From 943b27e1958aee67607c22f5a32feb740e9e932a Mon Sep 17 00:00:00 2001
From: Oliver <oliver.henry.walters@gmail.com>
Date: Mon, 20 Dec 2021 19:29:08 +1100
Subject: [PATCH] Adds "items" list to API endpoint

---
 InvenTree/order/models.py      | 28 ++++++++++++-----------
 InvenTree/stock/models.py      | 42 ++++++++++++++++++++++++++++++++++
 InvenTree/stock/serializers.py | 39 +++++++++++++++++++++++++++++--
 3 files changed, 94 insertions(+), 15 deletions(-)

diff --git a/InvenTree/order/models.py b/InvenTree/order/models.py
index 3a7d39d7b5..e798ee4e30 100644
--- a/InvenTree/order/models.py
+++ b/InvenTree/order/models.py
@@ -628,28 +628,30 @@ class SalesOrder(Order):
         Throws a ValidationError if cannot be completed.
         """
 
-        # Order without line items cannot be completed
-        if self.lines.count() == 0:
-            if raise_error:
+        try:
+
+            # Order without line items cannot be completed
+            if self.lines.count() == 0:
                 raise ValidationError(_('Order cannot be completed as no parts have been assigned'))
 
-        # Only a PENDING order can be marked as SHIPPED
-        elif self.status != SalesOrderStatus.PENDING:
-            if raise_error:
+            # Only a PENDING order can be marked as SHIPPED
+            elif self.status != SalesOrderStatus.PENDING:
                 raise ValidationError(_('Only a pending order can be marked as complete'))
 
-        elif self.pending_shipment_count > 0:
-            if raise_error:
+            elif self.pending_shipment_count > 0:
                 raise ValidationError(_("Order cannot be completed as there are incomplete shipments"))
 
-        elif self.pending_line_count > 0:
-            if raise_error:
+            elif self.pending_line_count > 0:
                 raise ValidationError(_("Order cannot be completed as there are incomplete line items"))
 
-        else:
-            return True
+        except ValidationError as e:
 
-        return False
+            if raise_error:
+                raise e
+            else:
+                return False
+
+        return True
 
     def complete_order(self, user):
         """
diff --git a/InvenTree/stock/models.py b/InvenTree/stock/models.py
index 7f385e7136..2c9773e6e7 100644
--- a/InvenTree/stock/models.py
+++ b/InvenTree/stock/models.py
@@ -1153,6 +1153,48 @@ class StockItem(MPTTModel):
             result.stock_item = self
             result.save()
 
+    def can_merge(self, other=None, raise_error=False):
+        """
+        Check if this stock item can be merged into another
+        """
+
+        try:
+            if not self.in_stock:
+                raise ValidationError(_("Item must be in stock"))
+
+            if self.serialized:
+                raise ValidationError(_("Serialized stock cannot be merged"))
+
+        except ValidationError as e:
+            if raise_error:
+                raise e
+            else:
+                return False
+
+        return True
+
+    @transaction.atomic
+    def merge_stock_item(self, other, **kwargs):
+        """
+        Merge another stock item into this one; the two become one!
+
+        *This* stock item subsumes the other, which is essentially deleted:
+
+        - The quantity of this StockItem is increased
+        - Tracking history for the *other* item is deleted
+        - Any allocations (build order, sales order) are moved to this StockItem
+        """
+
+        # If the stock item cannot be merged, return
+        if not self.can_merge(other):
+            return
+
+        user = kwargs.get('user', None)
+        location = kwargs.get('location', None)
+
+        # TODO: Merge!
+
+
     @transaction.atomic
     def splitStock(self, quantity, location, user, **kwargs):
         """ Split this stock item into two items, in the same location.
diff --git a/InvenTree/stock/serializers.py b/InvenTree/stock/serializers.py
index 551d660f7b..cf30252cac 100644
--- a/InvenTree/stock/serializers.py
+++ b/InvenTree/stock/serializers.py
@@ -674,6 +674,33 @@ class StockAssignmentSerializer(serializers.Serializer):
                 )
 
 
+class StockMergeItemSerializer(serializers.Serializer):
+    """
+    Serializer for a single StockItem within the StockMergeSerializer class.
+
+    Here, the individual StockItem is being checked for merge compatibility.
+    """
+
+    class Meta:
+        fields = [
+            'item',
+        ]
+
+    item = serializers.PrimaryKeyRelatedField(
+        queryset=StockItem.objects.all(),
+        many=False,
+        allow_null=False,
+        required=True,
+        label=_('Stock Item'),
+    )
+
+    def validate_item(self, item):
+
+        # Check that the stock item is able to be merged
+        item.can_merge(raise_error=True)
+
+        return item
+
 class StockMergeSerializer(serializers.Serializer):
     """
     Serializer for merging two (or more) stock items together
@@ -681,10 +708,15 @@ class StockMergeSerializer(serializers.Serializer):
 
     class Meta:
         fields = [
-            # 'items',
+            'items',
             'location',
         ]
 
+    items = StockMergeItemSerializer(
+        many=True,
+        required=True,
+    )
+
     location = serializers.PrimaryKeyRelatedField(
         queryset=StockLocation.objects.all(),
         many=False,
@@ -698,7 +730,10 @@ class StockMergeSerializer(serializers.Serializer):
 
         data = super().validate(data)
 
-        # TODO: Custom data validation
+        items = data['items']
+
+        if len(items) < 2:
+            raise ValidationError(_('At least two stock items must be provided'))
 
         return data