Swipe to reply in chat (#10920)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/ContextMenu/index.tsx

@@ -241,6 +241,7 @@ export function Trigger({
   contentLabel,
   style,
   onTap,
+  swipeGesture,
 }: TriggerProps) {
   const context = useContextMenuContext()
   const playHaptic = useHaptics()
@@ -364,12 +365,20 @@ export function Trigger({
   }, [open, hoverablesSV, onTouchUpMenuItem, hoveredItemSV, translationSV])
 
   // Order matters here: doubleTapGesture must come before tapGesture.
-  const composedGestures = Gesture.Exclusive(
+  const tapAndHoldGestures = Gesture.Exclusive(
     doubleTapGesture,
     tapGesture,
     pressAndHoldGesture,
   )
 
+  // An optional swipe gesture (e.g. swipe-to-reply) races against the tap/hold
+  // group: whichever activates first wins and cancels the rest, so they're
+  // mutually exclusive. Race (not Exclusive) avoids a held-but-not-yet-moved
+  // swipe Pan blocking the long-press from firing.
+  const composedGestures = swipeGesture
+    ? Gesture.Race(swipeGesture, tapAndHoldGestures)
+    : tapAndHoldGestures
+
   const measurement = context.measurement || pendingMeasurement?.measurement
 
   return (

src/components/ContextMenu/types.ts

@@ -4,6 +4,7 @@ import {
   type StyleProp,
   type ViewStyle,
 } from 'react-native'
+import {type GestureType} from 'react-native-gesture-handler'
 import {type SharedValue} from 'react-native-reanimated'
 
 import type * as Dialog from '#/components/Dialog'
@@ -94,6 +95,14 @@ export type TriggerProps = {
    * @platform ios, android
    */
   onTap?: () => void
+  /**
+   * An optional gesture (e.g. swipe-to-reply) composed into the same
+   * arbitration group as the tap and press-and-hold gestures via `Gesture.Race`,
+   * making it mutually exclusive with them - only one can win a given touch.
+   *
+   * @platform ios, android
+   */
+  swipeGesture?: GestureType
 }
 export type TriggerChildProps =
   | {

src/components/dms/ActionsWrapper.tsx

@@ -2,8 +2,9 @@ import {View} from 'react-native'
 import {type ChatBskyConvoDefs, type ModerationOpts} from '@atproto/api'
 import {useLingui} from '@lingui/react/macro'
 
-import {atoms as a} from '#/alf'
 import {MessageContextMenu} from '#/components/dms/MessageContextMenu'
+import {useMessageReplies} from '#/components/dms/MessageReplies'
+import {SwipeToReply} from '#/components/dms/SwipeToReply'
 import type * as bsky from '#/types/bsky'
 
 export function ActionsWrapper({
@@ -20,33 +21,31 @@ export function ActionsWrapper({
   children: React.ReactNode
 }) {
   const {t: l} = useLingui()
+  const {setReply} = useMessageReplies()
 
   return (
-    <MessageContextMenu
-      message={message}
-      senderProfile={senderProfile}
-      moderationOpts={moderationOpts}>
-      {trigger =>
-        // will always be true, since this file is platform split
-        trigger.IS_NATIVE && (
-          <View style={[a.flex_1, a.relative]}>
-            <View
-              style={[
-                {maxWidth: '80%'},
-                isFromSelf
-                  ? [a.self_end, a.align_end]
-                  : [a.self_start, a.align_start],
-              ]}
-              accessible={true}
-              accessibilityActions={[
-                {name: 'activate', label: l`Open message options`},
-              ]}
-              onAccessibilityAction={() => trigger.control.open('full')}>
-              {children}
-            </View>
-          </View>
-        )
-      }
-    </MessageContextMenu>
+    <SwipeToReply isFromSelf={isFromSelf} onReply={() => setReply(message)}>
+      {swipeGesture => (
+        <MessageContextMenu
+          message={message}
+          senderProfile={senderProfile}
+          moderationOpts={moderationOpts}
+          swipeGesture={swipeGesture}>
+          {trigger =>
+            // will always be true, since this file is platform split
+            trigger.IS_NATIVE && (
+              <View
+                accessible={true}
+                accessibilityActions={[
+                  {name: 'activate', label: l`Open message options`},
+                ]}
+                onAccessibilityAction={() => trigger.control.open('full')}>
+                {children}
+              </View>
+            )
+          }
+        </MessageContextMenu>
+      )}
+    </SwipeToReply>
   )
 }

src/components/dms/MessageContextMenu.tsx

@@ -1,5 +1,6 @@
 import {memo, useCallback} from 'react'
 import {Platform} from 'react-native'
+import {type GestureType} from 'react-native-gesture-handler'
 import * as Clipboard from 'expo-clipboard'
 import {
   type ChatBskyConvoDefs,
@@ -38,11 +39,17 @@ export let MessageContextMenu = ({
   senderProfile,
   moderationOpts,
   children,
+  swipeGesture,
 }: {
   message: ChatBskyConvoDefs.MessageView
   senderProfile?: bsky.profile.AnyProfileView
   moderationOpts: ModerationOpts | undefined
   children: TriggerProps['children']
+  /**
+   * Native only. A swipe gesture (swipe-to-reply) composed into the trigger's
+   * gesture group so it's mutually exclusive with the tap and long-press.
+   */
+  swipeGesture?: GestureType
 }): React.ReactNode => {
   const {t: l, i18n} = useLingui()
   const ax = useAnalytics()
@@ -144,7 +151,8 @@ export let MessageContextMenu = ({
         label={l`Message options`}
         contentLabel={l`Message from @${
           sender?.handle ?? 'unknown' // should always be defined
-        }: ${message.text}`}>
+        }: ${message.text}`}
+        swipeGesture={swipeGesture}>
         {children}
       </ContextMenu.Trigger>
 

src/components/dms/MessageItemEmbed.tsx

@@ -29,6 +29,7 @@ let MessageItemEmbed = ({
     <MessageContextProvider>
       <View
         style={[
+          isFromSelf ? a.self_end : a.self_start,
           !isFromSelf && isGroupChat && a.ml_sm,
           native({
             flexBasis: 0,

src/components/dms/MessageItemInviteEmbed.tsx

@@ -37,6 +37,7 @@ let MessageItemInviteEmbed = ({
     <MessageContextProvider>
       <View
         style={[
+          isFromSelf ? a.self_end : a.self_start,
           !isFromSelf && isGroupChat && a.ml_sm,
           native({
             flexBasis: 0,

src/components/dms/SwipeToReply.tsx

@@ -0,0 +1,195 @@
+import {useMemo} from 'react'
+import {View} from 'react-native'
+import {Gesture, type GestureType} from 'react-native-gesture-handler'
+import Animated, {
+  clamp,
+  interpolate,
+  runOnJS,
+  useAnimatedStyle,
+  useReducedMotion,
+  useSharedValue,
+  withSequence,
+  withTiming,
+} from 'react-native-reanimated'
+
+import {useHaptics} from '#/lib/haptics'
+import {atoms as a, tokens, useTheme} from '#/alf'
+import {ArrowCornerDownRight_Stroke2_Corner3_Rounded as ReplyIcon} from '#/components/icons/ArrowCornerDownRight'
+
+// Distance the bubble must travel before releasing fires a reply.
+const ACTIVATION_THRESHOLD = 56
+// Past the activation point the bubble keeps moving but with exponentially
+// increasing resistance, asymptotically approaching this much extra travel.
+const MAX_OVERSHOOT = 32
+const ICON_DIAMETER = 32
+// Absurdly high value so the gesture doesn't arm on the vertical axis and
+// hijack list scrolling. reanimated/RNGH don't offer clean per-axis disabling.
+const EFFECTIVELY_DISABLED_OFFSET = 200
+
+// 1:1 up to `threshold`, then exponentially diminishing travel: the marginal
+// movement decays the further you pull, easing toward a soft cap of
+// `threshold + MAX_OVERSHOOT` rather than hitting a hard wall.
+function applyResistance(value: number) {
+  'worklet'
+  const abs = Math.abs(value)
+  if (abs <= ACTIVATION_THRESHOLD) return value
+  const sign = value < 0 ? -1 : 1
+  const excess = abs - ACTIVATION_THRESHOLD
+  return (
+    sign *
+    (ACTIVATION_THRESHOLD +
+      MAX_OVERSHOOT * (1 - Math.exp(-excess / MAX_OVERSHOOT)))
+  )
+}
+
+/**
+ * Swipe a message bubble inward to reply, Signal/WhatsApp style. Self messages
+ * (right-aligned) swipe left; others' messages (left-aligned) swipe right. A
+ * reply icon sits stationary in the gutter on the bubble's resting edge and is
+ * revealed (fade + scale) as the bubble slides away from it. Crossing the
+ * activation threshold fires a haptic; releasing past it triggers `onReply`.
+ *
+ * The pan gesture is built here but handed to `children` via a render prop so
+ * the consumer can compose it into the message's context-menu gestures with
+ * `Gesture.Exclusive`. Sharing one arbitration group is what makes the swipe
+ * and the long-press mutually exclusive - only one can ever win the touch.
+ */
+export function SwipeToReply({
+  isFromSelf,
+  onReply,
+  enabled = true,
+  children,
+}: {
+  isFromSelf: boolean
+  onReply: () => void
+  enabled?: boolean
+  children: (swipeGesture: GestureType) => React.ReactNode
+}) {
+  const t = useTheme()
+  const playHaptic = useHaptics()
+  const isReducedMotion = useReducedMotion()
+
+  const transX = useSharedValue(0)
+  const hit = useSharedValue(false)
+  const iconScale = useSharedValue(1)
+
+  const swipeGesture = useMemo(() => {
+    const runPop = () => {
+      'worklet'
+      if (isReducedMotion) return
+      iconScale.set(() =>
+        withSequence(
+          withTiming(1.2, {duration: 175}),
+          withTiming(1, {duration: 100}),
+        ),
+      )
+    }
+
+    return (
+      Gesture.Pan()
+        .enabled(enabled)
+        // Arm only on the inward axis; the outward direction is effectively
+        // disabled so the bubble can't be dragged off its own edge.
+        .activeOffsetX(
+          isFromSelf
+            ? [-10, EFFECTIVELY_DISABLED_OFFSET]
+            : [-EFFECTIVELY_DISABLED_OFFSET, 10],
+        )
+        .activeOffsetY([
+          -EFFECTIVELY_DISABLED_OFFSET,
+          EFFECTIVELY_DISABLED_OFFSET,
+        ])
+        .onChange(e => {
+          'worklet'
+          const dir = isFromSelf
+            ? Math.min(e.translationX, 0)
+            : Math.max(e.translationX, 0)
+          transX.set(applyResistance(dir))
+
+          const pastThreshold = Math.abs(transX.get()) >= ACTIVATION_THRESHOLD
+          if (pastThreshold && !hit.get()) {
+            hit.set(true)
+            runPop()
+            runOnJS(playHaptic)('Medium')
+          } else if (!pastThreshold && hit.get()) {
+            hit.set(false)
+          }
+        })
+        .onEnd(() => {
+          'worklet'
+          // Only a clean end (finger lifted past threshold) triggers the reply.
+          if (hit.get()) {
+            runOnJS(onReply)()
+          }
+        })
+        .onFinalize(() => {
+          'worklet'
+          // Runs on both end and cancellation, so the bubble always animates
+          // home even if the gesture is interrupted mid-swipe.
+          transX.set(withTiming(0, {duration: 200}))
+          hit.set(false)
+        })
+    )
+  }, [
+    isFromSelf,
+    enabled,
+    onReply,
+    playHaptic,
+    isReducedMotion,
+    transX,
+    hit,
+    iconScale,
+  ])
+
+  const contentStyle = useAnimatedStyle(() => ({
+    transform: [{translateX: transX.get()}],
+  }))
+
+  const iconStyle = useAnimatedStyle(() => {
+    const progress = clamp(Math.abs(transX.get()) / ACTIVATION_THRESHOLD, 0, 1)
+    return {
+      opacity: progress,
+      transform: [
+        {scale: iconScale.get() * interpolate(progress, [0, 1], [0.5, 1])},
+      ],
+    }
+  })
+
+  return (
+    <View style={[a.flex_1, a.relative]}>
+      <Animated.View
+        pointerEvents="none"
+        style={[
+          a.absolute,
+          a.justify_center,
+          {top: 0, bottom: 0},
+          // Centred roughly half the activation threshold in from the bubble's
+          // resting edge, so it lands in the gap the bubble reveals.
+          isFromSelf ? {right: tokens.space.md} : {left: tokens.space.md},
+          iconStyle,
+        ]}>
+        <View
+          style={[
+            a.justify_center,
+            a.align_center,
+            a.rounded_full,
+            t.atoms.bg_contrast_50,
+            {width: ICON_DIAMETER, height: ICON_DIAMETER},
+          ]}>
+          <ReplyIcon size="sm" style={t.atoms.text_contrast_medium} />
+        </View>
+      </Animated.View>
+      {/* Sized + aligned to the bubble so the consumer's GestureDetector (the
+          context menu's, which composes `swipeGesture`) covers only the bubble,
+          leaving the gutter free for the back/scroll gestures. */}
+      <Animated.View
+        style={[
+          {maxWidth: '80%'},
+          isFromSelf ? a.self_end : a.self_start,
+          contentStyle,
+        ]}>
+        {children(swipeGesture)}
+      </Animated.View>
+    </View>
+  )
+}