Merge pull request #98 from samstorment/ThemeSwitcher

OS Independent Theme Switcher

code/services-application/search-service/resources/static/search/main.js

@@ -1,6 +1,6 @@
-// This sets the data-has-js attribute on the body tag to true, so we can style the page with the assumption that
+// This sets the data-has-js attribute on the html tag to true, so we can style the page with the assumption that
 // the browser supports JS. This is a progressive enhancement, so the page will still work without JS.
-document.getElementsByTagName('body')[0].setAttribute('data-has-js', 'true');
+document.documentElement.setAttribute('data-has-js', 'true');
 
 // To prevent the filter menu from being opened when the user hits enter on the search box, we need to add a keydown
 // handler to the search box that stops the event from propagating.  Janky hack, but it works.

code/services-application/search-service/resources/static/search/serp.scss

@@ -1,4 +1,6 @@
 :root {
+  color-scheme: light;
+
   --clr-bg-page: hsl(60, 42%, 95%); // $nicotine-light
 
   --clr-bg-ui: hsl(0, 0%, 100%);
@@ -26,8 +28,10 @@
   --font-family-heading: serif; // $heading-fonts
 }
 
-@media (prefers-color-scheme: dark) {
-  :root {
+
+@mixin dark-theme-mixin {
+  color-scheme: dark;
+
   --clr-bg-page: hsl(0, 0%, 6%);
 
   --clr-bg-ui: hsl(0, 0%, 18%);
@@ -50,16 +54,22 @@
   --clr-link-visited: #ffadff;
   --clr-heading-link-visited: var(--clr-link-visited);
 }
+ 
+:root[data-theme='dark'] {
+  @include dark-theme-mixin;
+}
+
+// Makes theme match the user's OS preference when JS is disabled
+@media (prefers-color-scheme: dark) {
+  :root:not([data-has-js="true"]) {
+    @include dark-theme-mixin;
+  }
 }
 
 * {
   box-sizing: border-box;
 }
 
-html {
-  color-scheme: light dark;
-}
-
 a {
   color: var(--clr-link);
 }
@@ -199,6 +209,9 @@ header {
   color: var(--clr-text-ui);
   box-shadow: 0 0 0.5ch var(--clr-shadow);
   margin-bottom: 1ch;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
 
   nav {
     a {
@@ -228,6 +241,15 @@ header {
   }
 }
 
+#theme {
+  padding: .5ch;
+  display: none;
+
+  [data-has-js='true'] & {
+    display: block;
+  }
+}
+
 #complaint {
   @extend .dialog;
   max-width: 60ch;
@@ -333,13 +355,11 @@ section.cards {
       line-height: 1.6;
     }
 
-    @media (prefers-color-scheme: dark) {
-      & {
+    [data-theme='dark'] & {
       border: 1px solid var(--clr-border);
     }
   }
 }
-}
 
 .positions {
   box-shadow: 0 0 2px var(--clr-shadow);
@@ -525,6 +545,8 @@ footer {
     font-family: var(--font-family-heading);
     font-weight: normal;
     text-align: center;
+    display: flex;
+    justify-content: space-between;
   }
 
   #suggestions-anchor {
@@ -717,7 +739,7 @@ footer {
 }
 
 @media (max-device-width: 624px) {
-  body[data-has-js="true"] { // This property is set via js so we can selectively enable these changes only if JS is enabled;
+  [data-has-js="true"] body { // This property is set via js so we can selectively enable these changes only if JS is enabled;
                              // This is desirable since mobile navigation is JS-driven.  If JS is disabled, having a squished
                              // GUI is better than having no working UI.
     margin: 0 !important;
@@ -733,6 +755,8 @@ footer {
     #mcfeast {
       display: inline;
       float: right;
+      width: 2rem;
+      font-size: 1rem;
     }
 
     #menu-close {

code/services-application/search-service/resources/static/search/theme.js

@@ -0,0 +1,57 @@
+function getTheme() {
+    const theme = window.localStorage.getItem('theme');
+
+    // if a valid theme is set in localStorage, return it
+    if (theme === 'dark' || theme === 'light') {
+        return { value: theme, system: false };
+    }
+
+    // if matchMedia is supported and OS theme is dark
+    if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
+        return { value: 'dark', system: true };
+    }
+
+    return { value: 'light', system: true };
+}
+
+function setTheme(value) {
+    if (value === 'dark' || value === 'light') {
+        window.localStorage.setItem('theme', value);
+    } else {
+        window.localStorage.removeItem('theme');
+    }
+
+    const theme = getTheme();
+
+    document.documentElement.setAttribute('data-theme', theme.value);
+}
+
+function initializeTheme() {
+    const themeSelect = document.getElementById('theme-select');
+
+    const theme = getTheme();
+
+    document.documentElement.setAttribute('data-theme', theme.value);
+
+    // system is selected by default in the themeSwitcher so ignore it here
+    if (!theme.system) {
+        themeSelect.value = theme.value;
+    }
+
+    themeSelect.addEventListener('change', e => {
+        setTheme(e.target.value);
+    });
+    
+    const mql = window.matchMedia('(prefers-color-scheme: dark)');
+
+    // if someone changes their theme at the OS level we need to update 
+    // their theme immediately if they're using their OS theme
+    mql.addEventListener('change', e => {    
+        if (themeSelect.value !== 'system') return;
+        
+        if (e.matches) setTheme('dark');
+        else setTheme('light');
+    });
+}
+
+initializeTheme();

code/services-application/search-service/resources/templates/search/parts/search-header.hdb

@@ -7,4 +7,15 @@
         <a href="https://memex.marginalia.nu/projects/edge/supporting.gmi">Donate</a>
         <a class="extra" href="https://search.marginalia.nu/explore/random">Random</a>
     </nav>
+    <div id="theme">
+        <label for="theme-select" class="screenreader-only">Color Theme</label>
+        <select id="theme-select">
+            <option value="system" selected>System</option>
+            <option value="light">Light</option>
+            <option value="dark">Dark</option>
+        </select>
+    </div>
 </header>
+
+<!-- load this ASAP to avoid color theme flicker -->
+<script src="/theme.js"></script>