"""Tests for the OKF adapter (v0.2 stream 1).

The adapter sits *on top of* the format-agnostic core: the core stays
`text -> findings`; the adapter knows OKF structure and feeds scannable text
regions into the existing machinery. No YAML/format awareness leaks into core.

T2 — frontmatter parse-safety gate. A *strict, reject-by-default* loader for the
minimal OKF frontmatter subset (flat `key: value` scalars + block `- item`
lists). Every construct the "block anchor/alias DoS + dangerous type coercion"
requirement names is a hard reject, by construction — you cannot suffer a
billion-laughs expansion if anchors are refused before parsing.

OKF spec facts used here (verified against okf/SPEC.md, 2026-07-06):
- `type` is the only REQUIRED frontmatter key; `title`/`description`/`resource`/
  `tags`/`timestamp` are recommended; producers MAY add arbitrary keys.
- frontmatter is minimal by design — a flat block of scalars plus a `tags` list.
"""
import pytest

from llm_ingestion_guard.okf import parse_frontmatter, OKFFrontmatterError


# --- happy path: split + parse the minimal flat subset -----------------------

def test_splits_frontmatter_from_body():
    doc = "---\ntype: table\ntitle: Users\n---\nThe users table body.\n"
    frontmatter, body = parse_frontmatter(doc)
    assert frontmatter == {"type": "table", "title": "Users"}
    assert body == "The users table body.\n"


def test_no_frontmatter_returns_empty_and_full_body():
    doc = "Just a body with no frontmatter fence.\n"
    frontmatter, body = parse_frontmatter(doc)
    assert frontmatter == {}
    assert body == doc


def test_parses_block_tags_list():
    doc = "---\ntype: table\ntags:\n  - pii\n  - customers\n---\nbody\n"
    frontmatter, body = parse_frontmatter(doc)
    assert frontmatter == {"type": "table", "tags": ["pii", "customers"]}


def test_blank_and_comment_lines_are_ignored():
    doc = "---\ntype: table\n# a comment\n\ntitle: Users\n---\nbody\n"
    frontmatter, _ = parse_frontmatter(doc)
    assert frontmatter == {"type": "table", "title": "Users"}


# --- reject-by-default: the dangerous YAML constructs ------------------------

def test_rejects_anchor():
    doc = "---\ntype: &a table\n---\nbody\n"
    with pytest.raises(OKFFrontmatterError):
        parse_frontmatter(doc)


def test_rejects_alias():
    doc = "---\ntype: table\ntitle: *a\n---\nbody\n"
    with pytest.raises(OKFFrontmatterError):
        parse_frontmatter(doc)


def test_rejects_explicit_tag_type_coercion():
    # the classic PyYAML RCE shape
    doc = "---\ntype: !!python/object/apply:os.system ['id']\n---\nbody\n"
    with pytest.raises(OKFFrontmatterError):
        parse_frontmatter(doc)


def test_rejects_merge_key():
    doc = "---\ntype: table\n<<: *base\n---\nbody\n"
    with pytest.raises(OKFFrontmatterError):
        parse_frontmatter(doc)


def test_rejects_block_scalar():
    doc = "---\ntype: table\ndescription: |\n  multi\n  line\n---\nbody\n"
    with pytest.raises(OKFFrontmatterError):
        parse_frontmatter(doc)


def test_rejects_nested_mapping():
    doc = "---\ntype: table\nmeta:\n  nested: value\n---\nbody\n"
    with pytest.raises(OKFFrontmatterError):
        parse_frontmatter(doc)


def test_rejects_unterminated_frontmatter():
    doc = "---\ntype: table\ntitle: Users\n"  # no closing fence
    with pytest.raises(OKFFrontmatterError):
        parse_frontmatter(doc)


def test_rejects_flow_collection():
    # inline flow collections are outside the supported subset -> reject, don't
    # silently mis-parse the bracket string as a scalar.
    doc = "---\ntype: table\ntags: [pii, customers]\n---\nbody\n"
    with pytest.raises(OKFFrontmatterError):
        parse_frontmatter(doc)