"""Local project file management for ODS workbooks.

Mirrors the FreeCAD file path pattern from ``pkg/freecad/silo_commands.py``.
Project ODS files live at::

    ~/projects/sheets/{PROJECT_CODE}/{PROJECT_CODE}.ods

The ``SILO_PROJECTS_DIR`` env var (shared with the FreeCAD workbench)
controls the base directory.
"""

import os
from pathlib import Path
from typing import Optional

from . import settings as _settings


def get_sheets_dir() -> Path:
    """Return the base directory for ODS project sheets."""
    return _settings.get_projects_dir() / "sheets"


def get_project_sheet_path(project_code: str) -> Path:
    """Canonical path for a project workbook.

    Example: ``~/projects/sheets/3DX10/3DX10.ods``
    """
    return get_sheets_dir() / project_code / f"{project_code}.ods"


def ensure_project_dir(project_code: str) -> Path:
    """Create the project sheet directory if needed and return its path."""
    d = get_sheets_dir() / project_code
    d.mkdir(parents=True, exist_ok=True)
    return d


def project_sheet_exists(project_code: str) -> bool:
    """Check whether a project workbook already exists locally."""
    return get_project_sheet_path(project_code).is_file()


def save_project_sheet(project_code: str, ods_bytes: bytes) -> Path:
    """Write ODS bytes to the canonical project path.

    Returns the Path written to.
    """
    ensure_project_dir(project_code)
    path = get_project_sheet_path(project_code)
    with open(path, "wb") as f:
        f.write(ods_bytes)
    return path


def read_project_sheet(project_code: str) -> Optional[bytes]:
    """Read ODS bytes from the canonical project path, or None."""
    path = get_project_sheet_path(project_code)
    if not path.is_file():
        return None
    with open(path, "rb") as f:
        return f.read()


def list_project_sheets() -> list:
    """Return a list of (project_code, path) tuples for all local sheets."""
    sheets_dir = get_sheets_dir()
    results = []
    if not sheets_dir.is_dir():
        return results
    for entry in sorted(sheets_dir.iterdir()):
        if entry.is_dir():
            ods = entry / f"{entry.name}.ods"
            if ods.is_file():
                results.append((entry.name, ods))
    return results