From 4f84febbd11abc7852b14542a3f362e18526e84b Mon Sep 17 00:00:00 2001
From: Oliver Walters <oliver.henry.walters@gmail.com>
Date: Tue, 7 May 2019 22:46:37 +1000
Subject: [PATCH] More intelligent BuildItem allocation

- Set initial value for quantity based on how many parts are left to allocate
- Auto select the StockItem to take from (if there is only one)
---
 InvenTree/build/models.py           | 34 +++++++++++++++++++++++++++++
 InvenTree/build/views.py            | 21 +++++++++++++++++-
 InvenTree/templates/modal_form.html |  3 +++
 3 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/InvenTree/build/models.py b/InvenTree/build/models.py
index 504b57cc75..2a998dc26e 100644
--- a/InvenTree/build/models.py
+++ b/InvenTree/build/models.py
@@ -13,9 +13,11 @@ from django.core.exceptions import ValidationError
 
 from django.urls import reverse
 from django.db import models, transaction
+from django.db.models import Sum
 from django.core.validators import MinValueValidator
 
 from stock.models import StockItem
+from part.models import BomItem
 
 
 class Build(models.Model):
@@ -219,6 +221,38 @@ class Build(models.Model):
         self.status = self.COMPLETE
         self.save()
 
+    def getAllocatedQuantity(self, part):
+        """ Calculate the total number of <part> currently allocated to this build
+        """
+
+        allocated = BuildItem.objects.filter(build=self.id, stock_item__part=part.id).aggregate(Sum('quantity'))
+
+        q = allocated['quantity__sum']
+
+        if q:
+            return int(q)
+        else:
+            return 0
+
+    def getUnallocatedQuantity(self, part):
+        """ Calculate the quantity of <part> which still needs to be allocated to this build.
+
+        Args:
+            Part - the part to be tested
+
+        Returns:
+            The remaining allocated quantity
+        """
+
+        try:
+            bom_item = BomItem.objects.get(part=self.part.id, sub_part=part.id)
+        except BomItem.DoesNotExist:
+            return 0
+
+        quantity = bom_item.quantity * self.quantity
+
+        return quantity - self.getAllocatedQuantity(part)
+
     @property
     def required_parts(self):
         """ Returns a dict of parts required to build this part (BOM) """
diff --git a/InvenTree/build/views.py b/InvenTree/build/views.py
index cd2c87e814..cccd705e43 100644
--- a/InvenTree/build/views.py
+++ b/InvenTree/build/views.py
@@ -289,6 +289,12 @@ class BuildItemCreate(AjaxCreateView):
                     query = query.exclude(id__in=[item.stock_item.id for item in BuildItem.objects.filter(build=build_id, stock_item__part=part_id)])
 
                 form.fields['stock_item'].queryset = query
+
+                stocks = query.all()
+                # If there is only one item selected, select it
+                if len(stocks) == 1:
+                    form.fields['stock_item'].initial = stocks[0].id
+
             except Part.DoesNotExist:
                 pass
 
@@ -303,10 +309,23 @@ class BuildItemCreate(AjaxCreateView):
         initials = super(AjaxCreateView, self).get_initial().copy()
 
         build_id = self.get_param('build')
+        part_id = self.get_param('part')
+
+        if part_id:
+            try:
+                part = Part.objects.get(pk=part_id)
+            except Part.DoesNotExist:
+                part = None
         
         if build_id:
             try:
-                initials['build'] = Build.objects.get(pk=build_id)
+                build = Build.objects.get(pk=build_id)
+                initials['build'] = build
+
+                # Try to work out how many parts to allocate
+                if part:
+                    initials['quantity'] = build.getUnallocatedQuantity(part)
+
             except Build.DoesNotExist:
                 pass
 
diff --git a/InvenTree/templates/modal_form.html b/InvenTree/templates/modal_form.html
index 566671c657..3c0674fec8 100644
--- a/InvenTree/templates/modal_form.html
+++ b/InvenTree/templates/modal_form.html
@@ -14,6 +14,9 @@
   
   
   {% crispy form %}
+
+  {% block form_data %}
+  {% endblock %}
 </form>
 
 {% block post_form_content %}