"""软链创建、移除与健康检查。"""

from __future__ import annotations

import os
import shutil
from dataclasses import dataclass
from pathlib import Path


@dataclass
class LinkStatus:
    link: Path
    expected: Path
    ok: bool
    issue: str | None = None


def create_link(link: Path, target: Path) -> None:
    target = target.resolve()
    if not target.exists():
        raise FileNotFoundError(f"目标不存在: {target}")

    link.parent.mkdir(parents=True, exist_ok=True)

    if link.is_symlink():
        current = link.resolve()
        if current == target:
            return
        link.unlink()
    elif link.exists():
        raise FileExistsError(f"已存在非软链路径: {link}")

    link.symlink_to(target, target_is_directory=target.is_dir())


def remove_link(link: Path) -> bool:
    if link.is_symlink():
        link.unlink()
        return True
    if link.exists():
        raise FileExistsError(f"不是软链，未删除: {link}")
    return False


def check_link(link: Path, expected: Path) -> LinkStatus:
    expected = expected.resolve()
    if not link.exists() and not link.is_symlink():
        return LinkStatus(link, expected, False, "缺失")
    if not link.is_symlink():
        return LinkStatus(link, expected, False, "非软链（可能被 Agent 替换为普通目录）")
    actual = link.resolve()
    if actual != expected:
        return LinkStatus(link, expected, False, f"指向错误: {actual}")
    if not actual.exists():
        return LinkStatus(link, expected, False, "目标不存在")
    return LinkStatus(link, expected, True)


def copy_template(src: Path, dst: Path) -> None:
    if dst.exists():
        raise FileExistsError(f"已存在: {dst}")
    shutil.copytree(src, dst)


def find_repo_root(start: Path | None = None) -> Path | None:
    start = (start or Path.cwd()).resolve()
    for directory in [start, *start.parents]:
        if (directory / ".pouch.yaml").is_file() or (directory / ".skills.yaml").is_file():
            return directory
        if (directory / "skills").is_dir() and (
            (directory / "catalog.yaml").is_file()
            or (directory / "registry.yaml").is_file()
        ):
            return directory
    return None