"""虚拟文件系统 Backend（存储后端）配置。"""

from __future__ import annotations

from pathlib import Path

from deepagents import FilesystemPermission
from deepagents.backends import (
    CompositeBackend,
    FilesystemBackend,
    StateBackend,
    StoreBackend,
)


def build_backend(project_root: Path, namespace: tuple[str, ...]) -> CompositeBackend:
    """按路径划分真实文件、线程文件和长期记忆。"""
    return CompositeBackend(
        default=FilesystemBackend(
            root_dir=str(project_root.resolve()),
            virtual_mode=True,
        ),
        routes={
            "/workspace/": StateBackend(),
            "/memories/": StoreBackend(namespace=lambda _runtime: namespace),
        },
    )


def build_permissions() -> list[FilesystemPermission]:
    """保护原始资料、组织政策和 Skill，允许写报告与临时文件。"""
    return [
        FilesystemPermission(
            operations=["write"],
            paths=["/data-room/**", "/policies/**", "/skills/**"],
            mode="deny",
        )
    ]