From e51cde1770272eb339c76db4aa1a7addd1f46056 Mon Sep 17 00:00:00 2001
From: ayumi-signal <143036029+ayumi-signal@users.noreply.github.com>
Date: Tue, 24 Sep 2024 11:33:58 -0700
Subject: [PATCH] Animate call link join requests

---
 .../CallingPendingParticipants.scss           |  5 +-
 ts/components/CallScreen.tsx                  |  2 +-
 .../CallingPendingParticipants.stories.tsx    | 20 ++++
 ts/components/CallingPendingParticipants.tsx  | 97 ++++++++++++++++---
 ts/util/lint/exceptions.json                  |  8 ++
 5 files changed, 117 insertions(+), 15 deletions(-)

diff --git a/stylesheets/components/CallingPendingParticipants.scss b/stylesheets/components/CallingPendingParticipants.scss
index 245fbbaabf..bfed0a9b9b 100644
--- a/stylesheets/components/CallingPendingParticipants.scss
+++ b/stylesheets/components/CallingPendingParticipants.scss
@@ -14,10 +14,13 @@
   width: 364px;
   padding-inline: 0;
   padding-block-start: 0;
-  background: $color-gray-78;
   outline: 0;
 }
 
+.CallingPendingParticipants--Expandable {
+  background: $color-gray-78;
+}
+
 .CallingPendingParticipants--Expanded {
   padding-block-end: 2px;
 }
diff --git a/ts/components/CallScreen.tsx b/ts/components/CallScreen.tsx
index d491e7062c..b56bb92d97 100644
--- a/ts/components/CallScreen.tsx
+++ b/ts/components/CallScreen.tsx
@@ -858,7 +858,7 @@ export function CallScreen({
         renderRaisedHandsToast={renderRaisedHandsToast}
         i18n={i18n}
       />
-      {pendingParticipants.length ? (
+      {isCallLinkAdmin ? (
         <CallingPendingParticipants
           i18n={i18n}
           participants={pendingParticipants}
diff --git a/ts/components/CallingPendingParticipants.stories.tsx b/ts/components/CallingPendingParticipants.stories.tsx
index 1e53c566d6..c33b177910 100644
--- a/ts/components/CallingPendingParticipants.stories.tsx
+++ b/ts/components/CallingPendingParticipants.stories.tsx
@@ -60,6 +60,26 @@ export function Many(): JSX.Element {
   );
 }
 
+export function Changing(): JSX.Element {
+  const counts = [0, 1, 2, 3, 2, 1];
+  const [countIndex, setCountIndex] = React.useState<number>(0);
+  React.useEffect(() => {
+    const interval = setInterval(() => {
+      setCountIndex((countIndex + 1) % counts.length);
+    }, 1000);
+
+    return () => clearInterval(interval);
+  }, [countIndex, counts.length]);
+
+  return (
+    <CallingPendingParticipants
+      {...createProps({
+        participants: allRemoteParticipants.slice(0, counts[countIndex]),
+      })}
+    />
+  );
+}
+
 export function ExpandedOne(): JSX.Element {
   return (
     <CallingPendingParticipants
diff --git a/ts/components/CallingPendingParticipants.tsx b/ts/components/CallingPendingParticipants.tsx
index c7e0d50602..ef2013cd08 100644
--- a/ts/components/CallingPendingParticipants.tsx
+++ b/ts/components/CallingPendingParticipants.tsx
@@ -5,6 +5,8 @@
 
 import React, { useCallback, useEffect, useRef, useState } from 'react';
 import { noop } from 'lodash';
+import classNames from 'classnames';
+import { animated, useSpring } from '@react-spring/web';
 import { Avatar, AvatarSize } from './Avatar';
 import { ContactName } from './conversation/ContactName';
 import { InContactsIcon } from './InContactsIcon';
@@ -20,6 +22,9 @@ import type { ServiceIdString } from '../types/ServiceId';
 import { handleOutsideClick } from '../util/handleOutsideClick';
 import { Theme } from '../util/theme';
 import { ConfirmationDialog } from './ConfirmationDialog';
+import { usePrevious } from '../hooks/usePrevious';
+import { useReducedMotion } from '../hooks/useReducedMotion';
+import { drop } from '../util/drop';
 
 enum ConfirmDialogState {
   None = 'None',
@@ -49,11 +54,33 @@ export function CallingPendingParticipants({
   denyUser,
   toggleCallLinkPendingParticipantModal,
 }: PropsType): JSX.Element | null {
+  const reducedMotion = useReducedMotion();
+
+  // eslint-disable-next-line react-hooks/exhaustive-deps
+  const [opacitySpringProps, opacitySpringApi] = useSpring(
+    {
+      from: { opacity: 0 },
+      to: { opacity: 1 },
+      config: { clamp: true, friction: 22, tension: 360 },
+      immediate: reducedMotion,
+    },
+    []
+  );
+
+  // We show the first pending participant. Save this participant, so if all requests
+  // are resolved then we can keep showing the participant while fading out.
+  const lastParticipantRef = React.useRef<ConversationType | undefined>();
+  lastParticipantRef.current = participants[0] ?? lastParticipantRef.current;
+  const participantCount = participants.length;
+  const prevParticipantCount = usePrevious(participantCount, participantCount);
+
+  const [isVisible, setIsVisible] = useState(participantCount > 0);
   const [isExpanded, setIsExpanded] = useState(defaultIsExpanded ?? false);
   const [confirmDialogState, setConfirmDialogState] =
-    React.useState<ConfirmDialogState>(ConfirmDialogState.None);
-  const [serviceIdsStagedForAction, setServiceIdsStagedForAction] =
-    React.useState<Array<ServiceIdString>>([]);
+    useState<ConfirmDialogState>(ConfirmDialogState.None);
+  const [serviceIdsStagedForAction, setServiceIdsStagedForAction] = useState<
+    Array<ServiceIdString>
+  >([]);
 
   const expandedListRef = useRef<HTMLDivElement>(null);
 
@@ -120,7 +147,7 @@ export function CallingPendingParticipants({
   }, [serviceIdsStagedForAction, batchUserAction, hideConfirmDialog]);
 
   const renderApprovalButtons = useCallback(
-    (participant: ConversationType) => {
+    (participant: ConversationType, isEnabled: boolean = true) => {
       if (participant.serviceId == null) {
         return null;
       }
@@ -130,7 +157,7 @@ export function CallingPendingParticipants({
           <Button
             aria-label={i18n('icu:CallingPendingParticipants__DenyUser')}
             className="CallingPendingParticipants__PendingActionButton CallingButton__icon"
-            onClick={() => handleDeny(participant)}
+            onClick={isEnabled ? () => handleDeny(participant) : noop}
             variant={ButtonVariant.Destructive}
           >
             <span className="CallingPendingParticipants__PendingActionButtonIcon CallingPendingParticipants__PendingActionButtonIcon--Deny" />
@@ -138,7 +165,7 @@ export function CallingPendingParticipants({
           <Button
             aria-label={i18n('icu:CallingPendingParticipants__ApproveUser')}
             className="CallingPendingParticipants__PendingActionButton CallingButton__icon"
-            onClick={() => handleApprove(participant)}
+            onClick={isEnabled ? () => handleApprove(participant) : noop}
             variant={ButtonVariant.Calling}
           >
             <span className="CallingPendingParticipants__PendingActionButtonIcon CallingPendingParticipants__PendingActionButtonIcon--Approve" />
@@ -165,6 +192,32 @@ export function CallingPendingParticipants({
     );
   }, [isExpanded, handleHideAllRequests]);
 
+  useEffect(() => {
+    if (participantCount > prevParticipantCount) {
+      setIsVisible(true);
+      opacitySpringApi.stop();
+      drop(Promise.all(opacitySpringApi.start({ opacity: 1 })));
+    } else if (participantCount === 0) {
+      opacitySpringApi.stop();
+      drop(
+        Promise.all(
+          opacitySpringApi.start({
+            to: { opacity: 0 },
+            onRest: () => {
+              if (!participantCount) {
+                setIsVisible(false);
+              }
+            },
+          })
+        )
+      );
+    }
+  }, [opacitySpringApi, participantCount, prevParticipantCount, setIsVisible]);
+
+  if (!isVisible) {
+    return null;
+  }
+
   if (confirmDialogState === ConfirmDialogState.ApproveAll) {
     return (
       <ConfirmationDialog
@@ -228,7 +281,7 @@ export function CallingPendingParticipants({
         <div className="module-calling-participants-list__header">
           <div className="module-calling-participants-list__title">
             {i18n('icu:CallingPendingParticipants__RequestsToJoin', {
-              count: participants.length,
+              count: participantCount,
             })}
           </div>
           <button
@@ -311,15 +364,33 @@ export function CallingPendingParticipants({
     );
   }
 
-  const participant = participants[0];
+  const participant = lastParticipantRef.current;
+  if (!participant) {
+    return null;
+  }
+
+  const isExpandable = participantCount > 1;
   return (
-    <div className="CallingPendingParticipants CallingPendingParticipants--Compact module-calling-participants-list">
+    <animated.div
+      className={classNames(
+        'CallingPendingParticipants',
+        'CallingPendingParticipants--Compact',
+        'module-calling-participants-list',
+        isExpandable && 'CallingPendingParticipants--Expandable'
+      )}
+      style={opacitySpringProps}
+      aria-hidden={participantCount === 0}
+    >
       <div className="CallingPendingParticipants__CompactParticipant">
         <button
           type="button"
           onClick={ev => {
             ev.preventDefault();
             ev.stopPropagation();
+            if (participantCount === 0) {
+              return;
+            }
+
             toggleCallLinkPendingParticipantModal(participant.id);
           }}
           className="module-calling-participants-list__avatar-and-name CallingPendingParticipants__ParticipantButton"
@@ -353,9 +424,9 @@ export function CallingPendingParticipants({
             </div>
           </div>
         </button>
-        {renderApprovalButtons(participant)}
+        {renderApprovalButtons(participant, participantCount > 0)}
       </div>
-      {participants.length > 1 && (
+      {isExpandable && (
         <div className="CallingPendingParticipants__ShowAllRequestsButtonContainer">
           <button
             className="CallingPendingParticipants__ShowAllRequestsButton"
@@ -363,11 +434,11 @@ export function CallingPendingParticipants({
             type="button"
           >
             {i18n('icu:CallingPendingParticipants__AdditionalRequests', {
-              count: participants.length - 1,
+              count: participantCount - 1,
             })}
           </button>
         </div>
       )}
-    </div>
+    </animated.div>
   );
 }
diff --git a/ts/util/lint/exceptions.json b/ts/util/lint/exceptions.json
index b932b0f9f2..9506526bdb 100644
--- a/ts/util/lint/exceptions.json
+++ b/ts/util/lint/exceptions.json
@@ -3126,5 +3126,13 @@
     "line": "  message.innerHTML = window.i18n('icu:optimizingApplication');",
     "reasonCategory": "usageTrusted",
     "updated": "2021-09-17T21:02:59.414Z"
+  },
+  {
+    "rule": "React-useRef",
+    "path": "ts/components/CallingPendingParticipants.tsx",
+    "line": "  const lastParticipantRef = React.useRef<ConversationType | undefined>();",
+    "reasonCategory": "usageTrusted",
+    "updated": "2024-09-20T02:11:27.851Z",
+    "reasonDetail": "For fading out, to keep showing the last known participant"
   }
 ]