Update parameter report helper (#11690)

* Update parameter report helper

- Fallback to case insensitive lookup

* Add default value in case parameter is not found

* Add new report helper func

docs/docs/report/helpers.md

@@ -547,14 +547,18 @@ You can add asset images to the reports and labels by using the `{% raw %}{% ass
 
 ## Parameters
 
-If you need to load a parameter value for a particular model instance, within the context of your template, you can use the `parameter` template tag:
+If you need to reference a parameter for a particular model instance, within the context of your template, you can use the `parameter` template tag:
+
+### parameter
+
+This returns a [Parameter](../concepts/parameters.md) object which contains the value of the parameter, as well as any associated metadata (e.g. units, description, etc).
 
 ::: report.templatetags.report.parameter
     options:
         show_docstring_description: false
         show_source: False
 
-### Example
+#### Example
 
 The following example assumes that you have a report or label which contains a valid [Part](../part/index.md) instance:
 
@@ -580,6 +584,27 @@ A [Parameter](../concepts/parameters.md) has the following available attributes:
 | Units | The *units* of the parameter (e.g. "km") |
 | Template | A reference to a [ParameterTemplate](../concepts/parameters.md#parameter-templates) |
 
+### parameter_value
+
+To access just the value of a parameter, use the `parameter_value` template tag:
+
+::: report.templatetags.report.parameter_value
+    options:
+        show_docstring_description: false
+        show_source: False
+
+#### Example
+
+```
+{% raw %}
+{% load report %}
+
+{% parameter_value part "length" as length_value %}
+Part: {{ part.name }}<br>
+Length: {{ length_value }}
+{% endraw %}
+```
+
 ## Rendering Markdown
 
 Some data fields (such as the *Notes* field available on many internal database models) support [markdown formatting](https://en.wikipedia.org/wiki/Markdown). To render markdown content in a custom report, there are template filters made available through the [django-markdownify](https://github.com/erwinmatijsen/django-markdownify) library. This library provides functionality for converting markdown content to HTML representation, allowing it to be then rendered to PDF by the InvenTree report generation pipeline.

src/backend/InvenTree/report/templatetags/report.py

@@ -473,10 +473,10 @@ def parameter(
 
     Arguments:
         instance: A Model object
-        parameter_name: The name of the parameter to retrieve
+        parameter_name: The name of the parameter to retrieve (case insensitive)
 
     Returns:
-        A Parameter object, or None if not found
+        A Parameter object, or the provided default value if not found
     """
     if instance is None:
         raise ValueError('parameter tag requires a valid Model instance')
@@ -484,12 +484,46 @@ def parameter(
     if not isinstance(instance, Model) or not hasattr(instance, 'parameters'):
         raise TypeError("parameter tag requires a Model with 'parameters' attribute")
 
-    return (
+    # First try with exact match
-        instance.parameters
+    if (
+        parameter := instance.parameters
         .prefetch_related('template')
         .filter(template__name=parameter_name)
         .first()
-    )
+    ):
+        return parameter
+
+    # Next, try with case-insensitive match
+    if (
+        parameter := instance.parameters
+        .prefetch_related('template')
+        .filter(template__name__iexact=parameter_name)
+        .first()
+    ):
+        return parameter
+
+    return None
+
+
+@register.simple_tag()
+def parameter_value(
+    instance: Model, parameter_name: str, backup_value: Optional[Any] = None
+) -> str:
+    """Return the value of a Parameter for the given part and parameter name.
+
+    Arguments:
+        instance: A Model object
+        parameter_name: The name of the parameter to retrieve (case insensitive)
+        backup_value: A backup value to return if the parameter is not found
+
+    Returns:
+        The value of the Parameter, or the backup_value if not found
+    """
+    if param := parameter(instance, parameter_name):
+        return param.data
+
+    # If the matching parameter is not found, return the backup value
+    return backup_value
 
 
 @register.simple_tag()