From dd1ede93d914563e02d1ed8f21574e0dd5c0d845 Mon Sep 17 00:00:00 2001
From: JY Hsu <hsujoyao@gmail.com>
Date: Sun, 1 Sep 2024 00:38:50 +0800
Subject: [PATCH] feat: Add basic theme feature

---
 assets/scripts/features/index.js              |  4 +
 assets/scripts/features/theme/index.js        | 91 +++++++++++++++++++
 .../partials/helpers/get-esbuild-options.html | 11 ++-
 3 files changed, 105 insertions(+), 1 deletion(-)
 create mode 100644 assets/scripts/features/theme/index.js

diff --git a/assets/scripts/features/index.js b/assets/scripts/features/index.js
index 9682acf..9e4fb4f 100644
--- a/assets/scripts/features/index.js
+++ b/assets/scripts/features/index.js
@@ -10,6 +10,10 @@ if (process.env.FEATURE_DARKMODE === '1') {
   import('./darkmode')
 }
 
+if (process.env.FEATURE_THEME === '1') {
+  import('./theme')
+}
+
 if (process.env.FEATURE_FLOWCHART === '1') {
   import('./flowchart')
 }
diff --git a/assets/scripts/features/theme/index.js b/assets/scripts/features/theme/index.js
new file mode 100644
index 0000000..e0da3eb
--- /dev/null
+++ b/assets/scripts/features/theme/index.js
@@ -0,0 +1,91 @@
+const PERSISTENCE_KEY = 'lightmode:color-scheme'
+
+const THEME_DARK = typeof process.env.FEATURE_THEME_DARK === 'undefined' ? false : process.env.FEATURE_THEME_DARK;
+const THEME_LIGHT = typeof process.env.FEATURE_THEME_LIGHT === 'undefined' ? false : process.env.FEATURE_THEME_LIGHT;
+const THEME_DEFAULT = typeof process.env.FEATURE_THEME_DEFAULT === 'system' ? false : process.env.FEATURE_THEME_DEFAULT;
+
+window.addEventListener('load', async () => {
+  const menu = document.getElementById('themeMenu')
+  const $icon = document.getElementById('navbar-theme-icon-svg')
+  if (menu == null || $icon == null) return
+
+  const btns = menu.getElementsByTagName('a')
+  const iconMap = Array.from(btns).reduce((map, btn) => {
+    const $img = btn.getElementsByTagName('img')[0]
+    map[btn.dataset.scheme] = $img.src
+    return map
+  }, {})
+
+
+  function checkScheme(scheme) {
+    if (scheme === "light" && THEME_LIGHT) {
+      return "light"
+    }
+    if (scheme === "dark" && THEME_DARK) {
+      return "dark"
+    }
+    return "system"
+  }
+
+  function loadScheme() {
+    return localStorage.getItem(PERSISTENCE_KEY) || loadDefaultScheme()
+  }
+
+  function loadDefaultScheme() {
+    return THEME_DEFAULT || "system"
+  }
+
+  function saveScheme(scheme) {
+    localStorage.setItem(PERSISTENCE_KEY, scheme)
+  }
+
+  function getPreferredColorScheme() {
+    const isDarkMode = window.matchMedia("(prefers-color-scheme: dark)").matches;
+    return isDarkMode ? "dark" : "light";
+  }
+
+  function setScheme(newScheme) {
+    let theme = newScheme
+    if (newScheme === 'system') {
+      theme = getPreferredColorScheme()
+    }
+    // set data-theme attribute on html tag
+    document.querySelector("html").dataset.theme = theme;
+
+    // update icon
+    $icon.src = iconMap[newScheme]
+
+    // save preference to local storage
+    saveScheme(newScheme)
+
+    setImages(theme)
+  }
+
+  setScheme(loadScheme())
+
+  Array.from(menu.getElementsByTagName('a')).forEach((btn) => {
+    btn.addEventListener('click', () => {
+      const { scheme } = btn.dataset
+      setScheme(scheme)
+    })
+  })
+})
+
+function setImages(newScheme) {
+  const els = Array.from(document.getElementsByClassName('logo-holder'));
+  for (const el of els) {
+    const light = el.querySelector('.light-logo');
+    const dark = el.querySelector('.dark-logo');
+
+
+
+    if (newScheme === "dark" && dark !== null) {
+      if (light !== null) light.style.display = 'none'
+      dark.style.display = 'inline'
+    }
+    else {
+      if (light !== null) light.style.display = 'inline'
+      if (dark !== null) dark.style.display = 'none'
+    }
+  }
+}
\ No newline at end of file
diff --git a/layouts/partials/helpers/get-esbuild-options.html b/layouts/partials/helpers/get-esbuild-options.html
index e582786..bdc4d32 100644
--- a/layouts/partials/helpers/get-esbuild-options.html
+++ b/layouts/partials/helpers/get-esbuild-options.html
@@ -69,15 +69,24 @@ params:
         #  id: foo
         #  name: bar
     
-    # The `darkMode` feature
+    # The `darkMode` feature. It's a deprecated setting but keep backward compatibility 
     darkmode:
       enable: true
 
+    # Configure theme settings
+    theme:
+      enable: true
+      services:
+        light: true # enable light theme. default "true"
+        dark: true # enable dark theme. default "true"
+        defaultTheme: light # can be either light, dark or system. default "system"
+
 This helper will convert the above config into the following env vars:
 
   * `FEATURE_ANALYTICS=1`
   * `FEATURE_ANALYTICS_GOOGLE=1`
   * `FEATURE_DARKMODE=1`
+  * `FEATURE_THEME=1`
 
 In JS, you can use it like this: