"""IMP-45 (#74) u2 — frontmatter ``slide_overrides`` surfacing.

Covers ``src.mdx_normalizer.normalize_mdx_content`` and the helper
``_extract_slide_overrides``. The Stage 2 plan enumerates four cases:

1. Present — nested ``slide_overrides.css`` survives normalization verbatim.
2. Absent — return dict carries an empty ``slide_overrides`` mapping.
3. Non-string ``css`` — dropped (fail-closed against typo'd YAML shapes).
4. Title-only frontmatter — no ``slide_overrides`` key in metadata → ``{}``.

Scope-lock: this unit only adds the new key to the return dict. The four
pre-existing return keys (``clean_text``/``title``/``images``/``popups``/
``tables``/``sections``) are asserted unchanged at the structural level.
"""
from __future__ import annotations

from src.mdx_normalizer import _extract_slide_overrides, normalize_mdx_content


_CSS_BLOCK = "<style>.f29b__col_right { width: 320px; }</style>"


def _mdx_with_frontmatter(fm_body: str, body: str = "# 제목\n\n본문 한 줄.\n") -> str:
    return f"---\n{fm_body}---\n{body}"


# -- case 1: present (nested css string survives verbatim) ------------------


def test_normalize_surfaces_nested_slide_overrides_css():
    raw = _mdx_with_frontmatter(
        "title: 04 sample\n"
        "slide_overrides:\n"
        f"  css: \"{_CSS_BLOCK}\"\n"
    )

    result = normalize_mdx_content(raw)

    assert result["slide_overrides"] == {"css": _CSS_BLOCK}
    # Other axes unaffected by the new key.
    assert result["title"] == "04 sample"
    assert "본문" in result["clean_text"]


# -- case 2: absent (no slide_overrides key in frontmatter) -----------------


def test_normalize_returns_empty_slide_overrides_when_key_absent():
    raw = _mdx_with_frontmatter("title: 03 sample\n")

    result = normalize_mdx_content(raw)

    assert result["slide_overrides"] == {}
    # Confirm key is always present (callers can rely on .get without default).
    assert "slide_overrides" in result


# -- case 3: non-string css (fail-closed drop) ------------------------------


def test_normalize_drops_non_string_css_under_slide_overrides():
    # YAML list under .css should be dropped; sibling unknown keys survive
    # so the future generalization path (e.g., slide_overrides.js) stays
    # forward-compatible per the Stage 2 plan.
    raw = _mdx_with_frontmatter(
        "title: typo case\n"
        "slide_overrides:\n"
        "  css:\n"
        "    - .f29b__col_right { width: 320px; }\n"
        "  note: experimental sibling\n"
    )

    result = normalize_mdx_content(raw)

    assert "css" not in result["slide_overrides"]
    assert result["slide_overrides"].get("note") == "experimental sibling"


# -- case 4: title-only frontmatter (no slide_overrides at all) -------------


def test_normalize_title_only_frontmatter_yields_empty_slide_overrides():
    raw = _mdx_with_frontmatter("title: title only\n")

    result = normalize_mdx_content(raw)

    assert result["title"] == "title only"
    assert result["slide_overrides"] == {}


# -- direct helper coverage (defensive against future return-shape drift) ---


def test_extract_slide_overrides_non_mapping_returns_empty_dict():
    # Frontmatter parsers can yield odd types if the user writes
    # ``slide_overrides: 42`` or ``slide_overrides: ".x{}"``. The helper
    # must coerce to ``{}`` rather than raise.
    for bad in (None, 42, "literal string", ["css"]):
        assert _extract_slide_overrides({"slide_overrides": bad}) == {}


def test_extract_slide_overrides_passes_through_unknown_siblings():
    payload = {"slide_overrides": {"css": ".a{}", "js": "console.log(1)"}}
    assert _extract_slide_overrides(payload) == {
        "css": ".a{}",
        "js": "console.log(1)",
    }