oh-my-opencode/src/tools/delegate-task/sync-session-poller.ts

import type { ToolContextWithMetadata, OpencodeClient } from "./types"
import type { SessionMessage } from "./executor-types"
import { getDefaultSyncPollTimeoutMs, getTimingConfig } from "./timing"
import { log } from "../../shared/logger"
import { normalizeSDKResponse } from "../../shared"

const NON_TERMINAL_FINISH_REASONS = new Set(["tool-calls", "unknown"])

function wait(milliseconds: number): Promise<void> {
  const sharedBuffer = new SharedArrayBuffer(Int32Array.BYTES_PER_ELEMENT)
  const typedArray = new Int32Array(sharedBuffer)
  const result = Atomics.waitAsync(typedArray, 0, 0, milliseconds)
  return result.async ? result.value.then(() => undefined) : Promise.resolve()
}

function abortSyncSession(client: OpencodeClient, sessionID: string, reason: string): void {
  log("[task] Aborting sync session", { sessionID, reason })
  void client.session.abort({
    path: { id: sessionID },
  }).catch((error: unknown) => {
    log("[task] Failed to abort sync session", { sessionID, reason, error: String(error) })
  })
}

export function isSessionComplete(messages: SessionMessage[]): boolean {
  let lastUser: SessionMessage | undefined
  let lastAssistant: SessionMessage | undefined

  for (let i = messages.length - 1; i >= 0; i--) {
    const msg = messages[i]
    if (!lastAssistant && msg.info?.role === "assistant") lastAssistant = msg
    if (!lastUser && msg.info?.role === "user") lastUser = msg
    if (lastUser && lastAssistant) break
  }

  if (!lastAssistant?.info?.finish) return false
  if (NON_TERMINAL_FINISH_REASONS.has(lastAssistant.info.finish)) return false
  if (!lastUser?.info?.id || !lastAssistant?.info?.id) return false
  return lastUser.info.id < lastAssistant.info.id
}

const DEFAULT_MAX_ASSISTANT_TURNS = 300

export async function pollSyncSession(
  ctx: ToolContextWithMetadata,
  client: OpencodeClient,
  input: {
    sessionID: string
    agentToUse: string
    toastManager: { removeTask: (id: string) => void } | null | undefined
    taskId: string | undefined
    anchorMessageCount?: number
    maxAssistantTurns?: number
  },
  timeoutMs?: number
): Promise<string | null> {
  const syncTiming = getTimingConfig()
  const maxPollTimeMs = Math.max(timeoutMs ?? getDefaultSyncPollTimeoutMs(), 50)
  const maxTurns = input.maxAssistantTurns ?? DEFAULT_MAX_ASSISTANT_TURNS
  const pollStart = Date.now()
  let pollCount = 0
  let timedOut = false
  let assistantTurnCount = 0
  let lastSeenAssistantId: string | undefined

  log("[task] Starting poll loop", { sessionID: input.sessionID, agentToUse: input.agentToUse, maxTurns })

  while (Date.now() - pollStart < maxPollTimeMs) {
    if (ctx.abort?.aborted) {
      log("[task] Aborted by user", { sessionID: input.sessionID })
      abortSyncSession(client, input.sessionID, "parent_abort")
      if (input.toastManager && input.taskId) input.toastManager.removeTask(input.taskId)
      return `Task aborted.\n\nSession ID: ${input.sessionID}`
    }

    await wait(syncTiming.POLL_INTERVAL_MS)
    pollCount++

    let statusResult: { data?: Record<string, { type: string }> }
    try {
      statusResult = await client.session.status()
    } catch (error) {
      log("[task] Poll status fetch failed, retrying", { sessionID: input.sessionID, error: String(error) })
      continue
    }
    const allStatuses = normalizeSDKResponse(statusResult, {} as Record<string, { type: string }>)
    const sessionStatus = allStatuses[input.sessionID]

    if (pollCount % 10 === 0) {
      log("[task] Poll status", {
        sessionID: input.sessionID,
        pollCount,
        elapsed: Math.floor((Date.now() - pollStart) / 1000) + "s",
        sessionStatus: sessionStatus?.type ?? "not_in_status",
      })
    }

    if (sessionStatus && sessionStatus.type !== "idle") {
      continue
    }

    let messagesResult: { data?: unknown } | SessionMessage[]
    try {
      messagesResult = await client.session.messages({ path: { id: input.sessionID } })
    } catch (error) {
      log("[task] Poll messages fetch failed, retrying", { sessionID: input.sessionID, error: String(error) })
      continue
    }
    const rawData = (messagesResult as { data?: unknown })?.data ?? messagesResult
    const msgs = Array.isArray(rawData) ? (rawData as SessionMessage[]) : []

    if (input.anchorMessageCount !== undefined && msgs.length <= input.anchorMessageCount) {
      continue
    }

    if (isSessionComplete(msgs)) {
      log("[task] Poll complete - terminal finish detected", { sessionID: input.sessionID, pollCount })
      break
    }

    // 计数新出现的 assistant 轮次，用于熔断无限循环
    const lastAssistant = [...msgs].reverse().find((m) => m.info?.role === "assistant")
    if (lastAssistant?.info?.id && lastAssistant.info.id !== lastSeenAssistantId) {
      lastSeenAssistantId = lastAssistant.info.id
      assistantTurnCount++
      if (assistantTurnCount >= maxTurns) {
        log("[task] Max assistant turns reached, aborting to prevent infinite loop", {
          sessionID: input.sessionID,
          assistantTurnCount,
          maxTurns,
        })
        abortSyncSession(client, input.sessionID, "max_turns_exceeded")
        if (input.toastManager && input.taskId) input.toastManager.removeTask(input.taskId)
        return `Task aborted: subagent exceeded ${maxTurns} assistant turns without completing. This usually indicates an infinite tool-call loop. Session ID: ${input.sessionID}`
      }
    }

    const hasAssistantText = msgs.some((m) => {
      if (m.info?.role !== "assistant") return false
      const parts = m.parts ?? []
      return parts.some((p) => {
        if (p.type !== "text" && p.type !== "reasoning") return false
        const text = (p.text ?? "").trim()
        return text.length > 0
      })
    })

    if (!lastAssistant?.info?.finish && hasAssistantText) {
      log("[task] Poll complete - assistant text detected (fallback)", {
        sessionID: input.sessionID,
        pollCount,
      })
      break
    }
  }

  if (Date.now() - pollStart >= maxPollTimeMs) {
    timedOut = true
    log("[task] Poll timeout reached", { sessionID: input.sessionID, pollCount })
    abortSyncSession(client, input.sessionID, "poll_timeout")
  }

  return timedOut ? `Poll timeout reached after ${maxPollTimeMs}ms for session ${input.sessionID}` : null
}