use super::*;

fn at(text: &str, needle: &str) -> Result<LinkTarget, String> {
    let byte = text.find(needle).unwrap();
    let prefix = &text[..byte];
    let row = prefix.bytes().filter(|byte| *byte == b'\n').count();
    let column = prefix.rsplit('\n').next().unwrap().graphemes(true).count();
    link_at(text, TextPosition { row, column })
}

fn target(path: Option<&str>, fragment: Option<&str>) -> LinkTarget {
    LinkTarget {
        path: path.map(PathBuf::from),
        fragment: fragment.map(str::to_owned),
    }
}

#[test]
fn follows_inline_labels_destinations_and_grapheme_columns() {
    let text = "👩‍💻 [go **there**](<../My%20Notes/%E6%97%A5%E6%9C%AC\\(1\\).md#caf%C3%A9>)";
    let expected = target(Some("../My Notes/日本(1).md"), Some("café"));
    assert_eq!(at(text, "there").unwrap(), expected);
    assert_eq!(at(text, "My%20").unwrap(), expected);
    assert_eq!(
        at("[absolute](/Tmp/Note.md)", "absolute").unwrap(),
        target(Some("/Tmp/Note.md"), None)
    );
    assert_eq!(
        at("[here](#title)", "here").unwrap(),
        target(None, Some("title"))
    );
    assert_eq!(at("[top]()", "top").unwrap(), target(None, None));
    assert_eq!(
        at("[here](#title)", "[here").unwrap(),
        target(None, Some("title"))
    );
    assert_eq!(
        at("[file](literal%23name.md)", "file").unwrap(),
        target(Some("literal#name.md"), None)
    );
    assert_eq!(
        at("[file](My\\[Notes\\].md)", "file").unwrap(),
        target(Some("My[Notes].md"), None)
    );
}

#[test]
fn resolves_all_reference_forms_and_multiline_block_definitions() {
    let text = "[full][ A  B ] [a b][] [A B]\n\n> [a b]:\n>   <My%20Notes.md#title>\n>   \"A title\"\n\n[a b]: ignored.md\n";
    let expected = target(Some("My Notes.md"), Some("title"));
    for needle in ["full", " A  B ", "a b][]", "A B]"] {
        assert_eq!(at(text, needle).unwrap(), expected);
    }
    assert_eq!(
        at("[Straße]\n\n[STRASSE]: file.md", "Straße").unwrap(),
        target(Some("file.md"), None)
    );
    let text = "> [multi\n> line][target]\n\n[target]: other.md\n";
    assert_eq!(at(text, "line]").unwrap(), target(Some("other.md"), None));
}

#[test]
fn rejects_images_code_plaintext_and_external_urls() {
    for (text, needle) in [
        ("![image](file.md)", "image"),
        ("`[code](file.md)`", "code"),
        ("```md\n[code](file.md)\n```", "file"),
        ("    [code](file.md)", "code"),
        ("plain file.md text", "file"),
        ("[web](https://example.com)", "web"),
        ("[web](//example.com/a)", "web"),
        ("[web](mailto:a@example.com)", "web"),
        ("<https://example.com>", "example"),
    ] {
        assert!(at(text, needle).is_err(), "{text}");
    }
    assert!(
        at("[missing]", "missing")
            .unwrap_err()
            .contains("not defined")
    );
    assert!(
        at("[bad](file%ZZ.md)", "bad")
            .unwrap_err()
            .contains("percent")
    );
    assert!(
        at("[bad](file%FF.md)", "bad")
            .unwrap_err()
            .contains("UTF-8")
    );
    assert!(at("[bad](#)", "bad").unwrap_err().contains("empty"));
}

#[test]
fn locates_visible_unicode_headings_setext_and_unique_slugs() {
    let text = "# **Café** [日本](destination.md) `code` ###\n\n> ## Café 日本 code\n\nCafé 日本 code\n====\n\n# Café 日本 code-1\n\n# Cafe\u{301} _name_ ![alt](hidden.md)\n\n```md\n# Hidden\n```\n";
    assert_eq!(heading_row(text, "café-日本-code").unwrap(), 0);
    assert_eq!(heading_row(text, "café-日本-code-1").unwrap(), 2);
    assert_eq!(heading_row(text, "café-日本-code-2").unwrap(), 4);
    assert_eq!(heading_row(text, "café-日本-code-1-1").unwrap(), 7);
    assert_eq!(heading_row(text, "cafe\u{301}-name-alt").unwrap(), 9);
    assert!(heading_row(text, "hidden").is_err());
    assert!(heading_row(text, "destinationmd").is_err());
    assert!(heading_row(text, "").is_err());
    assert_eq!(
        heading_row("# [Heading][ref]\n\n[ref]: ignored.md", "heading").unwrap(),
        0
    );
    assert_eq!(
        heading_row("# ![Alt][ref]\n\n[ref]: ignored.md", "alt").unwrap(),
        0
    );
    assert_eq!(heading_row("# ![Alt][missing]", "altmissing").unwrap(), 0);
}

#[test]
fn renders_entities_or_reports_the_explicit_entity_ceiling() {
    assert_eq!(
        at("[file](a&amp;b&#x20;c.md)", "file").unwrap(),
        target(Some("a&b c.md"), None)
    );
    assert_eq!(
        at("[file](&lt;name&gt;)", "file").unwrap(),
        target(Some("<name>"), None)
    );
    assert!(
        at("[file](a&copy;b.md)", "file")
            .unwrap_err()
            .contains("Unsupported Markdown HTML entity")
    );
    assert_eq!(heading_row("# A &amp; B &#xE9;\n", "a--b-é").unwrap(), 0);
    assert!(
        heading_row("# &copy;\n", "copy")
            .unwrap_err()
            .contains("Unsupported Markdown HTML entity")
    );
    assert_eq!(heading_row("# &copy;\n# Valid\n", "valid").unwrap(), 1);
    assert_eq!(
        heading_row("> First\n> Second\n> ------\n", "first-second").unwrap(),
        0
    );
}