[Feature] Stocktake reports (#4345)

* Add settings to control upcoming stocktake features

* Adds migration for "cost range" when performing stocktake

* Add cost data to PartStocktakeSerializer

Implement a new custom serializer for currency data type

* Refactor existing currency serializers

* Update stocktake table and forms

* Prevent trailing zeroes in forms

* Calculate cost range when adding manual stocktake entry

* Display interactive chart for part stocktake history

* Ensure chart data are converted to common currency

* Adds new model for building stocktake reports

* Add admin integration for new model

* Adds API endpoint to expose list of stocktake reports available for download

- No ability to edit or delete via API

* Add setting to control automated deletion of old stocktake reports

* Updates for settings page

- Load part stocktake report table
- Refactor function to render a downloadable media file
- Fix bug with forcing files to be downloaded
- Split js code into separate templates
- Make use of onPanelLoad functionalitty

* Fix conflicting migration files

* Adds API endpoint for manual generation of stocktake report

* Offload task to generate new stocktake report

* Adds python function to perform stocktake on a single part instance

* Small bug fixes

* Various tweaks

- Prevent new stocktake models from triggering plugin events when created
- Construct a simple csv dataset

* Generate new report

* Updates for report generation

- Prefetch related data
- Add extra columns
- Keep track of stocktake instances (for saving to database later on)

* Updates:

- Add confirmation message
- Serializer validation checks

* Ensure that background worker is running before manually scheduling a new stocktake report

* Add extra fields to stocktake models

Also move code from part/models.py to part/tasks.py

* Add 'part_count' to PartStocktakeReport table

* Updates for stocktake generation

- remove old performStocktake javascript code
- Now handled by automated server-side calculation
- Generate report for a single part

* Add a new "role" for stocktake

- Allows fine-grained control on viewing / creating / deleting stocktake data
- More in-line with existing permission controls
- Remove STOCKTAKE_OWNER setting

* Add serializer field to limit stocktake report to particular locations

* Use location restriction when generating a stocktake report

* Add UI buttons to perform stocktake for a whole category tree

* Add button to perform stocktake report for a location tree

* Adds a background tasks to handle periodic generation of stocktake reports

- Reports are generated at fixed intervals
- Deletes old reports after certain number of days

* Implement notifications for new stocktake reports

- If manually requested by a user, notify that user
- Cleanup notification table
- Amend PartStocktakeModel for better notification rendering

* Hide buttons on location and category page if stocktake is not enabled

* Cleanup log messages during server start

* Extend functionality of RoleRequired permission mixin

- Allow 'role_required' attribute to be added to an API view
- Useful when using a serializer class that does not have a model defined

* Add boolean option to toggle whether a report will be generated

* Update generateStocktake function

* Improve location filtering

- Don't limit the actual stock items
- Instead, select only parts which exist within a given location tree

* Update API version

* String tweaks

* Fix permissions for PartStocktake API

* More unit testing for stocktake functionality

* QoL fix

* Fix for assigning inherited permissions

InvenTree/part/test_api.py

@@ -2839,6 +2839,7 @@ class PartStocktakeTest(InvenTreeAPITestCase):
         'category',
         'part',
         'location',
+        'stock',
     ]
 
     def test_list_endpoint(self):
@@ -2887,8 +2888,8 @@ class PartStocktakeTest(InvenTreeAPITestCase):
 
         url = reverse('api-part-stocktake-list')
 
-        self.assignRole('part.add')
-        self.assignRole('part.view')
+        self.assignRole('stocktake.add')
+        self.assignRole('stocktake.view')
 
         for p in Part.objects.all():
 
@@ -2930,12 +2931,6 @@ class PartStocktakeTest(InvenTreeAPITestCase):
         self.assignRole('part.view')
 
         # Test we can retrieve via API
-        self.get(url, expected_code=403)
-
-        # Assign staff permission
-        self.user.is_staff = True
-        self.user.save()
-
         self.get(url, expected_code=200)
 
         # Try to edit data
@@ -2948,7 +2943,7 @@ class PartStocktakeTest(InvenTreeAPITestCase):
         )
 
         # Assign 'edit' role permission
-        self.assignRole('part.change')
+        self.assignRole('stocktake.change')
 
         # Try again
         self.patch(
@@ -2962,6 +2957,59 @@ class PartStocktakeTest(InvenTreeAPITestCase):
         # Try to delete
         self.delete(url, expected_code=403)
 
-        self.assignRole('part.delete')
+        self.assignRole('stocktake.delete')
 
         self.delete(url, expected_code=204)
+
+    def test_report_list(self):
+        """Test for PartStocktakeReport list endpoint"""
+
+        from part.tasks import generate_stocktake_report
+
+        n_parts = Part.objects.count()
+
+        # Initially, no stocktake records are available
+        self.assertEqual(PartStocktake.objects.count(), 0)
+
+        # Generate stocktake data for all parts (default configuration)
+        generate_stocktake_report()
+
+        # There should now be 1 stocktake entry for each part
+        self.assertEqual(PartStocktake.objects.count(), n_parts)
+
+        self.assignRole('stocktake.view')
+
+        response = self.get(reverse('api-part-stocktake-list'), expected_code=200)
+
+        self.assertEqual(len(response.data), n_parts)
+
+        # Stocktake report should be available via the API, also
+        response = self.get(reverse('api-part-stocktake-report-list'), expected_code=200)
+
+        self.assertEqual(len(response.data), 1)
+
+        data = response.data[0]
+
+        self.assertEqual(data['part_count'], 14)
+        self.assertEqual(data['user'], None)
+        self.assertTrue(data['report'].endswith('.csv'))
+
+    def test_report_generate(self):
+        """Test API functionality for generating a new stocktake report"""
+
+        url = reverse('api-part-stocktake-report-generate')
+
+        # Permission denied, initially
+        self.assignRole('stocktake.view')
+        response = self.post(url, data={}, expected_code=403)
+
+        # Stocktake functionality disabled
+        InvenTreeSetting.set_setting('STOCKTAKE_ENABLE', False, None)
+        self.assignRole('stocktake.add')
+        response = self.post(url, data={}, expected_code=400)
+
+        self.assertIn('Stocktake functionality is not enabled', str(response.data))
+
+        InvenTreeSetting.set_setting('STOCKTAKE_ENABLE', True, None)
+        response = self.post(url, data={}, expected_code=400)
+        self.assertIn('Background worker check failed', str(response.data))