From ec941fb68d2f7c278e3d21e77660a48ec269ae8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jochen=20Wersd=C3=B6rfer?= <jochen@wersdoerfer.de>
Date: Tue, 21 Mar 2023 10:59:51 +0100
Subject: [PATCH] #88 include a hidden input field if the current option is
 selected to preserve it on form submit + test + release notes

---
 cast/filters.py          | 22 ++++++++++++++++------
 docs/releases/0.2.10.rst |  3 +--
 tests/filter_test.py     |  7 +++++++
 3 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/cast/filters.py b/cast/filters.py
index ea38618b..c0d605ee 100644
--- a/cast/filters.py
+++ b/cast/filters.py
@@ -68,20 +68,30 @@ def render_option(self, name: str, selected_choices: set[str], option_value: str
         data_dict = {k: str(v) for k, v in self.data.items() if k != "page"}
         data = QueryDict("", mutable=True)
         data.update(data_dict)
-
         data[name] = option_value
-        selected = data == self.data or option_value in selected_choices
+
+        # build the option string
         url = data.urlencode()
-        option_string = self.option_string()
-        return option_string % {
-            "attrs": selected and ' class="selected"' or "",
+        option_attrs, hidden_input = "", ""
+        if option_value in selected_choices:
+            # the current option is already selected, so add a hidden input field
+            # to preserve the selection and add the class "selected" to the link
+            option_attrs = ' class="selected"'
+            hidden_input = f'<input type="hidden" name="{name}" value="{option_value}" />'
+        option_string = self.option_string() % {
+            "attrs": option_attrs,
             "query_string": url,
             "label": force_str(option_label),
+            "hidden_input": hidden_input,
         }
+        return option_string
 
     @staticmethod
     def option_string() -> str:
-        return '<div class="cast-date-facet-item"><a%(attrs)s href="?%(query_string)s">%(label)s</a></div>'
+        return (
+            '<div class="cast-date-facet-item"><a%(attrs)s href="?%(query_string)s">%(label)s</a>'
+            "%(hidden_input)s</div>"
+        )
 
 
 def parse_date_facets(value: str) -> datetime:
diff --git a/docs/releases/0.2.10.rst b/docs/releases/0.2.10.rst
index 6a76eae6..28a94a4a 100644
--- a/docs/releases/0.2.10.rst
+++ b/docs/releases/0.2.10.rst
@@ -3,5 +3,4 @@
 
 Filter fixes + htmx.
 
-* #88 Fixed date facet removed after changing order
-* #89 Fixed date facet removed after adding date filter
+* #88 Fixed date facet is removed from form submit
diff --git a/tests/filter_test.py b/tests/filter_test.py
index 5a2adbd7..5eb10b2c 100644
--- a/tests/filter_test.py
+++ b/tests/filter_test.py
@@ -34,3 +34,10 @@ def test_active_pagination_is_removed_from_date_facet_filter():
     QueryDict
     option = dfw.render_option("name", set(), "value", "label")
     assert "page=3" not in option
+
+
+def test_selected_date_facet_is_in_hidden_input():
+    dfw = DateFacetWidget()
+    dfw.data = QueryDict("date_facets=2018-12")
+    option = dfw.render_option("date_facets", {"2018-12"}, "2018-12", "2018-12 (3)")
+    assert '<input type="hidden" name="date_facets" value="2018-12" />' in option