import os
from pathlib import Path

from resources.base import Refused

ENVIRONMENTS = "environments"
ROUTED = frozenset({"agent-controls", "agent-hooks", "hook", "journals", "plugins", "services", "sync", "update"})


def contained(folder: Path, name: str, nested: bool = False) -> Path:
    if not isinstance(name, str) or not name or "\\" in name or "\x00" in name:
        raise Refused(f"invalid path {name!r}")
    part = Path(name)
    if part.is_absolute() or any(piece in ("", ".", "..") for piece in name.split("/")) or (not nested and len(part.parts) != 1):
        raise Refused(f"invalid path {name!r}")
    target = folder / part
    if (nested or target.is_symlink()) and not target.resolve().is_relative_to(folder.resolve()):
        raise Refused(f"path {name!r} leaves its folder")
    return target


def environments(root: Path) -> Path:
    return Path(root) / ENVIRONMENTS


def environment_names(root: Path) -> tuple[str, ...]:
    try:
        with os.scandir(environments(root)) as found:
            return tuple(sorted(entry.name for entry in found if entry.is_dir()))
    except FileNotFoundError:
        return ()


def environment_home(root: Path, name: str) -> Path:
    return contained(environments(root), name)


def known_environment(root: Path, env: str) -> bool:
    try:
        return environment_home(root, env).is_dir()
    except Refused:
        return False