From 29696f8d83efb76fa07edf54a961e0d38778f67f Mon Sep 17 00:00:00 2001
From: Anton Ignatov <a.ignatov@truvity.com>
Date: Thu, 12 Sep 2024 13:29:34 +0200
Subject: [PATCH] fixed prefixCssSelectors implementation (fix #377)

---
 packages/docusaurus-theme-redoc/package.json  |  3 +
 .../src/theme/Redoc/ServerStyles.tsx          | 87 ++++++-------------
 yarn.lock                                     | 32 +++++++
 3 files changed, 60 insertions(+), 62 deletions(-)

diff --git a/packages/docusaurus-theme-redoc/package.json b/packages/docusaurus-theme-redoc/package.json
index 33044893..b1ac8c03 100644
--- a/packages/docusaurus-theme-redoc/package.json
+++ b/packages/docusaurus-theme-redoc/package.json
@@ -36,6 +36,8 @@
     "clsx": "^1.2.1",
     "lodash": "^4.17.21",
     "mobx": "^6.12.4",
+    "postcss": "^8.4.45",
+    "postcss-prefix-selector": "^1.16.1",
     "redoc": "2.1.5",
     "styled-components": "^6.1.11"
   },
@@ -45,6 +47,7 @@
     "@docusaurus/theme-common": "^3.4.0",
     "@docusaurus/types": "^3.4.0",
     "@types/lodash": "^4.14.200",
+    "@types/postcss-prefix-selector": "^1",
     "@types/react": "^18.3.3",
     "@types/react-dom": "^18.3.0",
     "@types/react-is": "^18.3.0",
diff --git a/packages/docusaurus-theme-redoc/src/theme/Redoc/ServerStyles.tsx b/packages/docusaurus-theme-redoc/src/theme/Redoc/ServerStyles.tsx
index 1969cdd5..afa8c5da 100644
--- a/packages/docusaurus-theme-redoc/src/theme/Redoc/ServerStyles.tsx
+++ b/packages/docusaurus-theme-redoc/src/theme/Redoc/ServerStyles.tsx
@@ -5,49 +5,27 @@ import { AppStore, Redoc, RedocRawOptions } from 'redoc';
 // eslint-disable-next-line import/no-extraneous-dependencies
 import { renderToString } from 'react-dom/server';
 import { ServerStyleSheet } from 'styled-components';
+import postcss from 'postcss';
+import prefixer from 'postcss-prefix-selector';
 
-/**
- * @see https://stackoverflow.com/a/54077142
- */
-const prefixCssSelectors = function (rules: string, className: string) {
-  const classLen = className.length;
-  let char, nextChar, isAt, isIn;
-
-  // makes sure the className will not concatenate the selector
-  className += ' ';
-
-  // removes comments
-  rules = rules.replace(/\/\*(?:(?!\*\/)[\s\S])*\*\/|[\r\n\t]+/g, '');
-
-  // makes sure nextChar will not target a space
-  rules = rules.replace(/}(\s*)@/g, '}@');
-  rules = rules.replace(/}(\s*)}/g, '}}');
-
-  for (let i = 0; i < rules.length - 2; i++) {
-    char = rules[i];
-    nextChar = rules[i + 1];
+const prefixCssSelectors = function (css: string, className: string): string {
+  const processor = postcss().use(
+    prefixer({
+      prefix: className,
+    }),
+  );
 
-    if (char === '@' && nextChar !== 'f') isAt = true;
-    if (!isAt && char === '{') isIn = true;
-    if (isIn && char === '}') isIn = false;
+  return processor.process(css).css;
+};
 
-    if (
-      !isIn &&
-      nextChar !== '@' &&
-      nextChar !== '}' &&
-      (char === '}' || char === ',' || ((char === '{' || char === ';') && isAt))
-    ) {
-      rules = rules.slice(0, i + 1) + className + rules.slice(i + 1);
-      i += classLen;
-      isAt = false;
-    }
-  }
+const renderCss = function (store: AppStore): string {
+  const styleSheet = new ServerStyleSheet();
 
-  // prefix the first select if it is not `@media` and if it is not yet prefixed
-  if (rules.indexOf(className) !== 0 && rules.indexOf('@') !== 0)
-    rules = className + rules;
+  renderToString(
+    styleSheet.collectStyles(React.createElement(Redoc, { store })),
+  );
 
-  return rules;
+  return String(styleSheet.instance);
 };
 
 const LIGHT_MODE_PREFIX = "html:not([data-theme='dark'])";
@@ -63,41 +41,26 @@ export function ServerStyles({
   darkThemeOptions: RedocRawOptions;
 }) {
   const fullUrl = useBaseUrl(specProps.url, { absolute: true });
-  const css = {
-    light: '',
-    dark: '',
-  };
-  const lightSheet = new ServerStyleSheet();
-  const lightStore = new AppStore(specProps.spec, fullUrl, lightThemeOptions);
-  renderToString(
-    lightSheet.collectStyles(React.createElement(Redoc, { store: lightStore })),
-  );
-  const lightStyleTag = lightSheet.getStyleTags();
-  let lightCss = lightStyleTag.slice(lightStyleTag.indexOf('>') + 1);
-  lightCss = lightCss.slice(0, lightCss.indexOf('<style'));
-  css.light = prefixCssSelectors(lightCss, LIGHT_MODE_PREFIX);
 
-  const darkSheet = new ServerStyleSheet();
-  const darkStore = new AppStore(specProps.spec, fullUrl, darkThemeOptions);
-  renderToString(
-    darkSheet.collectStyles(React.createElement(Redoc, { store: darkStore })),
+  const lightCss = prefixCssSelectors(
+    renderCss(new AppStore(specProps.spec, fullUrl, lightThemeOptions)),
+    LIGHT_MODE_PREFIX,
   );
-  const darkStyleTag = darkSheet.getStyleTags();
-  let darkCss = darkStyleTag.slice(darkStyleTag.indexOf('>') + 1);
-  darkCss = darkCss.slice(0, darkCss.indexOf('<style'));
-  css.dark = prefixCssSelectors(darkCss, DARK_MODE_PREFIX).slice(
-    DARK_MODE_PREFIX.length + 1,
+
+  const darkCss = prefixCssSelectors(
+    renderCss(new AppStore(specProps.spec, fullUrl, darkThemeOptions)),
+    DARK_MODE_PREFIX,
   );
 
   return (
     <div className="redocusaurus-styles">
       <style
         key="light-mode-styles"
-        dangerouslySetInnerHTML={{ __html: css.light }}
+        dangerouslySetInnerHTML={{ __html: lightCss }}
       />
       <style
         key="dark-mode-styles"
-        dangerouslySetInnerHTML={{ __html: css.dark }}
+        dangerouslySetInnerHTML={{ __html: darkCss }}
       />
     </div>
   );
diff --git a/yarn.lock b/yarn.lock
index 7b03aaf5..85e4c676 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3725,6 +3725,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/postcss-prefix-selector@npm:^1":
+  version: 1.16.3
+  resolution: "@types/postcss-prefix-selector@npm:1.16.3"
+  dependencies:
+    postcss: "npm:^8.4.27"
+  checksum: c0ece88bf7f5adfdcbf1f44436ce3e78d5fe0431fd84dce4040e53c03af2ca71fd3f1a36d127e1402c085c5507d5403fe461577670252c311556c102d7dc948d
+  languageName: node
+  linkType: hard
+
 "@types/prismjs@npm:^1.26.0":
   version: 1.26.2
   resolution: "@types/prismjs@npm:1.26.2"
@@ -6357,6 +6366,7 @@ __metadata:
     "@docusaurus/types": "npm:^3.4.0"
     "@redocly/openapi-core": "npm:1.16.0"
     "@types/lodash": "npm:^4.14.200"
+    "@types/postcss-prefix-selector": "npm:^1"
     "@types/react": "npm:^18.3.3"
     "@types/react-dom": "npm:^18.3.0"
     "@types/react-is": "npm:^18.3.0"
@@ -6368,6 +6378,8 @@ __metadata:
     lodash: "npm:^4.17.21"
     mobx: "npm:^6.12.4"
     nodemon: "npm:^3.1.0"
+    postcss: "npm:^8.4.45"
+    postcss-prefix-selector: "npm:^1.16.1"
     react: "npm:^18.3.1"
     react-dom: "npm:^18.3.1"
     react-is: "npm:^18.3.1"
@@ -12402,6 +12414,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"postcss-prefix-selector@npm:^1.16.1":
+  version: 1.16.1
+  resolution: "postcss-prefix-selector@npm:1.16.1"
+  peerDependencies:
+    postcss: ">4 <9"
+  checksum: e6a138f2c2f4be38013e778d0242f7fced1468759b508b3f85349ec1a5cd0bd6e7194998749508edb7a987fff9d4f3ee89b7d4f34e5df34dbf65130bf3bc680c
+  languageName: node
+  linkType: hard
+
 "postcss-reduce-idents@npm:^6.0.3":
   version: 6.0.3
   resolution: "postcss-reduce-idents@npm:6.0.3"
@@ -12507,6 +12528,17 @@ __metadata:
   languageName: node
   linkType: hard
 
+"postcss@npm:^8.4.27, postcss@npm:^8.4.45":
+  version: 8.4.45
+  resolution: "postcss@npm:8.4.45"
+  dependencies:
+    nanoid: "npm:^3.3.7"
+    picocolors: "npm:^1.0.1"
+    source-map-js: "npm:^1.2.0"
+  checksum: 7eaf7346d04929ee979548ece5e34d253eae6f175346e298b2c4621ad6f4ee00adfe7abe72688640e910c0361ae50537c5dda3e35fd1066491282c342b3ee5c8
+  languageName: node
+  linkType: hard
+
 "preferred-pm@npm:^3.0.0":
   version: 3.1.2
   resolution: "preferred-pm@npm:3.1.2"