feat: show link to Log record when viewing Quantity

src/wuttafarm/db/model/log.py

@@ -376,6 +376,7 @@ class LogQuantity(model.Base):
     quantity = orm.relationship(
         "Quantity",
         foreign_keys=quantity_uuid,
+        back_populates="_log",
     )
 
 

src/wuttafarm/db/model/quantities.py

@@ -26,6 +26,7 @@ Model definition for Quantities
 import sqlalchemy as sa
 from sqlalchemy import orm
 from sqlalchemy.ext.declarative import declared_attr
+from sqlalchemy.ext.associationproxy import association_proxy
 
 from wuttjamaican.db import model
 
@@ -161,6 +162,25 @@ class Quantity(model.Base):
         """,
     )
 
+    _log = orm.relationship(
+        "LogQuantity",
+        uselist=False,
+        cascade="all, delete-orphan",
+        cascade_backrefs=False,
+        back_populates="quantity",
+    )
+
+    def make_log_quantity(log):
+        from wuttafarm.db.model import LogQuantity
+
+        return LogQuantity(log=log)
+
+    log = association_proxy(
+        "_log",
+        "log",
+        creator=make_log_quantity,
+    )
+
     def render_as_text(self, config=None):
         measure = str(self.measure or self.measure_id or "")
         value = self.value_numerator / self.value_denominator
@@ -202,6 +222,7 @@ def add_quantity_proxies(subclass):
     Quantity.make_proxy(subclass, "quantity", "units_uuid")
     Quantity.make_proxy(subclass, "quantity", "units")
     Quantity.make_proxy(subclass, "quantity", "label")
+    Quantity.make_proxy(subclass, "quantity", "log")
 
 
 class StandardQuantity(QuantityMixin, model.Base):

src/wuttafarm/web/forms/schema.py

@@ -77,6 +77,31 @@ class LogQuick(WuttaSet):
         return LogQuickWidget(**kwargs)
 
 
+class LogRef(ObjectRef):
+    """
+    Custom schema type for a
+    :class:`~wuttafarm.db.model.log.Log` reference field.
+
+    This is a subclass of
+    :class:`~wuttaweb:wuttaweb.forms.schema.ObjectRef`.
+    """
+
+    @property
+    def model_class(self):  # pylint: disable=empty-docstring
+        """ """
+        model = self.app.model
+        return model.Log
+
+    def sort_query(self, query):  # pylint: disable=empty-docstring
+        """ """
+        return query.order_by(self.model_class.message)
+
+    def get_object_url(self, obj):  # pylint: disable=empty-docstring
+        """ """
+        log = obj
+        return self.request.route_url(f"logs_{log.log_type}.view", uuid=log.uuid)
+
+
 class FarmOSUnitRef(colander.SchemaType):
 
     def serialize(self, node, appstruct):

src/wuttafarm/web/views/quantities.py

@@ -29,7 +29,7 @@ from wuttaweb.db import Session
 
 from wuttafarm.web.views import WuttaFarmMasterView
 from wuttafarm.db.model import QuantityType, Quantity, StandardQuantity
-from wuttafarm.web.forms.schema import UnitRef
+from wuttafarm.web.forms.schema import UnitRef, LogRef
 
 
 def get_quantity_type_enum(config):
@@ -119,6 +119,7 @@ class QuantityMasterView(WuttaFarmMasterView):
         "value",
         "units",
         "label",
+        "log",
         "drupal_id",
         "farmos_uuid",
     ]
@@ -231,6 +232,13 @@ class QuantityMasterView(WuttaFarmMasterView):
             # TODO: ugh
             f.set_default("units", quantity.quantity.units)
 
+        # log
+        if self.creating or self.editing:
+            f.remove("log")
+        else:
+            f.set_node("log", LogRef(self.request))
+            f.set_default("log", quantity.log)
+
     def get_xref_buttons(self, quantity):
         buttons = super().get_xref_buttons(quantity)