feat(comments): support custom giscus themes (#1526)

Co-authored-by: Aaron Pham <Aaronpham0103@gmail.com>
Co-authored-by: Aaron Pham <contact@aarnphm.xyz>

quartz/components/Comments.tsx

@@ -10,6 +10,9 @@ type Options = {
     repoId: string
     category: string
     categoryId: string
+    themeUrl?: string
+    lightTheme?: string
+    darkTheme?: string
     mapping?: "url" | "title" | "og:title" | "specific" | "number" | "pathname"
     strict?: boolean
     reactionsEnabled?: boolean
@@ -34,6 +37,11 @@ export default ((opts: Options) => {
         data-strict={boolToStringBool(opts.options.strict ?? true)}
         data-reactions-enabled={boolToStringBool(opts.options.reactionsEnabled ?? true)}
         data-input-position={opts.options.inputPosition ?? "bottom"}
+        data-light-theme={opts.options.lightTheme ?? "light"}
+        data-dark-theme={opts.options.darkTheme ?? "dark"}
+        data-theme-url={
+          opts.options.themeUrl ?? `https://${cfg.baseUrl ?? "example.com"}/static/giscus`
+        }
       ></div>
     )
   }

quartz/components/scripts/comments.inline.ts

@@ -13,7 +13,7 @@ const changeTheme = (e: CustomEventMap["themechange"]) => {
     {
       giscus: {
         setConfig: {
-          theme: theme,
+          theme: getThemeUrl(getThemeName(theme)),
         },
       },
     },
@@ -21,12 +21,36 @@ const changeTheme = (e: CustomEventMap["themechange"]) => {
   )
 }
 
+const getThemeName = (theme: string) => {
+  if (theme !== "dark" && theme !== "light") {
+    return theme
+  }
+  const giscusContainer = document.querySelector(".giscus") as GiscusElement
+  if (!giscusContainer) {
+    return theme
+  }
+  const darkGiscus = giscusContainer.dataset.darkTheme ?? "dark"
+  const lightGiscus = giscusContainer.dataset.lightTheme ?? "light"
+  return theme === "dark" ? darkGiscus : lightGiscus
+}
+
+const getThemeUrl = (theme: string) => {
+  const giscusContainer = document.querySelector(".giscus") as GiscusElement
+  if (!giscusContainer) {
+    return `https://giscus.app/themes/${theme}.css`
+  }
+  return `${giscusContainer.dataset.themeUrl ?? "https://giscus.app/themes"}/${theme}.css`
+}
+
 type GiscusElement = Omit<HTMLElement, "dataset"> & {
   dataset: DOMStringMap & {
     repo: `${string}/${string}`
     repoId: string
     category: string
     categoryId: string
+    themeUrl: string
+    lightTheme: string
+    darkTheme: string
     mapping: "url" | "title" | "og:title" | "specific" | "number" | "pathname"
     strict: string
     reactionsEnabled: string
@@ -57,7 +81,7 @@ document.addEventListener("nav", () => {
 
   const theme = document.documentElement.getAttribute("saved-theme")
   if (theme) {
-    giscusScript.setAttribute("data-theme", theme)
+    giscusScript.setAttribute("data-theme", getThemeUrl(getThemeName(theme)))
   }
 
   giscusContainer.appendChild(giscusScript)