rumdl_lib/rules/

md033_no_inline_html.rs

//!
//! Rule MD033: No HTML tags
//!
//! See [docs/md033.md](../../docs/md033.md) for full documentation, configuration, and examples.

use crate::rule::{Fix, LintError, LintResult, LintWarning, Rule, RuleCategory, Severity};
use crate::utils::kramdown_utils::{is_kramdown_block_attribute, is_kramdown_extension};
use crate::utils::regex_cache::*;
use std::collections::HashSet;

mod md033_config;
use md033_config::MD033Config;

#[derive(Clone)]
pub struct MD033NoInlineHtml {
    config: MD033Config,
    allowed: HashSet<String>,
    disallowed: HashSet<String>,
}

impl Default for MD033NoInlineHtml {
    fn default() -> Self {
        let config = MD033Config::default();
        let allowed = config.allowed_set();
        let disallowed = config.disallowed_set();
        Self {
            config,
            allowed,
            disallowed,
        }
    }
}

impl MD033NoInlineHtml {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn with_allowed(allowed_vec: Vec<String>) -> Self {
        let config = MD033Config {
            allowed: allowed_vec.clone(),
            disallowed: Vec::new(),
            fix: false,
            br_style: md033_config::BrStyle::default(),
        };
        let allowed = config.allowed_set();
        let disallowed = config.disallowed_set();
        Self {
            config,
            allowed,
            disallowed,
        }
    }

    pub fn with_disallowed(disallowed_vec: Vec<String>) -> Self {
        let config = MD033Config {
            allowed: Vec::new(),
            disallowed: disallowed_vec.clone(),
            fix: false,
            br_style: md033_config::BrStyle::default(),
        };
        let allowed = config.allowed_set();
        let disallowed = config.disallowed_set();
        Self {
            config,
            allowed,
            disallowed,
        }
    }

    /// Create a new rule with auto-fix enabled
    pub fn with_fix(fix: bool) -> Self {
        let config = MD033Config {
            allowed: Vec::new(),
            disallowed: Vec::new(),
            fix,
            br_style: md033_config::BrStyle::default(),
        };
        let allowed = config.allowed_set();
        let disallowed = config.disallowed_set();
        Self {
            config,
            allowed,
            disallowed,
        }
    }

    pub fn from_config_struct(config: MD033Config) -> Self {
        let allowed = config.allowed_set();
        let disallowed = config.disallowed_set();
        Self {
            config,
            allowed,
            disallowed,
        }
    }

    // Efficient check for allowed tags using HashSet (case-insensitive)
    #[inline]
    fn is_tag_allowed(&self, tag: &str) -> bool {
        if self.allowed.is_empty() {
            return false;
        }
        // Remove angle brackets and slashes, then split by whitespace or '>'
        let tag = tag.trim_start_matches('<').trim_start_matches('/');
        let tag_name = tag
            .split(|c: char| c.is_whitespace() || c == '>' || c == '/')
            .next()
            .unwrap_or("");
        self.allowed.contains(&tag_name.to_lowercase())
    }

    /// Check if a tag is in the disallowed set (for disallowed-only mode)
    #[inline]
    fn is_tag_disallowed(&self, tag: &str) -> bool {
        if self.disallowed.is_empty() {
            return false;
        }
        // Remove angle brackets and slashes, then split by whitespace or '>'
        let tag = tag.trim_start_matches('<').trim_start_matches('/');
        let tag_name = tag
            .split(|c: char| c.is_whitespace() || c == '>' || c == '/')
            .next()
            .unwrap_or("");
        self.disallowed.contains(&tag_name.to_lowercase())
    }

    /// Check if operating in disallowed-only mode
    #[inline]
    fn is_disallowed_mode(&self) -> bool {
        self.config.is_disallowed_mode()
    }

    // Check if a tag is an HTML comment
    #[inline]
    fn is_html_comment(&self, tag: &str) -> bool {
        tag.starts_with("<!--") && tag.ends_with("-->")
    }

    /// Check if a tag name is a valid HTML element or custom element.
    /// Returns false for placeholder syntax like `<NAME>`, `<resource>`, `<actual>`.
    ///
    /// Per HTML spec, custom elements must contain a hyphen (e.g., `<my-component>`).
    #[inline]
    fn is_html_element_or_custom(tag_name: &str) -> bool {
        const HTML_ELEMENTS: &[&str] = &[
            // Document structure
            "html",
            "head",
            "body",
            "title",
            "base",
            "link",
            "meta",
            "style",
            // Sections
            "article",
            "section",
            "nav",
            "aside",
            "h1",
            "h2",
            "h3",
            "h4",
            "h5",
            "h6",
            "hgroup",
            "header",
            "footer",
            "address",
            "main",
            "search",
            // Grouping
            "p",
            "hr",
            "pre",
            "blockquote",
            "ol",
            "ul",
            "menu",
            "li",
            "dl",
            "dt",
            "dd",
            "figure",
            "figcaption",
            "div",
            // Text-level
            "a",
            "em",
            "strong",
            "small",
            "s",
            "cite",
            "q",
            "dfn",
            "abbr",
            "ruby",
            "rt",
            "rp",
            "data",
            "time",
            "code",
            "var",
            "samp",
            "kbd",
            "sub",
            "sup",
            "i",
            "b",
            "u",
            "mark",
            "bdi",
            "bdo",
            "span",
            "br",
            "wbr",
            // Edits
            "ins",
            "del",
            // Embedded
            "picture",
            "source",
            "img",
            "iframe",
            "embed",
            "object",
            "param",
            "video",
            "audio",
            "track",
            "map",
            "area",
            "svg",
            "math",
            "canvas",
            // Tables
            "table",
            "caption",
            "colgroup",
            "col",
            "tbody",
            "thead",
            "tfoot",
            "tr",
            "td",
            "th",
            // Forms
            "form",
            "label",
            "input",
            "button",
            "select",
            "datalist",
            "optgroup",
            "option",
            "textarea",
            "output",
            "progress",
            "meter",
            "fieldset",
            "legend",
            // Interactive
            "details",
            "summary",
            "dialog",
            // Scripting
            "script",
            "noscript",
            "template",
            "slot",
            // Deprecated but recognized
            "acronym",
            "applet",
            "basefont",
            "big",
            "center",
            "dir",
            "font",
            "frame",
            "frameset",
            "isindex",
            "marquee",
            "noembed",
            "noframes",
            "plaintext",
            "strike",
            "tt",
            "xmp",
        ];

        let lower = tag_name.to_ascii_lowercase();
        if HTML_ELEMENTS.contains(&lower.as_str()) {
            return true;
        }
        // Custom elements must contain a hyphen per HTML spec
        tag_name.contains('-')
    }

    // Check if a tag is likely a programming type annotation rather than HTML
    #[inline]
    fn is_likely_type_annotation(&self, tag: &str) -> bool {
        // Common programming type names that are often used in generics
        const COMMON_TYPES: &[&str] = &[
            "string",
            "number",
            "any",
            "void",
            "null",
            "undefined",
            "array",
            "promise",
            "function",
            "error",
            "date",
            "regexp",
            "symbol",
            "bigint",
            "map",
            "set",
            "weakmap",
            "weakset",
            "iterator",
            "generator",
            "t",
            "u",
            "v",
            "k",
            "e", // Common single-letter type parameters
            "userdata",
            "apiresponse",
            "config",
            "options",
            "params",
            "result",
            "response",
            "request",
            "data",
            "item",
            "element",
            "node",
        ];

        let tag_content = tag
            .trim_start_matches('<')
            .trim_end_matches('>')
            .trim_start_matches('/');
        let tag_name = tag_content
            .split(|c: char| c.is_whitespace() || c == '>' || c == '/')
            .next()
            .unwrap_or("");

        // Check if it's a simple tag (no attributes) with a common type name
        if !tag_content.contains(' ') && !tag_content.contains('=') {
            COMMON_TYPES.contains(&tag_name.to_ascii_lowercase().as_str())
        } else {
            false
        }
    }

    // Check if a tag is actually an email address in angle brackets
    #[inline]
    fn is_email_address(&self, tag: &str) -> bool {
        let content = tag.trim_start_matches('<').trim_end_matches('>');
        // Simple email pattern: contains @ and has reasonable structure
        content.contains('@')
            && content.chars().all(|c| c.is_alphanumeric() || "@.-_+".contains(c))
            && content.split('@').count() == 2
            && content.split('@').all(|part| !part.is_empty())
    }

    // Check if a tag has the markdown attribute (MkDocs/Material for MkDocs)
    #[inline]
    fn has_markdown_attribute(&self, tag: &str) -> bool {
        // Check for various forms of markdown attribute
        // Examples: <div markdown>, <div markdown="1">, <div class="result" markdown>
        tag.contains(" markdown>") || tag.contains(" markdown=") || tag.contains(" markdown ")
    }

    /// Check if a tag contains JSX-specific attributes that indicate it's JSX, not HTML
    /// JSX uses different attribute names than HTML:
    /// - `className` instead of `class`
    /// - `htmlFor` instead of `for`
    /// - camelCase event handlers (`onClick`, `onChange`, `onSubmit`, etc.)
    /// - JSX expression syntax `={...}` for dynamic values
    #[inline]
    fn has_jsx_attributes(tag: &str) -> bool {
        // JSX-specific attribute names (HTML uses class, for, onclick, etc.)
        tag.contains("className")
            || tag.contains("htmlFor")
            || tag.contains("dangerouslySetInnerHTML")
            // camelCase event handlers (JSX uses onClick, HTML uses onclick)
            || tag.contains("onClick")
            || tag.contains("onChange")
            || tag.contains("onSubmit")
            || tag.contains("onFocus")
            || tag.contains("onBlur")
            || tag.contains("onKeyDown")
            || tag.contains("onKeyUp")
            || tag.contains("onKeyPress")
            || tag.contains("onMouseDown")
            || tag.contains("onMouseUp")
            || tag.contains("onMouseEnter")
            || tag.contains("onMouseLeave")
            // JSX expression syntax: ={expression} or ={ expression }
            || tag.contains("={")
    }

    // Check if a tag is actually a URL in angle brackets
    #[inline]
    fn is_url_in_angle_brackets(&self, tag: &str) -> bool {
        let content = tag.trim_start_matches('<').trim_end_matches('>');
        // Check for common URL schemes
        content.starts_with("http://")
            || content.starts_with("https://")
            || content.starts_with("ftp://")
            || content.starts_with("ftps://")
            || content.starts_with("mailto:")
    }

    /// Convert paired HTML tags to their Markdown equivalents.
    /// Returns None if the tag cannot be safely converted (has nested tags, HTML entities, etc.)
    fn convert_to_markdown(tag_name: &str, inner_content: &str) -> Option<String> {
        // Skip if content contains nested HTML tags
        if inner_content.contains('<') {
            return None;
        }
        // Skip if content contains HTML entities (e.g., &vert;, &amp;, &lt;)
        // These need HTML context to render correctly; markdown won't process them
        if inner_content.contains('&') && inner_content.contains(';') {
            // Check for common HTML entity patterns
            let has_entity = inner_content
                .split('&')
                .skip(1)
                .any(|part| part.split(';').next().is_some_and(|e| !e.is_empty() && e.len() < 10));
            if has_entity {
                return None;
            }
        }
        match tag_name {
            "em" | "i" => Some(format!("*{inner_content}*")),
            "strong" | "b" => Some(format!("**{inner_content}**")),
            "code" => {
                // Handle backticks in content by using double backticks with padding
                if inner_content.contains('`') {
                    Some(format!("`` {inner_content} ``"))
                } else {
                    Some(format!("`{inner_content}`"))
                }
            }
            _ => None,
        }
    }

    /// Convert self-closing HTML tags to their Markdown equivalents.
    fn convert_self_closing_to_markdown(&self, tag_name: &str) -> Option<String> {
        match tag_name {
            "br" => match self.config.br_style {
                md033_config::BrStyle::TrailingSpaces => Some("  \n".to_string()),
                md033_config::BrStyle::Backslash => Some("\\\n".to_string()),
            },
            "hr" => Some("\n---\n".to_string()),
            _ => None,
        }
    }

    /// Check if an HTML tag has attributes that would make conversion unsafe
    fn has_significant_attributes(opening_tag: &str) -> bool {
        // Tags with just whitespace or empty are fine
        let tag_content = opening_tag
            .trim_start_matches('<')
            .trim_end_matches('>')
            .trim_end_matches('/');

        // Split by whitespace; if there's more than the tag name, it has attributes
        let parts: Vec<&str> = tag_content.split_whitespace().collect();
        parts.len() > 1
    }

    /// Check if a tag appears to be nested inside another HTML element
    /// by looking at the surrounding context (e.g., `<code><em>text</em></code>`)
    fn is_nested_in_html(content: &str, tag_byte_start: usize, tag_byte_end: usize) -> bool {
        // Check if there's a `>` immediately before this tag (indicating inside another element)
        if tag_byte_start > 0 {
            let before = &content[..tag_byte_start];
            let before_trimmed = before.trim_end();
            if before_trimmed.ends_with('>') && !before_trimmed.ends_with("->") {
                // Check it's not a closing tag or comment
                if let Some(last_lt) = before_trimmed.rfind('<') {
                    let potential_tag = &before_trimmed[last_lt..];
                    // Skip if it's a closing tag (</...>) or comment (<!--)
                    if !potential_tag.starts_with("</") && !potential_tag.starts_with("<!--") {
                        return true;
                    }
                }
            }
        }
        // Check if there's a `<` immediately after the closing tag (indicating inside another element)
        if tag_byte_end < content.len() {
            let after = &content[tag_byte_end..];
            let after_trimmed = after.trim_start();
            if after_trimmed.starts_with("</") {
                return true;
            }
        }
        false
    }

    /// Calculate fix to remove HTML tags while keeping content
    ///
    /// For self-closing tags like `<br/>`, returns a single fix to remove the tag.
    /// For paired tags like `<span>text</span>`, returns the replacement text (just the content).
    ///
    /// Returns (range, replacement_text) where range is the bytes to replace
    /// and replacement_text is what to put there (content without tags, or empty for self-closing).
    ///
    /// When `fix` is enabled and `in_html_block` is true, returns None to avoid
    /// converting tags that are nested inside HTML block elements (like `<pre>`).
    fn calculate_fix(
        &self,
        content: &str,
        opening_tag: &str,
        tag_byte_start: usize,
        in_html_block: bool,
    ) -> Option<(std::ops::Range<usize>, String)> {
        // Extract tag name from opening tag
        let tag_name = opening_tag
            .trim_start_matches('<')
            .split(|c: char| c.is_whitespace() || c == '>' || c == '/')
            .next()?
            .to_lowercase();

        // Check if it's a self-closing tag (ends with /> or is a void element like <br>)
        let is_self_closing =
            opening_tag.ends_with("/>") || matches!(tag_name.as_str(), "br" | "hr" | "img" | "input" | "meta" | "link");

        if is_self_closing {
            // When fix is enabled, try to convert to Markdown equivalent
            // But skip if we're inside an HTML block (would break structure)
            if self.config.fix
                && MD033Config::is_safe_fixable_tag(&tag_name)
                && !in_html_block
                && let Some(markdown) = self.convert_self_closing_to_markdown(&tag_name)
            {
                return Some((tag_byte_start..tag_byte_start + opening_tag.len(), markdown));
            }
            // Can't convert this self-closing tag to Markdown, don't provide a fix
            // (e.g., <img>, <input>, <meta> - these have no Markdown equivalent)
            return None;
        }

        // Search for the closing tag after the opening tag (case-insensitive)
        let search_start = tag_byte_start + opening_tag.len();
        let search_slice = &content[search_start..];

        // Find closing tag case-insensitively
        let closing_tag_lower = format!("</{tag_name}>");
        let closing_pos = search_slice.to_ascii_lowercase().find(&closing_tag_lower);

        if let Some(closing_pos) = closing_pos {
            // Get actual closing tag from original content to get correct byte length
            let closing_tag_len = closing_tag_lower.len();
            let closing_byte_start = search_start + closing_pos;
            let closing_byte_end = closing_byte_start + closing_tag_len;

            // Extract the content between tags
            let inner_content = &content[search_start..closing_byte_start];

            // Skip auto-fix if inside an HTML block (like <pre>, <div>, etc.)
            // Converting tags inside HTML blocks would break the intended structure
            if in_html_block {
                return None;
            }

            // Skip auto-fix if this tag is nested inside another HTML element
            // e.g., <code><em>text</em></code> - don't convert the inner <em>
            if Self::is_nested_in_html(content, tag_byte_start, closing_byte_end) {
                return None;
            }

            // When fix is enabled and tag is safe to convert, try markdown conversion
            // Tags with attributes are NOT converted - leave them as-is
            if self.config.fix && MD033Config::is_safe_fixable_tag(&tag_name) {
                if Self::has_significant_attributes(opening_tag) {
                    // Don't provide a fix for tags with attributes
                    // User may want to keep the attributes, so leave as-is
                    return None;
                }
                if let Some(markdown) = Self::convert_to_markdown(&tag_name, inner_content) {
                    return Some((tag_byte_start..closing_byte_end, markdown));
                }
                // convert_to_markdown returned None, meaning content has nested tags or
                // HTML entities that shouldn't be converted - leave as-is
                return None;
            }

            // For non-fixable tags, don't provide a fix
            // (e.g., <a href="...">Link</a>, <div>content</div>)
            return None;
        }

        // If no closing tag found, don't provide a fix (malformed HTML)
        None
    }
}

impl Rule for MD033NoInlineHtml {
    fn name(&self) -> &'static str {
        "MD033"
    }

    fn description(&self) -> &'static str {
        "Inline HTML is not allowed"
    }

    fn check(&self, ctx: &crate::lint_context::LintContext) -> LintResult {
        let content = ctx.content;

        // Early return: if no HTML tags at all, skip processing
        if content.is_empty() || !ctx.likely_has_html() {
            return Ok(Vec::new());
        }

        // Quick check for HTML tag pattern before expensive processing
        if !HTML_TAG_QUICK_CHECK.is_match(content) {
            return Ok(Vec::new());
        }

        let mut warnings = Vec::new();
        let lines: Vec<&str> = content.lines().collect();

        // Track nomarkdown and comment blocks (Kramdown extension)
        let mut in_nomarkdown = false;
        let mut in_comment = false;
        let mut nomarkdown_ranges: Vec<(usize, usize)> = Vec::new();
        let mut nomarkdown_start = 0;
        let mut comment_start = 0;

        for (i, line) in lines.iter().enumerate() {
            let line_num = i + 1;

            // Check for nomarkdown start
            if line.trim() == "{::nomarkdown}" {
                in_nomarkdown = true;
                nomarkdown_start = line_num;
            } else if line.trim() == "{:/nomarkdown}" && in_nomarkdown {
                in_nomarkdown = false;
                nomarkdown_ranges.push((nomarkdown_start, line_num));
            }

            // Check for comment blocks
            if line.trim() == "{::comment}" {
                in_comment = true;
                comment_start = line_num;
            } else if line.trim() == "{:/comment}" && in_comment {
                in_comment = false;
                nomarkdown_ranges.push((comment_start, line_num));
            }
        }

        // Use centralized HTML parser to get all HTML tags (including multiline)
        let html_tags = ctx.html_tags();

        for html_tag in html_tags.iter() {
            // Skip closing tags (only warn on opening tags)
            if html_tag.is_closing {
                continue;
            }

            let line_num = html_tag.line;
            let tag_byte_start = html_tag.byte_offset;

            // Reconstruct tag string from byte offsets
            let tag = &content[html_tag.byte_offset..html_tag.byte_end];

            // Skip tags in code blocks (uses proper code block detection from LintContext)
            if ctx.line_info(line_num).is_some_and(|info| info.in_code_block) {
                continue;
            }

            // Skip Kramdown extensions and block attributes
            if let Some(line) = lines.get(line_num.saturating_sub(1))
                && (is_kramdown_extension(line) || is_kramdown_block_attribute(line))
            {
                continue;
            }

            // Skip lines inside nomarkdown blocks
            if nomarkdown_ranges
                .iter()
                .any(|(start, end)| line_num >= *start && line_num <= *end)
            {
                continue;
            }

            // Skip HTML tags inside HTML comments
            if ctx.is_in_html_comment(tag_byte_start) {
                continue;
            }

            // Skip HTML comments themselves
            if self.is_html_comment(tag) {
                continue;
            }

            // Skip angle brackets inside link reference definition titles
            // e.g., [ref]: url "Title with <angle brackets>"
            if ctx.is_in_link_title(tag_byte_start) {
                continue;
            }

            // Skip JSX components in MDX files (e.g., <Chart />, <MyComponent>)
            if ctx.flavor.supports_jsx() && html_tag.tag_name.chars().next().is_some_and(|c| c.is_uppercase()) {
                continue;
            }

            // Skip JSX fragments in MDX files (<> and </>)
            if ctx.flavor.supports_jsx() && (html_tag.tag_name.is_empty() || tag == "<>" || tag == "</>") {
                continue;
            }

            // Skip elements with JSX-specific attributes in MDX files
            // e.g., <div className="...">, <button onClick={handler}>
            if ctx.flavor.supports_jsx() && Self::has_jsx_attributes(tag) {
                continue;
            }

            // Skip non-HTML elements (placeholder syntax like <NAME>, <resource>)
            if !Self::is_html_element_or_custom(&html_tag.tag_name) {
                continue;
            }

            // Skip likely programming type annotations
            if self.is_likely_type_annotation(tag) {
                continue;
            }

            // Skip email addresses in angle brackets
            if self.is_email_address(tag) {
                continue;
            }

            // Skip URLs in angle brackets
            if self.is_url_in_angle_brackets(tag) {
                continue;
            }

            // Skip tags inside code spans (use byte offset for reliable multi-line span detection)
            if ctx.is_byte_offset_in_code_span(tag_byte_start) {
                continue;
            }

            // Determine whether to report this tag based on mode:
            // - Disallowed mode: only report tags in the disallowed list
            // - Default mode: report all tags except those in the allowed list
            if self.is_disallowed_mode() {
                // In disallowed mode, skip tags NOT in the disallowed list
                if !self.is_tag_disallowed(tag) {
                    continue;
                }
            } else {
                // In default mode, skip allowed tags
                if self.is_tag_allowed(tag) {
                    continue;
                }
            }

            // Skip tags with markdown attribute in MkDocs mode
            if ctx.flavor == crate::config::MarkdownFlavor::MkDocs && self.has_markdown_attribute(tag) {
                continue;
            }

            // Check if we're inside an HTML block (like <pre>, <div>, etc.)
            let in_html_block = ctx.is_in_html_block(line_num);

            // Calculate fix to remove HTML tags but keep content
            let fix = self
                .calculate_fix(content, tag, tag_byte_start, in_html_block)
                .map(|(range, replacement)| Fix { range, replacement });

            // Calculate actual end line and column for multiline tags
            // Use byte_end - 1 to get the last character position of the tag
            let (end_line, end_col) = if html_tag.byte_end > 0 {
                ctx.offset_to_line_col(html_tag.byte_end - 1)
            } else {
                (line_num, html_tag.end_col + 1)
            };

            // Report the HTML tag
            warnings.push(LintWarning {
                rule_name: Some(self.name().to_string()),
                line: line_num,
                column: html_tag.start_col + 1, // Convert to 1-indexed
                end_line,                       // Actual end line for multiline tags
                end_column: end_col + 1,        // Actual end column
                message: format!("Inline HTML found: {tag}"),
                severity: Severity::Warning,
                fix,
            });
        }

        Ok(warnings)
    }

    fn fix(&self, ctx: &crate::lint_context::LintContext) -> Result<String, LintError> {
        // Auto-fix is opt-in: only apply if explicitly enabled in config
        if !self.config.fix {
            return Ok(ctx.content.to_string());
        }

        // Get warnings with their inline fixes
        let warnings = self.check(ctx)?;

        // If no warnings with fixes, return original content
        if warnings.is_empty() || !warnings.iter().any(|w| w.fix.is_some()) {
            return Ok(ctx.content.to_string());
        }

        // Collect all fixes and sort by range start (descending) to apply from end to beginning
        let mut fixes: Vec<_> = warnings
            .iter()
            .filter_map(|w| w.fix.as_ref().map(|f| (f.range.start, f.range.end, &f.replacement)))
            .collect();
        fixes.sort_by(|a, b| b.0.cmp(&a.0));

        // Apply fixes from end to beginning to preserve byte offsets
        let mut result = ctx.content.to_string();
        for (start, end, replacement) in fixes {
            if start < result.len() && end <= result.len() && start <= end {
                result.replace_range(start..end, replacement);
            }
        }

        Ok(result)
    }

    fn fix_capability(&self) -> crate::rule::FixCapability {
        if self.config.fix {
            crate::rule::FixCapability::FullyFixable
        } else {
            crate::rule::FixCapability::Unfixable
        }
    }

    /// Get the category of this rule for selective processing
    fn category(&self) -> RuleCategory {
        RuleCategory::Html
    }

    /// Check if this rule should be skipped
    fn should_skip(&self, ctx: &crate::lint_context::LintContext) -> bool {
        ctx.content.is_empty() || !ctx.likely_has_html()
    }

    fn as_any(&self) -> &dyn std::any::Any {
        self
    }

    fn default_config_section(&self) -> Option<(String, toml::Value)> {
        let json_value = serde_json::to_value(&self.config).ok()?;
        Some((
            self.name().to_string(),
            crate::rule_config_serde::json_to_toml_value(&json_value)?,
        ))
    }

    fn from_config(config: &crate::config::Config) -> Box<dyn Rule>
    where
        Self: Sized,
    {
        let rule_config = crate::rule_config_serde::load_rule_config::<MD033Config>(config);
        Box::new(Self::from_config_struct(rule_config))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::lint_context::LintContext;
    use crate::rule::Rule;

    #[test]
    fn test_md033_basic_html() {
        let rule = MD033NoInlineHtml::default();
        let content = "<div>Some content</div>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Only reports opening tags, not closing tags
        assert_eq!(result.len(), 1); // Only <div>, not </div>
        assert!(result[0].message.starts_with("Inline HTML found: <div>"));
    }

    #[test]
    fn test_md033_case_insensitive() {
        let rule = MD033NoInlineHtml::default();
        let content = "<DiV>Some <B>content</B></dIv>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Only reports opening tags, not closing tags
        assert_eq!(result.len(), 2); // <DiV>, <B> (not </B>, </dIv>)
        assert_eq!(result[0].message, "Inline HTML found: <DiV>");
        assert_eq!(result[1].message, "Inline HTML found: <B>");
    }

    #[test]
    fn test_md033_allowed_tags() {
        let rule = MD033NoInlineHtml::with_allowed(vec!["div".to_string(), "br".to_string()]);
        let content = "<div>Allowed</div><p>Not allowed</p><br/>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Only warnings for non-allowed opening tags (<p> only, div and br are allowed)
        assert_eq!(result.len(), 1);
        assert_eq!(result[0].message, "Inline HTML found: <p>");

        // Test case-insensitivity of allowed tags
        let content2 = "<DIV>Allowed</DIV><P>Not allowed</P><BR/>";
        let ctx2 = LintContext::new(content2, crate::config::MarkdownFlavor::Standard, None);
        let result2 = rule.check(&ctx2).unwrap();
        assert_eq!(result2.len(), 1); // Only <P> flagged
        assert_eq!(result2[0].message, "Inline HTML found: <P>");
    }

    #[test]
    fn test_md033_html_comments() {
        let rule = MD033NoInlineHtml::default();
        let content = "<!-- This is a comment --> <p>Not a comment</p>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Should detect warnings for HTML opening tags (comments are skipped, closing tags not reported)
        assert_eq!(result.len(), 1); // Only <p>
        assert_eq!(result[0].message, "Inline HTML found: <p>");
    }

    #[test]
    fn test_md033_tags_in_links() {
        let rule = MD033NoInlineHtml::default();
        let content = "[Link](http://example.com/<div>)";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // The <div> in the URL should be detected as HTML (not skipped)
        assert_eq!(result.len(), 1);
        assert_eq!(result[0].message, "Inline HTML found: <div>");

        let content2 = "[Link <a>text</a>](url)";
        let ctx2 = LintContext::new(content2, crate::config::MarkdownFlavor::Standard, None);
        let result2 = rule.check(&ctx2).unwrap();
        // Only reports opening tags
        assert_eq!(result2.len(), 1); // Only <a>
        assert_eq!(result2[0].message, "Inline HTML found: <a>");
    }

    #[test]
    fn test_md033_fix_escaping() {
        let rule = MD033NoInlineHtml::default();
        let content = "Text with <div> and <br/> tags.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed_content = rule.fix(&ctx).unwrap();
        // No fix for HTML tags; output should be unchanged
        assert_eq!(fixed_content, content);
    }

    #[test]
    fn test_md033_in_code_blocks() {
        let rule = MD033NoInlineHtml::default();
        let content = "```html\n<div>Code</div>\n```\n<div>Not code</div>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Only reports opening tags outside code block
        assert_eq!(result.len(), 1); // Only <div> outside code block
        assert_eq!(result[0].message, "Inline HTML found: <div>");
    }

    #[test]
    fn test_md033_in_code_spans() {
        let rule = MD033NoInlineHtml::default();
        let content = "Text with `<p>in code</p>` span. <br/> Not in span.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Should detect <br/> outside code span, but not tags inside code span
        assert_eq!(result.len(), 1);
        assert_eq!(result[0].message, "Inline HTML found: <br/>");
    }

    #[test]
    fn test_md033_issue_90_code_span_with_diff_block() {
        // Test for issue #90: inline code span followed by diff code block
        let rule = MD033NoInlineHtml::default();
        let content = r#"# Heading

`<env>`

```diff
- this
+ that
```"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Should NOT detect <env> as HTML since it's inside backticks
        assert_eq!(result.len(), 0, "Should not report HTML tags inside code spans");
    }

    #[test]
    fn test_md033_multiple_code_spans_with_angle_brackets() {
        // Test multiple code spans on same line
        let rule = MD033NoInlineHtml::default();
        let content = "`<one>` and `<two>` and `<three>` are all code spans";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 0, "Should not report HTML tags inside any code spans");
    }

    #[test]
    fn test_md033_nested_angle_brackets_in_code_span() {
        // Test nested angle brackets
        let rule = MD033NoInlineHtml::default();
        let content = "Text with `<<nested>>` brackets";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 0, "Should handle nested angle brackets in code spans");
    }

    #[test]
    fn test_md033_code_span_at_end_before_code_block() {
        // Test code span at end of line before code block
        let rule = MD033NoInlineHtml::default();
        let content = "Testing `<test>`\n```\ncode here\n```";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 0, "Should handle code span before code block");
    }

    #[test]
    fn test_md033_quick_fix_inline_tag() {
        // Test that non-fixable tags (like <span>) do NOT get a fix
        // Only safe fixable tags (em, i, strong, b, code, br, hr) with fix=true get fixes
        let rule = MD033NoInlineHtml::default();
        let content = "This has <span>inline text</span> that should keep content.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1, "Should find one HTML tag");
        // <span> is NOT a safe fixable tag, so no fix should be provided
        assert!(
            result[0].fix.is_none(),
            "Non-fixable tags like <span> should not have a fix"
        );
    }

    #[test]
    fn test_md033_quick_fix_multiline_tag() {
        // HTML block elements like <div> are intentionally NOT auto-fixed
        // Removing them would change document structure significantly
        let rule = MD033NoInlineHtml::default();
        let content = "<div>\nBlock content\n</div>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1, "Should find one HTML tag");
        // HTML block elements should NOT have auto-fix
        assert!(result[0].fix.is_none(), "HTML block elements should NOT have auto-fix");
    }

    #[test]
    fn test_md033_quick_fix_self_closing_tag() {
        // Test that self-closing tags with fix=false (default) do NOT get a fix
        let rule = MD033NoInlineHtml::default();
        let content = "Self-closing: <br/>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1, "Should find one HTML tag");
        // Default config has fix=false, so no fix should be provided
        assert!(
            result[0].fix.is_none(),
            "Self-closing tags should not have a fix when fix config is false"
        );
    }

    #[test]
    fn test_md033_quick_fix_multiple_tags() {
        // Test that multiple tags without fix=true do NOT get fixes
        // <span> is not a safe fixable tag, <strong> is but fix=false by default
        let rule = MD033NoInlineHtml::default();
        let content = "<span>first</span> and <strong>second</strong>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 2, "Should find two HTML tags");
        // Neither should have a fix: <span> is not fixable, <strong> is but fix=false
        assert!(result[0].fix.is_none(), "Non-fixable <span> should not have a fix");
        assert!(
            result[1].fix.is_none(),
            "<strong> should not have a fix when fix config is false"
        );
    }

    #[test]
    fn test_md033_skip_angle_brackets_in_link_titles() {
        // Angle brackets inside link reference definition titles should not be flagged as HTML
        let rule = MD033NoInlineHtml::default();
        let content = r#"# Test

[example]: <https://example.com> "Title with <Angle Brackets> inside"

Regular text with <div>content</div> HTML tag.
"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // Should only flag <div>, not <Angle Brackets> in the title (not a valid HTML element)
        // Opening tag only (markdownlint behavior)
        assert_eq!(result.len(), 1, "Should find opening div tag");
        assert!(
            result[0].message.contains("<div>"),
            "Should flag <div>, got: {}",
            result[0].message
        );
    }

    #[test]
    fn test_md033_skip_angle_brackets_in_link_title_single_quotes() {
        // Test with single-quoted title
        let rule = MD033NoInlineHtml::default();
        let content = r#"[ref]: url 'Title <Help Wanted> here'

<span>text</span> here
"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // <Help Wanted> is not a valid HTML element, so only <span> is flagged
        // Opening tag only (markdownlint behavior)
        assert_eq!(result.len(), 1, "Should find opening span tag");
        assert!(
            result[0].message.contains("<span>"),
            "Should flag <span>, got: {}",
            result[0].message
        );
    }

    #[test]
    fn test_md033_multiline_tag_end_line_calculation() {
        // Test that multiline HTML tags report correct end_line
        let rule = MD033NoInlineHtml::default();
        let content = "<div\n  class=\"test\"\n  id=\"example\">";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1, "Should find one HTML tag");
        // Tag starts on line 1
        assert_eq!(result[0].line, 1, "Start line should be 1");
        // Tag ends on line 3 (where the closing > is)
        assert_eq!(result[0].end_line, 3, "End line should be 3");
    }

    #[test]
    fn test_md033_single_line_tag_same_start_end_line() {
        // Test that single-line HTML tags have same start and end line
        let rule = MD033NoInlineHtml::default();
        let content = "Some text <div class=\"test\"> more text";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1, "Should find one HTML tag");
        assert_eq!(result[0].line, 1, "Start line should be 1");
        assert_eq!(result[0].end_line, 1, "End line should be 1 for single-line tag");
    }

    #[test]
    fn test_md033_multiline_tag_with_many_attributes() {
        // Test multiline tag spanning multiple lines
        let rule = MD033NoInlineHtml::default();
        let content =
            "Text\n<div\n  data-attr1=\"value1\"\n  data-attr2=\"value2\"\n  data-attr3=\"value3\">\nMore text";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1, "Should find one HTML tag");
        // Tag starts on line 2 (first line is "Text")
        assert_eq!(result[0].line, 2, "Start line should be 2");
        // Tag ends on line 5 (where the closing > is)
        assert_eq!(result[0].end_line, 5, "End line should be 5");
    }

    #[test]
    fn test_md033_disallowed_mode_basic() {
        // Test disallowed mode: only flags tags in the disallowed list
        let rule = MD033NoInlineHtml::with_disallowed(vec!["script".to_string(), "iframe".to_string()]);
        let content = "<div>Safe content</div><script>alert('xss')</script>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // Should only flag <script>, not <div>
        assert_eq!(result.len(), 1, "Should only flag disallowed tags");
        assert!(result[0].message.contains("<script>"), "Should flag script tag");
    }

    #[test]
    fn test_md033_disallowed_gfm_security_tags() {
        // Test GFM security tags expansion
        let rule = MD033NoInlineHtml::with_disallowed(vec!["gfm".to_string()]);
        let content = r#"
<div>Safe</div>
<title>Bad title</title>
<textarea>Bad textarea</textarea>
<style>.bad{}</style>
<iframe src="evil"></iframe>
<script>evil()</script>
<plaintext>old tag</plaintext>
<span>Safe span</span>
"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // Should flag: title, textarea, style, iframe, script, plaintext
        // Should NOT flag: div, span
        assert_eq!(result.len(), 6, "Should flag 6 GFM security tags");

        let flagged_tags: Vec<&str> = result
            .iter()
            .filter_map(|w| w.message.split("<").nth(1))
            .filter_map(|s| s.split(">").next())
            .filter_map(|s| s.split_whitespace().next())
            .collect();

        assert!(flagged_tags.contains(&"title"), "Should flag title");
        assert!(flagged_tags.contains(&"textarea"), "Should flag textarea");
        assert!(flagged_tags.contains(&"style"), "Should flag style");
        assert!(flagged_tags.contains(&"iframe"), "Should flag iframe");
        assert!(flagged_tags.contains(&"script"), "Should flag script");
        assert!(flagged_tags.contains(&"plaintext"), "Should flag plaintext");
        assert!(!flagged_tags.contains(&"div"), "Should NOT flag div");
        assert!(!flagged_tags.contains(&"span"), "Should NOT flag span");
    }

    #[test]
    fn test_md033_disallowed_case_insensitive() {
        // Test that disallowed check is case-insensitive
        let rule = MD033NoInlineHtml::with_disallowed(vec!["script".to_string()]);
        let content = "<SCRIPT>alert('xss')</SCRIPT><Script>alert('xss')</Script>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // Should flag both <SCRIPT> and <Script>
        assert_eq!(result.len(), 2, "Should flag both case variants");
    }

    #[test]
    fn test_md033_disallowed_with_attributes() {
        // Test that disallowed mode works with tags that have attributes
        let rule = MD033NoInlineHtml::with_disallowed(vec!["iframe".to_string()]);
        let content = r#"<iframe src="https://evil.com" width="100" height="100"></iframe>"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1, "Should flag iframe with attributes");
        assert!(result[0].message.contains("iframe"), "Should flag iframe");
    }

    #[test]
    fn test_md033_disallowed_all_gfm_tags() {
        // Verify all GFM disallowed tags are covered
        use md033_config::GFM_DISALLOWED_TAGS;
        let rule = MD033NoInlineHtml::with_disallowed(vec!["gfm".to_string()]);

        for tag in GFM_DISALLOWED_TAGS {
            let content = format!("<{tag}>content</{tag}>");
            let ctx = LintContext::new(&content, crate::config::MarkdownFlavor::Standard, None);
            let result = rule.check(&ctx).unwrap();

            assert_eq!(result.len(), 1, "GFM tag <{tag}> should be flagged");
        }
    }

    #[test]
    fn test_md033_disallowed_mixed_with_custom() {
        // Test mixing "gfm" with custom disallowed tags
        let rule = MD033NoInlineHtml::with_disallowed(vec![
            "gfm".to_string(),
            "marquee".to_string(), // Custom disallowed tag
        ]);
        let content = r#"<script>bad</script><marquee>annoying</marquee><div>ok</div>"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // Should flag script (gfm) and marquee (custom)
        assert_eq!(result.len(), 2, "Should flag both gfm and custom tags");
    }

    #[test]
    fn test_md033_disallowed_empty_means_default_mode() {
        // Empty disallowed list means default mode (flag all HTML)
        let rule = MD033NoInlineHtml::with_disallowed(vec![]);
        let content = "<div>content</div>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // Should flag <div> in default mode
        assert_eq!(result.len(), 1, "Empty disallowed = default mode");
    }

    #[test]
    fn test_md033_jsx_fragments_in_mdx() {
        // JSX fragments (<> and </>) should not trigger warnings in MDX
        let rule = MD033NoInlineHtml::default();
        let content = r#"# MDX Document

<>
  <Heading />
  <Content />
</>

<div>Regular HTML should still be flagged</div>
"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::MDX, None);
        let result = rule.check(&ctx).unwrap();

        // Should only flag <div>, not the fragments or JSX components
        assert_eq!(result.len(), 1, "Should only find one HTML tag (the div)");
        assert!(
            result[0].message.contains("<div>"),
            "Should flag <div>, not JSX fragments"
        );
    }

    #[test]
    fn test_md033_jsx_components_in_mdx() {
        // JSX components (capitalized) should not trigger warnings in MDX
        let rule = MD033NoInlineHtml::default();
        let content = r#"<CustomComponent prop="value">
  Content
</CustomComponent>

<MyButton onClick={handler}>Click</MyButton>
"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::MDX, None);
        let result = rule.check(&ctx).unwrap();

        // No warnings - all are JSX components
        assert_eq!(result.len(), 0, "Should not flag JSX components in MDX");
    }

    #[test]
    fn test_md033_jsx_not_skipped_in_standard_markdown() {
        // In standard markdown, capitalized tags should still be flagged if they're valid HTML
        let rule = MD033NoInlineHtml::default();
        let content = "<Script>alert(1)</Script>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // Should flag <Script> in standard markdown (it's a valid HTML element)
        assert_eq!(result.len(), 1, "Should flag <Script> in standard markdown");
    }

    #[test]
    fn test_md033_jsx_attributes_in_mdx() {
        // Elements with JSX-specific attributes should not trigger warnings in MDX
        let rule = MD033NoInlineHtml::default();
        let content = r#"# MDX with JSX Attributes

<div className="card big">Content</div>

<button onClick={handleClick}>Click me</button>

<label htmlFor="input-id">Label</label>

<input onChange={handleChange} />

<div class="html-class">Regular HTML should be flagged</div>
"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::MDX, None);
        let result = rule.check(&ctx).unwrap();

        // Should only flag the div with regular HTML "class" attribute
        assert_eq!(
            result.len(),
            1,
            "Should only flag HTML element without JSX attributes, got: {result:?}"
        );
        assert!(
            result[0].message.contains("<div class="),
            "Should flag the div with HTML class attribute"
        );
    }

    #[test]
    fn test_md033_jsx_attributes_not_skipped_in_standard() {
        // In standard markdown, JSX attributes should still be flagged
        let rule = MD033NoInlineHtml::default();
        let content = r#"<div className="card">Content</div>"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        // Should flag in standard markdown
        assert_eq!(result.len(), 1, "Should flag JSX-style elements in standard markdown");
    }

    // Auto-fix tests for MD033

    #[test]
    fn test_md033_fix_disabled_by_default() {
        // Auto-fix should be disabled by default
        let rule = MD033NoInlineHtml::default();
        assert!(!rule.config.fix, "Fix should be disabled by default");
        assert_eq!(rule.fix_capability(), crate::rule::FixCapability::Unfixable);
    }

    #[test]
    fn test_md033_fix_enabled_em_to_italic() {
        // When fix is enabled, <em>text</em> should convert to *text*
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <em>emphasized text</em> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This has *emphasized text* here.");
    }

    #[test]
    fn test_md033_fix_enabled_i_to_italic() {
        // <i>text</i> should convert to *text*
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <i>italic text</i> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This has *italic text* here.");
    }

    #[test]
    fn test_md033_fix_enabled_strong_to_bold() {
        // <strong>text</strong> should convert to **text**
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <strong>bold text</strong> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This has **bold text** here.");
    }

    #[test]
    fn test_md033_fix_enabled_b_to_bold() {
        // <b>text</b> should convert to **text**
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <b>bold text</b> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This has **bold text** here.");
    }

    #[test]
    fn test_md033_fix_enabled_code_to_backticks() {
        // <code>text</code> should convert to `text`
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <code>inline code</code> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This has `inline code` here.");
    }

    #[test]
    fn test_md033_fix_enabled_code_with_backticks() {
        // <code>text with `backticks`</code> should use double backticks
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <code>text with `backticks`</code> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This has `` text with `backticks` `` here.");
    }

    #[test]
    fn test_md033_fix_enabled_br_trailing_spaces() {
        // <br> should convert to two trailing spaces + newline (default)
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "First line<br>Second line";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "First line  \nSecond line");
    }

    #[test]
    fn test_md033_fix_enabled_br_self_closing() {
        // <br/> and <br /> should also convert
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "First<br/>second<br />third";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "First  \nsecond  \nthird");
    }

    #[test]
    fn test_md033_fix_enabled_br_backslash_style() {
        // With br_style = backslash, <br> should convert to backslash + newline
        let config = MD033Config {
            allowed: Vec::new(),
            disallowed: Vec::new(),
            fix: true,
            br_style: md033_config::BrStyle::Backslash,
        };
        let rule = MD033NoInlineHtml::from_config_struct(config);
        let content = "First line<br>Second line";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "First line\\\nSecond line");
    }

    #[test]
    fn test_md033_fix_enabled_hr() {
        // <hr> should convert to horizontal rule
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "Above<hr>Below";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "Above\n---\nBelow");
    }

    #[test]
    fn test_md033_fix_enabled_hr_self_closing() {
        // <hr/> should also convert
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "Above<hr/>Below";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "Above\n---\nBelow");
    }

    #[test]
    fn test_md033_fix_skips_nested_tags() {
        // Tags with nested HTML - outer tags may not be fully fixed due to overlapping ranges
        // The inner tags are processed first, which can invalidate outer tag ranges
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <em>text with <strong>nested</strong> tags</em> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Inner <strong> is converted to markdown, outer <em> range becomes invalid
        // This is expected behavior - user should run fix multiple times for nested tags
        assert_eq!(fixed, "This has <em>text with **nested** tags</em> here.");
    }

    #[test]
    fn test_md033_fix_skips_tags_with_attributes() {
        // Tags with attributes should NOT be fixed at all - leave as-is
        // User may want to keep the attributes (e.g., class="highlight" for styling)
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <em class=\"highlight\">emphasized</em> text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Content should remain unchanged - we don't know if attributes matter
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_md033_fix_disabled_no_changes() {
        // When fix is disabled, original content should be returned
        let rule = MD033NoInlineHtml::default(); // fix is false by default
        let content = "This has <em>emphasized text</em> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, content, "Should return original content when fix is disabled");
    }

    #[test]
    fn test_md033_fix_capability_enabled() {
        let rule = MD033NoInlineHtml::with_fix(true);
        assert_eq!(rule.fix_capability(), crate::rule::FixCapability::FullyFixable);
    }

    #[test]
    fn test_md033_fix_multiple_tags() {
        // Test fixing multiple HTML tags in one document
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "Here is <em>italic</em> and <strong>bold</strong> text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "Here is *italic* and **bold** text.");
    }

    #[test]
    fn test_md033_fix_uppercase_tags() {
        // HTML tags are case-insensitive
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <EM>emphasized</EM> text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This has *emphasized* text.");
    }

    #[test]
    fn test_md033_fix_unsafe_tags_not_modified() {
        // Tags without safe markdown equivalents should NOT be modified
        // Only safe fixable tags (em, i, strong, b, code, br, hr) get converted
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This has <div>a div</div> content.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // <div> is not a safe fixable tag, so content should be unchanged
        assert_eq!(fixed, "This has <div>a div</div> content.");
    }

    #[test]
    fn test_md033_fix_img_tag_not_removed() {
        // Regression test: <img> tags should NOT be removed or modified
        // They have no Markdown equivalent, so fix should leave them unchanged
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "Image: <img src=\"photo.jpg\" alt=\"My Photo\">";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // <img> is a self-closing tag without a Markdown equivalent - must be unchanged
        assert_eq!(fixed, "Image: <img src=\"photo.jpg\" alt=\"My Photo\">");
    }

    #[test]
    fn test_md033_fix_mixed_safe_and_unsafe_tags() {
        // Mix of safe fixable tags and unsafe tags on the same line
        // Safe tags should be converted, unsafe should be left unchanged
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<em>italic</em> and <img src=\"x.jpg\"> and <strong>bold</strong>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // <em> and <strong> are safe, <img> is not
        assert_eq!(fixed, "*italic* and <img src=\"x.jpg\"> and **bold**");
    }

    #[test]
    fn test_md033_fix_multiple_tags_same_line() {
        // Multiple tags on the same line should all be fixed correctly
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "Regular text <i>italic</i> and <b>bold</b> here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "Regular text *italic* and **bold** here.");
    }

    #[test]
    fn test_md033_fix_multiple_em_tags_same_line() {
        // Multiple em/strong tags on the same line
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<em>first</em> and <strong>second</strong> and <code>third</code>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "*first* and **second** and `third`");
    }

    #[test]
    fn test_md033_fix_skips_tags_inside_pre() {
        // Tags inside <pre> blocks should NOT be fixed (would break structure)
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<pre><code><em>VALUE</em></code></pre>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // The <em> inside <pre><code> should NOT be converted
        // Only the outer structure might be changed
        assert!(
            !fixed.contains("*VALUE*"),
            "Tags inside <pre> should not be converted to markdown. Got: {fixed}"
        );
    }

    #[test]
    fn test_md033_fix_skips_tags_inside_div() {
        // Tags inside HTML block elements should not be fixed
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<div>\n<em>emphasized</em>\n</div>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // The <em> inside <div> should not be converted to *emphasized*
        assert!(
            !fixed.contains("*emphasized*"),
            "Tags inside HTML blocks should not be converted. Got: {fixed}"
        );
    }

    #[test]
    fn test_md033_fix_outside_html_block() {
        // Tags outside HTML blocks should still be fixed
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<div>\ncontent\n</div>\n\nOutside <em>emphasized</em> text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // The <em> outside the div should be converted
        assert!(
            fixed.contains("*emphasized*"),
            "Tags outside HTML blocks should be converted. Got: {fixed}"
        );
    }

    #[test]
    fn test_md033_fix_with_id_attribute() {
        // Tags with id attributes should not be fixed (id might be used for anchors)
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "See <em id=\"important\">this note</em> for details.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Should remain unchanged - id attribute matters for linking
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_md033_fix_with_style_attribute() {
        // Tags with style attributes should not be fixed
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This is <strong style=\"color: red\">important</strong> text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Should remain unchanged - style attribute provides formatting
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_md033_fix_mixed_with_and_without_attributes() {
        // Mix of tags with and without attributes
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<em>normal</em> and <em class=\"special\">styled</em> text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Only the tag without attributes should be fixed
        assert_eq!(fixed, "*normal* and <em class=\"special\">styled</em> text.");
    }

    #[test]
    fn test_md033_quick_fix_tag_with_attributes_no_fix() {
        // Quick fix should not be provided for tags with attributes
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<em class=\"test\">emphasized</em>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1, "Should find one HTML tag");
        // No fix should be provided for tags with attributes
        assert!(
            result[0].fix.is_none(),
            "Should NOT have a fix for tags with attributes"
        );
    }

    #[test]
    fn test_md033_fix_skips_html_entities() {
        // Tags containing HTML entities should NOT be fixed
        // HTML entities need HTML context to render; markdown won't process them
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<code>&vert;</code>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Should remain unchanged - converting would break rendering
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_md033_fix_skips_multiple_html_entities() {
        // Multiple HTML entities should also be skipped
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<code>&lt;T&gt;</code>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Should remain unchanged
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_md033_fix_allows_ampersand_without_entity() {
        // Content with & but no semicolon should still be fixed
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<code>a & b</code>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Should be converted since & is not part of an entity
        assert_eq!(fixed, "`a & b`");
    }

    #[test]
    fn test_md033_fix_em_with_entities_skipped() {
        // <em> with entities should also be skipped
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<em>&nbsp;text</em>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Should remain unchanged
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_md033_fix_skips_nested_em_in_code() {
        // Tags nested inside other HTML elements should NOT be fixed
        // e.g., <code><em>n</em></code> - the <em> should not be converted
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "<code><em>n</em></code>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // The inner <em> should NOT be converted to *n* because it's nested
        // The whole structure should be left as-is (or outer code converted, but not inner)
        assert!(
            !fixed.contains("*n*"),
            "Nested <em> should not be converted to markdown. Got: {fixed}"
        );
    }

    #[test]
    fn test_md033_fix_skips_nested_in_table() {
        // Tags nested in HTML structures in tables should not be fixed
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "| <code>><em>n</em></code> | description |";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Should not convert nested <em> to *n*
        assert!(
            !fixed.contains("*n*"),
            "Nested tags in table should not be converted. Got: {fixed}"
        );
    }

    #[test]
    fn test_md033_fix_standalone_em_still_converted() {
        // Standalone (non-nested) <em> should still be converted
        let rule = MD033NoInlineHtml::with_fix(true);
        let content = "This is <em>emphasized</em> text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This is *emphasized* text.");
    }
}