1 files changed, 115 insertions, 0 deletions
diff --git a/src/view/com/util/text/RichText.tsx b/src/view/com/util/text/RichText.tsx
new file mode 100644
index 000000000..c9ed4b58e
--- /dev/null
+++ b/src/view/com/util/text/RichText.tsx
@@ -0,0 +1,115 @@
+import React from 'react'
+import {TextStyle, StyleProp} from 'react-native'
+import {TextLink} from '../Link'
+import {Text} from './Text'
+import {s} from '../../../lib/styles'
+import {toShortUrl} from '../../../../lib/strings'
+import {TypographyVariant} from '../../../lib/ThemeContext'
+import {usePalette} from '../../../lib/hooks/usePalette'
+
+type TextSlice = {start: number; end: number}
+type Entity = {
+  index: TextSlice
+  type: string
+  value: string
+}
+
+export function RichText({
+  type = 'body1',
+  text,
+  entities,
+  style,
+  numberOfLines,
+}: {
+  type: TypographyVariant
+  text: string
+  entities?: Entity[]
+  style?: StyleProp<TextStyle>
+  numberOfLines?: number
+}) {
+  const pal = usePalette('default')
+  if (!entities?.length) {
+    if (/^\p{Extended_Pictographic}+$/u.test(text) && text.length <= 5) {
+      style = {
+        fontSize: 26,
+        lineHeight: 30,
+      }
+      return <Text style={style}>{text}</Text>
+    }
+    return <Text style={style}>{text}</Text>
+  }
+  if (!style) style = []
+  else if (!Array.isArray(style)) style = [style]
+  entities.sort(sortByIndex)
+  const segments = Array.from(toSegments(text, entities))
+  const els = []
+  let key = 0
+  for (const segment of segments) {
+    if (typeof segment === 'string') {
+      els.push(segment)
+    } else {
+      if (segment.entity.type === 'mention') {
+        els.push(
+          <TextLink
+            key={key}
+            type={type}
+            text={segment.text}
+            href={`/profile/${segment.entity.value}`}
+            style={[style, pal.link]}
+          />,
+        )
+      } else if (segment.entity.type === 'link') {
+        els.push(
+          <TextLink
+            key={key}
+            type={type}
+            text={toShortUrl(segment.text)}
+            href={segment.entity.value}
+            style={[style, pal.link]}
+          />,
+        )
+      }
+    }
+    key++
+  }
+  return (
+    <Text type={type} style={[pal.text, style]} numberOfLines={numberOfLines}>
+      {els}
+    </Text>
+  )
+}
+
+function sortByIndex(a: Entity, b: Entity) {
+  return a.index.start - b.index.start
+}
+
+function* toSegments(text: string, entities: Entity[]) {
+  let cursor = 0
+  let i = 0
+  do {
+    let currEnt = entities[i]
+    if (cursor < currEnt.index.start) {
+      yield text.slice(cursor, currEnt.index.start)
+    } else if (cursor > currEnt.index.start) {
+      i++
+      continue
+    }
+    if (currEnt.index.start < currEnt.index.end) {
+      let subtext = text.slice(currEnt.index.start, currEnt.index.end)
+      if (!subtext.trim()) {
+        // dont yield links to empty strings
+        yield subtext
+      } else {
+        yield {
+          entity: currEnt,
+          text: subtext,
+        }
+      }
+    }
+    cursor = currEnt.index.end
+    i++
+  } while (i < entities.length)
+  if (cursor < text.length) {
+    yield text.slice(cursor, text.length)
+  }
+}