# pybsv - Backup, Synchronization, Versioning.
# Copyright (C) 2025  Simon Boyé
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
from __future__ import annotations

import os
from pathlib import Path
import platform


def default_repository_path() -> Path:
    """Return the system-dependent default repository path."""
    if platform.system() in ("Windows", "Darwin", "Java"):
        msg = f"default_repository_path does not support {platform.system()} system"
        raise NotImplementedError(msg)
    else:  # Assume Unix
        # See https://specifications.freedesktop.org/basedir-spec/latest/
        data_home = os.environ.get("XDG_DATA_HOME", "")
        if data_home:
            path = Path(data_home)
            if not path.is_absolute() or not path.exists():
                msg = (
                    f"invalid XDG_DATA_HOME ({path}): path is relative or does not "
                    "exists"
                )
                raise RuntimeError(msg)
        else:
            path = Path.home() / ".local/share"
        return path / "bsv/repo"