Function deleteMessage

src/renderer/src/services/messagesService.ts:57–97

(pageId: string, messageId: string)

}

export async function deleteMessage(pageId: string, messageId: string): Promise<void> {
  const record = stores.message.get(pageId)
  if (!record) return

  const { messageMap, childrenMap } = buildMessageMaps(record.messages)

  // 获取要删除的消息及其所有子消息 - O(N) 而非 O(N²)
  const idsToDelete = getDescendantIds(childrenMap, messageId)
  idsToDelete.add(messageId)

  const deletedMsg = messageMap.get(messageId)

  // 计算新的 leafMessageId
  let leafMessageId = record.leafMessageId
  if (leafMessageId && idsToDelete.has(leafMessageId)) {
    // 获取原始的 siblings（包含被删除的消息）
    const allSiblings = childrenMap.get(deletedMsg?.parentMessageId) ?? []
    // 找到被删除消息在兄弟中的位置
    const deletedIndex = allSiblings.findIndex((m) => m.id === messageId)
    // 过滤掉要删除的消息
    const remainingSiblings = allSiblings.filter((m) => !idsToDelete.has(m.id))

    if (remainingSiblings.length > 0) {
      // 优先选择上一个分支（index - 1），否则选择下一个
      const targetIndex = Math.min(Math.max(0, deletedIndex - 1), remainingSiblings.length - 1)
      const targetSibling = remainingSiblings[targetIndex]

      const remainingMessages = record.messages.filter((m) => !idsToDelete.has(m.id))
      const { childrenMap: remainingChildrenMap } = buildMessageMaps(remainingMessages)
      leafMessageId = findLeafFromMessage(remainingChildrenMap, targetSibling.id)
    } else {
      leafMessageId = deletedMsg?.parentMessageId
    }
  }

  await stores.message.update(pageId, (r) => ({
    ...r,
    messages: r.messages.filter((m) => !idsToDelete.has(m.id)),
    leafMessageId
  }))
}

// ==================== 分支操作 ====================