From 5b7ccf0b671e2999b62befc729a3e517a0433728 Mon Sep 17 00:00:00 2001
From: Bertrand Yuan <bert.yuan@outlook.com>
Date: Mon, 15 Dec 2025 23:48:10 +0800
Subject: initial commit -- the front-end prototype

The initial code is base on Anirudh's work.

More to see at:

    https://github.com/techwithanirudh/shadcn-blog

Therefore, the code in this commit is under MIT license.
---
 src/components/theme-toggle.tsx | 126 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 src/components/theme-toggle.tsx

(limited to 'src/components/theme-toggle.tsx')

diff --git a/src/components/theme-toggle.tsx b/src/components/theme-toggle.tsx
new file mode 100644
index 0000000..cca9d03
--- /dev/null
+++ b/src/components/theme-toggle.tsx
@@ -0,0 +1,126 @@
+'use client';
+
+import { cn } from '@/lib/utils';
+import { cva } from 'class-variance-authority';
+import { Airplay, Moon, Sun } from 'lucide-react';
+import { motion } from 'motion/react';
+import { useTheme } from 'next-themes';
+import { type HTMLAttributes, useLayoutEffect, useState } from 'react';
+
+const themes = [
+  {
+    key: 'light',
+    icon: Sun,
+    label: 'Light theme',
+  },
+  {
+    key: 'dark',
+    icon: Moon,
+    label: 'Dark theme',
+  },
+  {
+    key: 'system',
+    icon: Airplay,
+    label: 'System theme',
+  },
+];
+
+const itemVariants = cva(
+  'relative size-6.5 rounded-full p-1.5 text-fd-muted-foreground',
+  {
+    variants: {
+      active: {
+        true: 'text-fd-accent-foreground',
+        false: 'text-fd-muted-foreground',
+      },
+    },
+  },
+);
+
+type Theme = 'light' | 'dark' | 'system';
+
+export function ThemeToggle({
+  className,
+  mode = 'light-dark',
+  ...props
+}: HTMLAttributes<HTMLDivElement> & {
+  mode?: 'light-dark' | 'light-dark-system';
+}) {
+  const { setTheme, theme: currentTheme, resolvedTheme } = useTheme();
+  const [mounted, setMounted] = useState(false);
+
+  const container = cn(
+    'relative flex items-center rounded-full p-1 ring-1 ring-border',
+    className,
+  );
+
+  useLayoutEffect(() => {
+    setMounted(true);
+  }, []);
+
+  const handleChangeTheme = async (theme: Theme) => {
+    function update() {
+      setTheme(theme);
+    }
+
+    if (document.startViewTransition && theme !== resolvedTheme) {
+      document.documentElement.style.viewTransitionName = 'theme-transition';
+      await document.startViewTransition(update).finished;
+      document.documentElement.style.viewTransitionName = '';
+    } else {
+      update();
+    }
+  };
+
+  const value = mounted
+    ? mode === 'light-dark'
+      ? resolvedTheme
+      : currentTheme
+    : null;
+
+  return (
+    <div
+      className={container}
+      onClick={() => {
+        if (mode !== 'light-dark') return;
+        handleChangeTheme(resolvedTheme === 'dark' ? 'light' : 'dark');
+      }}
+      data-theme-toggle=''
+      aria-label={mode === 'light-dark' ? 'Toggle Theme' : undefined}
+      {...props}
+    >
+      {themes.map(({ key, icon: Icon, label }) => {
+        const isActive = value === key;
+        if (mode === 'light-dark' && key === 'system') return;
+
+        return (
+          <button
+            type='button'
+            key={key}
+            className={itemVariants({ active: isActive })}
+            onClick={() => {
+              if (mode === 'light-dark') return;
+              handleChangeTheme(key as Theme);
+            }}
+            aria-label={label}
+          >
+            {isActive && (
+              <motion.div
+                layoutId='activeTheme'
+                className='absolute inset-0 rounded-full bg-accent'
+                transition={{
+                  type: 'spring',
+                  duration: mode === 'light-dark' ? 1.5 : 1,
+                }}
+              />
+            )}
+            <Icon
+              className={'relative m-auto size-full'}
+              fill={'currentColor'}
+            />
+          </button>
+        );
+      })}
+    </div>
+  );
+}
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