feat(frontend): add search in cheatsheet view

Signed-off-by: Philip Molares <philip.molares@udo.edu>

frontend/locales/en.json

@@ -645,6 +645,7 @@
   },
   "cheatsheet": {
     "button": "Open Cheatsheet",
+    "search": "Search for Cheatsheets",
     "modal": {
       "popup": "Open in new tab",
       "title": "Cheatsheet",

frontend/src/components/editor-page/app-bar/cheatsheet/category-accordion.tsx

@@ -68,6 +68,12 @@ export const CategoryAccordion: React.FC<GroupAccordionProps> = ({ extensions, s
       </Accordion.Item>
     ))
   }, [groupEntries, onStateChange, selectedEntry])
-
+  const defaultActiveKey = useMemo(() => {
-  return <Accordion defaultActiveKey={groupEntries[0][0]}>{elements}</Accordion>
+    if (groupEntries.length === 0) {
+      return ''
+    }
+    return groupEntries[0][0]
+  }, [groupEntries])
+
+  return <Accordion defaultActiveKey={defaultActiveKey}>{elements}</Accordion>
 }

frontend/src/components/editor-page/app-bar/cheatsheet/cheatsheet-content.tsx

@@ -3,13 +3,14 @@
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
-import { allAppExtensions } from '../../../../extensions/all-app-extensions'
 import type { CheatsheetEntry, CheatsheetExtension } from '../../cheatsheet/cheatsheet-extension'
 import { isCheatsheetGroup } from '../../cheatsheet/cheatsheet-extension'
 import { CategoryAccordion } from './category-accordion'
 import { CheatsheetEntryPane } from './cheatsheet-entry-pane'
+import { CheatsheetSearch } from './cheatsheet-search'
+import styles from './cheatsheet.module.scss'
 import { TopicSelection } from './topic-selection'
-import React, { useCallback, useMemo, useState } from 'react'
+import React, { useCallback, useState } from 'react'
 import { Col, ListGroup, Row } from 'react-bootstrap'
 import { Trans } from 'react-i18next'
 
@@ -17,6 +18,7 @@ import { Trans } from 'react-i18next'
  * Renders the tab content for the cheatsheet.
  */
 export const CheatsheetContent: React.FC = () => {
+  const [visibleExtensions, setVisibleExtensions] = useState<CheatsheetExtension[]>([])
   const [selectedExtension, setSelectedExtension] = useState<CheatsheetExtension>()
   const [selectedEntry, setSelectedEntry] = useState<CheatsheetEntry>()
 
@@ -25,12 +27,15 @@ export const CheatsheetContent: React.FC = () => {
     setSelectedEntry(isCheatsheetGroup(value) ? value.entries[0] : value)
   }, [])
 
-  const extensions = useMemo(() => allAppExtensions.flatMap((extension) => extension.buildCheatsheetExtensions()), [])
-
   return (
     <Row className={`mt-2`}>
-      <Col xs={3}>
+      <Col xs={3} className={styles.sidebar}>
-        <CategoryAccordion extensions={extensions} selectedEntry={selectedExtension} onStateChange={changeExtension} />
+        <CheatsheetSearch setVisibleExtensions={setVisibleExtensions} />
+        <CategoryAccordion
+          extensions={visibleExtensions}
+          selectedEntry={selectedExtension}
+          onStateChange={changeExtension}
+        />
       </Col>
       <Col xs={9}>
         <ListGroup>

frontend/src/components/editor-page/app-bar/cheatsheet/cheatsheet-search.tsx

@@ -0,0 +1,104 @@
+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { allAppExtensions } from '../../../../extensions/all-app-extensions'
+import type { SearchIndexEntry } from '../../../../hooks/common/use-document-search'
+import { useDocumentSearch } from '../../../../hooks/common/use-document-search'
+import { useOnInputChange } from '../../../../hooks/common/use-on-input-change'
+import { UiIcon } from '../../../common/icons/ui-icon'
+import type { CheatsheetSingleEntry, CheatsheetExtension } from '../../cheatsheet/cheatsheet-extension'
+import { hasCheatsheetTopics } from '../../cheatsheet/cheatsheet-extension'
+import styles from './cheatsheet.module.scss'
+import type { IndexOptionsForDocumentSearch } from 'flexsearch-ts'
+import React, { useCallback, useEffect, useMemo, useState } from 'react'
+import { FormControl, InputGroup } from 'react-bootstrap'
+import { X } from 'react-bootstrap-icons'
+import { useTranslation } from 'react-i18next'
+
+interface CheatsheetSearchIndexEntry extends SearchIndexEntry {
+  title: string
+  description: string
+  example: string
+}
+
+const searchOptions: IndexOptionsForDocumentSearch<CheatsheetSearchIndexEntry> = {
+  document: {
+    id: 'id',
+    field: ['title', 'description', 'example']
+  }
+}
+
+export interface CheatsheetSearchProps {
+  setVisibleExtensions: React.Dispatch<React.SetStateAction<CheatsheetExtension[]>>
+}
+
+/**
+ * Renders a search field and handles the extension selection to display.
+ * An empty search input leads to all extensions being set.
+ *
+ * @param setVisibleExtensions This sets the extensions that are displayed in the cheatsheet view.
+ */
+export const CheatsheetSearch: React.FC<CheatsheetSearchProps> = ({ setVisibleExtensions }) => {
+  const { t } = useTranslation()
+  const [searchTerm, setSearchTerm] = useState('')
+  const allCheatsheetExtensions = useMemo(
+    () => allAppExtensions.flatMap((extension) => extension.buildCheatsheetExtensions()),
+    []
+  )
+  const buildSearchIndexDocument = useCallback(
+    (entry: CheatsheetEntry, rootI18nKey: string | undefined = undefined): CheatsheetSearchIndexEntry => {
+      const rootI18nKeyWithDot = rootI18nKey ? `${rootI18nKey}.` : ''
+      return {
+        id: rootI18nKey ? rootI18nKey : entry.i18nKey,
+        title: t(`cheatsheet.${rootI18nKeyWithDot}${entry.i18nKey}.title`),
+        description: t(`cheatsheet.${rootI18nKeyWithDot}${entry.i18nKey}.description`),
+        example: t(`cheatsheet.${rootI18nKeyWithDot}${entry.i18nKey}.example`)
+      }
+    },
+    [t]
+  )
+  const cheatsheetSearchIndexEntries = useMemo(
+    () =>
+      allCheatsheetExtensions.flatMap((entry) => {
+        if (hasCheatsheetTopics(entry)) {
+          return entry.topics.map((innerEntry) => buildSearchIndexEntry(innerEntry, entry.i18nKey))
+        }
+        return buildSearchIndexDocument(entry)
+      }),
+    [buildSearchIndexDocument, allCheatsheetExtensions]
+  )
+  const searchResults = useDocumentSearch(cheatsheetSearchIndexEntries, searchOptions, searchTerm)
+  useEffect(() => {
+    if (searchTerm.trim() === '') {
+      setVisibleExtensions(allCheatsheetExtensions)
+      return
+    }
+    const mappedResults = searchResults.flatMap((result) => result.result)
+    const extensionResults = allCheatsheetExtensions.filter((extension) => {
+      return mappedResults.includes(extension.i18nKey)
+    })
+    setVisibleExtensions(extensionResults)
+  }, [allCheatsheetExtensions, searchResults, searchTerm, setVisibleExtensions])
+  const onChange = useOnInputChange((search) => {
+    setSearchTerm(search)
+  })
+  const clearSearch = useCallback(() => {
+    setSearchTerm('')
+  }, [setSearchTerm])
+
+  return (
+    <InputGroup className='mb-3'>
+      <FormControl
+        placeholder={t('cheatsheet.search') ?? undefined}
+        aria-label={t('cheatsheet.search') ?? undefined}
+        onChange={onChange}
+        value={searchTerm}
+      />
+      <button className={styles.innerBtn} onClick={clearSearch}>
+        <UiIcon icon={X} />
+      </button>
+    </InputGroup>
+  )
+}

frontend/src/components/editor-page/app-bar/cheatsheet/cheatsheet.module.scss

@@ -1,5 +1,5 @@
-/*
+/*!
- * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
@@ -13,3 +13,27 @@
   top: 1rem;
   bottom: 1rem;
 }
+
+.sidebar {
+  display: flex;
+  flex-direction: column;
+  gap: 1rem;
+}
+
+.innerBtn {
+  position: absolute;
+  font-weight: 550;
+  border: none;
+  background-color: transparent;
+  align-self: center;
+  left: calc(100% - 30px);
+  z-index: 99999;
+  border-radius: var(--bs-border-radius);
+  filter: var(--bs-btn-close-white-filter);
+}
+
+.innerBtn:hover {
+  color: var(--bs-btn-close-color);
+  text-decoration: none;
+  opacity: var(--bs-btn-close-hover-opacity);
+}