overleaf-cep/services/web/frontend/js/features/chat/components/message-content.tsx

import { useRef, useEffect, type FC, useCallback, useState } from 'react'
import Linkify from 'react-linkify'
import useIsMounted from '../../../shared/hooks/use-is-mounted'
import { loadMathJax } from '../../mathjax/load-mathjax'
import { debugConsole } from '@/utils/debugging'
import { Message, useChatContext } from '@/features/chat/context/chat-context'
import OLButton from '@/shared/components/ol/ol-button'
import { useTranslation } from 'react-i18next'
import AutoExpandingTextArea from '@/shared/components/auto-expanding-text-area'

const MessageContent: FC<{
  content: Message['content']
  messageId: Message['id']
  edited: Message['edited']
}> = ({ content, messageId, edited }) => {
  const { t } = useTranslation()
  const root = useRef<HTMLDivElement | null>(null)
  const mounted = useIsMounted()
  const { idOfMessageBeingEdited, cancelMessageEdit, editMessage } =
    useChatContext()
  const [editedContent, setEditedContent] = useState(content)

  const editing = idOfMessageBeingEdited === messageId

  useEffect(() => {
    if (root.current) {
      // adds attributes to all the links generated by <Linkify/>, required due to https://github.com/tasti/react-linkify/issues/99
      for (const a of root.current.getElementsByTagName('a')) {
        a.setAttribute('target', '_blank')
        a.setAttribute('rel', 'noreferrer noopener')
      }

      // MathJax v3 typesetting
      loadMathJax()
        .then(async MathJax => {
          if (mounted.current) {
            const element = root.current
            try {
              await MathJax.typesetPromise([element])
              MathJax.typesetClear([element])
            } catch (error) {
              debugConsole.error(error)
            }
          }
        })
        .catch(debugConsole.error)
    }
  }, [content, mounted])

  const completeEdit = useCallback(() => {
    editMessage(messageId, editedContent)
  }, [editMessage, editedContent, messageId])

  const handleKeyDown = useCallback(
    (e: React.KeyboardEvent) => {
      if (e.key === 'Enter') {
        e.preventDefault()
        completeEdit()
      } else if (e.key === 'Escape') {
        e.preventDefault()
        cancelMessageEdit()
        setEditedContent(content)
      }
    },
    [cancelMessageEdit, completeEdit, content]
  )

  const handleChange = useCallback(
    (e: React.ChangeEvent<HTMLTextAreaElement>) => {
      setEditedContent(e.target.value)
    },
    []
  )

  const handleAutoFocus = useCallback(
    (textarea: HTMLTextAreaElement) => textarea.select(),
    []
  )

  return editing ? (
    <>
      <AutoExpandingTextArea
        value={editedContent}
        style={{ width: '100%' }}
        onKeyDown={handleKeyDown}
        onChange={handleChange}
        autoFocus // eslint-disable-line jsx-a11y/no-autofocus
        onAutoFocus={handleAutoFocus}
      />
      <br />
      <OLButton
        size="sm"
        variant="secondary"
        onClick={() => {
          cancelMessageEdit()
          setEditedContent(content)
        }}
      >
        {t('cancel')}
      </OLButton>
      <OLButton size="sm" variant="secondary" onClick={() => completeEdit()}>
        {t('save')}
      </OLButton>
    </>
  ) : (
    <p ref={root} translate="no">
      <Linkify>{content}</Linkify>
      {edited ? (
        <>
          {' '}
          <span className="message-edited">({t('edited')})</span>
        </>
      ) : null}
    </p>
  )
}

export default MessageContent