"""Unit tests for inline TeX-math normalization."""

from app.utilities.math_tex import convert_math


def test_schwarzschild_criterion_display_math():
    # The real bug: a $$...$$ formula leaks verbatim into the published HTML
    # (with > already HTML-escaped by the markdown renderer).
    html = '<p>The criterion: $$\\nabla_\\text{rad} &gt; \\nabla_\\text{ad}$$</p>'
    out = convert_math(html)
    assert out == (
        '<p>The criterion: '
        '<span class="tsai-math">∇<sub>rad</sub> &gt; ∇<sub>ad</sub></span></p>'
    )
    assert '$$' not in out
    assert '\\nabla' not in out


def test_ledoux_criterion_with_greek_subscript():
    html = '<p>$$\\nabla_\\text{rad} &gt; \\nabla_\\text{ad} + \\nabla_\\mu$$</p>'
    out = convert_math(html)
    assert out == (
        '<p><span class="tsai-math">'
        '∇<sub>rad</sub> &gt; ∇<sub>ad</sub> + ∇<sub>µ</sub>'
        '</span></p>'
    )


def test_inline_math_superscript():
    out = convert_math('<p>Energy is $E = mc^2$ exactly.</p>')
    assert out == '<p>Energy is <span class="tsai-math">E = mc<sup>2</sup></span> exactly.</p>'


def test_braced_superscript_and_symbol():
    out = convert_math('<p>Loses $10^{-6} M_\\odot$ per year.</p>')
    assert out == (
        '<p>Loses <span class="tsai-math">10<sup>-6</sup> M<sub>⊙</sub></span> per year.</p>'
    )


def test_currency_is_not_treated_as_math():
    html = '<p>It costs $5 to $10, not math.</p>'
    assert convert_math(html) == html


def test_no_dollar_signs_is_noop():
    html = '<p>Plain prose with no math at all.</p>'
    assert convert_math(html) == html


def test_idempotent():
    html = '<p>$$\\nabla_\\text{rad} &gt; \\nabla_\\text{ad}$$</p>'
    once = convert_math(html)
    assert convert_math(once) == once