"""Tests for harness/score.py — the frozen scoring function.

The score function takes a list of exemplars and a formatter callable,
produces per-exemplar results, and aggregates a scalar for the loop.
"""

from pathlib import Path

from harness.score import Exemplar, load_exemplars, score


def identity_formatter(messy: str) -> str:
    return messy


def perfect_formatter_for(fixtures: dict) -> callable:
    """Return a formatter that looks up the expected output by messy input."""

    def _fmt(messy: str) -> str:
        return fixtures[messy]

    return _fmt


BOOK = Exemplar(
    name="book_single_author",
    source="toy fixture",
    type="book",
    tags=["book"],
    canary=False,
    messy_input="smith, jane. the history of nothing. u of chicago press, 2023.",
    canonical={
        "author": "Smith, Jane",
        "title": "The History of Nothing",
        "publisher": "University of Chicago Press",
        "year": 2023,
    },
    expected_bibliography="Smith, Jane. *The History of Nothing*. University of Chicago Press, 2023.",
)

WEB = Exemplar(
    name="web_page",
    source="toy fixture",
    type="web",
    tags=["web"],
    canary=False,
    messy_input="modern language association. mla style center. 2024.",
    canonical={
        "author": "Modern Language Association",
        "title": "MLA Style Center",
        "year": 2024,
    },
    expected_bibliography='Modern Language Association. "MLA Style Center." 2024. https://style.mla.org/.',
)


def test_identity_formatter_scores_below_one():
    # Identity returns the messy input unchanged, so canonical fields should
    # mostly NOT appear in the output.
    result = score([BOOK, WEB], identity_formatter)
    assert result.scalar < 1.0
    assert len(result.per_exemplar) == 2


def test_perfect_formatter_scores_one():
    fixtures = {
        BOOK.messy_input: BOOK.expected_bibliography,
        WEB.messy_input: WEB.expected_bibliography,
    }
    result = score([BOOK, WEB], perfect_formatter_for(fixtures))
    assert result.scalar == 1.0
    assert result.field_match_rate == 1.0


def test_load_exemplars_reads_toml_files(tmp_path: Path):
    (tmp_path / "example.toml").write_text("""
source = "toy"
type = "book"
tags = ["book"]
canary = true
messy_input = "smith jane, nothing, 2023"
expected_bibliography = "Smith, Jane. *Nothing*. Publisher, 2023."

[canonical]
author = "Smith, Jane"
year = 2023
""".strip())
    loaded = load_exemplars(tmp_path)
    assert len(loaded) == 1
    ex = loaded[0]
    assert ex.name == "example"
    assert ex.canary is True
    assert ex.canonical["author"] == "Smith, Jane"
    assert ex.canonical["year"] == 2023


def test_canary_exact_match_tracked_separately():
    canary_book = Exemplar(
        name="book_canary",
        source="toy",
        type="book",
        tags=["book"],
        canary=True,
        messy_input=BOOK.messy_input,
        canonical=BOOK.canonical,
        expected_bibliography=BOOK.expected_bibliography,
    )

    # Formatter produces correct fields but with a trailing space — fields
    # match, exact-string doesn't.
    def nearly(_messy: str) -> str:
        return BOOK.expected_bibliography + " "

    result = score([canary_book], nearly)
    assert result.field_match_rate == 1.0
    assert result.canary_exact_match_rate == 0.0