feat(lightbox): add new Footer with alt text and pager dots

src/features/lightbox/chrome/Footer.tsx

@@ -0,0 +1,94 @@
+import {useRef} from 'react'
+import {
+  LayoutAnimation,
+  Pressable,
+  ScrollView,
+  StyleSheet,
+  View,
+} from 'react-native'
+import {useSafeAreaInsets} from 'react-native-safe-area-context'
+import {msg} from '@lingui/core/macro'
+import {useLingui} from '@lingui/react'
+
+import {atoms as a} from '#/alf'
+import {Text} from '#/components/Typography'
+import {PagerDots} from './PagerDots'
+
+type Props = {
+  altText: string | undefined
+  isAltExpanded: boolean
+  onToggleAltExpanded: () => void
+  imageCount: number
+  activeIndex: number
+}
+
+export function Footer({
+  altText,
+  isAltExpanded,
+  onToggleAltExpanded,
+  imageCount,
+  activeIndex,
+}: Props) {
+  const {_} = useLingui()
+  const insets = useSafeAreaInsets()
+  const isMomentumScrolling = useRef(false)
+
+  return (
+    <View
+      style={[styles.root, {paddingBottom: insets.bottom + 8}]}
+      pointerEvents="box-none">
+      {altText ? (
+        <View style={[a.mx_md, a.mb_sm, styles.altWrap]}>
+          <ScrollView
+            scrollEnabled={isAltExpanded}
+            onMomentumScrollBegin={() => {
+              isMomentumScrolling.current = true
+            }}
+            onMomentumScrollEnd={() => {
+              isMomentumScrolling.current = false
+            }}
+            contentContainerStyle={[a.px_md, a.py_sm]}>
+            <Pressable
+              accessibilityRole="button"
+              accessibilityLabel={_(msg`Expand alt text`)}
+              accessibilityHint=""
+              onPress={() => {
+                if (isMomentumScrolling.current) return
+                LayoutAnimation.configureNext({
+                  duration: 450,
+                  update: {type: 'spring', springDamping: 1},
+                })
+                onToggleAltExpanded()
+              }}>
+              <Text
+                emoji
+                selectable
+                style={[a.text_sm, styles.altText]}
+                numberOfLines={isAltExpanded ? undefined : 3}>
+                {altText}
+              </Text>
+            </Pressable>
+          </ScrollView>
+        </View>
+      ) : null}
+      <PagerDots count={imageCount} activeIndex={activeIndex} />
+    </View>
+  )
+}
+
+const styles = StyleSheet.create({
+  root: {
+    position: 'absolute',
+    bottom: 0,
+    left: 0,
+    right: 0,
+  },
+  altWrap: {
+    backgroundColor: 'rgba(0, 0, 0, 0.45)',
+    borderRadius: 12,
+    overflow: 'hidden',
+  },
+  altText: {
+    color: '#fff',
+  },
+})