Add event filter frontend module with server-side aggregates

contao/templates/frontend/event_filter.html.twig

@@ -0,0 +1,27 @@
+<div id="eventfilters">
+    <button type="button" data-filter-tag="all">Alle</button>
+
+    {% for tag in tagButtons|default([]) %}
+        <button type="button" data-filter-tag="{{ tag.id }}">{{ tag.title }} ({{ tag.count }})</button>
+    {% endfor %}
+
+    <div class="widget-select places">
+        <label for="location-filter">Orte:</label>
+        <select id="location-filter">
+            <option value="all">Orte</option>
+            {% for location in locations|default([]) %}
+                <option value="location-{{ location.id }}">{{ location.title }} ({{ location.count }})</option>
+            {% endfor %}
+        </select>
+    </div>
+
+    <div class="widget-select org">
+        <label for="org-filter">Veranstalter:</label>
+        <select id="org-filter">
+            <option value="all">Veranstalter</option>
+            {% for organization in organizations|default([]) %}
+                <option value="org-{{ organization.id }}">{{ organization.title }} ({{ organization.count }})</option>
+            {% endfor %}
+        </select>
+    </div>
+</div>