From 738ba4eddfa05f7a20e78b0c011bd88095bd774f Mon Sep 17 00:00:00 2001
From: Oliver <oliver.henry.walters@gmail.com>
Date: Wed, 10 Nov 2021 10:59:48 +1100
Subject: [PATCH] Data migration to initially update serial number fields for
 all stock items

- Also automatically updates serial_int field when saving StockItem
---
 .../migrations/0069_auto_20211109_2347.py     | 55 +++++++++++++++++++
 InvenTree/stock/models.py                     | 26 +++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 InvenTree/stock/migrations/0069_auto_20211109_2347.py

diff --git a/InvenTree/stock/migrations/0069_auto_20211109_2347.py b/InvenTree/stock/migrations/0069_auto_20211109_2347.py
new file mode 100644
index 0000000000..3eaa8c784d
--- /dev/null
+++ b/InvenTree/stock/migrations/0069_auto_20211109_2347.py
@@ -0,0 +1,55 @@
+# Generated by Django 3.2.5 on 2021-11-09 23:47
+
+import re
+
+from django.db import migrations
+
+
+def update_serials(apps, schema_editor):
+    """
+    Rebuild the integer serial number field for existing StockItem objects
+    """
+
+    StockItem = apps.get_model('stock', 'stockitem')
+
+    for item in StockItem.objects.all():
+
+        if item.serial is None:
+            # Skip items without existing serial numbers
+            continue
+
+        serial = 0
+
+        result = re.match(r"^(\d+)", item.serial or "")
+
+        if result and len(result.groups()) == 1:
+            try:
+                serial = int(result.groups()[0])
+            except:
+                serial = 0
+
+
+        item.serial_int = serial
+        print(item, item.serial, '->', item.serial_int)
+        item.save()
+
+
+def nupdate_serials(apps, schema_editor):
+    """
+    Provided only for reverse migration compatibility
+    """
+    pass
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0068_stockitem_serial_int'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            update_serials,
+            reverse_code=nupdate_serials,
+        )
+    ]
diff --git a/InvenTree/stock/models.py b/InvenTree/stock/models.py
index 8601e96f36..5bc56f4bc6 100644
--- a/InvenTree/stock/models.py
+++ b/InvenTree/stock/models.py
@@ -7,6 +7,7 @@ Stock database model definitions
 from __future__ import unicode_literals
 
 import os
+import re
 
 from django.utils.translation import gettext_lazy as _
 from django.core.exceptions import ValidationError, FieldError
@@ -223,6 +224,29 @@ class StockItem(MPTTModel):
         self.scheduled_for_deletion = True
         self.save()
 
+    def update_serial_number(self):
+        """
+        Update the 'serial_int' field, to be an integer representation of the serial number.
+        This is used for efficient numerical sorting
+        """
+
+        serial = getattr(self, 'serial', '')
+
+        # Default value if we cannot convert to an integer
+        serial_int = 0
+
+        # Look at the start of the string - can it be "integerized"?
+        result = re.match(r'^(\d+)', serial or "")
+
+        if result and len(result.groups()) == 1:
+            try:
+                serial_int = int(result.groups()[0])
+            except:
+                serial_int = 0
+
+        self.serial_int = serial_int
+
+
     def save(self, *args, **kwargs):
         """
         Save this StockItem to the database. Performs a number of checks:
@@ -234,6 +258,8 @@ class StockItem(MPTTModel):
         self.validate_unique()
         self.clean()
 
+        self.update_serial_number()
+
         user = kwargs.pop('user', None)
 
         # If 'add_note = False' specified, then no tracking note will be added for item creation