"""Execution backend selection.

inline: legacy mode; FastAPI spawns a local background thread.
dsh: workbench only creates CampaignRun/TaskQueueItem rows; an external DSH (default)
worker leases and executes the content production pipeline.
"""
from __future__ import annotations

import os


def execution_backend() -> str:
    value = os.getenv("YAWAN_EXECUTION_BACKEND", "dsh").strip().lower()
    return "dsh" if value == "dsh" else "inline"


def is_dsh_backend() -> bool:
    return execution_backend() == "dsh"