Function computeTopicGroups

src/renderer/src/services/messagesService.ts:306–364

(topics: Topic[], currentPath: ChatMessage[])

 * @returns 在当前路径上有效的 TopicGroup 列表
 */
export function computeTopicGroups(topics: Topic[], currentPath: ChatMessage[]): TopicGroup[] {
  if (currentPath.length === 0 || topics.length === 0) return []

  // 构建消息 ID 到索引的映射
  const messageIndexMap = new Map<string, number>()
  for (let i = 0; i < currentPath.length; i++) {
    messageIndexMap.set(currentPath[i].id, i)
  }

  // 筛选出 startMessageId 在当前路径上的 Topics，并按路径顺序排序
  const validTopics = topics
    .filter((t) => messageIndexMap.has(t.startMessageId))
    .map((t) => ({
      topic: t,
      startIndex: messageIndexMap.get(t.startMessageId)!
    }))
    .sort((a, b) => a.startIndex - b.startIndex)

  if (validTopics.length === 0) return []

  const groups: TopicGroup[] = []

  for (let i = 0; i < validTopics.length; i++) {
    const { topic, startIndex } = validTopics[i]
    let endIndex: number

    if (topic.endMessageId && messageIndexMap.has(topic.endMessageId)) {
      // 有明确的 endMessageId 且在路径上
      endIndex = messageIndexMap.get(topic.endMessageId)!
    } else {
      // 找下一个 Topic 作为结束边界
      if (i + 1 < validTopics.length) {
        endIndex = validTopics[i + 1].startIndex - 1
      } else {
        endIndex = currentPath.length - 1 // 默认到末尾
      }
    }

    // 确保 endIndex >= startIndex
    endIndex = Math.max(startIndex, endIndex)

    // 收集消息 ID
    const messageIds: string[] = []
    for (let k = startIndex; k <= endIndex; k++) {
      messageIds.push(currentPath[k].id)
    }

    groups.push({
      topicId: topic.id,
      startMessageId: topic.startMessageId,
      endMessageId: currentPath[endIndex].id,
      name: topic.name,
      messageIds,
      collapsed: topic.collapsed
    })
  }

  return groups