Function reorderAttachmentsForAPI

src/utils/messages.ts:1481–1527

(messages: Message[])

 * - Any assistant message
 */
export function reorderAttachmentsForAPI(messages: Message[]): Message[] {
  // We build `result` backwards (push) and reverse once at the end — O(N).
  // Using unshift inside the loop would be O(N²).
  const result: Message[] = []
  // Attachments are pushed as we encounter them scanning bottom-up, so
  // this buffer holds them in reverse order (relative to the input array).
  const pendingAttachments: AttachmentMessage[] = []

  // Scan from the bottom up
  for (let i = messages.length - 1; i >= 0; i--) {
    const message = messages[i]!

    if (message.type === 'attachment') {
      // Collect attachment to bubble up
      pendingAttachments.push(message)
    } else {
      // Check if this is a stopping point
      const isStoppingPoint =
        message.type === 'assistant' ||
        (message.type === 'user' &&
          Array.isArray(message.message.content) &&
          message.message.content[0]?.type === 'tool_result')

      if (isStoppingPoint && pendingAttachments.length > 0) {
        // Hit a stopping point — attachments stop here (go after the stopping point).
        // pendingAttachments is already reversed; after the final result.reverse()
        // they will appear in original order right after `message`.
        for (let j = 0; j < pendingAttachments.length; j++) {
          result.push(pendingAttachments[j]!)
        }
        result.push(message)
        pendingAttachments.length = 0
      } else {
        // Regular message
        result.push(message)
      }
    }
  }

  // Any remaining attachments bubble all the way to the top.
  for (let j = 0; j < pendingAttachments.length; j++) {
    result.push(pendingAttachments[j]!)
  }

  result.reverse()
  return result
}

export function isSystemLocalCommandMessage(
  message: Message,