From 290e4aba3167b282c9ee1e966c840a490b7c818b Mon Sep 17 00:00:00 2001
From: Eugen Rochko <eugen@zeonfederated.com>
Date: Mon, 24 Apr 2023 08:07:03 +0200
Subject: [PATCH] Add lines to threads in web UI (#24549)

---
 app/javascript/mastodon/components/status.jsx | 18 +++++--
 .../mastodon/containers/status_container.jsx  |  1 +
 .../mastodon/features/status/index.jsx        | 11 ++--
 .../styles/mastodon/components.scss           | 54 +++++++++++++++++++
 4 files changed, 76 insertions(+), 8 deletions(-)

diff --git a/app/javascript/mastodon/components/status.jsx b/app/javascript/mastodon/components/status.jsx
index f1dba566b..cd8423b2f 100644
--- a/app/javascript/mastodon/components/status.jsx
+++ b/app/javascript/mastodon/components/status.jsx
@@ -68,6 +68,9 @@ class Status extends ImmutablePureComponent {
   static propTypes = {
     status: ImmutablePropTypes.map,
     account: ImmutablePropTypes.map,
+    previousId: PropTypes.string,
+    nextInReplyToId: PropTypes.string,
+    rootId: PropTypes.string,
     onClick: PropTypes.func,
     onReply: PropTypes.func,
     onFavourite: PropTypes.func,
@@ -309,10 +312,7 @@ class Status extends ImmutablePureComponent {
   };
 
   render () {
-    let media = null;
-    let statusAvatar, prepend, rebloggedByText;
-
-    const { intl, hidden, featured, unread, showThread, scrollKey, pictureInPicture } = this.props;
+    const { intl, hidden, featured, unread, showThread, scrollKey, pictureInPicture, previousId, nextInReplyToId, rootId } = this.props;
 
     let { status, account, ...other } = this.props;
 
@@ -334,6 +334,8 @@ class Status extends ImmutablePureComponent {
       openMedia: this.handleHotkeyOpenMedia,
     };
 
+    let media, statusAvatar, prepend, rebloggedByText;
+
     if (hidden) {
       return (
         <HotKeys handlers={handlers}>
@@ -345,7 +347,11 @@ class Status extends ImmutablePureComponent {
       );
     }
 
+    const connectUp = previousId && previousId === status.get('in_reply_to_id');
+    const connectToRoot = rootId && rootId === status.get('in_reply_to_id');
+    const connectReply = nextInReplyToId && nextInReplyToId === status.get('id');
     const matchedFilters = status.get('matched_filters');
+
     if (this.state.forceFilter === undefined ? matchedFilters : this.state.forceFilter) {
       const minHandlers = this.props.muted ? {} : {
         moveUp: this.handleHotkeyMoveUp,
@@ -519,7 +525,9 @@ class Status extends ImmutablePureComponent {
         <div className={classNames('status__wrapper', `status__wrapper-${status.get('visibility')}`, { 'status__wrapper-reply': !!status.get('in_reply_to_id'), unread, focusable: !this.props.muted })} tabIndex={this.props.muted ? null : 0} data-featured={featured ? 'true' : null} aria-label={textForScreenReader(intl, status, rebloggedByText)} ref={this.handleRef}>
           {prepend}
 
-          <div className={classNames('status', `status-${status.get('visibility')}`, { 'status-reply': !!status.get('in_reply_to_id'), muted: this.props.muted })} data-id={status.get('id')}>
+          <div className={classNames('status', `status-${status.get('visibility')}`, { 'status-reply': !!status.get('in_reply_to_id'), 'status--in-thread': !!rootId, 'status--first-in-thread': previousId && (!connectUp || connectToRoot), muted: this.props.muted })} data-id={status.get('id')}>
+            {(connectReply || connectUp || connectToRoot) && <div className={classNames('status__line', { 'status__line--full': connectReply, 'status__line--first': !status.get('in_reply_to_id') && !connectToRoot })} />}
+
             {/* eslint-disable-next-line jsx-a11y/no-static-element-interactions */}
             <div onClick={this.handleClick} className='status__info'>
               <a href={`/@${status.getIn(['account', 'acct'])}/${status.get('id')}`} className='status__relative-time' target='_blank' rel='noopener noreferrer'>
diff --git a/app/javascript/mastodon/containers/status_container.jsx b/app/javascript/mastodon/containers/status_container.jsx
index 580f409e9..f48316654 100644
--- a/app/javascript/mastodon/containers/status_container.jsx
+++ b/app/javascript/mastodon/containers/status_container.jsx
@@ -67,6 +67,7 @@ const makeMapStateToProps = () => {
 
   const mapStateToProps = (state, props) => ({
     status: getStatus(state, props),
+    nextInReplyToId: props.nextId ? state.getIn(['statuses', props.nextId, 'in_reply_to_id']) : null,
     pictureInPicture: getPictureInPicture(state, props),
   });
 
diff --git a/app/javascript/mastodon/features/status/index.jsx b/app/javascript/mastodon/features/status/index.jsx
index 900b19c31..6f0336209 100644
--- a/app/javascript/mastodon/features/status/index.jsx
+++ b/app/javascript/mastodon/features/status/index.jsx
@@ -529,14 +529,19 @@ class Status extends ImmutablePureComponent {
     }
   }
 
-  renderChildren (list) {
-    return list.map(id => (
+  renderChildren (list, ancestors) {
+    const { params: { statusId } } = this.props;
+
+    return list.map((id, i) => (
       <StatusContainer
         key={id}
         id={id}
         onMoveUp={this.handleMoveUp}
         onMoveDown={this.handleMoveDown}
         contextType='thread'
+        previousId={i > 0 && list.get(i - 1)}
+        nextId={list.get(i + 1) || (ancestors && statusId)}
+        rootId={statusId}
       />
     ));
   }
@@ -590,7 +595,7 @@ class Status extends ImmutablePureComponent {
     }
 
     if (ancestorsIds && ancestorsIds.size > 0) {
-      ancestors = <>{this.renderChildren(ancestorsIds)}</>;
+      ancestors = <>{this.renderChildren(ancestorsIds, true)}</>;
     }
 
     if (descendantsIds && descendantsIds.size > 0) {
diff --git a/app/javascript/styles/mastodon/components.scss b/app/javascript/styles/mastodon/components.scss
index 7c8d700ad..248738f6b 100644
--- a/app/javascript/styles/mastodon/components.scss
+++ b/app/javascript/styles/mastodon/components.scss
@@ -1145,6 +1145,58 @@ body > [data-popper-placement] {
       }
     }
   }
+
+  &--in-thread {
+    border-bottom: 0;
+
+    .status__content,
+    .status__action-bar,
+    .media-gallery,
+    .video,
+    .audio,
+    .attachment-list {
+      margin-left: 46px + 10px;
+      width: calc(100% - (46px + 10px));
+    }
+  }
+
+  &--first-in-thread {
+    border-top: 1px solid lighten($ui-base-color, 8%);
+  }
+
+  &__line {
+    height: 16px - 4px;
+    border-inline-start: 2px solid lighten($ui-base-color, 8%);
+    width: 0;
+    position: absolute;
+    top: 0;
+    inset-inline-start: 16px + ((46px - 2px) / 2);
+
+    &--full {
+      top: 0;
+      height: 100%;
+
+      &::before {
+        content: '';
+        display: block;
+        position: absolute;
+        top: 16px - 4px;
+        height: 46px + 4px + 4px;
+        width: 2px;
+        background: $ui-base-color;
+        inset-inline-start: -2px;
+      }
+    }
+
+    &--first {
+      top: 16px + 46px + 4px;
+      height: calc(100% - (16px + 46px + 4px));
+
+      &::before {
+        display: none;
+      }
+    }
+  }
 }
 
 .status__relative-time {
@@ -1293,6 +1345,7 @@ body > [data-popper-placement] {
 .detailed-status {
   background: lighten($ui-base-color, 4%);
   padding: 16px;
+  border-top: 1px solid lighten($ui-base-color, 8%);
 
   &--flex {
     display: flex;
@@ -1729,6 +1782,7 @@ a.account__display-name {
 .status__avatar {
   width: 46px;
   height: 46px;
+  box-shadow: 0 0 0 2px $ui-base-color;
 }
 
 .muted {