add a short description to transformers

2 files changed, 21 insertions, 4 deletions

diff --git a/fietsboek/templates/edit_form.jinja2 b/fietsboek/templates/edit_form.jinja2
index 67c01c9..491db98 100644
--- a/fietsboek/templates/edit_form.jinja2
+++ b/fietsboek/templates/edit_form.jinja2
@@ -156,6 +156,8 @@
     <div id="transformer-{{ loop.index}}" class="accordion-collapse collapse" aria-labelledby="transformer-heading-{{ loop.index }}">
       <div class="accordion-body">
         {% set params = track.transformer_params_for(transformer.identifier()) %}
+        <!-- Short transformer description -->
+        <p>{{ _(transformer.description()) }}</p>
 
         <!-- Checkbox to enable the transformer -->
         <div class="form-check">
diff --git a/fietsboek/transformers/__init__.py b/fietsboek/transformers/__init__.py
index b4ed532..1a9517e 100644
--- a/fietsboek/transformers/__init__.py
+++ b/fietsboek/transformers/__init__.py
@@ -11,6 +11,7 @@ function to load and apply transformers.
 
 from abc import ABC, abstractmethod
 from collections.abc import Mapping
+from typing import TypeVar
 
 from gpxpy.gpx import GPX
 from markupsafe import Markup
@@ -19,6 +20,8 @@ from pyramid.i18n import TranslationString
 
 _ = TranslationString
 
+T = TypeVar("T", bound="Transformer")
+
 
 class Parameters(BaseModel):
     """Parameters for a transformer.
@@ -54,7 +57,7 @@ class Transformer(ABC):
 
     @classmethod
     @abstractmethod
-    def identifier(cls) -> str:
+    def identifier(cls: type[T]) -> str:
         """Returns a string identifier for this transformer.
 
         This identifier is used when serializing/deserializing the filters.
@@ -64,7 +67,7 @@ class Transformer(ABC):
 
     @classmethod
     @abstractmethod
-    def name(cls) -> TranslationString:
+    def name(cls: type[T]) -> TranslationString:
         """The human-readable name of this transformer, as a translateable string.
 
         :return: The transformer's name.
@@ -72,7 +75,15 @@ class Transformer(ABC):
 
     @classmethod
     @abstractmethod
-    def parameter_model(cls) -> type[Parameters]:
+    def description(cls: type[T]) -> TranslationString:
+        """A short description of what this transformer does.
+
+        :return: The transformer's description.
+        """
+
+    @classmethod
+    @abstractmethod
+    def parameter_model(cls: type[T]) -> type[Parameters]:
         """Returns the parameter model that this transformer expects.
 
         :return: The parameter model class.
@@ -114,7 +125,11 @@ class FixNullElevation(Transformer):
 
     @classmethod
     def name(cls) -> TranslationString:
-        return _("transformers.fix-null-elevation")
+        return _("transformers.fix-null-elevation.title")
+
+    @classmethod
+    def description(cls) -> TranslationString:
+        return _("transformers.fix-null-elevation.description")
 
     @classmethod
     def parameter_model(cls) -> type[Parameters]: