Fix RTL post alignment on native

src/components/Post/Embed/index.tsx

@@ -326,6 +326,11 @@ export function QuoteEmbed({
       {richText ? (
         <RichText
           value={richText}
+          language={
+            bsky.isType(app.bsky.feed.post, quote.record)
+              ? quote.record.langs?.[0]
+              : undefined
+          }
           style={a.text_md}
           numberOfLines={20}
           disableLinks

src/components/RichText.tsx

@@ -2,8 +2,9 @@ import {useMemo} from 'react'
 import {type StyleProp, type TextStyle} from 'react-native'
 import {RichText as RichTextAPI} from '@bsky/sdk/richtext'
 
+import {isRTL} from '#/lib/strings/bidi'
 import {toShortUrl} from '#/lib/strings/url-helpers'
-import {android, atoms as a, flatten, type TextStyleProp} from '#/alf'
+import {android, atoms as a, flatten, native, type TextStyleProp} from '#/alf'
 import {isOnlyEmoji} from '#/alf/typography'
 import {InlineLinkText, type LinkProps} from '#/components/Link'
 import {ProfileHoverCard} from '#/components/ProfileHoverCard'
@@ -20,6 +21,7 @@ const URL_REGEX =
 export type RichTextProps = TextStyleProp &
   Pick<TextProps, 'selectable' | 'onLayout' | 'onTextLayout'> & {
     value: RichTextAPI | string
+    language?: string
     testID?: string
     numberOfLines?: number
     disableLinks?: boolean
@@ -56,6 +58,7 @@ export type RichTextProps = TextStyleProp &
 export function RichText({
   testID,
   value,
+  language,
   style,
   numberOfLines,
   disableLinks,
@@ -82,7 +85,10 @@ export function RichText({
     }
   }, [value])
 
-  const plainStyles = style
+  const plainStyles = [
+    style,
+    isRTL(language) ? native({textAlign: 'right'}) : null,
+  ]
   const suffixStyles =
     suffix && suffixOffset
       ? android({paddingBottom: suffixOffset, marginBottom: -suffixOffset})

src/lib/strings/__tests__/bidi.test.ts

@@ -11,7 +11,7 @@ jest.mock('#/env', () => ({
   },
 }))
 
-import {forceLTR} from '../bidi'
+import {forceLTR, isRTL} from '../bidi'
 
 const LEFT_TO_RIGHT_EMBEDDING = '\u202A'
 const POP_DIRECTIONAL_FORMATTING = '\u202C'
@@ -31,3 +31,21 @@ describe('forceLTR', () => {
     expect(forceLTR('@alice.bsky.social')).toBe('@alice.bsky.social')
   })
 })
+
+describe('isRTL', () => {
+  it('recognizes right-to-left languages and scripts', () => {
+    expect(isRTL('he')).toBe(true)
+    expect(isRTL('ar')).toBe(true)
+    expect(isRTL('az-Arab')).toBe(true)
+  })
+
+  it('recognizes left-to-right languages and scripts', () => {
+    expect(isRTL('en')).toBe(false)
+    expect(isRTL('az-Latn')).toBe(false)
+  })
+
+  it('handles missing and invalid language tags', () => {
+    expect(isRTL(undefined)).toBe(false)
+    expect(isRTL('not_a_language')).toBe(false)
+  })
+})

src/lib/strings/bidi.ts

@@ -17,3 +17,17 @@ export function forceLTR(str: string) {
   if (IS_WEB) return str
   return LEFT_TO_RIGHT_EMBEDDING + str + POP_DIRECTIONAL_FORMATTING
 }
+
+/**
+ * Determines whether a BCP 47 language tag uses a right-to-left script.
+ */
+export function isRTL(language: string | undefined) {
+  if (!language) return false
+
+  try {
+    return new Intl.Locale(language).getTextInfo().direction === 'rtl'
+  } catch (error) {
+    if (error instanceof RangeError) return false
+    throw error
+  }
+}

src/screens/Messages/components/MessageInputEmbed.tsx

@@ -239,6 +239,7 @@ function MessageInputPostEmbed({
                 enableTags
                 testID="postText"
                 value={rt}
+                language={record.langs?.[0]}
                 style={[a.text_sm, t.atoms.text_contrast_high]}
                 authorHandle={post.author.handle}
                 numberOfLines={3}

src/screens/PostThread/components/ThreadItemAnchor.tsx

@@ -405,6 +405,7 @@ const ThreadItemAnchorInner = memo(function ThreadItemAnchorInner({
                   enableTags
                   selectable
                   value={richText}
+                  language={record.langs?.[0]}
                   style={[a.flex_1, a.text_lg]}
                   authorHandle={post.author.handle}
                   shouldProxyLinks={true}

src/screens/PostThread/components/ThreadItemPost.tsx

@@ -327,6 +327,7 @@ const ThreadItemPostInner = memo(function ThreadItemPostInner({
                   <RichText
                     enableTags
                     value={richText}
+                    language={record.langs?.[0]}
                     style={[a.flex_1, a.text_md]}
                     numberOfLines={limitLines ? MAX_POST_LINES : undefined}
                     authorHandle={post.author.handle}

src/screens/PostThread/components/ThreadItemTreePost.tsx

@@ -355,6 +355,7 @@ const ThreadItemTreePostInner = memo(function ThreadItemTreePostInner({
                       <RichText
                         enableTags
                         value={richText}
+                        language={record.langs?.[0]}
                         style={[a.flex_1, a.text_md]}
                         numberOfLines={limitLines ? MAX_POST_LINES : undefined}
                         authorHandle={post.author.handle}

src/screens/VideoFeed/index.tsx

@@ -963,6 +963,7 @@ function Overlay({
               {record?.text?.trim() && (
                 <ExpandableRichTextView
                   value={richText}
+                  language={record.langs?.[0]}
                   authorHandle={post.author.handle}
                 />
               )}
@@ -1020,9 +1021,11 @@ function Overlay({
 
 function ExpandableRichTextView({
   value,
+  language,
   authorHandle,
 }: {
   value: RichTextAPI
+  language?: string
   authorHandle?: string
 }) {
   const {height: screenHeight} = useSafeAreaFrame()
@@ -1057,6 +1060,7 @@ function ExpandableRichTextView({
       ]}>
       <RichText
         value={value}
+        language={language}
         style={[a.text_sm, a.flex_1, a.leading_relaxed]}
         authorHandle={authorHandle}
         enableTags

src/view/com/post/Post.tsx

@@ -226,6 +226,7 @@ function PostInner({
                     enableTags
                     testID="postText"
                     value={richText}
+                    language={record?.langs?.[0]}
                     numberOfLines={limitLines ? MAX_POST_LINES : undefined}
                     style={[a.flex_1, a.text_md]}
                     authorHandle={post.author.handle}

src/view/com/posts/PostFeedItem.tsx

@@ -520,6 +520,7 @@ let PostContent = ({
             enableTags
             testID="postText"
             value={richText}
+            language={record?.langs?.[0]}
             numberOfLines={limitLines ? MAX_POST_LINES : undefined}
             style={[a.flex_1, a.text_md]}
             authorHandle={postAuthor.handle}