"""Composition root for the ingest producer (Deck #183).

The transport is selected from ``INGEST_QUEUE``:

- ``postgres`` → :class:`ProcrastinateTaskProducer`, which defers jobs into the
  per-tenant Postgres for the out-of-process ``worker`` role to drain.
- ``memory`` (SQLite/dev default) → the in-process anyio stream, built inline by
  the server lifespan (it owns both the send and receive ends), so it is not
  produced here.
"""

from __future__ import annotations

import logging

from ...config import Settings
from .ports import TaskProducer

logger = logging.getLogger(__name__)


async def build_producer(settings: Settings) -> TaskProducer:
    """Build the Postgres (procrastinate) ingest producer.

    Precondition: ``settings.ingest_queue == "postgres"`` (the memory transport
    is constructed inline by the lifespan because it needs the paired receive
    stream for the in-process processor pool).
    """
    if settings.ingest_queue != "postgres":
        raise ValueError(
            "build_producer is only for INGEST_QUEUE=postgres; the memory "
            f"transport is built inline by the lifespan (got {settings.ingest_queue!r})"
        )

    from .procrastinate import ProcrastinateTaskProducer  # noqa: PLC0415

    return await ProcrastinateTaskProducer.connect()