Fix markdown code rendering in file previews

packages/app/src/components/file-pane.tsx

@@ -1,15 +1,26 @@
-import React, { useEffect, useMemo, useRef } from "react";
+import React, { useCallback, useEffect, useMemo, useRef, type ReactNode } from "react";
 import { useQuery } from "@tanstack/react-query";
 import type { FileReadResult } from "@getpaseo/client/internal/daemon-client";
-import Markdown, { MarkdownIt } from "react-native-markdown-display";
+import Markdown, {
+  type ASTNode,
+  MarkdownIt,
+  type RenderRules,
+} from "react-native-markdown-display";
 import {
   ActivityIndicator,
   Image as RNImage,
+  Linking,
   ScrollView as RNScrollView,
   Text,
+  type TextProps,
+  type TextStyle,
   View,
+  type ViewStyle,
 } from "react-native";
 import { StyleSheet, useUnistyles } from "react-native-unistyles";
+import { AppearanceStyleBoundary } from "@/components/appearance-style-boundary";
+import { HighlightedCodeBlock } from "@/components/highlighted-code-block";
+import { MarkdownParagraphView, MarkdownTextSpan } from "@/components/markdown-text";
 import { useIsCompactFormFactor } from "@/constants/layout";
 import { useSessionStore, type ExplorerFile } from "@/stores/session-store";
 import { useWebScrollViewScrollbar } from "@/components/use-web-scrollbar";
@@ -22,6 +33,7 @@ import { CODE_SURFACE_DATASET } from "@/styles/code-surface";
 import { isRenderedMarkdownFile } from "@/components/file-pane-render-mode";
 import { isWeb } from "@/constants/platform";
 import { createMarkdownStyles } from "@/styles/markdown-styles";
+import { getMarkdownListMarker, getMarkdownListSpacing } from "@/utils/markdown-list";
 import type { AttachmentMetadata } from "@/attachments/types";
 import { useAttachmentPreviewUrl } from "@/attachments/use-attachment-preview-url";
 import { persistAttachmentFromBytes } from "@/attachments/service";
@@ -46,6 +58,8 @@ interface FilePreviewBodyProps {
   imagePreviewUri: string | null;
 }
 
+type MarkdownStyles = Record<string, TextStyle & ViewStyle & { [key: string]: unknown }>;
+
 function trimNonEmpty(value: string | null | undefined): string | null {
   if (typeof value !== "string") {
     return null;
@@ -116,6 +130,295 @@ function clampLineSelection(input: {
   return { lineStart, lineEnd: Math.max(lineStart, lineEnd) };
 }
 
+interface MarkdownInheritedTextProps {
+  inheritedStyles: TextStyle;
+  textStyle: TextStyle;
+  style?: TextStyle;
+  monoSurface?: boolean;
+  onPress?: TextProps["onPress"];
+  accessibilityRole?: TextProps["accessibilityRole"];
+  children: ReactNode;
+}
+
+function MarkdownInheritedText({
+  inheritedStyles,
+  textStyle,
+  style: overrideStyle,
+  monoSurface,
+  onPress,
+  accessibilityRole,
+  children,
+}: MarkdownInheritedTextProps) {
+  const style = useMemo(
+    () => [inheritedStyles, textStyle, overrideStyle],
+    [inheritedStyles, textStyle, overrideStyle],
+  );
+  return (
+    <MarkdownTextSpan
+      monoSurface={monoSurface}
+      onPress={onPress}
+      accessibilityRole={accessibilityRole}
+      style={style}
+    >
+      {children}
+    </MarkdownTextSpan>
+  );
+}
+
+interface MarkdownListItemContentProps {
+  contentStyle: ViewStyle;
+  children: ReactNode;
+}
+
+const MARKDOWN_LIST_ITEM_CONTENT_FLEX: ViewStyle = { flex: 1, flexShrink: 1, minWidth: 0 };
+const EMPTY_TEXT_STYLE: TextStyle = {};
+
+function MarkdownListItemContent({ contentStyle, children }: MarkdownListItemContentProps) {
+  const style = useMemo(() => [contentStyle, MARKDOWN_LIST_ITEM_CONTENT_FLEX], [contentStyle]);
+  return <View style={style}>{children}</View>;
+}
+
+interface MarkdownListViewProps {
+  baseStyle: ViewStyle;
+  spacing: { marginTop: number; marginBottom: number };
+  children: ReactNode;
+}
+
+function MarkdownListView({ baseStyle, spacing, children }: MarkdownListViewProps) {
+  const style = useMemo(() => [baseStyle, spacing], [baseStyle, spacing]);
+  return <View style={style}>{children}</View>;
+}
+
+interface FilePreviewMarkdownLinkProps {
+  href: string;
+  inheritedStyles: TextStyle;
+  linkStyle: TextStyle;
+  onLinkPress?: (url: string) => boolean;
+  children: ReactNode;
+}
+
+function FilePreviewMarkdownLink({
+  href,
+  inheritedStyles,
+  linkStyle,
+  onLinkPress,
+  children,
+}: FilePreviewMarkdownLinkProps) {
+  const handlePress = useCallback(() => {
+    if (!href) return;
+    if (onLinkPress?.(href) === false) return;
+    void Linking.openURL(href);
+  }, [href, onLinkPress]);
+
+  return (
+    <MarkdownInheritedText
+      inheritedStyles={inheritedStyles}
+      textStyle={linkStyle}
+      accessibilityRole="link"
+      onPress={handlePress}
+    >
+      {children}
+    </MarkdownInheritedText>
+  );
+}
+
+function getMarkdownLinkHref(node: ASTNode): string {
+  const href = node.attributes?.href;
+  return typeof href === "string" ? href : "";
+}
+
+function createFilePreviewMarkdownRules(): RenderRules {
+  return {
+    text: (
+      node: ASTNode,
+      _children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      inheritedStyles: TextStyle = {},
+    ) => (
+      <MarkdownInheritedText
+        key={node.key}
+        inheritedStyles={inheritedStyles}
+        textStyle={styles.text}
+      >
+        {node.content}
+      </MarkdownInheritedText>
+    ),
+    textgroup: (
+      node: ASTNode,
+      children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      inheritedStyles: TextStyle = {},
+    ) => (
+      <MarkdownInheritedText
+        key={node.key}
+        inheritedStyles={inheritedStyles}
+        textStyle={styles.textgroup}
+      >
+        {children}
+      </MarkdownInheritedText>
+    ),
+    strong: (
+      node: ASTNode,
+      children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      inheritedStyles: TextStyle = {},
+    ) => (
+      <MarkdownInheritedText
+        key={node.key}
+        inheritedStyles={inheritedStyles}
+        textStyle={styles.strong}
+      >
+        {children}
+      </MarkdownInheritedText>
+    ),
+    em: (
+      node: ASTNode,
+      children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      inheritedStyles: TextStyle = {},
+    ) => (
+      <MarkdownInheritedText key={node.key} inheritedStyles={inheritedStyles} textStyle={styles.em}>
+        {children}
+      </MarkdownInheritedText>
+    ),
+    s: (
+      node: ASTNode,
+      children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      inheritedStyles: TextStyle = {},
+    ) => (
+      <MarkdownInheritedText key={node.key} inheritedStyles={inheritedStyles} textStyle={styles.s}>
+        {children}
+      </MarkdownInheritedText>
+    ),
+    hardbreak: (node: ASTNode) => <MarkdownTextSpan key={node.key}>{"\n"}</MarkdownTextSpan>,
+    softbreak: (node: ASTNode) => <MarkdownTextSpan key={node.key}>{"\n"}</MarkdownTextSpan>,
+    code_block: (
+      node: ASTNode,
+      _children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      inheritedStyles: TextStyle = {},
+    ) => (
+      <HighlightedCodeBlock
+        key={node.key}
+        code={node.content}
+        language={null}
+        inheritedStyles={inheritedStyles}
+        textStyle={styles.code_block}
+      />
+    ),
+    fence: (
+      node: ASTNode,
+      _children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      inheritedStyles: TextStyle = {},
+    ) => (
+      <HighlightedCodeBlock
+        key={node.key}
+        code={node.content}
+        language={node.sourceInfo}
+        inheritedStyles={inheritedStyles}
+        textStyle={styles.fence}
+      />
+    ),
+    code_inline: (
+      node: ASTNode,
+      _children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      inheritedStyles: TextStyle = {},
+    ) => (
+      <MarkdownInheritedText
+        key={node.key}
+        inheritedStyles={inheritedStyles}
+        textStyle={styles.code_inline}
+        monoSurface
+      >
+        {node.content ?? ""}
+      </MarkdownInheritedText>
+    ),
+    bullet_list: (
+      node: ASTNode,
+      children: ReactNode[],
+      parent: ASTNode[],
+      styles: MarkdownStyles,
+    ) => (
+      <MarkdownListView
+        key={node.key}
+        baseStyle={styles.bullet_list}
+        spacing={getMarkdownListSpacing(node, parent)}
+      >
+        {children}
+      </MarkdownListView>
+    ),
+    ordered_list: (
+      node: ASTNode,
+      children: ReactNode[],
+      parent: ASTNode[],
+      styles: MarkdownStyles,
+    ) => (
+      <MarkdownListView
+        key={node.key}
+        baseStyle={styles.ordered_list}
+        spacing={getMarkdownListSpacing(node, parent)}
+      >
+        {children}
+      </MarkdownListView>
+    ),
+    list_item: (
+      node: ASTNode,
+      children: ReactNode[],
+      parent: ASTNode[],
+      styles: MarkdownStyles,
+    ) => {
+      const { isOrdered, marker } = getMarkdownListMarker(node, parent);
+      const iconStyle = isOrdered ? styles.ordered_list_icon : styles.bullet_list_icon;
+      const contentStyle = isOrdered ? styles.ordered_list_content : styles.bullet_list_content;
+
+      return (
+        <View key={node.key} style={styles.list_item}>
+          <Text style={iconStyle}>{marker}</Text>
+          <MarkdownListItemContent contentStyle={contentStyle}>{children}</MarkdownListItemContent>
+        </View>
+      );
+    },
+    paragraph: (
+      node: ASTNode,
+      children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+    ) => (
+      <MarkdownParagraphView key={node.key} paragraphStyle={styles.paragraph}>
+        {children}
+      </MarkdownParagraphView>
+    ),
+    link: (
+      node: ASTNode,
+      children: ReactNode[],
+      _parent: ASTNode[],
+      styles: MarkdownStyles,
+      onLinkPress?: (url: string) => boolean,
+    ) => (
+      <FilePreviewMarkdownLink
+        key={node.key}
+        href={getMarkdownLinkHref(node)}
+        inheritedStyles={EMPTY_TEXT_STYLE}
+        linkStyle={styles.link}
+        onLinkPress={onLinkPress}
+      >
+        {children}
+      </FilePreviewMarkdownLink>
+    ),
+  };
+}
+
 const CodeLine = React.memo(function CodeLine({
   tokens,
   lineNumber,
@@ -198,6 +501,7 @@ function FilePreviewBody({
   const filePath = location.path;
   const markdownStyles = useMemo(() => createMarkdownStyles(theme), [theme]);
   const markdownParser = useMemo(() => MarkdownIt({ typographer: true, linkify: true }), []);
+  const markdownRules = useMemo(() => createFilePreviewMarkdownRules(), []);
   const isMarkdownFile =
     preview?.kind === "text" && isRenderedMarkdownFile(filePath) && !location.lineStart;
 
@@ -280,9 +584,11 @@ function FilePreviewBody({
             scrollEventThrottle={16}
             showsVerticalScrollIndicator={!showDesktopWebScrollbar}
           >
-            <Markdown style={markdownStyles} markdownit={markdownParser}>
-              {preview.content ?? ""}
-            </Markdown>
+            <AppearanceStyleBoundary>
+              <Markdown style={markdownStyles} rules={markdownRules} markdownit={markdownParser}>
+                {preview.content ?? ""}
+              </Markdown>
+            </AppearanceStyleBoundary>
           </RNScrollView>
           {scrollbar.overlay}
         </View>