"""Step selector — picks the next pending step from a plan."""
from __future__ import annotations

from typing import Optional

from core.state import Plan, PlanStep, StepStatus


def select_next_step(plan: Plan) -> Optional[PlanStep]:
    """Return the first step with PENDING status, or None if all steps are done."""
    for step in plan.steps:
        if step.status == StepStatus.PENDING:
            return step
    return None