"""Filesystem helpers (Windows MAX_PATH / long paths)."""

from __future__ import annotations

import os
import shutil
from pathlib import Path


def fs_path(path: Path | str) -> Path:
    """
    On Windows, prefix with ``\\\\?\\`` so open/mkdir work beyond MAX_PATH (~260).

    No-op on other platforms. Idempotent if already prefixed.
    """
    p = Path(path)
    if os.name != "nt":
        return p
    s = os.fspath(p)
    if s.startswith("\\\\?\\"):
        return p
    if not p.is_absolute():
        p = p.resolve()
        s = os.fspath(p)
    if s.startswith("\\\\"):
        # UNC: \\server\share\... → \\?\UNC\server\share\...
        return Path("\\\\?\\UNC\\" + s[2:])
    return Path("\\\\?\\" + s)


def ensure_dir(path: Path) -> Path:
    p = fs_path(path)
    p.mkdir(parents=True, exist_ok=True)
    return p


def write_text(path: Path, text: str, *, encoding: str = "utf-8") -> None:
    p = fs_path(path)
    p.parent.mkdir(parents=True, exist_ok=True)
    p.write_text(text, encoding=encoding)


def copy_file(src: Path, dst: Path) -> None:
    s = fs_path(src)
    d = fs_path(dst)
    d.parent.mkdir(parents=True, exist_ok=True)
    shutil.copy2(s, d)


def remove_file(path: Path) -> None:
    p = fs_path(path)
    if p.is_file():
        p.unlink()