"""Local file storage for documents. Path derived from document_id."""
import logging
from pathlib import Path

from app.config import get_storage_path

logger = logging.getLogger(__name__)


def _ensure_storage() -> Path:
    root = get_storage_path()
    root.mkdir(parents=True, exist_ok=True)
    return root


def get_document_path(document_id: str) -> Path:
    """Path to the file for document_id. Does not create parent."""
    root = _ensure_storage()
    return root / document_id


def write_document(document_id: str, content: bytes) -> None:
    """Write document bytes. Overwrites if exists."""
    path = get_document_path(document_id)
    path.parent.mkdir(parents=True, exist_ok=True)
    path.write_bytes(content)
    logger.info("Wrote document %s (%d bytes)", document_id, len(content))


def read_document(document_id: str) -> bytes:
    """Read document bytes. Raises FileNotFoundError if missing."""
    path = get_document_path(document_id)
    if not path.is_file():
        raise FileNotFoundError(f"Document not found: {document_id}")
    return path.read_bytes()


def delete_document_file(document_id: str) -> None:
    """Remove document file. No-op if missing."""
    path = get_document_path(document_id)
    if path.is_file():
        path.unlink()
        logger.info("Deleted document file %s", document_id)


def document_file_exists(document_id: str) -> bool:
    """Return True if file exists."""
    return get_document_path(document_id).is_file()