"""Filesystem locking helpers for generated output artifacts.

Outputs under `output/` are sealed read-only (file 0o444, parent dir 0o555)
to prevent accidental in-place mutation. The pipeline briefly relaxes those
bits to rewrite, then reseals.
"""

from pathlib import Path


FILE_WRITABLE = 0o644
FILE_SEALED = 0o444
DIR_WRITABLE = 0o755
DIR_SEALED = 0o555


def unlock_for_write(path: Path) -> None:
    path = Path(path)
    parent = path.parent
    if parent.exists():
        parent.chmod(DIR_WRITABLE)
    if path.exists():
        path.chmod(FILE_WRITABLE)


def seal_output(path: Path) -> None:
    path = Path(path)
    if path.exists():
        path.chmod(FILE_SEALED)
    parent = path.parent
    if parent.exists():
        parent.chmod(DIR_SEALED)