"""
Single source of truth for required packages across all task difficulties.

Add new entries here when implementing medium and hard scenarios.
"""

PACKAGES: dict[str, list[str]] = {
    "easy": ["flask", "numpy", "pandas", "requests", "pydantic"],
    "medium": ["flask", "numpy", "pandas", "requests", "pydantic"],  # install always passes; failures are in Dockerfile + .env.ci
    "hard": ["flask", "numpy", "pandas", "requests", "pydantic"],  # install failure is from a numpy version conflict, not a missing package
}


def get_packages(task: str) -> list[str]:
    """Return the required package list for a given task difficulty."""
    if task not in PACKAGES:
        raise ValueError(f"Unknown task: {task!r}. Valid tasks: {list(PACKAGES)}")
    return PACKAGES[task]


def get_packages_set(task: str) -> set[str]:
    """Return required packages as a set (used for O(1) lookup in stage_runner)."""
    return set(get_packages(task))