feat(explore): add pinned notes carousel

Co-authored-by: Erik Michelson <github@erik.michelson.eu>
Signed-off-by: Erik Michelson <github@erik.michelson.eu>
Signed-off-by: Philip Molares <philip.molares@udo.edu>

frontend/src/components/explore-page/pinned-notes/caret.module.scss

@@ -0,0 +1,10 @@
+/*!
+ * SPDX-FileCopyrightText: 2025 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+.active:hover {
+    cursor: pointer;
+    color: var(--bs-emphasis-color);
+}

frontend/src/components/explore-page/pinned-notes/caret.tsx

@@ -0,0 +1,32 @@
+/*
+ * SPDX-FileCopyrightText: 2025 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import React, { useMemo } from 'react'
+import {
+  CaretLeft as IconCaretLeftEmpty,
+  CaretLeftFill as IconCaretLeft,
+  CaretRight as IconCaretRightEmpty,
+  CaretRightFill as IconCaretRight
+} from 'react-bootstrap-icons'
+import styles from './caret.module.scss'
+import { UiIcon } from '../../common/icons/ui-icon'
+
+interface CaretProps {
+  left: boolean
+  active: boolean
+  onClick?: () => void
+}
+
+export const Caret: React.FC<CaretProps> = ({ active, left, onClick }) => {
+  const activeIcon = useMemo(() => (left ? IconCaretLeft : IconCaretRight), [left])
+  const inactiveIcon = useMemo(() => (left ? IconCaretLeftEmpty : IconCaretRightEmpty), [left])
+
+  return (
+    <div onClick={active ? onClick : undefined} className={`${active ? styles.active : undefined}`}>
+      <UiIcon icon={active ? activeIcon : inactiveIcon} size={2} />
+    </div>
+  )
+}

frontend/src/components/explore-page/pinned-notes/pinned-note-card.module.scss

@@ -1,20 +1,29 @@
-/*
+/*!
  * SPDX-FileCopyrightText: 2025 The HedgeDoc developers (see AUTHORS file)
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
 .card {
+    width: 25rem;
     min-width: 25rem;
     height: 8rem;
     position: relative;
     text-decoration: none;
+    scroll-snap-align: start;
+    scroll-snap-stop: always;
 }
 
 .card:hover {
     background-color: var(--bs-card-border-color);
 }
 
+.cardBody {
+    display: flex;
+    flex-direction: column;
+    justify-content: space-between;
+}
+
 .bookmark {
     position: absolute;
     top: -2px;

frontend/src/components/explore-page/pinned-notes/pinned-note-card.tsx

@@ -7,7 +7,7 @@ import React, { type MouseEvent, useMemo } from 'react'
 import { Badge, Card } from 'react-bootstrap'
 import { DateTime } from 'luxon'
 import { BookmarkStarFill as IconPinned } from 'react-bootstrap-icons'
-import styles from './pinned-note-card.module.css'
+import styles from './pinned-note-card.module.scss'
 import { useCallback } from 'react'
 import { NoteTypeIcon } from '../../common/note-type-icon/note-type-icon'
 import type { NoteType } from '@hedgedoc/commons'
@@ -60,9 +60,8 @@ export const PinnedNoteCard: React.FC<NoteCardProps> = ({ title, id, lastVisited
   }, [tags, onClickTag, labelTag])
 
   return (
-    <li className={'d-block'}>
     <Card className={`${styles.card}`} as={Link} href={`/n/${primaryAddress}`}>
-        <Card.Body>
+      <Card.Body className={`${styles.cardBody}`}>
         <div onClick={onClickUnpin} title={labelUnpinNote}>
           <UiIcon icon={IconPinned} size={1.5} className={`${styles.bookmark}`} />
           <div className={`${styles.star}`} />
@@ -74,9 +73,8 @@ export const PinnedNoteCard: React.FC<NoteCardProps> = ({ title, id, lastVisited
           </span>
         </Card.Title>
         <Card.Subtitle className='mb-2 text-muted'>{lastVisitedString}</Card.Subtitle>
-          {tagsChips}
+        <div>{tagsChips}</div>
       </Card.Body>
     </Card>
-    </li>
   )
 }

frontend/src/components/explore-page/pinned-notes/pinned-notes.module.css

@@ -0,0 +1,14 @@
+/*
+ * SPDX-FileCopyrightText: 2025 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+.scrollbox {
+    display: flex;
+    flex-flow: row;
+    overflow-x: scroll;
+    gap: 0.5rem;
+    scroll-snap-type: x mandatory;
+    scrollbar-width: none;
+}

frontend/src/components/explore-page/pinned-notes/pinned-notes.tsx

@@ -3,11 +3,13 @@
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
-import React, { Fragment, useMemo } from 'react'
+import React, { Fragment, useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import type { NoteCardProps } from './pinned-note-card'
 import { PinnedNoteCard } from './pinned-note-card'
 import { Trans, useTranslation } from 'react-i18next'
 import { NoteType } from '@hedgedoc/commons'
+import { Caret } from './caret'
+import styles from './pinned-notes.module.css'
 
 const mockListPinnedNotes: NoteCardProps[] = [
   {
@@ -74,9 +76,47 @@ const mockListPinnedNotes: NoteCardProps[] = [
 
 export const PinnedNotes: React.FC = () => {
   useTranslation()
+  const scrollboxRef = useRef<HTMLDivElement>(null)
+  const [enableScrollLeft, setEnableScrollLeft] = useState(false)
+  const [enableScrollRight, setEnableScrollRight] = useState(true)
 
-  const cards = useMemo(() => {
-    return mockListPinnedNotes.map((note: NoteCardProps) => <PinnedNoteCard key={note.id} {...note} />)
+  const pinnedNotes = useMemo(() => {
+    return mockListPinnedNotes
+  }, [])
+
+  const leftClick = useCallback(() => {
+    if (!scrollboxRef.current) {
+      return
+    }
+    scrollboxRef.current.scrollBy({
+      left: -400,
+      behavior: 'smooth'
+    })
+  }, [])
+  const rightClick = useCallback(() => {
+    if (!scrollboxRef.current) {
+      return
+    }
+    scrollboxRef.current.scrollBy({
+      left: 400,
+      behavior: 'smooth'
+    })
+  }, [])
+
+  useEffect(() => {
+    if (!scrollboxRef.current) {
+      return
+    }
+    const scrollbox = scrollboxRef.current
+    const scrollHandler = () => {
+      setEnableScrollLeft(scrollbox.scrollLeft > 0)
+      setEnableScrollRight(Math.ceil(scrollbox.scrollLeft + scrollbox.clientWidth) < scrollbox.scrollWidth)
+    }
+    scrollbox.addEventListener('scroll', scrollHandler)
+    scrollHandler()
+    return () => {
+      scrollbox.removeEventListener('scroll', scrollHandler)
+    }
   }, [])
 
   return (
@@ -84,7 +124,15 @@ export const PinnedNotes: React.FC = () => {
       <h2 className={'mb-2'}>
         <Trans i18nKey={'explore.pinnedNotes.title'} />
       </h2>
-      <ul className={'d-block mx-2 py-2 mb-5 d-flex gap-2 w-100 overflow-x-auto'}>{cards}</ul>
+      <div className={'d-flex flex-row gap-2 align-items-center mb-4'}>
+        <Caret active={enableScrollLeft} left={true} onClick={leftClick} />
+        <div className={styles.scrollbox} ref={scrollboxRef}>
+          {pinnedNotes.map((note: NoteCardProps) => (
+            <PinnedNoteCard key={note.id} {...note} />
+          ))}
+        </div>
+        <Caret active={enableScrollRight} left={false} onClick={rightClick} />
+      </div>
     </Fragment>
   )
 }