Elternbeirat/Elternbeirat.Web.Tests/MarkdownTests.cs

using Elternbeirat.Web.Shared;

namespace Elternbeirat.Web.Tests;

/// <summary>
/// Unit tests for the Markdown pipeline behind every editor-written body. Pure logic,
/// no PocketBase needed.
/// </summary>
public class MarkdownTests
{
    [Theory]
    [InlineData(null)]
    [InlineData("")]
    public void Empty_input_renders_nothing(string? markdown) =>
        Markdown.ToHtml(markdown).ShouldBe("");

    [Fact]
    public void Custom_container_renders_a_div_with_its_name_as_class()
    {
        var html = Markdown.ToHtml("::: kennzahlen\n- **seit 1975** Gründung\n:::");

        html.ShouldContain("<div class=\"kennzahlen\">");
        html.ShouldContain("<strong>seit 1975</strong>");
    }

    [Fact]
    public void Unknown_container_renders_its_content_as_normal_text()
    {
        // A typo in the block name must cost the styling, never the text.
        var html = Markdown.ToHtml("::: gibtsnicht\nNormaler Text.\n:::");

        html.ShouldContain("<p>Normaler Text.</p>");
        html.ShouldNotContain(":::");
    }

    [Fact]
    public void Raw_html_is_escaped_not_passed_through()
    {
        // The body is rendered as a MarkupString; a passed-through <script> would run
        // in the visitor's browser.
        var html = Markdown.ToHtml("Hallo <script>alert(1)</script>\n\n<div onclick=\"x()\">Box</div>");

        html.ShouldNotContain("<script>");
        html.ShouldNotContain("<div onclick");
        html.ShouldContain("&lt;script&gt;");
    }

    [Fact]
    public void Pipe_table_renders_a_table()
    {
        var html = Markdown.ToHtml("| Fach | Raum |\n|---|---|\n| Mathe | A1 |");

        html.ShouldContain("<table>");
        html.ShouldContain("<td>Mathe</td>");
    }

    [Theory]
    [InlineData("[kontakt@example.org](mailto:kontakt@example.org)")]
    [InlineData("<mailto:kontakt@example.org>")] // autolink
    [InlineData("[Satzung](/dokumente/satzung.pdf)  ")] // trailing whitespace ignored
    public void Link_alone_in_its_paragraph_is_marked(string markdown) =>
        Markdown.ToHtml(markdown).ShouldStartWith($"<p class=\"{Markdown.LoneLinkClass}\">");

    [Theory]
    [InlineData("Schreiben Sie an [uns](mailto:kontakt@example.org).")]
    [InlineData("[eins](/a) und [zwei](/b)")]
    [InlineData("![Foto](/bild.jpg)")] // an image is not a link
    [InlineData("Nur Text.")]
    public void Paragraph_that_is_not_a_single_link_is_not_marked(string markdown) =>
        Markdown.ToHtml(markdown).ShouldNotContain(Markdown.LoneLinkClass);

    [Fact]
    public void Lone_link_in_a_tight_list_marks_the_list_item()
    {
        // A tight list renders no <p>, so the class has to sit on the <li>.
        var html = Markdown.ToHtml("- [Antrag](/dokumente/antrag.pdf)\n- Text mit [Link](/x)");

        html.ShouldContain($"<li class=\"{Markdown.LoneLinkClass}\"><a href=\"/dokumente/antrag.pdf\">");
        html.ShouldContain("<li>Text mit");
    }

    [Fact]
    public void First_sentence_skips_the_heading_and_drops_the_markdown()
    {
        var sentence = Markdown.FirstSentence(
            "# Vorstand\n\nWir sind **sieben** [Eltern](/board). Der Rest folgt.");

        sentence.ShouldBe("Wir sind sieben Eltern.");
    }

    [Theory]
    [InlineData("Wir helfen z. B. bei Anträgen. Mehr dazu unten.", "Wir helfen z. B. bei Anträgen.")]
    [InlineData("Gewählt am 13. November 2025. Danach mehr.", "Gewählt am 13. November 2025.")]
    [InlineData("Haben Sie Fragen? Schreiben Sie uns.", "Haben Sie Fragen?")]
    [InlineData("Ohne Satzzeichen am Ende", "Ohne Satzzeichen am Ende")]
    public void First_sentence_ends_at_a_real_sentence_end(string markdown, string expected) =>
        Markdown.FirstSentence(markdown).ShouldBe(expected);

    [Fact]
    public void First_sentence_joins_soft_line_breaks_with_a_space()
    {
        // Editors wrap long lines; the wrap must not glue two words together.
        Markdown.FirstSentence("Erste Zeile\nzweite Zeile.").ShouldBe("Erste Zeile zweite Zeile.");
    }

    [Fact]
    public void First_sentence_drops_a_colon_that_leads_into_a_list() =>
        Markdown.FirstSentence("Formulare zum Herunterladen:\n\n- Antrag")
            .ShouldBe("Formulare zum Herunterladen");

    [Fact]
    public void First_sentence_is_never_cut_short()
    {
        // Long teasers are clamped by the tile's CSS, not by a character count.
        var sentence = string.Join(' ', Enumerable.Repeat("Wort", 60)) + ".";

        Markdown.FirstSentence(sentence).ShouldBe(sentence);
    }

    [Theory]
    [InlineData(null)]
    [InlineData("")]
    [InlineData("# Nur eine Überschrift")]
    [InlineData("- nur\n- eine Liste")]
    [InlineData("::: hinweis\nText im Baustein.\n:::")]
    public void First_sentence_is_empty_without_a_top_level_paragraph(string? markdown) =>
        Markdown.FirstSentence(markdown).ShouldBe("");

    [Theory]
    [InlineData(null)]
    [InlineData("")]
    [InlineData("   ")]
    [InlineData("## Nur eine Überschrift")]
    public void Teaser_is_empty_without_paragraph_text(string? markdown) =>
        Markdown.Teaser(markdown).ShouldBe("");

    [Fact]
    public void Teaser_keeps_a_short_body_whole() =>
        Markdown.Teaser("Kurzer Text.").ShouldBe("Kurzer Text.");

    [Fact]
    public void Teaser_removes_markdown_and_skips_headings()
    {
        // Emphasis and link markup go, link text stays; the heading would repeat the
        // card title, so it is left out. Paragraphs and list items are joined.
        var teaser = Markdown.Teaser(
            "## Rückblick\n\nDer **Basar** war ein [Erfolg](/posts).\n\n- Danke an alle\n- Bis bald");

        teaser.ShouldBe("Der Basar war ein Erfolg. Danke an alle Bis bald");
    }

    [Fact]
    public void Teaser_cuts_a_long_body_at_a_word_boundary()
    {
        var teaser = Markdown.Teaser("Der Basar war ein voller Erfolg.", 20);

        // 20 characters end inside "voller"; the cut falls back to the space before it.
        teaser.ShouldBe("Der Basar war ein…");
    }

    [Fact]
    public void Teaser_keeps_a_word_that_ends_exactly_at_the_limit() =>
        Markdown.Teaser("Der Basar war ein voller Erfolg.", 17).ShouldBe("Der Basar war ein…");

    [Fact]
    public void Teaser_drops_punctuation_left_at_the_cut() =>
        Markdown.Teaser("Liebe Eltern, der Basar war schön.", 14).ShouldBe("Liebe Eltern…");

    [Fact]
    public void Teaser_cuts_a_single_overlong_word_hard() =>
        Markdown.Teaser("Donaudampfschifffahrtsgesellschaft", 10).ShouldBe("Donaudampf…");

    [Fact]
    public void Teaser_defaults_to_160_characters_plus_ellipsis()
    {
        var body = string.Join(' ', Enumerable.Repeat("Wort", 100)); // 499 characters

        var teaser = Markdown.Teaser(body);

        teaser.Length.ShouldBeLessThanOrEqualTo(Markdown.TeaserLength + 1);
        teaser.ShouldEndWith("Wort…");
    }

    [Fact]
    public void Teaser_rejects_a_length_of_zero() =>
        Should.Throw<ArgumentOutOfRangeException>(() => Markdown.Teaser("Text", 0));
}