"""Content-addressed file storage for driver packages."""
import hashlib
from pathlib import Path


class DriverStore:
    """SHA256 content-addressed file storage for printer driver packages.

    Files are stored as DRIVERS_DIR/{sha256} so identical uploads are
    deduplicated automatically.
    """

    def __init__(self, base_dir: str) -> None:
        self._base = Path(base_dir)
        self._base.mkdir(parents=True, exist_ok=True)

    def save(self, data: bytes) -> str:
        """Persist *data* and return its SHA256 hex digest.

        If the file already exists the write is skipped (deduplication).
        """
        digest = hashlib.sha256(data).hexdigest()
        dest = self._base / digest
        if not dest.exists():
            dest.write_bytes(data)
        return digest

    def get_path(self, sha256: str) -> Path:
        """Return the filesystem path for a given SHA256 digest."""
        return self._base / sha256

    def exists(self, sha256: str) -> bool:
        """Return True if the file for *sha256* exists on disk."""
        return (self._base / sha256).exists()