From 96ab77fd1e0c787902652d4f63ba751c18ecf322 Mon Sep 17 00:00:00 2001
From: Philipp Oppermann <dev@phil-opp.com>
Date: Sun, 17 Oct 2021 14:18:08 +0200
Subject: [PATCH] Implement a switch for switching between light and dark mode

---
 blog/sass/css/edition-2/main.scss  | 46 ++++++++++++++++++++++++++++++
 blog/static/js/edition-2/main.js   | 24 ++++++++++++++++
 blog/templates/edition-2/base.html |  2 ++
 3 files changed, 72 insertions(+)

diff --git a/blog/sass/css/edition-2/main.scss b/blog/sass/css/edition-2/main.scss
index f4712bbe..c8ca740f 100644
--- a/blog/sass/css/edition-2/main.scss
+++ b/blog/sass/css/edition-2/main.scss
@@ -961,6 +961,7 @@ img {
     background-color: white;
 }
 
+/* Note that dark mode is experimental */
 
 .dark-mode-note {
     display: none;
@@ -978,3 +979,48 @@ body.dark .dark-mode-note {
         display: none;
     }
 }
+
+/* Manual switch between dark and light mode */
+
+@mixin light-switch-light {
+    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='%23004' class='bi bi-moon' viewBox='0 0 16 16'%3E%3Cpath fill-rule='evenodd' d='M14.53 10.53a7 7 0 0 1-9.058-9.058A7.003 7.003 0 0 0 8 15a7.002 7.002 0 0 0 6.53-4.47z'/%3E%3C/svg%3E");
+}
+
+@mixin light-switch-dark {
+    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='%23ff9' class='bi bi-brightness-high-fill' viewBox='0 0 16 16'%3E%3Cpath d='M12 8a4 4 0 1 1-8 0 4 4 0 0 1 8 0zM8 0a.5.5 0 0 1 .5.5v2a.5.5 0 0 1-1 0v-2A.5.5 0 0 1 8 0zm0 13a.5.5 0 0 1 .5.5v2a.5.5 0 0 1-1 0v-2A.5.5 0 0 1 8 13zm8-5a.5.5 0 0 1-.5.5h-2a.5.5 0 0 1 0-1h2a.5.5 0 0 1 .5.5zM3 8a.5.5 0 0 1-.5.5h-2a.5.5 0 0 1 0-1h2A.5.5 0 0 1 3 8zm10.657-5.657a.5.5 0 0 1 0 .707l-1.414 1.415a.5.5 0 1 1-.707-.708l1.414-1.414a.5.5 0 0 1 .707 0zm-9.193 9.193a.5.5 0 0 1 0 .707L3.05 13.657a.5.5 0 0 1-.707-.707l1.414-1.414a.5.5 0 0 1 .707 0zm9.193 2.121a.5.5 0 0 1-.707 0l-1.414-1.414a.5.5 0 0 1 .707-.707l1.414 1.414a.5.5 0 0 1 0 .707zM4.464 4.465a.5.5 0 0 1-.707 0L2.343 3.05a.5.5 0 1 1 .707-.707l1.414 1.414a.5.5 0 0 1 0 .708z'/%3E%3C/svg%3E");
+}
+
+.light-switch {
+    @include light-switch-light();
+}
+
+body.dark .light-switch {
+    @include light-switch-dark();
+}
+
+@media (prefers-color-scheme: dark) {
+    .light-switch {
+        @include light-switch-dark();
+    }
+
+    body.light .light-switch {
+        @include light-switch-light();
+    }
+}
+
+.light-switch {
+    position: fixed;
+    left: 2rem;
+    bottom: 2rem;
+    background-repeat: no-repeat;
+    width: 2rem;
+    height: 2rem;
+    cursor: pointer;
+    opacity: 0.6;
+}
+
+.light-switch:hover {
+    transform: scale(1.3);
+    transition: 200ms ease-out;
+    opacity: 1;
+}
diff --git a/blog/static/js/edition-2/main.js b/blog/static/js/edition-2/main.js
index dfa1dd4d..513fcd9d 100644
--- a/blog/static/js/edition-2/main.js
+++ b/blog/static/js/edition-2/main.js
@@ -61,3 +61,27 @@ function toc_scroll_position(container) {
     current_toc_item.classList.add("active");
   }
 }
+
+function toggle_lights() {
+  var body = document.querySelector("body");
+  var comment_form = document.querySelector("iframe.giscus-frame");
+  if (body != null) {
+    if (body.classList.contains("dark")) {
+      body.classList.replace("dark", "light");
+      if (comment_form != null) {
+        comment_form.contentWindow.postMessage({
+          giscus: { setConfig: { theme: 'light' } }
+        }, "https://giscus.app")
+      }
+    } else {
+      body.classList.remove("light");
+      body.classList.add("dark");
+      if (comment_form != null) {
+        comment_form.contentWindow.postMessage({
+          giscus: { setConfig: { theme: 'dark' } }
+        }, "https://giscus.app")
+      }
+    }
+    console.log(body)
+  }
+}
diff --git a/blog/templates/edition-2/base.html b/blog/templates/edition-2/base.html
index 1a2ab2e7..f7baa22d 100644
--- a/blog/templates/edition-2/base.html
+++ b/blog/templates/edition-2/base.html
@@ -50,6 +50,8 @@
         </footer>
     </div>
 
+    <div class="light-switch" onclick="toggle_lights()" title="Switch between light and dark theme"></div>
+
     <script data-goatcounter="https://phil-opp.goatcounter.com/count" async src="//gc.zgo.at/count.js"></script>
 </body>