From cda97829ab7280b36b27df08823f7061f8bab054 Mon Sep 17 00:00:00 2001
From: Oliver Walters <oliver.henry.walters@gmail.com>
Date: Wed, 17 Feb 2021 10:27:36 +1100
Subject: [PATCH] Add function for required build order quantity

---
 InvenTree/part/models.py                     | 56 ++++++++++++++++++++
 InvenTree/part/templates/part/part_base.html |  7 +++
 2 files changed, 63 insertions(+)

diff --git a/InvenTree/part/models.py b/InvenTree/part/models.py
index 8ba7ba799d..85e7c051bf 100644
--- a/InvenTree/part/models.py
+++ b/InvenTree/part/models.py
@@ -884,6 +884,62 @@ class Part(MPTTModel):
 
         return max(total, 0)
 
+    def requiring_build_orders(self):
+        """
+        Return list of outstanding build orders which require this part
+        """
+
+        # List of BOM that this part is required for
+        boms = BomItem.objects.filter(sub_part=self)
+
+        part_ids = [bom.part.pk for bom in boms]
+
+        # Now, get a list of outstanding build orders which require this part
+        builds = BuildModels.Build.objects.filter(
+            part__in=part_ids,
+            status__in=BuildStatus.ACTIVE_CODES
+        )
+
+        return builds
+
+    def required_build_order_quantity(self):
+        """
+        Return the quantity of this part required for active build orders
+        """
+
+        # List of BOM that this part is required for
+        boms = BomItem.objects.filter(sub_part=self)
+
+        part_ids = [bom.part.pk for bom in boms]
+
+        # Now, get a list of outstanding build orders which require this part
+        builds = BuildModels.Build.objects.filter(
+            part__in=part_ids,
+            status__in=BuildStatus.ACTIVE_CODES
+        )
+
+        quantity = 0
+
+        for build in builds:
+            
+            bom_item = None
+
+            # Match BOM item to build
+            for bom in boms:
+                if bom.part == build.part:
+                    bom_item = bom
+                    break
+
+            if bom_item is None:
+                logger.warning("Found null BomItem when calculating required quantity")
+                continue
+
+            build_quantity = build.quantity *  bom_item.quantity
+
+            quantity += build_quantity
+        
+        return quantity
+
     @property
     def quantity_to_order(self):
         """ Return the quantity needing to be ordered for this part. """
diff --git a/InvenTree/part/templates/part/part_base.html b/InvenTree/part/templates/part/part_base.html
index eb347fc29e..0ddb5d2180 100644
--- a/InvenTree/part/templates/part/part_base.html
+++ b/InvenTree/part/templates/part/part_base.html
@@ -127,6 +127,13 @@
             <td>{% include "part/stock_count.html" %}</td>
         </tr>
         {% if not part.is_template %}
+        {% if part.required_build_order_quantity > 0 %}
+        <tr>
+            <td><span class='fas fa-hand-holding'></span></td>
+            <td>{% trans "Required for Build Orders" %}</td>
+            <td>{% decimal part.required_build_order_quantity %}</td>
+        </tr>
+        {% endif %}
         {% if part.build_order_allocation_count > 0 %}
         <tr>
             <td><span class='fas fa-dolly'></span></td>