unit conversion cleanups

cookbook/helper/unit_conversion_helper.py

@@ -0,0 +1,48 @@
+def base_conversions():
+    METRIC_MASS_CONVERSIONS = {
+        'g':  {'base_amount': 1000, 'base_unit': 'mg', 'converted_amount': 1, 'converted_unit': 'g'},
+        'mg':  {'base_amount': 1000, 'base_unit': 'g', 'converted_amount': 1, 'converted_unit': 'kg'},
+    }
+
+
+
+    METRIC_LIQUID_CONVERSIONS = [
+        {'base_amount': 1000, 'base_unit': 'ml', 'converted_amount': 1, 'converted_unit': 'l'},
+    ]
+
+
+def get_conversions(amount, unit, food):
+    conversions = []
+    if unit:
+        for c in unit.unit_conversion_base_relation.all():
+            r = _uc_convert(c, amount, unit, food)
+            if r not in conversions:
+                conversions.append(r)
+        for c in unit.unit_conversion_converted_relation.all():
+            r = _uc_convert(c, amount, unit, food)
+            if r not in conversions:
+                conversions.append(r)
+
+    return conversions
+
+
+def _uc_convert(uc, amount, unit, food):
+    if uc.food is None or uc.food == food:
+        if unit == uc.base_unit:
+            return {
+                'amount': amount * (uc.converted_amount / uc.base_amount),
+                'unit': {
+                    'id': uc.converted_unit.id,
+                    'name': uc.converted_unit.name,
+                    'plural_name': uc.converted_unit.plural_name
+                },
+            }
+        else:
+            return {
+                'amount': amount * (uc.base_amount / uc.converted_amount),
+                'unit': {
+                    'id': uc.base_unit.id,
+                    'name': uc.base_unit.name,
+                    'plural_name': uc.base_unit.plural_name
+                },
+            }