"""Streaming callback protocol and helpers."""

import logging

from typing import Protocol

from coder_eval.streaming.events import StreamEvent

logger = logging.getLogger(__name__)

class StreamCallback(Protocol):

"""Protocol for receiving streaming events."""

def on_event(self, event: StreamEvent) -> None:

"""Handle a streaming event."""

pass

class TaskScopedCallback:

"""Wrapper that overrides task_id on all events before forwarding to the inner callback.

Used by the orchestrator to ensure agent-emitted events carry the correct

task ID, since agents don't know about evaluation-level task identity.

"""

def __init__(self, inner: StreamCallback, task_id: str) -> None:

self._inner = inner

self._task_id = task_id

def on_event(self, event: StreamEvent) -> None:

event.task_id = self._task_id

self._inner.on_event(event)

class CompositeStreamCallback:

"""Composite callback that forwards events to multiple handlers.

Useful for dispatching events to both logging and display renderers.

"""

def __init__(self, callbacks: list[StreamCallback]) -> None:

self._callbacks = callbacks

def on_event(self, event: StreamEvent) -> None:

for callback in self._callbacks:

safe_emit(callback, event)

def safe_emit(callback: StreamCallback | None, event: StreamEvent) -> None:

"""Emit an event to the callback, catching and logging any exceptions."""

if callback is None:

return

try:

callback.on_event(event)

except Exception:

logger.warning("Stream callback failed (ignored)", exc_info=True)