"""Resolve which program is the default for scheduling and /api/today."""

from __future__ import annotations

from sqlmodel import Session, select

from tracker.config import TrackerConfig
from tracker.models import Program


def resolve_active_program(session: Session, config: TrackerConfig) -> Program | None:
    """Return the configured active program, or the first program row if unset or invalid.

    When ``config.active_program_id`` is set and exists in the DB, use it. Otherwise
    fall back to ``select(Program).limit(1)`` for backward compatibility.
    """
    if config.active_program_id is not None:
        program = session.get(Program, config.active_program_id)
        if program is not None:
            return program
    return session.exec(select(Program).limit(1)).first()