"""Summary-hook dispatch and cancellation rollback for context compression."""

from __future__ import annotations

import inspect
from typing import TYPE_CHECKING, Any, Dict, List, Optional

from agent.auxiliary_client import AuxiliaryExplicitCancellation

if TYPE_CHECKING:
    from agent.context_compressor import _HandoffScan


def _accepts_keyword_argument(callable_obj: Any, name: str) -> bool:
    """Return whether an inspectable callable accepts ``name`` as a keyword."""
    try:
        parameters = inspect.signature(callable_obj).parameters
    except (TypeError, ValueError):
        return False
    if any(parameter.kind is inspect.Parameter.VAR_KEYWORD for parameter in parameters.values()):
        return True
    parameter = parameters.get(name)
    return parameter is not None and parameter.kind in (
        inspect.Parameter.POSITIONAL_OR_KEYWORD,
        inspect.Parameter.KEYWORD_ONLY,
    )


class SummaryDispatchMixin:
    def _summarize_window(
        self, messages: List[Dict[str, Any]], turns_to_summarize: List[Dict[str, Any]], scan: "_HandoffScan",
        focus_topic: Optional[str], memory_context: str, bypass_cooldown: bool,
    ) -> Optional[str]:
        """Run the summary LLM; a cancellation rolls back the handoff scan's self-heal mutation first.
        A deterministic pin (repeated stall, #112420) skips the LLM: ``None`` lets Phase 3 insert the static
        fallback summary, or abort under ``abort_on_summary_failure`` exactly like a failed summary call."""
        from agent.context_compressor import take_deterministic_summary_pin
        if take_deterministic_summary_pin():
            # A detached stale attempt must not stamp error state or mutate the shared telemetry dict
            # the fallback owns; unwind as a cancellation before any write lands.
            from agent.conversation_compression import _raise_if_stale_attempt

            _raise_if_stale_attempt(self)
            # Surfaces through the fallback summary's reason line and the host's one-shot user warning.
            self._last_summary_error = (
                "summary model stalled on every route; deterministic fallback summary inserted"
            )
            telemetry = getattr(self, "_active_compression_telemetry", None)
            if isinstance(telemetry, dict):
                telemetry["failure_class"] = "stall_deterministic_fallback"
            return None
        # Focus-topic derivation scans user turns; only pay when a summary is generated.
        summary_kwargs: Dict[str, Any] = {
            "focus_topic": focus_topic or self._derive_auto_focus_topic(messages),
            "memory_context": memory_context,
        }
        if _accepts_keyword_argument(self._generate_summary, "bypass_cooldown"):
            summary_kwargs["bypass_cooldown"] = bypass_cooldown
        try:
            return self._generate_summary(turns_to_summarize, **summary_kwargs)
        except AuxiliaryExplicitCancellation:
            # Cancellation is a true no-op: restore the scan's mutation before the exception escapes.
            # Guard by THIS attempt's ownership: a detached stale attempt (a fallback already claimed
            # and is working the compressor) must not revert summary state the newer attempt advanced.
            # The caller's own generation rides a ContextVar because shared compressor attributes can
            # only name the current owner, never the caller's attempt. Working-attempt comparison (not
            # the entry generation) so a no-op claim does not suppress the owning attempt's rollback.
            from agent.conversation_compression import _caller_attempt_is_current

            if _caller_attempt_is_current(self):
                self._previous_summary = scan.previous_summary_before
                self._summary_has_user_turn = scan.has_user_turn_before
            raise