feat(source list): add sorting by country and source columns

- add functionality to sort by a source's holding institution
country (the "Country" column) and city/name/siglum (the "Source"
column) in the Source List view
- use the sortable_header helper tag for sortable column headers
in the source_list.html template
- fix the value used in the source column to the source's heading
property

django/cantusdb_project/main_app/templates/source_list.html

@@ -1,4 +1,6 @@
 {% extends "base.html" %}
+{% load helper_tags %}
+
 
 {% block title %}
     <title>Browse Sources | Cantus Database</title>
@@ -76,8 +78,8 @@ <h3>Browse Sources</h3>
         <table class="table table-sm small table-bordered table-responsive">
             <thead>
                 <tr>
-                    <th scope="col" class="text-wrap" style="text-align:center">Country</th>
-                    <th scope="col" class="text-wrap" style="text-align:center">Source</th>
+                    {% sortable_header request "country" %}
+                    {% sortable_header request "heading" "Source" %}
                     <th scope="col" class="text-wrap" style="text-align:center">Summary</th>
                     <th scope="col" class="text-wrap" style="text-align:center">Date/Origin</th>
                     <th scope="col" class="text-wrap" style="text-align:center">Image Link</th>
@@ -90,9 +92,9 @@ <h3>Browse Sources</h3>
                         <td class="text-wrap" style="text-align:center">
                             <b>{{ source.holding_institution.country }}</b>
                         </td>
-                        <td class="text-wrap" style="text-align:center" title="{{ source.title }}">
+                        <td class="text-wrap" style="text-align:center" title="{{ source.heading }}">
                             <a href="{% url 'source-detail' source.id %}">
-                                <b>{{ source.title|truncatechars_html:100 }}</b>
+                                <b>{{ source.heading|truncatechars_html:100 }}</b>
                             </a>
                         </td>
                         <td class="text-wrap" style="text-align:center" title="{{ source.summary|default:""|truncatechars_html:500 }}">

django/cantusdb_project/main_app/views/source.py

@@ -1,3 +1,5 @@
+from typing import Any
+
 from django.contrib import messages
 from django.contrib.auth.mixins import LoginRequiredMixin
 from django.contrib.auth.mixins import UserPassesTestMixin
@@ -214,7 +216,7 @@ class SourceListView(ListView):
     context_object_name = "sources"
     template_name = "source_list.html"
 
-    def get_context_data(self, **kwargs):
+    def get_context_data(self, **kwargs: Any) -> dict[str, Any]:
         context = super().get_context_data(**kwargs)
         context["provenances"] = (
             Provenance.objects.all().order_by("name").values("id", "name")
@@ -224,11 +226,11 @@ def get_context_data(self, **kwargs):
         )
         return context
 
-    def get_queryset(self):
+    def get_queryset(self) -> QuerySet[Source]:
         # use select_related() for foreign keys to reduce DB queries
         queryset = Source.objects.select_related(
             "segment", "provenance", "holding_institution"
-        ).order_by("siglum")
+        )
 
         display_unpublished: bool = self.request.user.is_authenticated
         if display_unpublished:
@@ -338,8 +340,23 @@ def get_queryset(self):
             )
             q_obj_filter &= indexing_search_q
 
+        order_param = self.request.GET.get("order")
+        order_fields = ["siglum"]
+        if order_param == "country":
+            order_fields.insert(0, "holding_institution__country")
+        if order_param == "heading":
+            order_fields.insert(0, "holding_institution__city")
+            order_fields.insert(1, "holding_institution__name")
+        if self.request.GET.get("sort") == "desc":
+            sort_prefix = "-"
+        else:
+            sort_prefix = ""
+
+        order_by_args = [f"{sort_prefix}{field}" for field in order_fields]
+
         return (
             queryset.filter(q_obj_filter)
+            .order_by(*order_by_args)
             .distinct()
             .prefetch_related(
                 Prefetch("century", queryset=Century.objects.all().order_by("id"))