict, List
 
 from dirtyfields import DirtyFieldsMixin
 from django.conf import settings
+from django.core.exceptions import ObjectDoesNotExist
 from django.db import models
 
 from mia_core.utils import new_pk, Language
 
 
-class BaseModel(models.Model):
-    """The common abstract base model that has id, created_at, created_by,
-    updated_at, and updated_by."""
+class RandomPkModel(models.Model):
+    """The abstract data model that uses 9-digit random primary keys."""
     id = models.PositiveIntegerField(primary_key=True)
+
+    def save(self, force_insert=False, force_update=False, using=None,
+             update_fields=None):
+        if self.pk is None:
+            self.pk = new_pk(self.__class__)
+        super().save(force_insert=force_insert, force_update=force_update,
+                     using=using, update_fields=update_fields)
+
+    class Meta:
+        abstract = True
+
+
+class StampedModel(models.Model):
+    """The abstract base model that has created_at, created_by, updated_at, and
+    updated_by."""
     created_at = models.DateTimeField(auto_now_add=True)
     created_by = models.ForeignKey(
         settings.AUTH_USER_MODEL, on_delete=models.PROTECT,
@@ -46,8 +61,9 @@ class BaseModel(models.Model):
 
     def save(self, force_insert=False, force_update=False, using=None,
              update_fields=None):
-        if self.pk is None:
-            self.pk = new_pk(self.__class__)
+        try:
+            self.created_by
+        except ObjectDoesNotExist as e:
             if self.current_user is not None:
                 self.created_by = self.current_user
         if self.current_user is not None:
@@ -122,7 +138,8 @@ class LocalizedModel(models.Model):
         super().save(force_insert=force_insert, force_update=force_update,
                      using=using, update_fields=update_fields)
         for l10n_rec in l10n_to_save:
-            if isinstance(self, BaseModel) and isinstance(l10n_rec, BaseModel):
+            if isinstance(self, StampedModel)\
+                    and isinstance(l10n_rec, StampedModel):
                 l10n_rec.current_user = self.current_user
             l10n_rec.save(force_insert=force_insert, force_update=force_update,
                           using=using, update_fields=update_fields)
diff --git a/mia_core/views.py b/mia_core/views.py
index 9df380b..11b703b 100644
--- a/mia_core/views.py
+++ b/mia_core/views.py
@@ -35,7 +35,7 @@ from django.views.generic import DeleteView as CoreDeleteView, \
 from django.views.generic.base import View
 
 from . import stored_post, utils
-from .models import BaseModel
+from .models import StampedModel
 from .utils import UrlBuilder
 
 
@@ -141,7 +141,7 @@ class FormView(View):
         """Fills in the data model from the form."""
         for name in form.fields:
             setattr(obj, name, form[name].value())
-        if isinstance(obj, BaseModel):
+        if isinstance(obj, StampedModel):
             obj.current_user = self.request.user
 
     def form_invalid(self, form: forms.Form) -> HttpResponseRedirect: