Merge branch 'feature/multi-comments'

_includes/comments.html

@@ -0,0 +1,5 @@
+<!--  The comments switcher -->
+{% if page.comments and site.comments.active %}
+  {% capture path %}comments/{{ site.comments.active }}.html{% endcapture %}
+  {% include {{ path }} %}
+{% endif %}

_includes/comments/disqus.html

@@ -1,9 +1,6 @@
 <!--
   The Disqus lazy loading.
 -->
-
-{% if site.disqus.comments and page.comments %}
-
 <div id="disqus_thread" class="pt-2 pb-2">
   <p class="text-center text-muted small">
     Comments powered by <a href="https://disqus.com/">Disqus</a>.
@@ -11,6 +8,7 @@
 </div>
 
 <script type="text/javascript">
+
   var disqus_config = function () {
     this.page.url = '{{ page.url | absolute_url }}';
     this.page.identifier = '{{ page.url }}';
@@ -22,7 +20,7 @@
     if(entries[0].isIntersecting) {
         (function () {
             var d = document, s = d.createElement('script');
-            s.src = 'https://{{ site.disqus.shortname }}.disqus.com/embed.js';
+            s.src = 'https://{{ site.comments.disqus.shortname }}.disqus.com/embed.js';
             s.setAttribute('data-timestamp', +new Date());
             (d.head || d.body).appendChild(s);
         })();
@@ -54,5 +52,3 @@
   }
 
 </script>
-
-{% endif %}

_includes/comments/utterances.html

@@ -0,0 +1,51 @@
+<!-- https://utteranc.es/ -->
+<script src="https://utteranc.es/client.js"
+        repo="{{ site.comments.utterances.repo }}"
+        issue-term="{{ site.comments.utterances.issue_term }}"
+        crossorigin="anonymous"
+        async>
+</script>
+
+<script type="text/javascript">
+  $(function() {
+    const origin = "https://utteranc.es";
+    const iframe = "iframe.utterances-frame";
+    const lightTheme = "github-light";
+    const darkTheme = "github-dark";
+    let initTheme = lightTheme;
+
+    if ($("html[mode=dark]").length > 0
+        || ($("html[mode]").length == 0
+            && window.matchMedia("(prefers-color-scheme: dark)").matches)) {
+      initTheme = darkTheme;
+    }
+
+    addEventListener("message", (event) => {
+      let theme;
+
+      /* credit to <https://github.com/utterance/utterances/issues/170#issuecomment-594036347> */
+      if (event.origin === origin) {
+        /* page initial */
+        theme = initTheme;
+
+      } else if (event.source === window && event.data &&
+            event.data.direction === ModeToggle.ID) {
+        /* global theme mode changed */
+        const mode = event.data.message;
+        theme = (mode === ModeToggle.DARK_MODE ? darkTheme : lightTheme);
+
+      } else {
+        return;
+      }
+
+      const message = {
+        type: "set-theme",
+        theme: theme
+      };
+
+      const utterances = document.querySelector(iframe).contentWindow;
+      utterances.postMessage(message, origin);
+    });
+
+  });
+</script>