# coding=utf-8
"""
@Time   :2026/6/30
@Author :tao.chen
"""
from pathlib import Path

import pytest

from files_mcp.core import path_guard


@pytest.fixture
def sandbox_root(tmp_path, monkeypatch):
    """Fresh tmp_path-based sandbox root for each test.

    Pre-populates a regular file, a nested file inside a subdir, and a
    symlink that points outside the sandbox (for the symlink-escape test).
    """
    monkeypatch.setenv("FILES_MCP_ROOT", str(tmp_path))
    path_guard.set_root_for_testing(tmp_path.resolve())
    (tmp_path / "inside.txt").write_text("hi", encoding="utf-8")
    (tmp_path / "subdir").mkdir()
    (tmp_path / "subdir" / "nested.txt").write_text("nested", encoding="utf-8")
    (tmp_path / "escape_link").symlink_to("/etc/passwd")
    return tmp_path.resolve()


class TestResolveAndCheck:
    def test_accepts_inside_path(self, sandbox_root):
        p = path_guard.resolve_and_check("inside.txt")
        assert p == sandbox_root / "inside.txt"

    def test_accepts_nested_path(self, sandbox_root):
        p = path_guard.resolve_and_check("subdir/nested.txt")
        assert p == sandbox_root / "subdir" / "nested.txt"

    def test_accepts_dot_segments(self, sandbox_root):
        p = path_guard.resolve_and_check("subdir/../inside.txt")
        assert p == sandbox_root / "inside.txt"

    def test_rejects_double_dot_escape(self, sandbox_root):
        with pytest.raises(ValueError, match="escapes sandbox"):
            path_guard.resolve_and_check("../etc/passwd")

    def test_rejects_absolute_outside_path(self, sandbox_root):
        with pytest.raises(ValueError, match="escapes sandbox"):
            path_guard.resolve_and_check("/etc/passwd")

    def test_rejects_mixed_escape(self, sandbox_root):
        with pytest.raises(ValueError, match="escapes sandbox"):
            path_guard.resolve_and_check("subdir/../../etc/passwd")

    def test_rejects_symlink_escape(self, sandbox_root):
        # escape_link -> /etc/passwd; resolve() follows the link first.
        with pytest.raises(ValueError, match="escapes sandbox"):
            path_guard.resolve_and_check("escape_link")

    def test_rejects_empty(self, sandbox_root):
        with pytest.raises(ValueError, match="path is empty"):
            path_guard.resolve_and_check("")

    def test_rejects_nul_byte(self, sandbox_root):
        with pytest.raises(ValueError, match="NUL byte"):
            path_guard.resolve_and_check("foo\x00bar")


class TestInitRoot:
    def test_init_root_raises_if_unset(self, monkeypatch):
        monkeypatch.delenv("FILES_MCP_ROOT", raising=False)
        path_guard._ROOT = None
        with pytest.raises(RuntimeError, match="FILES_MCP_ROOT"):
            path_guard._init_root()

    def test_init_root_raises_if_not_directory(self, tmp_path, monkeypatch):
        monkeypatch.setenv("FILES_MCP_ROOT", str(tmp_path / "missing"))
        path_guard._ROOT = None
        with pytest.raises(RuntimeError, match="not an existing directory"):
            path_guard._init_root()

    def test_init_root_is_idempotent(self, sandbox_root):
        first = path_guard._ROOT
        path_guard._init_root()
        assert path_guard._ROOT == first