first conversions working

cookbook/admin.py

@@ -15,7 +15,7 @@ from .models import (BookmarkletImport, Comment, CookLog, Food, FoodInheritField
                      Recipe, RecipeBook, RecipeBookEntry, RecipeImport, SearchPreference, ShareLink,
                      ShoppingList, ShoppingListEntry, ShoppingListRecipe, Space, Step, Storage,
                      Supermarket, SupermarketCategory, SupermarketCategoryRelation, Sync, SyncLog,
-                     TelegramBot, Unit, UserFile, UserPreference, ViewLog, Automation, UserSpace)
+                     TelegramBot, Unit, UserFile, UserPreference, ViewLog, Automation, UserSpace, UnitConversion)
 
 
 class CustomUserAdmin(UserAdmin):
@@ -201,6 +201,14 @@ class FoodAdmin(TreeAdmin):
 admin.site.register(Food, FoodAdmin)
 
 
+class UnitConversionAdmin(admin.ModelAdmin):
+    list_display = ('base_amount', 'base_unit', 'food', 'converted_amount', 'converted_unit')
+    search_fields = ('food__name', 'unit__name')
+
+
+admin.site.register(UnitConversion, UnitConversionAdmin)
+
+
 class IngredientAdmin(admin.ModelAdmin):
     list_display = ('food', 'amount', 'unit')
     search_fields = ('food__name', 'unit__name')

cookbook/migrations/0187_unitconversion.py

@@ -0,0 +1,34 @@
+# Generated by Django 4.1.4 on 2023-01-09 16:41
+
+import cookbook.models
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import django_prometheus.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('cookbook', '0186_automation_order_alter_automation_type'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='UnitConversion',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('base_amount', models.DecimalField(decimal_places=16, default=0, max_digits=32)),
+                ('converted_amount', models.DecimalField(decimal_places=16, default=0, max_digits=32)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('base_unit', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='base_unit', to='cookbook.unit')),
+                ('converted_unit', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='converted_unit', to='cookbook.unit')),
+                ('created_by', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL)),
+                ('food', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='cookbook.food')),
+                ('space', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='cookbook.space')),
+            ],
+            bases=(django_prometheus.models.ExportModelOperationsMixin('unit_conversion'), models.Model, cookbook.models.PermissionModelMixin),
+        ),
+    ]

cookbook/models.py

@@ -649,6 +649,25 @@ class Food(ExportModelOperationsMixin('food'), TreeModel, PermissionModelMixin):
         )
 
 
+class UnitConversion(ExportModelOperationsMixin('unit_conversion'), models.Model, PermissionModelMixin):
+    base_amount = models.DecimalField(default=0, decimal_places=16, max_digits=32)
+    base_unit = models.ForeignKey('Unit', on_delete=models.CASCADE, related_name='base_unit')
+    converted_amount = models.DecimalField(default=0, decimal_places=16, max_digits=32)
+    converted_unit = models.ForeignKey('Unit', on_delete=models.CASCADE, related_name='converted_unit')
+
+    food = models.ForeignKey('Food', on_delete=models.CASCADE, null=True, blank=True)
+
+    created_by = models.ForeignKey(User, on_delete=models.PROTECT)
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    space = models.ForeignKey(Space, on_delete=models.CASCADE)
+    objects = ScopedManager(space='space')
+
+    def __str__(self):
+        return f'{self.base_amount} {self.base_unit} -> {self.converted_amount} {self.converted_unit} {self.food}'
+
+
 class Ingredient(ExportModelOperationsMixin('ingredient'), models.Model, PermissionModelMixin):
     # delete method on Food and Unit checks if they are part of a Recipe, if it is raises a ProtectedError instead of cascading the delete
     food = models.ForeignKey(Food, on_delete=models.CASCADE, null=True, blank=True)

cookbook/serializer.py

@@ -29,7 +29,7 @@ from cookbook.models import (Automation, BookmarkletImport, Comment, CookLog, Cu
                              RecipeBookEntry, RecipeImport, ShareLink, ShoppingList,
                              ShoppingListEntry, ShoppingListRecipe, Space, Step, Storage,
                              Supermarket, SupermarketCategory, SupermarketCategoryRelation, Sync,
-                             SyncLog, Unit, UserFile, UserPreference, UserSpace, ViewLog)
+                             SyncLog, Unit, UserFile, UserPreference, UserSpace, ViewLog, UnitConversion)
 from cookbook.templatetags.custom_tags import markdown
 from recipes.settings import AWS_ENABLED, MEDIA_URL
 
@@ -610,10 +610,28 @@ class IngredientSimpleSerializer(WritableNestedModelSerializer):
     unit = UnitSerializer(allow_null=True)
     used_in_recipes = serializers.SerializerMethodField('get_used_in_recipes')
     amount = CustomDecimalField()
+    conversions = serializers.SerializerMethodField('get_conversions')
 
     def get_used_in_recipes(self, obj):
         return list(Recipe.objects.filter(steps__ingredients=obj.id).values('id', 'name'))
 
+    def get_conversions(self, obj):
+        conversions = []
+
+        for c in UnitConversion.objects.filter(space=self.context['request'].space).filter(Q(food__isnull=True) | Q(food=obj.food)).filter(Q(base_unit=obj.unit) | Q(converted_unit=obj.unit)):
+            if obj.unit == c.base_unit:
+                conversions.append({
+                    'amount': obj.amount * (c.converted_amount/c.base_amount),
+                    'unit': UnitSerializer(c.converted_unit, context={'request': self.context['request']}).data,
+                })
+            else:
+                conversions.append({
+                    'amount': obj.amount * (c.base_amount / c.converted_amount),
+                    'unit': UnitSerializer(c.base_unit, context={'request': self.context['request']}).data,
+                })
+
+        return conversions
+
     def create(self, validated_data):
         validated_data['space'] = self.context['request'].space
         return super().create(validated_data)
@@ -625,7 +643,7 @@ class IngredientSimpleSerializer(WritableNestedModelSerializer):
     class Meta:
         model = Ingredient
         fields = (
-            'id', 'food', 'unit', 'amount', 'note', 'order',
+            'id', 'food', 'unit', 'amount', 'conversions', 'note', 'order',
             'is_header', 'no_amount', 'original_text', 'used_in_recipes',
             'always_use_plural_unit', 'always_use_plural_food',
         )