Avoid hardcoding breakcrumb links, automatically use link to deepest …

…page that exists

_includes/breadcrumbs.html

@@ -1,36 +1,36 @@
 <div class="breadcrumbs">
-  {%- if page.categories.first == "News" -%}
-    {%- assign url = "/news/" -%}
-  {%- elsif page.categories.first == "Newsletters" -%}
-    {%- assign url = "/news/newsletter/" -%}
-  {%- elsif page.categories.first == "Mappy Hours" -%}
-    {%- assign url = "/events/mappy-hours/" -%}
-  {%- elsif page.categories.first == "Out & About" -%}
-    {%- assign url = "/news/appearances/" -%}
-  {%- else -%}
-    {%- assign path_parts = page.url | remove: "index" | split: "/" -%}
-    {%- if path_parts.size > 2 -%}
-      {% assign prior_index = path_parts.size | minus: 2 %}
-      {% assign prior_parts_size = path_parts.size | minus: 1 %}
-      {% assign part = path_parts | slice: prior_index, prior_index | first %}
-      {% assign url = path_parts | slice: 0, prior_parts_size | join: "/" | append: "/" %}
-    {%- endif -%}
-  {%- endif -%}
-  {%- if url -%}
-    <a href="{{url | absolute_url}}">
-      <svg class="iconsvg"><use xlink:href="#arrow-left"></use></svg>
-      {% assign part_page=site.documents | find: "url", url -%}
-      {%- if part_page.title -%}
-        {{part_page.title}}
-      {%- else -%}
-        {% assign derived_label=part | replace: "-", " " | url_decode %}
-        {% assign derived_label_as_num=derived_label | plus: 0 %}
-        {% if derived_label.size==2 and derived_label_as_num<=12  %}
-          {{ page.date | date: "%B" }}
+  {%- assign path_parts = page.url | split: "/" -%}
+  {%- if path_parts.size > 2 -%}
+    {%- assign urlsString = "" -%}
+    {%- assign composite_url = "" -%}
+    {%- for part in path_parts -%}
+      {%- assign composite_url = composite_url | append: part | append: "/" -%}
+      {%- assign urlsString = urlsString | append: composite_url | append: ";" -%}
+    {%- endfor -%}
+    {%- assign urls = urlsString | split: ";" | reverse | slice: 1, 100 -%}
+    {%- for url in urls -%}
+      {%- assign part_page = site.documents | find: "url", url -%}
+      {%- unless part_page -%}
+        {%- continue -%}
+      {%- endunless -%}
+      {%- if part_page.layout == "redirect" and part_page.redirect == page.url -%}
+        {%- continue -%}
+      {%- endif -%}
+      <a href="{{url | absolute_url}}">
+        <svg class="iconsvg"><use xlink:href="#arrow-left"></use></svg>
+        {% if part_page.title -%}
+          {{ part_page.title }}
         {%- else -%}
-          {{derived_label}}
+          {% assign derived_label=part | replace: "-", " " | url_decode %}
+          {% assign derived_label_as_num=derived_label | plus: 0 %}
+          {% if derived_label.size==2 and derived_label_as_num<=12  %}
+            {{ page.date | date: "%B" }}
+          {%- else -%}
+            {{ derived_label }}
+          {%- endif -%}
         {%- endif -%}
-      {%- endif -%}
-    </a>
+      </a>
+      {%- break -%}
+    {%- endfor -%}
   {%- endif -%}
 </div>