"""Tests for load_concepts() — YAML parsing of wiki/concepts.yaml."""

from __future__ import annotations

import textwrap
from pathlib import Path

import pytest

from codex.wiki import Concept, load_concepts

# ---------------------------------------------------------------------------
# Fixtures
# ---------------------------------------------------------------------------

FIXTURE_YAML = textwrap.dedent(
    """\
    concepts:
      - slug: discrete-conformal-map
        title: Discrete Conformal Map
        aliases: [discrete conformal equivalence, discrete uniformization]
        emphasis: Fokus auf die variationelle Charakterisierung (BPS 2015).
      - slug: circle-packing
        title: Circle Packing
        aliases: [Koebe-Andreev-Thurston, circle pattern]
      - slug: lobachevsky-function
        title: Lobachevsky Function
        aliases: [Milnor Lobachevsky, Clausen function]
        emphasis: Verwendung in hyperbolischen Volumenformeln (Springborn 2008).
      - slug: discrete-yamabe-flow
        title: Discrete Yamabe Flow
        aliases: [discrete Ricci flow, Chow-Luo]
      - slug: hyperideal-tetrahedron
        title: Hyperideal Tetrahedron
        aliases: [hyperbolic volume, Schläfli, Ushijima]
    """
)


@pytest.fixture
def concepts_yaml(tmp_path: Path) -> Path:
    """Write fixture YAML to a temp file and return the path."""
    p = tmp_path / "concepts.yaml"
    p.write_text(FIXTURE_YAML, encoding="utf-8")
    return p


# ---------------------------------------------------------------------------
# Tests
# ---------------------------------------------------------------------------


def test_load_concepts_returns_all_concepts(concepts_yaml: Path) -> None:
    """All five concept entries are returned."""
    concepts = load_concepts(str(concepts_yaml))
    assert len(concepts) == 5


def test_load_concepts_types(concepts_yaml: Path) -> None:
    """Every returned item is a Concept instance."""
    concepts = load_concepts(str(concepts_yaml))
    for c in concepts:
        assert isinstance(c, Concept)


def test_load_concepts_first_slug_and_title(concepts_yaml: Path) -> None:
    """First concept has correct slug and title."""
    concepts = load_concepts(str(concepts_yaml))
    assert concepts[0].slug == "discrete-conformal-map"
    assert concepts[0].title == "Discrete Conformal Map"


def test_load_concepts_aliases_are_lists(concepts_yaml: Path) -> None:
    """Aliases are parsed as a list of strings."""
    concepts = load_concepts(str(concepts_yaml))
    for c in concepts:
        assert isinstance(c.aliases, list)
        for alias in c.aliases:
            assert isinstance(alias, str)


def test_load_concepts_first_has_two_aliases(concepts_yaml: Path) -> None:
    """First concept has exactly two aliases."""
    concepts = load_concepts(str(concepts_yaml))
    assert concepts[0].aliases == ["discrete conformal equivalence", "discrete uniformization"]


def test_load_concepts_emphasis_present(concepts_yaml: Path) -> None:
    """Concepts with emphasis field have it parsed correctly."""
    concepts = load_concepts(str(concepts_yaml))
    dcm = next(c for c in concepts if c.slug == "discrete-conformal-map")
    assert dcm.emphasis is not None
    assert "variationelle" in dcm.emphasis


def test_load_concepts_emphasis_absent_is_none(concepts_yaml: Path) -> None:
    """Concepts without emphasis field have emphasis=None."""
    concepts = load_concepts(str(concepts_yaml))
    cp = next(c for c in concepts if c.slug == "circle-packing")
    assert cp.emphasis is None


def test_load_concepts_slugs_unique(concepts_yaml: Path) -> None:
    """All slugs are distinct."""
    concepts = load_concepts(str(concepts_yaml))
    slugs = [c.slug for c in concepts]
    assert len(slugs) == len(set(slugs))


def test_load_concepts_unicode_in_aliases(concepts_yaml: Path) -> None:
    """Aliases with non-ASCII characters (Schläfli) are parsed without error."""
    concepts = load_concepts(str(concepts_yaml))
    ht = next(c for c in concepts if c.slug == "hyperideal-tetrahedron")
    assert any("Schläfli" in a for a in ht.aliases)


def test_load_concepts_empty_yaml(tmp_path: Path) -> None:
    """An empty concepts list returns an empty list (no crash)."""
    p = tmp_path / "concepts.yaml"
    p.write_text("concepts: []\n", encoding="utf-8")
    concepts = load_concepts(str(p))
    assert concepts == []