import os

import pytest

from tht.adapters.evidence import FilesystemEvidenceSource
from tht.ports.evidence import EvidenceSourceError


def test_filesystem_discovery_is_stable_and_acquisition_is_bounded(tmp_path):
    (tmp_path / "z.md").write_text("z")
    (tmp_path / "nested").mkdir()
    (tmp_path / "nested" / "a.md").write_text("alpha")
    source = FilesystemEvidenceSource(tmp_path, max_bytes=5)

    first = list(source.discover())
    assert [item.uri for item in first] == sorted(item.uri for item in first)
    assert all(item.source_id.startswith("filesystem:") for item in first)
    assert all(item.fingerprint.startswith("sha256:") for item in first)
    assert source.acquire(first[0]).content in {b"alpha", b"z"}

    (tmp_path / "large.md").write_bytes(b"123456")
    with pytest.raises(EvidenceSourceError) as caught:
        list(source.discover())
    assert not caught.value.retryable
    assert "large.md" not in str(caught.value)


def test_filesystem_rejects_symlink_escape(tmp_path):
    root = tmp_path / "root"
    root.mkdir()
    outside = tmp_path / "secret.md"
    outside.write_text("secret")
    (root / "escape.md").symlink_to(outside)

    with pytest.raises(EvidenceSourceError) as caught:
        list(FilesystemEvidenceSource(root).discover())
    assert not caught.value.retryable
    assert str(outside) not in str(caught.value)


def test_filesystem_acquire_rejects_object_from_another_source(tmp_path):
    left = tmp_path / "left"
    right = tmp_path / "right"
    left.mkdir()
    right.mkdir()
    (left / "doc.md").write_text("left")
    (right / "doc.md").write_text("right")
    item = next(iter(FilesystemEvidenceSource(left).discover()))

    with pytest.raises(EvidenceSourceError):
        FilesystemEvidenceSource(right).acquire(item)


def test_filesystem_acquire_rejects_content_changed_since_discovery(tmp_path):
    path = tmp_path / "doc.md"
    path.write_text("first")
    source = FilesystemEvidenceSource(tmp_path)
    item = next(iter(source.discover()))
    path.write_text("second")

    with pytest.raises(EvidenceSourceError) as caught:
        source.acquire(item)
    assert not caught.value.retryable


def test_filesystem_open_is_safe_when_file_is_swapped_for_symlink(tmp_path, monkeypatch):
    root = tmp_path / "root"
    root.mkdir()
    path = root / "doc.md"
    path.write_text("safe")
    outside = tmp_path / "outside.md"
    outside.write_text("secret")
    source = FilesystemEvidenceSource(root)
    real_open = os.open
    swapped = False

    def racing_open(name, flags, *args, **kwargs):
        nonlocal swapped
        if name == "doc.md" and not swapped:
            swapped = True
            path.unlink()
            path.symlink_to(outside)
        return real_open(name, flags, *args, **kwargs)

    monkeypatch.setattr(os, "open", racing_open)
    with pytest.raises(EvidenceSourceError):
        list(source.discover())


def test_filesystem_open_is_safe_when_ancestor_is_swapped_for_symlink(tmp_path, monkeypatch):
    root = tmp_path / "root"
    nested = root / "nested"
    nested.mkdir(parents=True)
    (nested / "doc.md").write_text("safe")
    outside = tmp_path / "outside"
    outside.mkdir()
    (outside / "doc.md").write_text("secret")
    source = FilesystemEvidenceSource(root)
    real_open = os.open
    swapped = False

    def racing_open(name, flags, *args, **kwargs):
        nonlocal swapped
        if name == "nested" and not swapped and kwargs.get("dir_fd") is not None:
            swapped = True
            (nested / "doc.md").unlink()
            nested.rmdir()
            nested.symlink_to(outside, target_is_directory=True)
        return real_open(name, flags, *args, **kwargs)

    monkeypatch.setattr(os, "open", racing_open)
    with pytest.raises(EvidenceSourceError):
        list(source.discover())