/**
 * One-line rendering for the non-`Default` message kinds the backend writes into
 * a room (`ChatMessageType`). These are events, not posts, so they render as a
 * compact grey line instead of a message row — and a webhook/bot post carries
 * real content, which must not be swallowed by the system styling.
 */
import type { ChatMessage } from '@app/domains/chat/model'
import { t } from '@app/i18n'

export function systemLine(message: ChatMessage, nameOf: (userId: number | null | undefined) => string): string {
  const who = nameOf(message.author_id)
  if (message.author_type !== 'User') {
    // Bots and webhooks post normal text; the label keeps it attributable.
    const label = message.author?.display_name || message.author?.username || t('chat.system.integration')
    return message.content
      ? t('chat.system.postWithContent', { author: label, content: message.content })
      : t('chat.system.post', { author: label })
  }
  switch (message.message_type) {
    case 'ThreadCreated':
      return t('chat.system.threadCreated', { author: who })
    case 'ChannelJoin':
      return t('chat.system.joined', { author: who })
    case 'ChannelLeave':
      return t('chat.system.left', { author: who })
    case 'ChannelTopic':
      return message.content
        ? t('chat.system.topicChanged', { author: who, topic: message.content })
        : t('chat.system.topicUpdated', { author: who })
    case 'ChannelPinnedItem':
      return t('chat.system.pinned', { author: who })
    case 'Reminder':
      return message.content
        ? t('chat.system.reminder', { author: who, content: message.content })
        : t('chat.system.reminderSet', { author: who })
    case 'System':
      return message.content || t('chat.system.message')
    default:
      return message.content || t('chat.system.sent', { author: who })
  }
}