"""The fidelity instrument: it must be able to see a loss before a 100 % means anything.

This module exists because the arm A report of 2026-08-29 published `docx`
193/196 and `xlsx` 193/193 without shipping the command that produced them.
Those figures could not be re-measured against a new converter version, against
the product path, or at all -- so a later run reporting the same numbers would
have been agreement with a memory rather than with a measurement.

The load-bearing test here is the NEGATIVE CONTROL: an instrument that returns
100 % on text with strings deliberately removed is an instrument that returns
100 % on everything, and every green figure it ever produced would be
worthless. `test_a_dropped_string_is_counted_as_lost` is what makes the rest
of the numbers mean something.
"""

from __future__ import annotations

import sys
import zipfile
from pathlib import Path

import pytest

sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "tools"))

import okf_fidelity  # noqa: E402

DOCUMENT_XML = """<?xml version="1.0"?>
<w:document xmlns:w="x"><w:body>
<w:p><w:r><w:t>Krav til seksjonering av bygget</w:t></w:r></w:p>
<w:p><w:r><w:t>Navn tilbyder:</w:t></w:r></w:p>
<w:p><w:r><w:t>Roemningsveier skal vaere uavhengige</w:t></w:r></w:p>
<w:p><w:r><w:t>ok</w:t></w:r></w:p>
</w:body></w:document>
"""

SHARED_XML = """<?xml version="1.0"?>
<sst xmlns="x"><si><t>Prisskjema for entreprisen</t></si><si><t>Sum eks mva</t></si></sst>
"""


def docx(tmp_path: Path) -> Path:
    path = tmp_path / "d.docx"
    with zipfile.ZipFile(path, "w") as archive:
        archive.writestr("word/document.xml", DOCUMENT_XML)
    return path


def xlsx(tmp_path: Path) -> Path:
    path = tmp_path / "s.xlsx"
    with zipfile.ZipFile(path, "w") as archive:
        archive.writestr("xl/sharedStrings.xml", SHARED_XML)
    return path


def test_the_fasit_comes_from_the_file_not_from_a_converter(tmp_path: Path) -> None:
    """A fasit derived from one converter would score it on its own homework."""
    strings = okf_fidelity.source_strings(docx(tmp_path))
    assert "krav til seksjonering av bygget" in strings
    # Below the floor: a two-character string appears in almost any output by
    # accident and would inflate every converter's score equally.
    assert "ok" not in strings


def test_full_coverage_is_reported_when_every_string_survives(tmp_path: Path) -> None:
    path = docx(tmp_path)
    text = "\n".join(okf_fidelity.source_strings(path))
    result = okf_fidelity.score(path, text)
    assert (result.covered, result.total) == (3, 3)


def test_a_dropped_string_is_counted_as_lost(tmp_path: Path) -> None:
    """THE negative control. An instrument that cannot see a loss measures nothing.

    Without this test every 100 % above is compatible with a matcher that
    always says yes, and the whole K2 figure would be decoration.
    """
    path = docx(tmp_path)
    kept = list(okf_fidelity.source_strings(path))[:-1]
    result = okf_fidelity.score(path, "\n".join(kept))
    assert result.covered == 2
    assert result.total == 3
    assert result.covered < result.total


def test_the_converters_own_markup_is_not_counted_as_a_loss(tmp_path: Path) -> None:
    """Measured on the corpus: markdown escapes read as 47 missing strings.

    The question is whether the STRING survived, not whether the markup
    matches -- a converter is entitled to escape a bracket and to wrap a bold
    run, and scoring that as data loss would attribute a formatting choice to
    the pipeline.
    """
    path = docx(tmp_path)
    escaped = "\\[Krav til seksjonering av bygget\\] **Navn tilbyder:** value\nRoemningsveier skal vaere uavhengige"
    result = okf_fidelity.score(path, escaped)
    assert result.covered == 3


def test_pairing_needs_a_value_beside_the_label_not_just_the_label(tmp_path: Path) -> None:
    """A label alone on a line is the failure the criterion exists to catch."""
    path = docx(tmp_path)
    alone = "Navn tilbyder:\nKrav til seksjonering av bygget"
    beside = "Navn tilbyder: Entreprenoer AS\nKrav til seksjonering av bygget"
    assert okf_fidelity.score(path, alone).paired == 0
    assert okf_fidelity.score(path, beside).paired == 1
    assert okf_fidelity.score(path, beside).pairable == 1


def test_a_workbooks_shared_strings_are_read(tmp_path: Path) -> None:
    strings = okf_fidelity.source_strings(xlsx(tmp_path))
    assert set(strings) == {"prisskjema for entreprisen", "sum eks mva"}


def test_a_type_with_no_reader_is_refused_rather_than_scored_zero(tmp_path: Path) -> None:
    """Zero coverage and "no instrument" are different facts."""
    path = tmp_path / "x.pptx"
    with zipfile.ZipFile(path, "w") as archive:
        archive.writestr("a", "b")
    with pytest.raises(ValueError):
        okf_fidelity.source_strings(path)