"""HTTP 流适配器：编码事件并传播断连，不执行 Agent 业务逻辑。"""
from contextlib import aclosing
from typing import AsyncIterator

from runtime.engine import Execution, ExecutionRequest
from runtime.interrupts import pending_interrupts  # 兼容旧导入
from api.sse_events import serialize_event


async def stream_sse(execution: Execution) -> AsyncIterator[str]:
    async with aclosing(execution.events()) as events:
        async for event in events:
            yield serialize_event(event)


# 旧内部调用入口保留；新入口直接使用 runtime.execution 和 stream_sse。
StreamRequest = ExecutionRequest


class ChatStream(Execution):
    def generate(self) -> AsyncIterator[str]:
        return stream_sse(self)


def sse_headers(session_id: str) -> dict[str, str]:
    return {"Cache-Control": "no-cache", "Connection": "keep-alive",
            "X-Accel-Buffering": "no", "X-Session-Id": session_id}