"""Memoir ingest scheduling boundary.

The real batching logic still lives in ``BackgroundTaskRunner``. This adapter
keeps conversation code from depending on that implementation directly.
"""

from __future__ import annotations

from dataclasses import dataclass
from typing import Literal, Sequence

from app.features.memoir.background_runner import BackgroundTaskRunner

MemoirTrigger = Literal[
    "turn",
    "conversation_end",
    "manual_flush",
    "evaluation_replay",
]


@dataclass(frozen=True)
class MemoirPhasePlan:
    """A visible plan for submitting segments into the memoir pipeline."""

    user_id: str
    segment_ids: tuple[str, ...]
    trigger: MemoirTrigger


class MemoirIngestScheduler:
    """Small facade over debounce batching and Phase2 flush dispatch."""

    def __init__(self, runner: BackgroundTaskRunner | None = None) -> None:
        self._runner = runner or BackgroundTaskRunner()

    @property
    def runner(self) -> BackgroundTaskRunner:
        """Compatibility escape hatch for existing tests and eval utilities."""

        return self._runner

    async def queue_segment(
        self,
        user_id: str,
        segment_id: str,
        *,
        text_char_count: int = 0,
        trigger: MemoirTrigger = "turn",
    ) -> MemoirPhasePlan:
        await self._runner.queue_message(
            user_id,
            segment_id,
            text_char_count=text_char_count,
        )
        return MemoirPhasePlan(
            user_id=user_id,
            segment_ids=(segment_id,),
            trigger=trigger,
        )

    async def flush_pending(
        self,
        user_id: str,
        *,
        extra_segment_ids: Sequence[str] | None = None,
        trigger: MemoirTrigger = "manual_flush",
    ) -> tuple[MemoirPhasePlan, str | None]:
        ids = tuple(str(x) for x in (extra_segment_ids or ()) if str(x).strip())
        task_id = await self._runner.flush_pending(
            user_id,
            extra_segment_ids=list(ids),
        )
        return MemoirPhasePlan(user_id=user_id, segment_ids=ids, trigger=trigger), task_id


__all__ = ["MemoirIngestScheduler", "MemoirPhasePlan", "MemoirTrigger"]