From 4b8ef2ad626f6518548743b65a7c773bd445ac03 Mon Sep 17 00:00:00 2001
From: Oliver <oliver.henry.walters@gmail.com>
Date: Wed, 25 Aug 2021 17:46:42 +1000
Subject: [PATCH] Implements custom filtering back end

---
 InvenTree/InvenTree/filters.py | 39 ++++++++++++++++++++++++----------
 InvenTree/order/api.py         | 12 ++++++++---
 2 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/InvenTree/InvenTree/filters.py b/InvenTree/InvenTree/filters.py
index b7ee52fb5a..cd1b769646 100644
--- a/InvenTree/InvenTree/filters.py
+++ b/InvenTree/InvenTree/filters.py
@@ -10,25 +10,42 @@ class InvenTreeOrderingFilter(OrderingFilter):
 
     To use, simply specify this filter in the "filter_backends" section.
 
-    Then, you can specify aliasing for ordering fields (or use ordering_fields as normal), e.g.
-
     filter_backends = [
         InvenTreeOrderingFilter,
     ]
 
-    ordering_fields = [
-        'name',
-        'quantity',
-        ('part__SKU', 'SKU')
-    ]
-
-    Here, ordering by "SKU" will actually order by the "SKU" field on the related part field
+    Then, specify a ordering_field_aliases attribute:
 
+    ordering_field_alises = {
+        'name': 'part__part__name',
+        'SKU': 'part__SKU',
+    }
     """
 
     def get_ordering(self, request, queryset, view):
 
         ordering = super().get_ordering(request, queryset, view)
 
-        print("ORDERING:", ordering)
-        return ordering
\ No newline at end of file
+        aliases = getattr(view, 'ordering_field_aliases', None)
+
+        # Attempt to map ordering fields based on provided aliases
+        if ordering is not None and aliases is not None:
+            """
+            Ordering fields should be mapped to separate fields
+            """
+
+            for idx, field in enumerate(ordering):
+
+                reverse = False
+
+                if field.startswith('-'):
+                    field = field[1:]
+                    reverse = True
+
+                if field in aliases:
+                    ordering[idx] = aliases[field]
+
+                    if reverse:
+                        ordering[idx] = '-' + ordering[idx]
+
+        return ordering
diff --git a/InvenTree/order/api.py b/InvenTree/order/api.py
index b4c0022604..e728b19226 100644
--- a/InvenTree/order/api.py
+++ b/InvenTree/order/api.py
@@ -232,10 +232,16 @@ class POLineItemList(generics.ListCreateAPIView):
         InvenTreeOrderingFilter
     ]
 
+    ordering_field_aliases = {
+        'MPN': 'part__manufacturer_part__MPN',
+        'SKU': 'part__SKU',
+        'part_name': 'part__part__name',
+    }
+
     ordering_fields = [
-        'part__part__name',
-        'part__MPN',
-        'part__SKU',
+        'part_name',
+        'MPN',
+        'SKU',
         'reference',
         'quantity',
         'received',