rumdl_lib/rules/

md013_line_length.rs

/// Rule MD013: Line length
///
/// See [docs/md013.md](../../docs/md013.md) for full documentation, configuration, and examples.
use crate::rule::{LintError, LintResult, LintWarning, Rule, RuleCategory, Severity};
use crate::rule_config_serde::RuleConfig;
use crate::utils::range_utils::LineIndex;
use crate::utils::range_utils::calculate_excess_range;
use crate::utils::regex_cache::{
    IMAGE_REF_PATTERN, INLINE_LINK_REGEX as MARKDOWN_LINK_PATTERN, LINK_REF_PATTERN, URL_IN_TEXT, URL_PATTERN,
};
use crate::utils::table_utils::TableUtils;
use crate::utils::text_reflow::split_into_sentences;
use toml;

pub mod md013_config;
pub use md013_config::MD013Config;
use md013_config::ReflowMode;

#[derive(Clone, Default)]
pub struct MD013LineLength {
    pub(crate) config: MD013Config,
}

impl MD013LineLength {
    pub fn new(line_length: usize, code_blocks: bool, tables: bool, headings: bool, strict: bool) -> Self {
        Self {
            config: MD013Config {
                line_length,
                code_blocks,
                tables,
                headings,
                paragraphs: true, // Default to true for backwards compatibility
                strict,
                reflow: false,
                reflow_mode: ReflowMode::default(),
            },
        }
    }

    pub fn from_config_struct(config: MD013Config) -> Self {
        Self { config }
    }

    fn should_ignore_line(
        &self,
        line: &str,
        _lines: &[&str],
        current_line: usize,
        ctx: &crate::lint_context::LintContext,
    ) -> bool {
        if self.config.strict {
            return false;
        }

        // Quick check for common patterns before expensive regex
        let trimmed = line.trim();

        // Only skip if the entire line is a URL (quick check first)
        if (trimmed.starts_with("http://") || trimmed.starts_with("https://")) && URL_PATTERN.is_match(trimmed) {
            return true;
        }

        // Only skip if the entire line is an image reference (quick check first)
        if trimmed.starts_with("![") && trimmed.ends_with(']') && IMAGE_REF_PATTERN.is_match(trimmed) {
            return true;
        }

        // Only skip if the entire line is a link reference (quick check first)
        if trimmed.starts_with('[') && trimmed.contains("]:") && LINK_REF_PATTERN.is_match(trimmed) {
            return true;
        }

        // Code blocks with long strings (only check if in code block)
        if ctx.line_info(current_line + 1).is_some_and(|info| info.in_code_block)
            && !trimmed.is_empty()
            && !line.contains(' ')
            && !line.contains('\t')
        {
            return true;
        }

        false
    }
}

impl Rule for MD013LineLength {
    fn name(&self) -> &'static str {
        "MD013"
    }

    fn description(&self) -> &'static str {
        "Line length should not be excessive"
    }

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

        // Fast early return using should_skip
        // But don't skip if we're in reflow mode with Normalize or SentencePerLine
        if self.should_skip(ctx)
            && !(self.config.reflow
                && (self.config.reflow_mode == ReflowMode::Normalize
                    || self.config.reflow_mode == ReflowMode::SentencePerLine))
        {
            return Ok(Vec::new());
        }

        // Direct implementation without DocumentStructure
        let mut warnings = Vec::new();

        // Check for inline configuration overrides
        let inline_config = crate::inline_config::InlineConfig::from_content(content);
        let config_override = inline_config.get_rule_config("MD013");

        // Apply configuration override if present
        let effective_config = if let Some(json_config) = config_override {
            if let Some(obj) = json_config.as_object() {
                let mut config = self.config.clone();
                if let Some(line_length) = obj.get("line_length").and_then(|v| v.as_u64()) {
                    config.line_length = line_length as usize;
                }
                if let Some(code_blocks) = obj.get("code_blocks").and_then(|v| v.as_bool()) {
                    config.code_blocks = code_blocks;
                }
                if let Some(tables) = obj.get("tables").and_then(|v| v.as_bool()) {
                    config.tables = tables;
                }
                if let Some(headings) = obj.get("headings").and_then(|v| v.as_bool()) {
                    config.headings = headings;
                }
                if let Some(strict) = obj.get("strict").and_then(|v| v.as_bool()) {
                    config.strict = strict;
                }
                if let Some(reflow) = obj.get("reflow").and_then(|v| v.as_bool()) {
                    config.reflow = reflow;
                }
                if let Some(reflow_mode) = obj.get("reflow_mode").and_then(|v| v.as_str()) {
                    config.reflow_mode = match reflow_mode {
                        "default" => ReflowMode::Default,
                        "normalize" => ReflowMode::Normalize,
                        "sentence-per-line" => ReflowMode::SentencePerLine,
                        _ => ReflowMode::default(),
                    };
                }
                config
            } else {
                self.config.clone()
            }
        } else {
            self.config.clone()
        };

        // Special handling: line_length = 0 means "no line length limit"
        // Skip all line length checks, but still allow reflow if enabled
        let skip_length_checks = effective_config.line_length == 0;

        // Pre-filter lines that could be problematic to avoid processing all lines
        let mut candidate_lines = Vec::new();
        if !skip_length_checks {
            for (line_idx, line_info) in ctx.lines.iter().enumerate() {
                // Quick length check first
                if line_info.content.len() > effective_config.line_length {
                    candidate_lines.push(line_idx);
                }
            }
        }

        // If no candidate lines and not in normalize or sentence-per-line mode, early return
        if candidate_lines.is_empty()
            && !(effective_config.reflow
                && (effective_config.reflow_mode == ReflowMode::Normalize
                    || effective_config.reflow_mode == ReflowMode::SentencePerLine))
        {
            return Ok(warnings);
        }

        // Use ctx.lines if available for better performance
        let lines: Vec<&str> = if !ctx.lines.is_empty() {
            ctx.lines.iter().map(|l| l.content.as_str()).collect()
        } else {
            content.lines().collect()
        };

        // Create a quick lookup set for heading lines
        // We need this for both the heading skip check AND the paragraphs check
        let heading_lines_set: std::collections::HashSet<usize> = ctx
            .lines
            .iter()
            .enumerate()
            .filter(|(_, line)| line.heading.is_some())
            .map(|(idx, _)| idx + 1)
            .collect();

        // Use pre-computed table blocks from context
        // We need this for both the table skip check AND the paragraphs check
        let table_blocks = &ctx.table_blocks;
        let mut table_lines_set = std::collections::HashSet::new();
        for table in table_blocks {
            table_lines_set.insert(table.header_line + 1);
            table_lines_set.insert(table.delimiter_line + 1);
            for &line in &table.content_lines {
                table_lines_set.insert(line + 1);
            }
        }

        // Process candidate lines for line length checks
        for &line_idx in &candidate_lines {
            let line_number = line_idx + 1;
            let line = lines[line_idx];

            // Calculate effective length excluding unbreakable URLs
            let effective_length = self.calculate_effective_length(line);

            // Use single line length limit for all content
            let line_limit = effective_config.line_length;

            // Skip short lines immediately (double-check after effective length calculation)
            if effective_length <= line_limit {
                continue;
            }

            // Skip mkdocstrings blocks (already handled by LintContext)
            if ctx.lines[line_idx].in_mkdocstrings {
                continue;
            }

            // Skip various block types efficiently
            if !effective_config.strict {
                // Skip setext heading underlines
                if !line.trim().is_empty() && line.trim().chars().all(|c| c == '=' || c == '-') {
                    continue;
                }

                // Skip block elements according to config flags
                // The flags mean: true = check these elements, false = skip these elements
                // So we skip when the flag is FALSE and the line is in that element type
                if (!effective_config.headings && heading_lines_set.contains(&line_number))
                    || (!effective_config.code_blocks
                        && ctx.line_info(line_number).is_some_and(|info| info.in_code_block))
                    || (!effective_config.tables && table_lines_set.contains(&line_number))
                    || ctx.lines[line_number - 1].blockquote.is_some()
                    || ctx.line_info(line_number).is_some_and(|info| info.in_html_block)
                    || ctx.line_info(line_number).is_some_and(|info| info.in_html_comment)
                    || ctx.line_info(line_number).is_some_and(|info| info.in_esm_block)
                {
                    continue;
                }

                // Check if this is a paragraph/regular text line
                // If paragraphs = false, skip lines that are NOT in special blocks
                if !effective_config.paragraphs {
                    let is_special_block = heading_lines_set.contains(&line_number)
                        || ctx.line_info(line_number).is_some_and(|info| info.in_code_block)
                        || table_lines_set.contains(&line_number)
                        || ctx.lines[line_number - 1].blockquote.is_some()
                        || ctx.line_info(line_number).is_some_and(|info| info.in_html_block)
                        || ctx.line_info(line_number).is_some_and(|info| info.in_html_comment)
                        || ctx.line_info(line_number).is_some_and(|info| info.in_esm_block);

                    // Skip regular paragraph text when paragraphs = false
                    if !is_special_block {
                        continue;
                    }
                }

                // Skip lines that are only a URL, image ref, or link ref
                if self.should_ignore_line(line, &lines, line_idx, ctx) {
                    continue;
                }
            }

            // In sentence-per-line mode, check if this is a single long sentence
            // If so, emit a warning without a fix (user must manually rephrase)
            if effective_config.reflow_mode == ReflowMode::SentencePerLine {
                let sentences = split_into_sentences(line.trim());
                if sentences.len() == 1 {
                    // Single sentence that's too long - warn but don't auto-fix
                    let message = format!("Line length {effective_length} exceeds {line_limit} characters");

                    let (start_line, start_col, end_line, end_col) =
                        calculate_excess_range(line_number, line, line_limit);

                    warnings.push(LintWarning {
                        rule_name: Some(self.name().to_string()),
                        message,
                        line: start_line,
                        column: start_col,
                        end_line,
                        end_column: end_col,
                        severity: Severity::Warning,
                        fix: None, // No auto-fix for long single sentences
                    });
                    continue;
                }
                // Multiple sentences will be handled by paragraph-based reflow
                continue;
            }

            // Don't provide fix for individual lines when reflow is enabled
            // Paragraph-based fixes will be handled separately
            let fix = None;

            let message = format!("Line length {effective_length} exceeds {line_limit} characters");

            // Calculate precise character range for the excess portion
            let (start_line, start_col, end_line, end_col) = calculate_excess_range(line_number, line, line_limit);

            warnings.push(LintWarning {
                rule_name: Some(self.name().to_string()),
                message,
                line: start_line,
                column: start_col,
                end_line,
                end_column: end_col,
                severity: Severity::Warning,
                fix,
            });
        }

        // If reflow is enabled, generate paragraph-based fixes
        if effective_config.reflow {
            let paragraph_warnings = self.generate_paragraph_fixes(ctx, &effective_config, &lines);
            // Merge paragraph warnings with line warnings, removing duplicates
            for pw in paragraph_warnings {
                // Remove any line warnings that overlap with this paragraph
                warnings.retain(|w| w.line < pw.line || w.line > pw.end_line);
                warnings.push(pw);
            }
        }

        Ok(warnings)
    }

    fn fix(&self, ctx: &crate::lint_context::LintContext) -> Result<String, LintError> {
        // For CLI usage, apply fixes from warnings
        // LSP will use the warning-based fixes directly
        let warnings = self.check(ctx)?;

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

        // Apply warning-based fixes
        crate::utils::fix_utils::apply_warning_fixes(ctx.content, &warnings)
            .map_err(|e| LintError::FixFailed(format!("Failed to apply fixes: {e}")))
    }

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

    fn category(&self) -> RuleCategory {
        RuleCategory::Whitespace
    }

    fn should_skip(&self, ctx: &crate::lint_context::LintContext) -> bool {
        // Skip if content is empty
        if ctx.content.is_empty() {
            return true;
        }

        // For sentence-per-line or normalize mode, never skip based on line length
        if self.config.reflow
            && (self.config.reflow_mode == ReflowMode::SentencePerLine
                || self.config.reflow_mode == ReflowMode::Normalize)
        {
            return false;
        }

        // Quick check: if total content is shorter than line limit, definitely skip
        if ctx.content.len() <= self.config.line_length {
            return true;
        }

        // Use more efficient check - any() with early termination instead of all()
        !ctx.lines
            .iter()
            .any(|line| line.content.len() > self.config.line_length)
    }

    fn default_config_section(&self) -> Option<(String, toml::Value)> {
        let default_config = MD013Config::default();
        let json_value = serde_json::to_value(&default_config).ok()?;
        let toml_value = crate::rule_config_serde::json_to_toml_value(&json_value)?;

        if let toml::Value::Table(table) = toml_value {
            if !table.is_empty() {
                Some((MD013Config::RULE_NAME.to_string(), toml::Value::Table(table)))
            } else {
                None
            }
        } else {
            None
        }
    }

    fn config_aliases(&self) -> Option<std::collections::HashMap<String, String>> {
        let mut aliases = std::collections::HashMap::new();
        aliases.insert("enable_reflow".to_string(), "reflow".to_string());
        Some(aliases)
    }

    fn from_config(config: &crate::config::Config) -> Box<dyn Rule>
    where
        Self: Sized,
    {
        let mut rule_config = crate::rule_config_serde::load_rule_config::<MD013Config>(config);
        // Special handling for line_length from global config
        if rule_config.line_length == 80 {
            // default value
            rule_config.line_length = config.global.line_length as usize;
        }
        Box::new(Self::from_config_struct(rule_config))
    }
}

impl MD013LineLength {
    /// Generate paragraph-based fixes
    fn generate_paragraph_fixes(
        &self,
        ctx: &crate::lint_context::LintContext,
        config: &MD013Config,
        lines: &[&str],
    ) -> Vec<LintWarning> {
        let mut warnings = Vec::new();
        let line_index = LineIndex::new(ctx.content.to_string());

        let mut i = 0;
        while i < lines.len() {
            let line_num = i + 1;

            // Skip special structures
            let should_skip_due_to_line_info = ctx.line_info(line_num).is_some_and(|info| {
                info.in_code_block
                    || info.in_front_matter
                    || info.in_html_block
                    || info.in_html_comment
                    || info.in_esm_block
            });

            if should_skip_due_to_line_info
                || (line_num > 0 && line_num <= ctx.lines.len() && ctx.lines[line_num - 1].blockquote.is_some())
                || lines[i].trim().starts_with('#')
                || TableUtils::is_potential_table_row(lines[i])
                || lines[i].trim().is_empty()
                || is_horizontal_rule(lines[i].trim())
                || is_template_directive_only(lines[i])
            {
                i += 1;
                continue;
            }

            // Helper function to detect semantic line markers
            let is_semantic_line = |content: &str| -> bool {
                let trimmed = content.trim_start();
                let semantic_markers = [
                    "NOTE:",
                    "WARNING:",
                    "IMPORTANT:",
                    "CAUTION:",
                    "TIP:",
                    "DANGER:",
                    "HINT:",
                    "INFO:",
                ];
                semantic_markers.iter().any(|marker| trimmed.starts_with(marker))
            };

            // Helper function to detect fence markers (opening or closing)
            let is_fence_marker = |content: &str| -> bool {
                let trimmed = content.trim_start();
                trimmed.starts_with("```") || trimmed.starts_with("~~~")
            };

            // Check if this is a list item - handle it specially
            let trimmed = lines[i].trim();
            if is_list_item(trimmed) {
                // Collect the entire list item including continuation lines
                let list_start = i;
                let (marker, first_content) = extract_list_marker_and_content(lines[i]);
                let marker_len = marker.len();

                // Track lines and their types (content, code block, fence, nested list)
                #[derive(Clone)]
                enum LineType {
                    Content(String),
                    CodeBlock(String, usize),      // content and original indent
                    NestedListItem(String, usize), // full line content and original indent
                    SemanticLine(String),          // Lines starting with NOTE:, WARNING:, etc that should stay separate
                    Empty,
                }

                let mut actual_indent: Option<usize> = None;
                let mut list_item_lines: Vec<LineType> = vec![LineType::Content(first_content)];
                i += 1;

                // Collect continuation lines using ctx.lines for metadata
                while i < lines.len() {
                    let line_info = &ctx.lines[i];

                    // Use pre-computed is_blank from ctx
                    if line_info.is_blank {
                        // Empty line - check if next line is indented (part of list item)
                        if i + 1 < lines.len() {
                            let next_info = &ctx.lines[i + 1];

                            // Check if next line is indented enough to be continuation
                            if !next_info.is_blank && next_info.indent >= marker_len {
                                // This blank line is between paragraphs/blocks in the list item
                                list_item_lines.push(LineType::Empty);
                                i += 1;
                                continue;
                            }
                        }
                        // No indented line after blank, end of list item
                        break;
                    }

                    // Use pre-computed indent from ctx
                    let indent = line_info.indent;

                    // Valid continuation must be indented at least marker_len
                    if indent >= marker_len {
                        let trimmed = line_info.content.trim();

                        // Use pre-computed in_code_block from ctx
                        if line_info.in_code_block {
                            list_item_lines.push(LineType::CodeBlock(line_info.content[indent..].to_string(), indent));
                            i += 1;
                            continue;
                        }

                        // Check if this is a SIBLING list item (breaks parent)
                        // Nested lists are indented >= marker_len and are PART of the parent item
                        // Siblings are at indent < marker_len (at or before parent marker)
                        if is_list_item(trimmed) && indent < marker_len {
                            // This is a sibling item at same or higher level - end parent item
                            break;
                        }

                        // Check if this is a NESTED list item marker
                        // Nested lists should be processed separately UNLESS they're part of a
                        // multi-paragraph list item (indicated by a blank line before them OR
                        // it's a continuation of an already-started nested list)
                        if is_list_item(trimmed) && indent >= marker_len {
                            // Check if there was a blank line before this (multi-paragraph context)
                            let has_blank_before = matches!(list_item_lines.last(), Some(LineType::Empty));

                            // Check if we've already seen nested list content (another nested item)
                            let has_nested_content = list_item_lines.iter().any(|line| {
                                matches!(line, LineType::Content(c) if is_list_item(c.trim()))
                                    || matches!(line, LineType::NestedListItem(_, _))
                            });

                            if !has_blank_before && !has_nested_content {
                                // Single-paragraph context with no prior nested items: starts a new item
                                // End parent collection; nested list will be processed next
                                break;
                            }
                            // else: multi-paragraph context or continuation of nested list, keep collecting
                            // Mark this as a nested list item to preserve its structure
                            list_item_lines.push(LineType::NestedListItem(
                                line_info.content[indent..].to_string(),
                                indent,
                            ));
                            i += 1;
                            continue;
                        }

                        // Normal continuation: marker_len to marker_len+3
                        if indent <= marker_len + 3 {
                            // Set actual_indent from first non-code continuation if not set
                            if actual_indent.is_none() {
                                actual_indent = Some(indent);
                            }

                            // Extract content (remove indentation and trailing whitespace)
                            // Preserve hard breaks (2 trailing spaces) while removing excessive whitespace
                            // See: https://github.com/rvben/rumdl/issues/76
                            let content = trim_preserving_hard_break(&line_info.content[indent..]);

                            // Check if this is a fence marker (opening or closing)
                            // These should be treated as code block lines, not paragraph content
                            if is_fence_marker(&content) {
                                list_item_lines.push(LineType::CodeBlock(content, indent));
                            }
                            // Check if this is a semantic line (NOTE:, WARNING:, etc.)
                            else if is_semantic_line(&content) {
                                list_item_lines.push(LineType::SemanticLine(content));
                            } else {
                                list_item_lines.push(LineType::Content(content));
                            }
                            i += 1;
                        } else {
                            // indent >= marker_len + 4: indented code block
                            list_item_lines.push(LineType::CodeBlock(line_info.content[indent..].to_string(), indent));
                            i += 1;
                        }
                    } else {
                        // Not indented enough, end of list item
                        break;
                    }
                }

                // Use detected indent or fallback to marker length
                let indent_size = actual_indent.unwrap_or(marker_len);
                let expected_indent = " ".repeat(indent_size);

                // Split list_item_lines into blocks (paragraphs, code blocks, nested lists, semantic lines, and HTML blocks)
                #[derive(Clone)]
                enum Block {
                    Paragraph(Vec<String>),
                    Code {
                        lines: Vec<(String, usize)>, // (content, indent) pairs
                        has_preceding_blank: bool,   // Whether there was a blank line before this block
                    },
                    NestedList(Vec<(String, usize)>), // (content, indent) pairs for nested list items
                    SemanticLine(String), // Semantic markers like NOTE:, WARNING: that stay on their own line
                    Html {
                        lines: Vec<String>,        // HTML content preserved exactly as-is
                        has_preceding_blank: bool, // Whether there was a blank line before this block
                    },
                }

                // HTML tag detection helpers
                // Block-level HTML tags that should trigger HTML block detection
                const BLOCK_LEVEL_TAGS: &[&str] = &[
                    "div",
                    "details",
                    "summary",
                    "section",
                    "article",
                    "header",
                    "footer",
                    "nav",
                    "aside",
                    "main",
                    "table",
                    "thead",
                    "tbody",
                    "tfoot",
                    "tr",
                    "td",
                    "th",
                    "ul",
                    "ol",
                    "li",
                    "dl",
                    "dt",
                    "dd",
                    "pre",
                    "blockquote",
                    "figure",
                    "figcaption",
                    "form",
                    "fieldset",
                    "legend",
                    "hr",
                    "p",
                    "h1",
                    "h2",
                    "h3",
                    "h4",
                    "h5",
                    "h6",
                    "style",
                    "script",
                    "noscript",
                ];

                fn is_block_html_opening_tag(line: &str) -> Option<String> {
                    let trimmed = line.trim();

                    // Check for HTML comments
                    if trimmed.starts_with("<!--") {
                        return Some("!--".to_string());
                    }

                    // Check for opening tags
                    if trimmed.starts_with('<') && !trimmed.starts_with("</") && !trimmed.starts_with("<!") {
                        // Extract tag name from <tagname ...> or <tagname>
                        let after_bracket = &trimmed[1..];
                        if let Some(end) = after_bracket.find(|c: char| c.is_whitespace() || c == '>' || c == '/') {
                            let tag_name = after_bracket[..end].to_lowercase();

                            // Only treat as block if it's a known block-level tag
                            if BLOCK_LEVEL_TAGS.contains(&tag_name.as_str()) {
                                return Some(tag_name);
                            }
                        }
                    }
                    None
                }

                fn is_html_closing_tag(line: &str, tag_name: &str) -> bool {
                    let trimmed = line.trim();

                    // Special handling for HTML comments
                    if tag_name == "!--" {
                        return trimmed.ends_with("-->");
                    }

                    // Check for closing tags: </tagname> or </tagname ...>
                    trimmed.starts_with(&format!("</{tag_name}>"))
                        || trimmed.starts_with(&format!("</{tag_name}  "))
                        || (trimmed.starts_with("</") && trimmed[2..].trim_start().starts_with(tag_name))
                }

                fn is_self_closing_tag(line: &str) -> bool {
                    let trimmed = line.trim();
                    trimmed.ends_with("/>")
                }

                let mut blocks: Vec<Block> = Vec::new();
                let mut current_paragraph: Vec<String> = Vec::new();
                let mut current_code_block: Vec<(String, usize)> = Vec::new();
                let mut current_nested_list: Vec<(String, usize)> = Vec::new();
                let mut current_html_block: Vec<String> = Vec::new();
                let mut html_tag_stack: Vec<String> = Vec::new();
                let mut in_code = false;
                let mut in_nested_list = false;
                let mut in_html_block = false;
                let mut had_preceding_blank = false; // Track if we just saw an empty line
                let mut code_block_has_preceding_blank = false; // Track blank before current code block
                let mut html_block_has_preceding_blank = false; // Track blank before current HTML block

                for line in &list_item_lines {
                    match line {
                        LineType::Empty => {
                            if in_code {
                                current_code_block.push((String::new(), 0));
                            } else if in_nested_list {
                                current_nested_list.push((String::new(), 0));
                            } else if in_html_block {
                                // Allow blank lines inside HTML blocks
                                current_html_block.push(String::new());
                            } else if !current_paragraph.is_empty() {
                                blocks.push(Block::Paragraph(current_paragraph.clone()));
                                current_paragraph.clear();
                            }
                            // Mark that we saw a blank line
                            had_preceding_blank = true;
                        }
                        LineType::Content(content) => {
                            // Check if we're currently in an HTML block
                            if in_html_block {
                                current_html_block.push(content.clone());

                                // Check if this line closes any open HTML tags
                                if let Some(last_tag) = html_tag_stack.last() {
                                    if is_html_closing_tag(content, last_tag) {
                                        html_tag_stack.pop();

                                        // If stack is empty, HTML block is complete
                                        if html_tag_stack.is_empty() {
                                            blocks.push(Block::Html {
                                                lines: current_html_block.clone(),
                                                has_preceding_blank: html_block_has_preceding_blank,
                                            });
                                            current_html_block.clear();
                                            in_html_block = false;
                                        }
                                    } else if let Some(new_tag) = is_block_html_opening_tag(content) {
                                        // Nested opening tag within HTML block
                                        if !is_self_closing_tag(content) {
                                            html_tag_stack.push(new_tag);
                                        }
                                    }
                                }
                                had_preceding_blank = false;
                            } else {
                                // Not in HTML block - check if this line starts one
                                if let Some(tag_name) = is_block_html_opening_tag(content) {
                                    // Flush current paragraph before starting HTML block
                                    if in_code {
                                        blocks.push(Block::Code {
                                            lines: current_code_block.clone(),
                                            has_preceding_blank: code_block_has_preceding_blank,
                                        });
                                        current_code_block.clear();
                                        in_code = false;
                                    } else if in_nested_list {
                                        blocks.push(Block::NestedList(current_nested_list.clone()));
                                        current_nested_list.clear();
                                        in_nested_list = false;
                                    } else if !current_paragraph.is_empty() {
                                        blocks.push(Block::Paragraph(current_paragraph.clone()));
                                        current_paragraph.clear();
                                    }

                                    // Start new HTML block
                                    in_html_block = true;
                                    html_block_has_preceding_blank = had_preceding_blank;
                                    current_html_block.push(content.clone());

                                    // Check if it's self-closing or needs a closing tag
                                    if is_self_closing_tag(content) {
                                        // Self-closing tag - complete the HTML block immediately
                                        blocks.push(Block::Html {
                                            lines: current_html_block.clone(),
                                            has_preceding_blank: html_block_has_preceding_blank,
                                        });
                                        current_html_block.clear();
                                        in_html_block = false;
                                    } else {
                                        // Regular opening tag - push to stack
                                        html_tag_stack.push(tag_name);
                                    }
                                } else {
                                    // Regular content line - add to paragraph
                                    if in_code {
                                        // Switching from code to content
                                        blocks.push(Block::Code {
                                            lines: current_code_block.clone(),
                                            has_preceding_blank: code_block_has_preceding_blank,
                                        });
                                        current_code_block.clear();
                                        in_code = false;
                                    } else if in_nested_list {
                                        // Switching from nested list to content
                                        blocks.push(Block::NestedList(current_nested_list.clone()));
                                        current_nested_list.clear();
                                        in_nested_list = false;
                                    }
                                    current_paragraph.push(content.clone());
                                }
                                had_preceding_blank = false; // Reset after content
                            }
                        }
                        LineType::CodeBlock(content, indent) => {
                            if in_nested_list {
                                // Switching from nested list to code
                                blocks.push(Block::NestedList(current_nested_list.clone()));
                                current_nested_list.clear();
                                in_nested_list = false;
                            } else if in_html_block {
                                // Switching from HTML block to code (shouldn't happen normally, but handle it)
                                blocks.push(Block::Html {
                                    lines: current_html_block.clone(),
                                    has_preceding_blank: html_block_has_preceding_blank,
                                });
                                current_html_block.clear();
                                html_tag_stack.clear();
                                in_html_block = false;
                            }
                            if !in_code {
                                // Switching from content to code
                                if !current_paragraph.is_empty() {
                                    blocks.push(Block::Paragraph(current_paragraph.clone()));
                                    current_paragraph.clear();
                                }
                                in_code = true;
                                // Record whether there was a blank line before this code block
                                code_block_has_preceding_blank = had_preceding_blank;
                            }
                            current_code_block.push((content.clone(), *indent));
                            had_preceding_blank = false; // Reset after code
                        }
                        LineType::NestedListItem(content, indent) => {
                            if in_code {
                                // Switching from code to nested list
                                blocks.push(Block::Code {
                                    lines: current_code_block.clone(),
                                    has_preceding_blank: code_block_has_preceding_blank,
                                });
                                current_code_block.clear();
                                in_code = false;
                            } else if in_html_block {
                                // Switching from HTML block to nested list (shouldn't happen normally, but handle it)
                                blocks.push(Block::Html {
                                    lines: current_html_block.clone(),
                                    has_preceding_blank: html_block_has_preceding_blank,
                                });
                                current_html_block.clear();
                                html_tag_stack.clear();
                                in_html_block = false;
                            }
                            if !in_nested_list {
                                // Switching from content to nested list
                                if !current_paragraph.is_empty() {
                                    blocks.push(Block::Paragraph(current_paragraph.clone()));
                                    current_paragraph.clear();
                                }
                                in_nested_list = true;
                            }
                            current_nested_list.push((content.clone(), *indent));
                            had_preceding_blank = false; // Reset after nested list
                        }
                        LineType::SemanticLine(content) => {
                            // Semantic lines are standalone - flush any current block and add as separate block
                            if in_code {
                                blocks.push(Block::Code {
                                    lines: current_code_block.clone(),
                                    has_preceding_blank: code_block_has_preceding_blank,
                                });
                                current_code_block.clear();
                                in_code = false;
                            } else if in_nested_list {
                                blocks.push(Block::NestedList(current_nested_list.clone()));
                                current_nested_list.clear();
                                in_nested_list = false;
                            } else if in_html_block {
                                blocks.push(Block::Html {
                                    lines: current_html_block.clone(),
                                    has_preceding_blank: html_block_has_preceding_blank,
                                });
                                current_html_block.clear();
                                html_tag_stack.clear();
                                in_html_block = false;
                            } else if !current_paragraph.is_empty() {
                                blocks.push(Block::Paragraph(current_paragraph.clone()));
                                current_paragraph.clear();
                            }
                            // Add semantic line as its own block
                            blocks.push(Block::SemanticLine(content.clone()));
                            had_preceding_blank = false; // Reset after semantic line
                        }
                    }
                }

                // Push remaining block
                if in_code && !current_code_block.is_empty() {
                    blocks.push(Block::Code {
                        lines: current_code_block,
                        has_preceding_blank: code_block_has_preceding_blank,
                    });
                } else if in_nested_list && !current_nested_list.is_empty() {
                    blocks.push(Block::NestedList(current_nested_list));
                } else if in_html_block && !current_html_block.is_empty() {
                    // If we still have an unclosed HTML block, push it anyway
                    // (malformed HTML - missing closing tag)
                    blocks.push(Block::Html {
                        lines: current_html_block,
                        has_preceding_blank: html_block_has_preceding_blank,
                    });
                } else if !current_paragraph.is_empty() {
                    blocks.push(Block::Paragraph(current_paragraph));
                }

                // Check if reflowing is needed (only for content paragraphs, not code blocks or nested lists)
                let content_lines: Vec<String> = list_item_lines
                    .iter()
                    .filter_map(|line| {
                        if let LineType::Content(s) = line {
                            Some(s.clone())
                        } else {
                            None
                        }
                    })
                    .collect();

                // Check if we need to reflow this list item
                // We check the combined content to see if it exceeds length limits
                let combined_content = content_lines.join(" ").trim().to_string();
                let full_line = format!("{marker}{combined_content}");

                // Helper to check if we should reflow in normalize mode
                let should_normalize = || {
                    // Don't normalize if the list item only contains nested lists, code blocks, or semantic lines
                    // DO normalize if it has plain text content that spans multiple lines
                    let has_nested_lists = blocks.iter().any(|b| matches!(b, Block::NestedList(_)));
                    let has_code_blocks = blocks.iter().any(|b| matches!(b, Block::Code { .. }));
                    let has_semantic_lines = blocks.iter().any(|b| matches!(b, Block::SemanticLine(_)));
                    let has_paragraphs = blocks.iter().any(|b| matches!(b, Block::Paragraph(_)));

                    // If we have nested lists, code blocks, or semantic lines but no paragraphs, don't normalize
                    if (has_nested_lists || has_code_blocks || has_semantic_lines) && !has_paragraphs {
                        return false;
                    }

                    // If we have paragraphs, check if they span multiple lines or there are multiple blocks
                    if has_paragraphs {
                        let paragraph_count = blocks.iter().filter(|b| matches!(b, Block::Paragraph(_))).count();
                        if paragraph_count > 1 {
                            // Multiple paragraph blocks should be normalized
                            return true;
                        }

                        // Single paragraph block: normalize if it has multiple content lines
                        if content_lines.len() > 1 {
                            return true;
                        }
                    }

                    false
                };

                let needs_reflow = match config.reflow_mode {
                    ReflowMode::Normalize => {
                        // Only reflow if:
                        // 1. The combined line would exceed the limit, OR
                        // 2. The list item should be normalized (has multi-line plain text)
                        let combined_length = self.calculate_effective_length(&full_line);
                        if combined_length > config.line_length {
                            true
                        } else {
                            should_normalize()
                        }
                    }
                    ReflowMode::SentencePerLine => {
                        // Check if list item has multiple sentences
                        let sentences = split_into_sentences(&combined_content);
                        sentences.len() > 1
                    }
                    ReflowMode::Default => {
                        // In default mode, only reflow if lines exceed limit
                        self.calculate_effective_length(&full_line) > config.line_length
                    }
                };

                if needs_reflow {
                    let start_range = line_index.whole_line_range(list_start + 1);
                    let end_line = i - 1;
                    let end_range = if end_line == lines.len() - 1 && !ctx.content.ends_with('\n') {
                        line_index.line_text_range(end_line + 1, 1, lines[end_line].len() + 1)
                    } else {
                        line_index.whole_line_range(end_line + 1)
                    };
                    let byte_range = start_range.start..end_range.end;

                    // Reflow each block (paragraphs only, preserve code blocks)
                    // When line_length = 0 (no limit), use a very large value for reflow
                    let reflow_line_length = if config.line_length == 0 {
                        usize::MAX
                    } else {
                        config.line_length.saturating_sub(indent_size).max(1)
                    };
                    let reflow_options = crate::utils::text_reflow::ReflowOptions {
                        line_length: reflow_line_length,
                        break_on_sentences: true,
                        preserve_breaks: false,
                        sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
                    };

                    let mut result: Vec<String> = Vec::new();
                    let mut is_first_block = true;

                    for (block_idx, block) in blocks.iter().enumerate() {
                        match block {
                            Block::Paragraph(para_lines) => {
                                // Split the paragraph into segments at hard break boundaries
                                // Each segment can be reflowed independently
                                let segments = split_into_segments(para_lines);

                                for (segment_idx, segment) in segments.iter().enumerate() {
                                    // Check if this segment ends with a hard break and what type
                                    let hard_break_type = segment.last().and_then(|line| {
                                        let line = line.strip_suffix('\r').unwrap_or(line);
                                        if line.ends_with('\\') {
                                            Some("\\")
                                        } else if line.ends_with("  ") {
                                            Some("  ")
                                        } else {
                                            None
                                        }
                                    });

                                    // Join and reflow the segment (removing the hard break marker for processing)
                                    let segment_for_reflow: Vec<String> = segment
                                        .iter()
                                        .map(|line| {
                                            // Strip hard break marker (2 spaces or backslash) for reflow processing
                                            if line.ends_with('\\') {
                                                line[..line.len() - 1].trim_end().to_string()
                                            } else if line.ends_with("  ") {
                                                line[..line.len() - 2].trim_end().to_string()
                                            } else {
                                                line.clone()
                                            }
                                        })
                                        .collect();

                                    let segment_text = segment_for_reflow.join(" ").trim().to_string();
                                    if !segment_text.is_empty() {
                                        let reflowed =
                                            crate::utils::text_reflow::reflow_line(&segment_text, &reflow_options);

                                        if is_first_block && segment_idx == 0 {
                                            // First segment of first block starts with marker
                                            result.push(format!("{marker}{}", reflowed[0]));
                                            for line in reflowed.iter().skip(1) {
                                                result.push(format!("{expected_indent}{line}"));
                                            }
                                            is_first_block = false;
                                        } else {
                                            // Subsequent segments
                                            for line in reflowed {
                                                result.push(format!("{expected_indent}{line}"));
                                            }
                                        }

                                        // If this segment had a hard break, add it back to the last line
                                        // Preserve the original hard break format (backslash or two spaces)
                                        if let Some(break_marker) = hard_break_type
                                            && let Some(last_line) = result.last_mut()
                                        {
                                            last_line.push_str(break_marker);
                                        }
                                    }
                                }

                                // Add blank line after paragraph block if there's a next block
                                // BUT: check if next block is a code block that doesn't want a preceding blank
                                if block_idx < blocks.len() - 1 {
                                    let next_block = &blocks[block_idx + 1];
                                    let should_add_blank = match next_block {
                                        Block::Code {
                                            has_preceding_blank, ..
                                        } => *has_preceding_blank,
                                        _ => true, // For all other blocks, add blank line
                                    };
                                    if should_add_blank {
                                        result.push(String::new());
                                    }
                                }
                            }
                            Block::Code {
                                lines: code_lines,
                                has_preceding_blank: _,
                            } => {
                                // Preserve code blocks as-is with original indentation
                                // NOTE: Blank line before code block is handled by the previous block
                                // (see paragraph block's logic above)

                                for (idx, (content, orig_indent)) in code_lines.iter().enumerate() {
                                    if is_first_block && idx == 0 {
                                        // First line of first block gets marker
                                        result.push(format!(
                                            "{marker}{}",
                                            " ".repeat(orig_indent - marker_len) + content
                                        ));
                                        is_first_block = false;
                                    } else if content.is_empty() {
                                        result.push(String::new());
                                    } else {
                                        result.push(format!("{}{}", " ".repeat(*orig_indent), content));
                                    }
                                }
                            }
                            Block::NestedList(nested_items) => {
                                // Preserve nested list items as-is with original indentation
                                if !is_first_block {
                                    result.push(String::new());
                                }

                                for (idx, (content, orig_indent)) in nested_items.iter().enumerate() {
                                    if is_first_block && idx == 0 {
                                        // First line of first block gets marker
                                        result.push(format!(
                                            "{marker}{}",
                                            " ".repeat(orig_indent - marker_len) + content
                                        ));
                                        is_first_block = false;
                                    } else if content.is_empty() {
                                        result.push(String::new());
                                    } else {
                                        result.push(format!("{}{}", " ".repeat(*orig_indent), content));
                                    }
                                }

                                // Add blank line after nested list if there's a next block
                                // Check if next block is a code block that doesn't want a preceding blank
                                if block_idx < blocks.len() - 1 {
                                    let next_block = &blocks[block_idx + 1];
                                    let should_add_blank = match next_block {
                                        Block::Code {
                                            has_preceding_blank, ..
                                        } => *has_preceding_blank,
                                        _ => true, // For all other blocks, add blank line
                                    };
                                    if should_add_blank {
                                        result.push(String::new());
                                    }
                                }
                            }
                            Block::SemanticLine(content) => {
                                // Preserve semantic lines (NOTE:, WARNING:, etc.) as-is on their own line
                                // Add blank line before if not first block
                                if !is_first_block {
                                    result.push(String::new());
                                }

                                if is_first_block {
                                    // First block starts with marker
                                    result.push(format!("{marker}{content}"));
                                    is_first_block = false;
                                } else {
                                    // Subsequent blocks use expected indent
                                    result.push(format!("{expected_indent}{content}"));
                                }

                                // Add blank line after semantic line if there's a next block
                                // Check if next block is a code block that doesn't want a preceding blank
                                if block_idx < blocks.len() - 1 {
                                    let next_block = &blocks[block_idx + 1];
                                    let should_add_blank = match next_block {
                                        Block::Code {
                                            has_preceding_blank, ..
                                        } => *has_preceding_blank,
                                        _ => true, // For all other blocks, add blank line
                                    };
                                    if should_add_blank {
                                        result.push(String::new());
                                    }
                                }
                            }
                            Block::Html {
                                lines: html_lines,
                                has_preceding_blank: _,
                            } => {
                                // Preserve HTML blocks exactly as-is with original indentation
                                // NOTE: Blank line before HTML block is handled by the previous block

                                for (idx, line) in html_lines.iter().enumerate() {
                                    if is_first_block && idx == 0 {
                                        // First line of first block gets marker
                                        result.push(format!("{marker}{line}"));
                                        is_first_block = false;
                                    } else if line.is_empty() {
                                        // Preserve blank lines inside HTML blocks
                                        result.push(String::new());
                                    } else {
                                        // Preserve lines with their original content (already includes indentation)
                                        result.push(format!("{expected_indent}{line}"));
                                    }
                                }

                                // Add blank line after HTML block if there's a next block
                                if block_idx < blocks.len() - 1 {
                                    let next_block = &blocks[block_idx + 1];
                                    let should_add_blank = match next_block {
                                        Block::Code {
                                            has_preceding_blank, ..
                                        } => *has_preceding_blank,
                                        Block::Html {
                                            has_preceding_blank, ..
                                        } => *has_preceding_blank,
                                        _ => true, // For all other blocks, add blank line
                                    };
                                    if should_add_blank {
                                        result.push(String::new());
                                    }
                                }
                            }
                        }
                    }

                    let reflowed_text = result.join("\n");

                    // Preserve trailing newline
                    let replacement = if end_line < lines.len() - 1 || ctx.content.ends_with('\n') {
                        format!("{reflowed_text}\n")
                    } else {
                        reflowed_text
                    };

                    // Get the original text to compare
                    let original_text = &ctx.content[byte_range.clone()];

                    // Only generate a warning if the replacement is different from the original
                    if original_text != replacement {
                        // Generate an appropriate message based on why reflow is needed
                        let message = match config.reflow_mode {
                            ReflowMode::SentencePerLine => {
                                let num_sentences = split_into_sentences(&combined_content).len();
                                let num_lines = content_lines.len();
                                if num_lines == 1 {
                                    // Single line with multiple sentences
                                    format!("Line contains {num_sentences} sentences (one sentence per line required)")
                                } else {
                                    // Multiple lines - could be split sentences or mixed
                                    format!(
                                        "Paragraph should have one sentence per line (found {num_sentences} sentences across {num_lines} lines)"
                                    )
                                }
                            }
                            ReflowMode::Normalize => {
                                let combined_length = self.calculate_effective_length(&full_line);
                                if combined_length > config.line_length {
                                    format!(
                                        "Line length {} exceeds {} characters",
                                        combined_length, config.line_length
                                    )
                                } else {
                                    "Multi-line content can be normalized".to_string()
                                }
                            }
                            ReflowMode::Default => {
                                let combined_length = self.calculate_effective_length(&full_line);
                                format!(
                                    "Line length {} exceeds {} characters",
                                    combined_length, config.line_length
                                )
                            }
                        };

                        warnings.push(LintWarning {
                            rule_name: Some(self.name().to_string()),
                            message,
                            line: list_start + 1,
                            column: 1,
                            end_line: end_line + 1,
                            end_column: lines[end_line].len() + 1,
                            severity: Severity::Warning,
                            fix: Some(crate::rule::Fix {
                                range: byte_range,
                                replacement,
                            }),
                        });
                    }
                }
                continue;
            }

            // Found start of a paragraph - collect all lines in it
            let paragraph_start = i;
            let mut paragraph_lines = vec![lines[i]];
            i += 1;

            while i < lines.len() {
                let next_line = lines[i];
                let next_line_num = i + 1;
                let next_trimmed = next_line.trim();

                // Stop at paragraph boundaries
                if next_trimmed.is_empty()
                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_code_block)
                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_front_matter)
                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_html_block)
                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_html_comment)
                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_esm_block)
                    || (next_line_num > 0
                        && next_line_num <= ctx.lines.len()
                        && ctx.lines[next_line_num - 1].blockquote.is_some())
                    || next_trimmed.starts_with('#')
                    || TableUtils::is_potential_table_row(next_line)
                    || is_list_item(next_trimmed)
                    || is_horizontal_rule(next_trimmed)
                    || (next_trimmed.starts_with('[') && next_line.contains("]:"))
                    || is_template_directive_only(next_line)
                {
                    break;
                }

                // Check if the previous line ends with a hard break (2+ spaces or backslash)
                if i > 0 && has_hard_break(lines[i - 1]) {
                    // Don't include lines after hard breaks in the same paragraph
                    break;
                }

                paragraph_lines.push(next_line);
                i += 1;
            }

            // Combine paragraph lines into a single string for processing
            // This must be done BEFORE the needs_reflow check for sentence-per-line mode
            let paragraph_text = paragraph_lines.join(" ");

            // Skip reflowing if this paragraph contains definition list items
            // Definition lists are multi-line structures that should not be joined
            let contains_definition_list = paragraph_lines
                .iter()
                .any(|line| crate::utils::is_definition_list_item(line));

            if contains_definition_list {
                // Don't reflow definition lists - skip this paragraph
                i = paragraph_start + paragraph_lines.len();
                continue;
            }

            // Check if this paragraph needs reflowing
            let needs_reflow = match config.reflow_mode {
                ReflowMode::Normalize => {
                    // In normalize mode, reflow multi-line paragraphs
                    paragraph_lines.len() > 1
                }
                ReflowMode::SentencePerLine => {
                    // In sentence-per-line mode, check if the JOINED paragraph has multiple sentences
                    // Note: we check the joined text because sentences can span multiple lines
                    let sentences = split_into_sentences(&paragraph_text);

                    // Always reflow if multiple sentences on one line
                    if sentences.len() > 1 {
                        true
                    } else if paragraph_lines.len() > 1 {
                        // For single-sentence paragraphs spanning multiple lines:
                        // Reflow if they COULD fit on one line (respecting line-length constraint)
                        if config.line_length == 0 {
                            // No line-length constraint - always join single sentences
                            true
                        } else {
                            // Only join if it fits within line-length
                            let effective_length = self.calculate_effective_length(&paragraph_text);
                            effective_length <= config.line_length
                        }
                    } else {
                        false
                    }
                }
                ReflowMode::Default => {
                    // In default mode, only reflow if lines exceed limit
                    paragraph_lines
                        .iter()
                        .any(|line| self.calculate_effective_length(line) > config.line_length)
                }
            };

            if needs_reflow {
                // Calculate byte range for this paragraph
                // Use whole_line_range for each line and combine
                let start_range = line_index.whole_line_range(paragraph_start + 1);
                let end_line = paragraph_start + paragraph_lines.len() - 1;

                // For the last line, we want to preserve any trailing newline
                let end_range = if end_line == lines.len() - 1 && !ctx.content.ends_with('\n') {
                    // Last line without trailing newline - use line_text_range
                    line_index.line_text_range(end_line + 1, 1, lines[end_line].len() + 1)
                } else {
                    // Not the last line or has trailing newline - use whole_line_range
                    line_index.whole_line_range(end_line + 1)
                };

                let byte_range = start_range.start..end_range.end;

                // Check if the paragraph ends with a hard break and what type
                let hard_break_type = paragraph_lines.last().and_then(|line| {
                    let line = line.strip_suffix('\r').unwrap_or(line);
                    if line.ends_with('\\') {
                        Some("\\")
                    } else if line.ends_with("  ") {
                        Some("  ")
                    } else {
                        None
                    }
                });

                // Reflow the paragraph
                // When line_length = 0 (no limit), use a very large value for reflow
                let reflow_line_length = if config.line_length == 0 {
                    usize::MAX
                } else {
                    config.line_length
                };
                let reflow_options = crate::utils::text_reflow::ReflowOptions {
                    line_length: reflow_line_length,
                    break_on_sentences: true,
                    preserve_breaks: false,
                    sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
                };
                let mut reflowed = crate::utils::text_reflow::reflow_line(&paragraph_text, &reflow_options);

                // If the original paragraph ended with a hard break, preserve it
                // Preserve the original hard break format (backslash or two spaces)
                if let Some(break_marker) = hard_break_type
                    && !reflowed.is_empty()
                {
                    let last_idx = reflowed.len() - 1;
                    if !has_hard_break(&reflowed[last_idx]) {
                        reflowed[last_idx].push_str(break_marker);
                    }
                }

                let reflowed_text = reflowed.join("\n");

                // Preserve trailing newline if the original paragraph had one
                let replacement = if end_line < lines.len() - 1 || ctx.content.ends_with('\n') {
                    format!("{reflowed_text}\n")
                } else {
                    reflowed_text
                };

                // Get the original text to compare
                let original_text = &ctx.content[byte_range.clone()];

                // Only generate a warning if the replacement is different from the original
                if original_text != replacement {
                    // Create warning with actual fix
                    // In default mode, report the specific line that violates
                    // In normalize mode, report the whole paragraph
                    // In sentence-per-line mode, report the entire paragraph
                    let (warning_line, warning_end_line) = match config.reflow_mode {
                        ReflowMode::Normalize => (paragraph_start + 1, end_line + 1),
                        ReflowMode::SentencePerLine => {
                            // Highlight the entire paragraph that needs reformatting
                            (paragraph_start + 1, paragraph_start + paragraph_lines.len())
                        }
                        ReflowMode::Default => {
                            // Find the first line that exceeds the limit
                            let mut violating_line = paragraph_start;
                            for (idx, line) in paragraph_lines.iter().enumerate() {
                                if self.calculate_effective_length(line) > config.line_length {
                                    violating_line = paragraph_start + idx;
                                    break;
                                }
                            }
                            (violating_line + 1, violating_line + 1)
                        }
                    };

                    warnings.push(LintWarning {
                        rule_name: Some(self.name().to_string()),
                        message: match config.reflow_mode {
                            ReflowMode::Normalize => format!(
                                "Paragraph could be normalized to use line length of {} characters",
                                config.line_length
                            ),
                            ReflowMode::SentencePerLine => {
                                let num_sentences = split_into_sentences(&paragraph_text).len();
                                if paragraph_lines.len() == 1 {
                                    // Single line with multiple sentences
                                    format!("Line contains {num_sentences} sentences (one sentence per line required)")
                                } else {
                                    let num_lines = paragraph_lines.len();
                                    // Multiple lines - could be split sentences or mixed
                                    format!("Paragraph should have one sentence per line (found {num_sentences} sentences across {num_lines} lines)")
                                }
                            },
                            ReflowMode::Default => format!("Line length exceeds {} characters", config.line_length),
                        },
                        line: warning_line,
                        column: 1,
                        end_line: warning_end_line,
                        end_column: lines[warning_end_line.saturating_sub(1)].len() + 1,
                        severity: Severity::Warning,
                        fix: Some(crate::rule::Fix {
                            range: byte_range,
                            replacement,
                        }),
                    });
                }
            }
        }

        warnings
    }

    /// Calculate effective line length excluding unbreakable URLs
    fn calculate_effective_length(&self, line: &str) -> usize {
        if self.config.strict {
            // In strict mode, count everything
            return line.chars().count();
        }

        // Quick byte-level check: if line doesn't contain "http" or "[", it can't have URLs or markdown links
        let bytes = line.as_bytes();
        if !bytes.contains(&b'h') && !bytes.contains(&b'[') {
            return line.chars().count();
        }

        // More precise check for URLs and links
        if !line.contains("http") && !line.contains('[') {
            return line.chars().count();
        }

        let mut effective_line = line.to_string();

        // First handle markdown links to avoid double-counting URLs
        // Pattern: [text](very-long-url) -> [text](url)
        if line.contains('[') && line.contains("](") {
            for cap in MARKDOWN_LINK_PATTERN.captures_iter(&effective_line.clone()) {
                if let (Some(full_match), Some(text), Some(url)) = (cap.get(0), cap.get(1), cap.get(2))
                    && url.as_str().len() > 15
                {
                    let replacement = format!("[{}](url)", text.as_str());
                    effective_line = effective_line.replacen(full_match.as_str(), &replacement, 1);
                }
            }
        }

        // Then replace bare URLs with a placeholder of reasonable length
        // This allows lines with long URLs to pass if the rest of the content is reasonable
        if effective_line.contains("http") {
            for url_match in URL_IN_TEXT.find_iter(&effective_line.clone()) {
                let url = url_match.as_str();
                // Skip if this URL is already part of a markdown link we handled
                if !effective_line.contains(&format!("({url})")) {
                    // Replace URL with placeholder that represents a "reasonable" URL length
                    // Using 15 chars as a reasonable URL placeholder (e.g., "https://ex.com")
                    let placeholder = "x".repeat(15.min(url.len()));
                    effective_line = effective_line.replacen(url, &placeholder, 1);
                }
            }
        }

        effective_line.chars().count()
    }
}

/// Check if a line ends with a hard break (either two spaces or backslash)
///
/// CommonMark supports two formats for hard line breaks:
/// 1. Two or more trailing spaces
/// 2. A backslash at the end of the line
fn has_hard_break(line: &str) -> bool {
    let line = line.strip_suffix('\r').unwrap_or(line);
    line.ends_with("  ") || line.ends_with('\\')
}

/// Extract list marker and content from a list item
/// Trim trailing whitespace while preserving hard breaks (two trailing spaces or backslash)
///
/// Hard breaks in Markdown can be indicated by:
/// 1. Two trailing spaces before a newline (traditional)
/// 2. A backslash at the end of the line (mdformat style)
fn trim_preserving_hard_break(s: &str) -> String {
    // Strip trailing \r from CRLF line endings first to handle Windows files
    let s = s.strip_suffix('\r').unwrap_or(s);

    // Check for backslash hard break (mdformat style)
    if s.ends_with('\\') {
        // Preserve the backslash exactly as-is
        return s.to_string();
    }

    // Check if there are at least 2 trailing spaces (traditional hard break)
    if s.ends_with("  ") {
        // Find the position where non-space content ends
        let content_end = s.trim_end().len();
        if content_end == 0 {
            // String is all whitespace
            return String::new();
        }
        // Preserve exactly 2 trailing spaces for hard break
        format!("{}  ", &s[..content_end])
    } else {
        // No hard break, just trim all trailing whitespace
        s.trim_end().to_string()
    }
}

/// Split paragraph lines into segments at hard break boundaries.
/// Each segment is a group of lines that can be reflowed together.
/// Lines with hard breaks (ending with 2+ spaces or backslash) form segment boundaries.
///
/// Example:
///   Input:  ["Line 1", "Line 2  ", "Line 3", "Line 4"]
///   Output: [["Line 1", "Line 2  "], ["Line 3", "Line 4"]]
///
/// The first segment includes "Line 2  " which has a hard break at the end.
/// The second segment starts after the hard break.
fn split_into_segments(para_lines: &[String]) -> Vec<Vec<String>> {
    let mut segments: Vec<Vec<String>> = Vec::new();
    let mut current_segment: Vec<String> = Vec::new();

    for line in para_lines {
        current_segment.push(line.clone());

        // If this line has a hard break, end the current segment
        if has_hard_break(line) {
            segments.push(current_segment.clone());
            current_segment.clear();
        }
    }

    // Add any remaining lines as the final segment
    if !current_segment.is_empty() {
        segments.push(current_segment);
    }

    segments
}

fn extract_list_marker_and_content(line: &str) -> (String, String) {
    // First, find the leading indentation
    let indent_len = line.len() - line.trim_start().len();
    let indent = &line[..indent_len];
    let trimmed = &line[indent_len..];

    // Handle bullet lists
    // Trim trailing whitespace while preserving hard breaks
    if let Some(rest) = trimmed.strip_prefix("- ") {
        return (format!("{indent}- "), trim_preserving_hard_break(rest));
    }
    if let Some(rest) = trimmed.strip_prefix("* ") {
        return (format!("{indent}* "), trim_preserving_hard_break(rest));
    }
    if let Some(rest) = trimmed.strip_prefix("+ ") {
        return (format!("{indent}+ "), trim_preserving_hard_break(rest));
    }

    // Handle numbered lists on trimmed content
    let mut chars = trimmed.chars();
    let mut marker_content = String::new();

    while let Some(c) = chars.next() {
        marker_content.push(c);
        if c == '.' {
            // Check if next char is a space
            if let Some(next) = chars.next()
                && next == ' '
            {
                marker_content.push(next);
                // Trim trailing whitespace while preserving hard breaks
                let content = trim_preserving_hard_break(chars.as_str());
                return (format!("{indent}{marker_content}"), content);
            }
            break;
        }
    }

    // Fallback - shouldn't happen if is_list_item was correct
    (String::new(), line.to_string())
}

// Helper functions
fn is_horizontal_rule(line: &str) -> bool {
    if line.len() < 3 {
        return false;
    }
    // Check if line consists only of -, _, or * characters (at least 3)
    let chars: Vec<char> = line.chars().collect();
    if chars.is_empty() {
        return false;
    }
    let first_char = chars[0];
    if first_char != '-' && first_char != '_' && first_char != '*' {
        return false;
    }
    // All characters should be the same (allowing spaces between)
    for c in &chars {
        if *c != first_char && *c != ' ' {
            return false;
        }
    }
    // Must have at least 3 of the marker character
    chars.iter().filter(|c| **c == first_char).count() >= 3
}

fn is_numbered_list_item(line: &str) -> bool {
    let mut chars = line.chars();
    // Must start with a digit
    if !chars.next().is_some_and(|c| c.is_numeric()) {
        return false;
    }
    // Can have more digits
    while let Some(c) = chars.next() {
        if c == '.' {
            // After period, must have a space or be end of line
            return chars.next().is_none_or(|c| c == ' ');
        }
        if !c.is_numeric() {
            return false;
        }
    }
    false
}

fn is_list_item(line: &str) -> bool {
    // Bullet lists
    if (line.starts_with('-') || line.starts_with('*') || line.starts_with('+'))
        && line.len() > 1
        && line.chars().nth(1) == Some(' ')
    {
        return true;
    }
    // Numbered lists
    is_numbered_list_item(line)
}

/// Check if a line contains only template directives (no other content)
///
/// Detects common template syntax used in static site generators:
/// - Handlebars/mdBook/Mustache: `{{...}}`
/// - Jinja2/Liquid/Jekyll: `{%...%}`
/// - Hugo shortcodes: `{{<...>}}` or `{{%...%}}`
///
/// Template directives are preprocessor directives, not Markdown content,
/// so they should be treated as paragraph boundaries like HTML comments.
fn is_template_directive_only(line: &str) -> bool {
    let trimmed = line.trim();

    // Empty lines are not template directives
    if trimmed.is_empty() {
        return false;
    }

    // Check for various template syntaxes
    // Handlebars/mdBook/Mustache: {{...}}
    if trimmed.starts_with("{{") && trimmed.ends_with("}}") {
        return true;
    }

    // Jinja2/Liquid/Jekyll: {%...%}
    if trimmed.starts_with("{%") && trimmed.ends_with("%}") {
        return true;
    }

    false
}

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

    #[test]
    fn test_default_config() {
        let rule = MD013LineLength::default();
        assert_eq!(rule.config.line_length, 80);
        assert!(rule.config.code_blocks); // Default is true
        assert!(!rule.config.tables); // Default is false (changed to prevent conflicts with MD060)
        assert!(rule.config.headings); // Default is true
        assert!(!rule.config.strict);
    }

    #[test]
    fn test_custom_config() {
        let rule = MD013LineLength::new(100, true, true, false, true);
        assert_eq!(rule.config.line_length, 100);
        assert!(rule.config.code_blocks);
        assert!(rule.config.tables);
        assert!(!rule.config.headings);
        assert!(rule.config.strict);
    }

    #[test]
    fn test_basic_line_length_violation() {
        let rule = MD013LineLength::new(50, false, false, false, false);
        let content = "This is a line that is definitely longer than fifty characters and should trigger a warning.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1);
        assert!(result[0].message.contains("Line length"));
        assert!(result[0].message.contains("exceeds 50 characters"));
    }

    #[test]
    fn test_no_violation_under_limit() {
        let rule = MD013LineLength::new(100, false, false, false, false);
        let content = "Short line.\nAnother short line.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_multiple_violations() {
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "This line is definitely longer than thirty chars.\nThis is also a line that exceeds the limit.\nShort line.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 2);
        assert_eq!(result[0].line, 1);
        assert_eq!(result[1].line, 2);
    }

    #[test]
    fn test_code_blocks_exemption() {
        // With code_blocks = false, code blocks should be skipped
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "```\nThis is a very long line inside a code block that should be ignored.\n```";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_code_blocks_not_exempt_when_configured() {
        // With code_blocks = true, code blocks should be checked
        let rule = MD013LineLength::new(30, true, false, false, false);
        let content = "```\nThis is a very long line inside a code block that should NOT be ignored.\n```";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty());
    }

    #[test]
    fn test_heading_checked_when_enabled() {
        let rule = MD013LineLength::new(30, false, false, true, false);
        let content = "# This is a very long heading that would normally exceed the limit";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1);
    }

    #[test]
    fn test_heading_exempt_when_disabled() {
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "# This is a very long heading that should trigger a warning";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_table_checked_when_enabled() {
        let rule = MD013LineLength::new(30, false, true, false, false);
        let content = "| This is a very long table header | Another long column header |\n|-----------------------------------|-------------------------------|";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 2); // Both table lines exceed limit
    }

    #[test]
    fn test_issue_78_tables_after_fenced_code_blocks() {
        // Test for GitHub issue #78 - tables with tables=false after fenced code blocks
        let rule = MD013LineLength::new(20, false, false, false, false); // tables=false
        let content = r#"# heading

```plain
some code block longer than 20 chars length
```

this is a very long line

| column A | column B |
| -------- | -------- |
| `var` | `val` |
| value 1 | value 2 |

correct length line"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should only flag line 7 ("this is a very long line"), not the table lines
        assert_eq!(result.len(), 1, "Should only flag 1 line (the non-table long line)");
        assert_eq!(result[0].line, 7, "Should flag line 7");
        assert!(result[0].message.contains("24 exceeds 20"));
    }

    #[test]
    fn test_issue_78_tables_with_inline_code() {
        // Test that tables with inline code (backticks) are properly detected as tables
        let rule = MD013LineLength::new(20, false, false, false, false); // tables=false
        let content = r#"| column A | column B |
| -------- | -------- |
| `var with very long name` | `val exceeding limit` |
| value 1 | value 2 |

This line exceeds limit"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should only flag the last line, not the table lines
        assert_eq!(result.len(), 1, "Should only flag the non-table line");
        assert_eq!(result[0].line, 6, "Should flag line 6");
    }

    #[test]
    fn test_issue_78_indented_code_blocks() {
        // Test with indented code blocks instead of fenced
        let rule = MD013LineLength::new(20, false, false, false, false); // tables=false
        let content = r#"# heading

    some code block longer than 20 chars length

this is a very long line

| column A | column B |
| -------- | -------- |
| value 1 | value 2 |

correct length line"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should only flag line 5 ("this is a very long line"), not the table lines
        assert_eq!(result.len(), 1, "Should only flag 1 line (the non-table long line)");
        assert_eq!(result[0].line, 5, "Should flag line 5");
    }

    #[test]
    fn test_url_exemption() {
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "https://example.com/this/is/a/very/long/url/that/exceeds/the/limit";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_image_reference_exemption() {
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "![This is a very long image alt text that exceeds limit][reference]";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_link_reference_exemption() {
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "[reference]: https://example.com/very/long/url/that/exceeds/limit";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_strict_mode() {
        let rule = MD013LineLength::new(30, false, false, false, true);
        let content = "https://example.com/this/is/a/very/long/url/that/exceeds/the/limit";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // In strict mode, even URLs trigger warnings
        assert_eq!(result.len(), 1);
    }

    #[test]
    fn test_blockquote_exemption() {
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "> This is a very long line inside a blockquote that should be ignored.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_setext_heading_underline_exemption() {
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "Heading\n========================================";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // The underline should be exempt
        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_no_fix_without_reflow() {
        let rule = MD013LineLength::new(60, false, false, false, false);
        let content = "This line has trailing whitespace that makes it too long      ";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1);
        // Without reflow, no fix is provided
        assert!(result[0].fix.is_none());

        // Fix method returns content unchanged
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_character_vs_byte_counting() {
        let rule = MD013LineLength::new(10, false, false, false, false);
        // Unicode characters should count as 1 character each
        let content = "你好世界这是测试文字超过限制"; // 14 characters
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1);
        assert_eq!(result[0].line, 1);
    }

    #[test]
    fn test_empty_content() {
        let rule = MD013LineLength::default();
        let ctx = LintContext::new("", crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_excess_range_calculation() {
        let rule = MD013LineLength::new(10, false, false, false, false);
        let content = "12345678901234567890"; // 20 chars, limit is 10
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert_eq!(result.len(), 1);
        // The warning should highlight from character 11 onwards
        assert_eq!(result[0].column, 11);
        assert_eq!(result[0].end_column, 21);
    }

    #[test]
    fn test_html_block_exemption() {
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = "<div>\nThis is a very long line inside an HTML block that should be ignored.\n</div>";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // HTML blocks should be exempt
        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_mixed_content() {
        // code_blocks=false, tables=false, headings=false (all skipped/exempt)
        let rule = MD013LineLength::new(30, false, false, false, false);
        let content = r#"# This heading is very long but should be exempt

This regular paragraph line is too long and should trigger.

```
Code block line that is very long but exempt.
```

| Table | With very long content |
|-------|------------------------|

Another long line that should trigger a warning."#;

        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should have warnings for the two regular paragraph lines only
        assert_eq!(result.len(), 2);
        assert_eq!(result[0].line, 3);
        assert_eq!(result[1].line, 12);
    }

    #[test]
    fn test_fix_without_reflow_preserves_content() {
        let rule = MD013LineLength::new(50, false, false, false, false);
        let content = "Line 1\nThis line has trailing spaces and is too long      \nLine 3";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        // Without reflow, content is unchanged
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_content_detection() {
        let rule = MD013LineLength::default();

        // Use a line longer than default line_length (80) to ensure it's not skipped
        let long_line = "a".repeat(100);
        let ctx = LintContext::new(&long_line, crate::config::MarkdownFlavor::Standard);
        assert!(!rule.should_skip(&ctx)); // Should not skip processing when there's long content

        let empty_ctx = LintContext::new("", crate::config::MarkdownFlavor::Standard);
        assert!(rule.should_skip(&empty_ctx)); // Should skip processing when content is empty
    }

    #[test]
    fn test_rule_metadata() {
        let rule = MD013LineLength::default();
        assert_eq!(rule.name(), "MD013");
        assert_eq!(rule.description(), "Line length should not be excessive");
        assert_eq!(rule.category(), RuleCategory::Whitespace);
    }

    #[test]
    fn test_url_embedded_in_text() {
        let rule = MD013LineLength::new(50, false, false, false, false);

        // This line would be 85 chars, but only ~45 without the URL
        let content = "Check the docs at https://example.com/very/long/url/that/exceeds/limit for info";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should not flag because effective length (with URL placeholder) is under 50
        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_multiple_urls_in_line() {
        let rule = MD013LineLength::new(50, false, false, false, false);

        // Line with multiple URLs
        let content = "See https://first-url.com/long and https://second-url.com/also/very/long here";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let result = rule.check(&ctx).unwrap();

        // Should not flag because effective length is reasonable
        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_markdown_link_with_long_url() {
        let rule = MD013LineLength::new(50, false, false, false, false);

        // Markdown link with very long URL
        let content = "Check the [documentation](https://example.com/very/long/path/to/documentation/page) for details";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should not flag because effective length counts link as short
        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_line_too_long_even_without_urls() {
        let rule = MD013LineLength::new(50, false, false, false, false);

        // Line that's too long even after URL exclusion
        let content = "This is a very long line with lots of text and https://url.com that still exceeds the limit";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should flag because even with URL placeholder, line is too long
        assert_eq!(result.len(), 1);
    }

    #[test]
    fn test_strict_mode_counts_urls() {
        let rule = MD013LineLength::new(50, false, false, false, true); // strict=true

        // Same line that passes in non-strict mode
        let content = "Check the docs at https://example.com/very/long/url/that/exceeds/limit for info";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // In strict mode, should flag because full URL is counted
        assert_eq!(result.len(), 1);
    }

    #[test]
    fn test_documentation_example_from_md051() {
        let rule = MD013LineLength::new(80, false, false, false, false);

        // This is the actual line from md051.md that was causing issues
        let content = r#"For more information, see the [CommonMark specification](https://spec.commonmark.org/0.30/#link-reference-definitions)."#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should not flag because the URL is in a markdown link
        assert_eq!(result.len(), 0);
    }

    #[test]
    fn test_text_reflow_simple() {
        let config = MD013Config {
            line_length: 30,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a very long line that definitely exceeds thirty characters and needs to be wrapped.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();

        // Verify all lines are under 30 chars
        for line in fixed.lines() {
            assert!(
                line.chars().count() <= 30,
                "Line too long: {} (len={})",
                line,
                line.chars().count()
            );
        }

        // Verify content is preserved
        let fixed_words: Vec<&str> = fixed.split_whitespace().collect();
        let original_words: Vec<&str> = content.split_whitespace().collect();
        assert_eq!(fixed_words, original_words);
    }

    #[test]
    fn test_text_reflow_preserves_markdown_elements() {
        let config = MD013Config {
            line_length: 40,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This paragraph has **bold text** and *italic text* and [a link](https://example.com) that should be preserved.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();

        // Verify markdown elements are preserved
        assert!(fixed.contains("**bold text**"), "Bold text not preserved in: {fixed}");
        assert!(fixed.contains("*italic text*"), "Italic text not preserved in: {fixed}");
        assert!(
            fixed.contains("[a link](https://example.com)"),
            "Link not preserved in: {fixed}"
        );

        // Verify all lines are under 40 chars
        for line in fixed.lines() {
            assert!(line.len() <= 40, "Line too long: {line}");
        }
    }

    #[test]
    fn test_text_reflow_preserves_code_blocks() {
        let config = MD013Config {
            line_length: 30,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = r#"Here is some text.

```python
def very_long_function_name_that_exceeds_limit():
    return "This should not be wrapped"
```

More text after code block."#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();

        // Verify code block is preserved
        assert!(fixed.contains("def very_long_function_name_that_exceeds_limit():"));
        assert!(fixed.contains("```python"));
        assert!(fixed.contains("```"));
    }

    #[test]
    fn test_text_reflow_preserves_lists() {
        let config = MD013Config {
            line_length: 30,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = r#"Here is a list:

1. First item with a very long line that needs wrapping
2. Second item is short
3. Third item also has a long line that exceeds the limit

And a bullet list:

- Bullet item with very long content that needs wrapping
- Short bullet"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();

        // Verify list structure is preserved
        assert!(fixed.contains("1. "));
        assert!(fixed.contains("2. "));
        assert!(fixed.contains("3. "));
        assert!(fixed.contains("- "));

        // Verify proper indentation for wrapped lines
        let lines: Vec<&str> = fixed.lines().collect();
        for (i, line) in lines.iter().enumerate() {
            if line.trim().starts_with("1.") || line.trim().starts_with("2.") || line.trim().starts_with("3.") {
                // Check if next line is a continuation (should be indented with 3 spaces for numbered lists)
                if i + 1 < lines.len()
                    && !lines[i + 1].trim().is_empty()
                    && !lines[i + 1].trim().starts_with(char::is_numeric)
                    && !lines[i + 1].trim().starts_with("-")
                {
                    // Numbered list continuation lines should have 3 spaces
                    assert!(lines[i + 1].starts_with("   ") || lines[i + 1].trim().is_empty());
                }
            } else if line.trim().starts_with("-") {
                // Check if next line is a continuation (should be indented with 2 spaces for dash lists)
                if i + 1 < lines.len()
                    && !lines[i + 1].trim().is_empty()
                    && !lines[i + 1].trim().starts_with(char::is_numeric)
                    && !lines[i + 1].trim().starts_with("-")
                {
                    // Dash list continuation lines should have 2 spaces
                    assert!(lines[i + 1].starts_with("  ") || lines[i + 1].trim().is_empty());
                }
            }
        }
    }

    #[test]
    fn test_issue_83_numbered_list_with_backticks() {
        // Test for issue #83: enable_reflow was incorrectly handling numbered lists
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // The exact case from issue #83
        let content = "1. List `manifest` to find the manifest with the largest ID. Say it's `00000000000000000002.manifest` in this example.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();

        // The expected output: properly wrapped at 100 chars with correct list formatting
        // After the fix, it correctly accounts for "1. " (3 chars) leaving 97 for content
        let expected = "1. List `manifest` to find the manifest with the largest ID. Say it's\n   `00000000000000000002.manifest` in this example.";

        assert_eq!(
            fixed, expected,
            "List should be properly reflowed with correct marker and indentation.\nExpected:\n{expected}\nGot:\n{fixed}"
        );
    }

    #[test]
    fn test_text_reflow_disabled_by_default() {
        let rule = MD013LineLength::new(30, false, false, false, false);

        let content = "This is a very long line that definitely exceeds thirty characters.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();

        // Without reflow enabled, it should only trim whitespace (if any)
        // Since there's no trailing whitespace, content should be unchanged
        assert_eq!(fixed, content);
    }

    #[test]
    fn test_reflow_with_hard_line_breaks() {
        // Test that lines with exactly 2 trailing spaces are preserved as hard breaks
        let config = MD013Config {
            line_length: 40,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Test with exactly 2 spaces (hard line break)
        let content = "This line has a hard break at the end  \nAnd this continues on the next line that is also quite long and needs wrapping";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Should preserve the hard line break (2 spaces)
        assert!(
            fixed.contains("  \n"),
            "Hard line break with exactly 2 spaces should be preserved"
        );
    }

    #[test]
    fn test_reflow_preserves_reference_links() {
        let config = MD013Config {
            line_length: 40,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a very long line with a [reference link][ref] that should not be broken apart when reflowing the text.

[ref]: https://example.com";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Reference link should remain intact
        assert!(fixed.contains("[reference link][ref]"));
        assert!(!fixed.contains("[ reference link]"));
        assert!(!fixed.contains("[ref ]"));
    }

    #[test]
    fn test_reflow_with_nested_markdown_elements() {
        let config = MD013Config {
            line_length: 35,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This text has **bold with `code` inside** and should handle it properly when wrapping";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Nested elements should be preserved
        assert!(fixed.contains("**bold with `code` inside**"));
    }

    #[test]
    fn test_reflow_with_unbalanced_markdown() {
        // Test edge case with unbalanced markdown
        let config = MD013Config {
            line_length: 30,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This has **unbalanced bold that goes on for a very long time without closing";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Should handle gracefully without panic
        // The text reflow handles unbalanced markdown by treating it as a bold element
        // Check that the content is properly reflowed without panic
        assert!(!fixed.is_empty());
        // Verify the content is wrapped to 30 chars
        for line in fixed.lines() {
            assert!(line.len() <= 30 || line.starts_with("**"), "Line exceeds limit: {line}");
        }
    }

    #[test]
    fn test_reflow_fix_indicator() {
        // Test that reflow provides fix indicators
        let config = MD013Config {
            line_length: 30,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a very long line that definitely exceeds the thirty character limit";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let warnings = rule.check(&ctx).unwrap();

        // Should have a fix indicator when reflow is true
        assert!(!warnings.is_empty());
        assert!(
            warnings[0].fix.is_some(),
            "Should provide fix indicator when reflow is true"
        );
    }

    #[test]
    fn test_no_fix_indicator_without_reflow() {
        // Test that without reflow, no fix is provided
        let config = MD013Config {
            line_length: 30,
            reflow: false,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a very long line that definitely exceeds the thirty character limit";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let warnings = rule.check(&ctx).unwrap();

        // Should NOT have a fix indicator when reflow is false
        assert!(!warnings.is_empty());
        assert!(warnings[0].fix.is_none(), "Should not provide fix when reflow is false");
    }

    #[test]
    fn test_reflow_preserves_all_reference_link_types() {
        let config = MD013Config {
            line_length: 40,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "Test [full reference][ref] and [collapsed][] and [shortcut] reference links in a very long line.

[ref]: https://example.com
[collapsed]: https://example.com
[shortcut]: https://example.com";

        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // All reference link types should be preserved
        assert!(fixed.contains("[full reference][ref]"));
        assert!(fixed.contains("[collapsed][]"));
        assert!(fixed.contains("[shortcut]"));
    }

    #[test]
    fn test_reflow_handles_images_correctly() {
        let config = MD013Config {
            line_length: 40,
            reflow: true,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This line has an ![image alt text](https://example.com/image.png) that should not be broken when reflowing.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Image should remain intact
        assert!(fixed.contains("![image alt text](https://example.com/image.png)"));
    }

    #[test]
    fn test_normalize_mode_flags_short_lines() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Content with short lines that could be combined
        let content = "This is a short line.\nAnother short line.\nA third short line that could be combined.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let warnings = rule.check(&ctx).unwrap();

        // Should flag the paragraph as needing normalization
        assert!(!warnings.is_empty(), "Should flag paragraph for normalization");
        assert!(warnings[0].message.contains("normalized"));
    }

    #[test]
    fn test_normalize_mode_combines_short_lines() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Content with short lines that should be combined
        let content =
            "This is a line with\nmanual line breaks at\n80 characters that should\nbe combined into longer lines.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Should combine into a single line since it's under 100 chars total
        let lines: Vec<&str> = fixed.lines().collect();
        assert_eq!(lines.len(), 1, "Should combine into single line");
        assert!(lines[0].len() > 80, "Should use more of the 100 char limit");
    }

    #[test]
    fn test_normalize_mode_preserves_paragraph_breaks() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "First paragraph with\nshort lines.\n\nSecond paragraph with\nshort lines too.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Should preserve paragraph breaks (empty lines)
        assert!(fixed.contains("\n\n"), "Should preserve paragraph breaks");

        let paragraphs: Vec<&str> = fixed.split("\n\n").collect();
        assert_eq!(paragraphs.len(), 2, "Should have two paragraphs");
    }

    #[test]
    fn test_default_mode_only_fixes_violations() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Default, // Default mode
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Content with short lines that are NOT violations
        let content = "This is a short line.\nAnother short line.\nA third short line.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let warnings = rule.check(&ctx).unwrap();

        // Should NOT flag anything in default mode
        assert!(warnings.is_empty(), "Should not flag short lines in default mode");

        // Fix should preserve the short lines
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed.lines().count(), 3, "Should preserve line breaks in default mode");
    }

    #[test]
    fn test_normalize_mode_with_lists() {
        let config = MD013Config {
            line_length: 80,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = r#"A paragraph with
short lines.

1. List item with
   short lines
2. Another item"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Should normalize the paragraph but preserve list structure
        let lines: Vec<&str> = fixed.lines().collect();
        assert!(lines[0].len() > 20, "First paragraph should be normalized");
        assert!(fixed.contains("1. "), "Should preserve list markers");
        assert!(fixed.contains("2. "), "Should preserve list markers");
    }

    #[test]
    fn test_normalize_mode_with_code_blocks() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = r#"A paragraph with
short lines.

```
code block should not be normalized
even with short lines
```

Another paragraph with
short lines."#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Code block should be preserved as-is
        assert!(fixed.contains("code block should not be normalized\neven with short lines"));
        // But paragraphs should be normalized
        let lines: Vec<&str> = fixed.lines().collect();
        assert!(lines[0].len() > 20, "First paragraph should be normalized");
    }

    #[test]
    fn test_issue_76_use_case() {
        // This tests the exact use case from issue #76
        let config = MD013Config {
            line_length: 999999, // Set absurdly high
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Content with manual line breaks at 80 characters (typical markdown)
        let content = "We've decided to eliminate line-breaks in paragraphs. The obvious solution is\nto disable MD013, and call it good. However, that doesn't deal with the\nexisting content's line-breaks. My initial thought was to set line_length to\n999999 and enable_reflow, but realised after doing so, that it never triggers\nthe error, so nothing happens.";

        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        // Should flag for normalization even though no lines exceed limit
        let warnings = rule.check(&ctx).unwrap();
        assert!(!warnings.is_empty(), "Should flag paragraph for normalization");

        // Should combine into a single line
        let fixed = rule.fix(&ctx).unwrap();
        let lines: Vec<&str> = fixed.lines().collect();
        assert_eq!(lines.len(), 1, "Should combine into single line with high limit");
        assert!(!fixed.contains("\n"), "Should remove all line breaks within paragraph");
    }

    #[test]
    fn test_normalize_mode_single_line_unchanged() {
        // Single lines should not be flagged or changed
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a single line that should not be changed.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let warnings = rule.check(&ctx).unwrap();
        assert!(warnings.is_empty(), "Single line should not be flagged");

        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, content, "Single line should remain unchanged");
    }

    #[test]
    fn test_normalize_mode_with_inline_code() {
        let config = MD013Config {
            line_length: 80,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content =
            "This paragraph has `inline code` and\nshould still be normalized properly\nwithout breaking the code.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let warnings = rule.check(&ctx).unwrap();
        assert!(!warnings.is_empty(), "Multi-line paragraph should be flagged");

        let fixed = rule.fix(&ctx).unwrap();
        assert!(fixed.contains("`inline code`"), "Inline code should be preserved");
        assert!(fixed.lines().count() < 3, "Lines should be combined");
    }

    #[test]
    fn test_normalize_mode_with_emphasis() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This has **bold** and\n*italic* text that\nshould be preserved.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        assert!(fixed.contains("**bold**"), "Bold should be preserved");
        assert!(fixed.contains("*italic*"), "Italic should be preserved");
        assert_eq!(fixed.lines().count(), 1, "Should be combined into one line");
    }

    #[test]
    fn test_normalize_mode_respects_hard_breaks() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Two spaces at end of line = hard break
        let content = "First line with hard break  \nSecond line after break\nThird line";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        // Hard break should be preserved
        assert!(fixed.contains("  \n"), "Hard break should be preserved");
        // But lines without hard break should be combined
        assert!(
            fixed.contains("Second line after break Third line"),
            "Lines without hard break should combine"
        );
    }

    #[test]
    fn test_normalize_mode_with_links() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content =
            "This has a [link](https://example.com) that\nshould be preserved when\nnormalizing the paragraph.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        assert!(
            fixed.contains("[link](https://example.com)"),
            "Link should be preserved"
        );
        assert_eq!(fixed.lines().count(), 1, "Should be combined into one line");
    }

    #[test]
    fn test_normalize_mode_empty_lines_between_paragraphs() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "First paragraph\nwith multiple lines.\n\n\nSecond paragraph\nwith multiple lines.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        // Multiple empty lines should be preserved
        assert!(fixed.contains("\n\n\n"), "Multiple empty lines should be preserved");
        // Each paragraph should be normalized
        let parts: Vec<&str> = fixed.split("\n\n\n").collect();
        assert_eq!(parts.len(), 2, "Should have two parts");
        assert_eq!(parts[0].lines().count(), 1, "First paragraph should be one line");
        assert_eq!(parts[1].lines().count(), 1, "Second paragraph should be one line");
    }

    #[test]
    fn test_normalize_mode_mixed_list_types() {
        let config = MD013Config {
            line_length: 80,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = r#"Paragraph before list
with multiple lines.

- Bullet item
* Another bullet
+ Plus bullet

1. Numbered item
2. Another number

Paragraph after list
with multiple lines."#;

        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Lists should be preserved
        assert!(fixed.contains("- Bullet item"), "Dash list should be preserved");
        assert!(fixed.contains("* Another bullet"), "Star list should be preserved");
        assert!(fixed.contains("+ Plus bullet"), "Plus list should be preserved");
        assert!(fixed.contains("1. Numbered item"), "Numbered list should be preserved");

        // But paragraphs should be normalized
        assert!(
            fixed.starts_with("Paragraph before list with multiple lines."),
            "First paragraph should be normalized"
        );
        assert!(
            fixed.ends_with("Paragraph after list with multiple lines."),
            "Last paragraph should be normalized"
        );
    }

    #[test]
    fn test_normalize_mode_with_horizontal_rules() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "Paragraph before\nhorizontal rule.\n\n---\n\nParagraph after\nhorizontal rule.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        assert!(fixed.contains("---"), "Horizontal rule should be preserved");
        assert!(
            fixed.contains("Paragraph before horizontal rule."),
            "First paragraph normalized"
        );
        assert!(
            fixed.contains("Paragraph after horizontal rule."),
            "Second paragraph normalized"
        );
    }

    #[test]
    fn test_normalize_mode_with_indented_code() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "Paragraph before\nindented code.\n\n    This is indented code\n    Should not be normalized\n\nParagraph after\nindented code.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        assert!(
            fixed.contains("    This is indented code\n    Should not be normalized"),
            "Indented code preserved"
        );
        assert!(
            fixed.contains("Paragraph before indented code."),
            "First paragraph normalized"
        );
        assert!(
            fixed.contains("Paragraph after indented code."),
            "Second paragraph normalized"
        );
    }

    #[test]
    fn test_normalize_mode_disabled_without_reflow() {
        // Normalize mode should have no effect if reflow is disabled
        let config = MD013Config {
            line_length: 100,
            reflow: false, // Disabled
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a line\nwith breaks that\nshould not be changed.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let warnings = rule.check(&ctx).unwrap();
        assert!(warnings.is_empty(), "Should not flag when reflow is disabled");

        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, content, "Content should be unchanged when reflow is disabled");
    }

    #[test]
    fn test_default_mode_with_long_lines() {
        // Default mode should fix paragraphs that contain lines exceeding limit
        // The paragraph-based approach treats consecutive lines as a unit
        let config = MD013Config {
            line_length: 50,
            reflow: true,
            reflow_mode: ReflowMode::Default,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "Short line.\nThis is a very long line that definitely exceeds the fifty character limit and needs wrapping.\nAnother short line.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let warnings = rule.check(&ctx).unwrap();
        assert_eq!(warnings.len(), 1, "Should flag the paragraph with long line");
        // The warning reports the line that violates in default mode
        assert_eq!(warnings[0].line, 2, "Should flag line 2 that exceeds limit");

        let fixed = rule.fix(&ctx).unwrap();
        // The paragraph gets reflowed as a unit
        assert!(
            fixed.contains("Short line. This is"),
            "Should combine and reflow the paragraph"
        );
        assert!(
            fixed.contains("wrapping. Another short"),
            "Should include all paragraph content"
        );
    }

    #[test]
    fn test_normalize_vs_default_mode_same_content() {
        let content = "This is a paragraph\nwith multiple lines\nthat could be combined.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        // Test default mode
        let default_config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Default,
            ..Default::default()
        };
        let default_rule = MD013LineLength::from_config_struct(default_config);
        let default_warnings = default_rule.check(&ctx).unwrap();
        let default_fixed = default_rule.fix(&ctx).unwrap();

        // Test normalize mode
        let normalize_config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let normalize_rule = MD013LineLength::from_config_struct(normalize_config);
        let normalize_warnings = normalize_rule.check(&ctx).unwrap();
        let normalize_fixed = normalize_rule.fix(&ctx).unwrap();

        // Verify different behavior
        assert!(default_warnings.is_empty(), "Default mode should not flag short lines");
        assert!(
            !normalize_warnings.is_empty(),
            "Normalize mode should flag multi-line paragraphs"
        );

        assert_eq!(
            default_fixed, content,
            "Default mode should not change content without violations"
        );
        assert_ne!(
            normalize_fixed, content,
            "Normalize mode should change multi-line paragraphs"
        );
        assert_eq!(
            normalize_fixed.lines().count(),
            1,
            "Normalize should combine into single line"
        );
    }

    #[test]
    fn test_normalize_mode_with_reference_definitions() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content =
            "This paragraph uses\na reference [link][ref]\nacross multiple lines.\n\n[ref]: https://example.com";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        assert!(fixed.contains("[link][ref]"), "Reference link should be preserved");
        assert!(
            fixed.contains("[ref]: https://example.com"),
            "Reference definition should be preserved"
        );
        assert!(
            fixed.starts_with("This paragraph uses a reference [link][ref] across multiple lines."),
            "Paragraph should be normalized"
        );
    }

    #[test]
    fn test_normalize_mode_with_html_comments() {
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "Paragraph before\nHTML comment.\n\n<!-- This is a comment -->\n\nParagraph after\nHTML comment.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        assert!(
            fixed.contains("<!-- This is a comment -->"),
            "HTML comment should be preserved"
        );
        assert!(
            fixed.contains("Paragraph before HTML comment."),
            "First paragraph normalized"
        );
        assert!(
            fixed.contains("Paragraph after HTML comment."),
            "Second paragraph normalized"
        );
    }

    #[test]
    fn test_normalize_mode_line_starting_with_number() {
        // Regression test for the bug we fixed where "80 characters" was treated as a list
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This line mentions\n80 characters which\nshould not break the paragraph.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed.lines().count(), 1, "Should be combined into single line");
        assert!(
            fixed.contains("80 characters"),
            "Number at start of line should be preserved"
        );
    }

    #[test]
    fn test_default_mode_preserves_list_structure() {
        // In default mode, list continuation lines should be preserved
        let config = MD013Config {
            line_length: 80,
            reflow: true,
            reflow_mode: ReflowMode::Default,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = r#"- This is a bullet point that has
  some text on multiple lines
  that should stay separate

1. Numbered list item with
   multiple lines that should
   also stay separate"#;

        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // In default mode, the structure should be preserved
        let lines: Vec<&str> = fixed.lines().collect();
        assert_eq!(
            lines[0], "- This is a bullet point that has",
            "First line should be unchanged"
        );
        assert_eq!(
            lines[1], "  some text on multiple lines",
            "Continuation should be preserved"
        );
        assert_eq!(
            lines[2], "  that should stay separate",
            "Second continuation should be preserved"
        );
    }

    #[test]
    fn test_normalize_mode_multi_line_list_items_no_extra_spaces() {
        // Test that multi-line list items don't get extra spaces when normalized
        let config = MD013Config {
            line_length: 80,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = r#"- This is a bullet point that has
  some text on multiple lines
  that should be combined

1. Numbered list item with
   multiple lines that need
   to be properly combined
2. Second item"#;

        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let fixed = rule.fix(&ctx).unwrap();

        // Check that there are no extra spaces in the combined list items
        assert!(
            !fixed.contains("lines  that"),
            "Should not have double spaces in bullet list"
        );
        assert!(
            !fixed.contains("need  to"),
            "Should not have double spaces in numbered list"
        );

        // Check that the list items are properly combined
        assert!(
            fixed.contains("- This is a bullet point that has some text on multiple lines that should be"),
            "Bullet list should be properly combined"
        );
        assert!(
            fixed.contains("1. Numbered list item with multiple lines that need to be properly combined"),
            "Numbered list should be properly combined"
        );
    }

    #[test]
    fn test_normalize_mode_actual_numbered_list() {
        // Ensure actual numbered lists are still detected correctly
        let config = MD013Config {
            line_length: 100,
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "Paragraph before list\nwith multiple lines.\n\n1. First item\n2. Second item\n10. Tenth item";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        let fixed = rule.fix(&ctx).unwrap();
        assert!(fixed.contains("1. First item"), "Numbered list 1 should be preserved");
        assert!(fixed.contains("2. Second item"), "Numbered list 2 should be preserved");
        assert!(fixed.contains("10. Tenth item"), "Numbered list 10 should be preserved");
        assert!(
            fixed.starts_with("Paragraph before list with multiple lines."),
            "Paragraph should be normalized"
        );
    }

    #[test]
    fn test_sentence_per_line_detection() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config.clone());

        // Test detection of multiple sentences
        let content = "This is sentence one. This is sentence two. And sentence three!";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);

        // Debug: check if should_skip returns false
        assert!(!rule.should_skip(&ctx), "Should not skip for sentence-per-line mode");

        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty(), "Should detect multiple sentences on one line");
        assert_eq!(
            result[0].message,
            "Line contains 3 sentences (one sentence per line required)"
        );
    }

    #[test]
    fn test_sentence_per_line_fix() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "First sentence. Second sentence.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty(), "Should detect violation");
        assert!(result[0].fix.is_some(), "Should provide a fix");

        let fix = result[0].fix.as_ref().unwrap();
        assert_eq!(fix.replacement.trim(), "First sentence.\nSecond sentence.");
    }

    #[test]
    fn test_sentence_per_line_abbreviations() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Should NOT trigger on abbreviations
        let content = "Mr. Smith met Dr. Jones at 3:00 PM.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(
            result.is_empty(),
            "Should not detect abbreviations as sentence boundaries"
        );
    }

    #[test]
    fn test_sentence_per_line_with_markdown() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "# Heading\n\nSentence with **bold**. Another with [link](url).";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty(), "Should detect multiple sentences with markdown");
        assert_eq!(result[0].line, 3); // Third line has the violation
    }

    #[test]
    fn test_sentence_per_line_questions_exclamations() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "Is this a question? Yes it is! And a statement.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty(), "Should detect sentences with ? and !");

        let fix = result[0].fix.as_ref().unwrap();
        let lines: Vec<&str> = fix.replacement.trim().lines().collect();
        assert_eq!(lines.len(), 3);
        assert_eq!(lines[0], "Is this a question?");
        assert_eq!(lines[1], "Yes it is!");
        assert_eq!(lines[2], "And a statement.");
    }

    #[test]
    fn test_sentence_per_line_in_lists() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "- List item one. With two sentences.\n- Another item.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty(), "Should detect sentences in list items");
        // The fix should preserve list formatting
        let fix = result[0].fix.as_ref().unwrap();
        assert!(fix.replacement.starts_with("- "), "Should preserve list marker");
    }

    #[test]
    fn test_multi_paragraph_list_item_with_3_space_indent() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 999999,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "1. First paragraph\n   continuation line.\n\n   Second paragraph\n   more content.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty(), "Should detect multi-line paragraphs in list item");
        let fix = result[0].fix.as_ref().unwrap();

        // Should preserve paragraph structure, not collapse everything
        assert!(
            fix.replacement.contains("\n\n"),
            "Should preserve blank line between paragraphs"
        );
        assert!(fix.replacement.starts_with("1. "), "Should preserve list marker");
    }

    #[test]
    fn test_multi_paragraph_list_item_with_4_space_indent() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 999999,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // User's example from issue #76 - uses 4 spaces for continuation
        let content = "1. It **generated an application template**. There's a lot of files and\n    configurations required to build a native installer, above and\n    beyond the code of your actual application.\n\n    If you're not happy with the template provided by Briefcase, you can\n    provide your own.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(
            !result.is_empty(),
            "Should detect multi-line paragraphs in list item with 4-space indent"
        );
        let fix = result[0].fix.as_ref().unwrap();

        // Should preserve paragraph structure
        assert!(
            fix.replacement.contains("\n\n"),
            "Should preserve blank line between paragraphs"
        );
        assert!(fix.replacement.starts_with("1. "), "Should preserve list marker");

        // Both paragraphs should be reflowed but kept separate
        let lines: Vec<&str> = fix.replacement.split('\n').collect();
        let blank_line_idx = lines.iter().position(|l| l.trim().is_empty());
        assert!(blank_line_idx.is_some(), "Should have blank line separating paragraphs");
    }

    #[test]
    fn test_multi_paragraph_bullet_list_item() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 999999,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "- First paragraph\n  continuation.\n\n  Second paragraph\n  more text.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty(), "Should detect multi-line paragraphs in bullet list");
        let fix = result[0].fix.as_ref().unwrap();

        assert!(
            fix.replacement.contains("\n\n"),
            "Should preserve blank line between paragraphs"
        );
        assert!(fix.replacement.starts_with("- "), "Should preserve bullet marker");
    }

    #[test]
    fn test_code_block_in_list_item_five_spaces() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 80,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // 5 spaces = code block indentation (marker_len=3 + 4 = 7, but we have 5 which is marker_len+2, still valid continuation but >= marker_len+4 would be code)
        // For "1. " marker (3 chars), 3+4=7 spaces would be code block
        let content = "1. First paragraph with some text that should be reflowed.\n\n       code_block()\n       more_code()\n\n   Second paragraph.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        if !result.is_empty() {
            let fix = result[0].fix.as_ref().unwrap();
            // Code block lines should NOT be reflowed - they should be preserved with original indentation
            assert!(
                fix.replacement.contains("       code_block()"),
                "Code block should be preserved: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("       more_code()"),
                "Code block should be preserved: {}",
                fix.replacement
            );
        }
    }

    #[test]
    fn test_fenced_code_block_in_list_item() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 80,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "1. First paragraph with some text.\n\n   ```rust\n   fn foo() {}\n   let x = 1;\n   ```\n\n   Second paragraph.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        if !result.is_empty() {
            let fix = result[0].fix.as_ref().unwrap();
            // Fenced code block should be preserved
            assert!(
                fix.replacement.contains("```rust"),
                "Should preserve fence: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("fn foo() {}"),
                "Should preserve code: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("```"),
                "Should preserve closing fence: {}",
                fix.replacement
            );
        }
    }

    #[test]
    fn test_mixed_indentation_3_and_4_spaces() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 999999,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // First continuation has 3 spaces, second has 4 - both should be accepted
        let content = "1. Text\n   3 space continuation\n    4 space continuation";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        assert!(!result.is_empty(), "Should detect multi-line list item");
        let fix = result[0].fix.as_ref().unwrap();
        // Should reflow all content together
        assert!(
            fix.replacement.contains("3 space continuation"),
            "Should include 3-space line: {}",
            fix.replacement
        );
        assert!(
            fix.replacement.contains("4 space continuation"),
            "Should include 4-space line: {}",
            fix.replacement
        );
    }

    #[test]
    fn test_nested_list_in_multi_paragraph_item() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 999999,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "1. First paragraph.\n\n   - Nested item\n     continuation\n\n   Second paragraph.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Nested lists at continuation indent should be INCLUDED in parent item
        assert!(!result.is_empty(), "Should detect and reflow parent item");
        if let Some(fix) = result[0].fix.as_ref() {
            // The nested list should be preserved in the output
            assert!(
                fix.replacement.contains("- Nested"),
                "Should preserve nested list: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("Second paragraph"),
                "Should include content after nested list: {}",
                fix.replacement
            );
        }
    }

    #[test]
    fn test_nested_fence_markers_different_types() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 80,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Nested fences with different markers (backticks inside tildes)
        let content = "1. Example with nested fences:\n\n   ~~~markdown\n   This shows ```python\n   code = True\n   ```\n   ~~~\n\n   Text after.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        if !result.is_empty() {
            let fix = result[0].fix.as_ref().unwrap();
            // Inner fence should NOT close outer fence (different markers)
            assert!(
                fix.replacement.contains("```python"),
                "Should preserve inner fence: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("~~~"),
                "Should preserve outer fence: {}",
                fix.replacement
            );
            // All lines should remain as code
            assert!(
                fix.replacement.contains("code = True"),
                "Should preserve code: {}",
                fix.replacement
            );
        }
    }

    #[test]
    fn test_nested_fence_markers_same_type() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 80,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Nested backticks - inner must have different length or won't work
        let content =
            "1. Example:\n\n   ````markdown\n   Shows ```python in code\n   ```\n   text here\n   ````\n\n   After.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        if !result.is_empty() {
            let fix = result[0].fix.as_ref().unwrap();
            // 4 backticks opened, 3 backticks shouldn't close it
            assert!(
                fix.replacement.contains("```python"),
                "Should preserve inner fence: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("````"),
                "Should preserve outer fence: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("text here"),
                "Should keep text as code: {}",
                fix.replacement
            );
        }
    }

    #[test]
    fn test_sibling_list_item_breaks_parent() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 999999,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Sibling list item (at indent 0, before parent marker at 3)
        let content = "1. First item\n   continuation.\n2. Second item";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should process first item only, second item breaks it
        if !result.is_empty() {
            let fix = result[0].fix.as_ref().unwrap();
            // Should only include first item
            assert!(fix.replacement.starts_with("1. "), "Should start with first marker");
            assert!(fix.replacement.contains("continuation"), "Should include continuation");
            // Should NOT include second item (it's outside the byte range)
        }
    }

    #[test]
    fn test_nested_list_at_continuation_indent_preserved() {
        let config = MD013Config {
            reflow: true,
            reflow_mode: ReflowMode::Normalize,
            line_length: 999999,
            ..Default::default()
        };
        let rule = MD013LineLength::from_config_struct(config);

        // Nested list at exactly continuation indent (3 spaces for "1. ")
        let content = "1. Parent paragraph\n   with continuation.\n\n   - Nested at 3 spaces\n   - Another nested\n\n   After nested.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        if !result.is_empty() {
            let fix = result[0].fix.as_ref().unwrap();
            // All nested content should be preserved
            assert!(
                fix.replacement.contains("- Nested"),
                "Should include first nested item: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("- Another"),
                "Should include second nested item: {}",
                fix.replacement
            );
            assert!(
                fix.replacement.contains("After nested"),
                "Should include content after nested list: {}",
                fix.replacement
            );
        }
    }

    #[test]
    fn test_paragraphs_false_skips_regular_text() {
        // Test that paragraphs=false skips checking regular text
        let config = MD013Config {
            line_length: 50,
            paragraphs: false, // Don't check paragraphs
            code_blocks: true,
            tables: true,
            headings: true,
            strict: false,
            reflow: false,
            reflow_mode: ReflowMode::default(),
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content =
            "This is a very long line of regular text that exceeds fifty characters and should not trigger a warning.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should not report any warnings when paragraphs=false
        assert_eq!(
            result.len(),
            0,
            "Should not warn about long paragraph text when paragraphs=false"
        );
    }

    #[test]
    fn test_paragraphs_false_still_checks_code_blocks() {
        // Test that paragraphs=false still checks code blocks
        let config = MD013Config {
            line_length: 50,
            paragraphs: false, // Don't check paragraphs
            code_blocks: true, // But DO check code blocks
            tables: true,
            headings: true,
            strict: false,
            reflow: false,
            reflow_mode: ReflowMode::default(),
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = r#"```
This is a very long line in a code block that exceeds fifty characters.
```"#;
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // SHOULD report warnings for code blocks even when paragraphs=false
        assert_eq!(
            result.len(),
            1,
            "Should warn about long lines in code blocks even when paragraphs=false"
        );
    }

    #[test]
    fn test_paragraphs_false_still_checks_headings() {
        // Test that paragraphs=false still checks headings
        let config = MD013Config {
            line_length: 50,
            paragraphs: false, // Don't check paragraphs
            code_blocks: true,
            tables: true,
            headings: true, // But DO check headings
            strict: false,
            reflow: false,
            reflow_mode: ReflowMode::default(),
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "# This is a very long heading that exceeds fifty characters and should trigger a warning";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // SHOULD report warnings for headings even when paragraphs=false
        assert_eq!(
            result.len(),
            1,
            "Should warn about long headings even when paragraphs=false"
        );
    }

    #[test]
    fn test_paragraphs_false_with_reflow_sentence_per_line() {
        // Test issue #121 use case: paragraphs=false with sentence-per-line reflow
        let config = MD013Config {
            line_length: 80,
            paragraphs: false,
            code_blocks: true,
            tables: true,
            headings: false,
            strict: false,
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a very long sentence that exceeds eighty characters and contains important information that should not be flagged.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should NOT warn when paragraphs=false
        assert_eq!(
            result.len(),
            0,
            "Should not warn about long sentences when paragraphs=false"
        );
    }

    #[test]
    fn test_paragraphs_true_checks_regular_text() {
        // Test that paragraphs=true (default) checks regular text
        let config = MD013Config {
            line_length: 50,
            paragraphs: true, // Default: DO check paragraphs
            code_blocks: true,
            tables: true,
            headings: true,
            strict: false,
            reflow: false,
            reflow_mode: ReflowMode::default(),
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a very long line of regular text that exceeds fifty characters.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // SHOULD report warnings when paragraphs=true
        assert_eq!(
            result.len(),
            1,
            "Should warn about long paragraph text when paragraphs=true"
        );
    }

    #[test]
    fn test_line_length_zero_disables_all_checks() {
        // Test that line_length = 0 disables all line length checks
        let config = MD013Config {
            line_length: 0, // 0 = no limit
            paragraphs: true,
            code_blocks: true,
            tables: true,
            headings: true,
            strict: false,
            reflow: false,
            reflow_mode: ReflowMode::default(),
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is a very very very very very very very very very very very very very very very very very very very very very very very very long line that would normally trigger MD013.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should NOT warn when line_length = 0
        assert_eq!(
            result.len(),
            0,
            "Should not warn about any line length when line_length = 0"
        );
    }

    #[test]
    fn test_line_length_zero_with_headings() {
        // Test that line_length = 0 disables checks even for headings
        let config = MD013Config {
            line_length: 0, // 0 = no limit
            paragraphs: true,
            code_blocks: true,
            tables: true,
            headings: true, // Even with headings enabled
            strict: false,
            reflow: false,
            reflow_mode: ReflowMode::default(),
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "# This is a very very very very very very very very very very very very very very very very very very very very very long heading";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should NOT warn when line_length = 0
        assert_eq!(
            result.len(),
            0,
            "Should not warn about heading line length when line_length = 0"
        );
    }

    #[test]
    fn test_line_length_zero_with_code_blocks() {
        // Test that line_length = 0 disables checks even for code blocks
        let config = MD013Config {
            line_length: 0, // 0 = no limit
            paragraphs: true,
            code_blocks: true, // Even with code_blocks enabled
            tables: true,
            headings: true,
            strict: false,
            reflow: false,
            reflow_mode: ReflowMode::default(),
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "```\nThis is a very very very very very very very very very very very very very very very very very very very very very long code line\n```";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should NOT warn when line_length = 0
        assert_eq!(
            result.len(),
            0,
            "Should not warn about code block line length when line_length = 0"
        );
    }

    #[test]
    fn test_line_length_zero_with_sentence_per_line_reflow() {
        // Test issue #121 use case: line_length = 0 with sentence-per-line reflow
        let config = MD013Config {
            line_length: 0, // 0 = no limit
            paragraphs: true,
            code_blocks: true,
            tables: true,
            headings: true,
            strict: false,
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
        };
        let rule = MD013LineLength::from_config_struct(config);

        let content = "This is sentence one. This is sentence two. This is sentence three.";
        let ctx = crate::lint_context::LintContext::new(content, crate::config::MarkdownFlavor::Standard);
        let result = rule.check(&ctx).unwrap();

        // Should have warnings with fixes (reflow enabled)
        assert_eq!(result.len(), 1, "Should provide reflow fix for multiple sentences");
        assert!(result[0].fix.is_some(), "Should have a fix available");
    }

    #[test]
    fn test_line_length_zero_config_parsing() {
        // Test that line_length = 0 can be parsed from TOML config
        let toml_str = r#"
            line-length = 0
            paragraphs = true
            reflow = true
            reflow-mode = "sentence-per-line"
        "#;
        let config: MD013Config = toml::from_str(toml_str).unwrap();
        assert_eq!(config.line_length, 0, "Should parse line_length = 0");
        assert!(config.paragraphs);
        assert!(config.reflow);
        assert_eq!(config.reflow_mode, ReflowMode::SentencePerLine);
    }

    #[test]
    fn test_template_directives_as_paragraph_boundaries() {
        // mdBook template tags should act as paragraph boundaries
        let content = r#"Some regular text here.

{{#tabs }}
{{#tab name="Tab 1" }}

More text in the tab.

{{#endtab }}
{{#tabs }}

Final paragraph.
"#;

        let ctx = LintContext::new(content, MarkdownFlavor::Standard);
        let config = MD013Config {
            line_length: 80,
            code_blocks: true,
            tables: true,
            headings: true,
            paragraphs: true,
            strict: false,
            reflow: true,
            reflow_mode: ReflowMode::SentencePerLine,
        };
        let rule = MD013LineLength::from_config_struct(config);
        let result = rule.check(&ctx).unwrap();

        // Template directives should not be flagged as "multiple sentences"
        // because they act as paragraph boundaries
        for warning in &result {
            assert!(
                !warning.message.contains("multiple sentences"),
                "Template directives should not trigger 'multiple sentences' warning. Got: {}",
                warning.message
            );
        }
    }

    #[test]
    fn test_template_directive_detection() {
        // Handlebars/mdBook/Mustache syntax
        assert!(is_template_directive_only("{{#tabs }}"));
        assert!(is_template_directive_only("{{#endtab }}"));
        assert!(is_template_directive_only("{{variable}}"));
        assert!(is_template_directive_only("  {{#tabs }}  "));

        // Jinja2/Liquid syntax
        assert!(is_template_directive_only("{% for item in items %}"));
        assert!(is_template_directive_only("{%endfor%}"));
        assert!(is_template_directive_only("  {% if condition %}  "));

        // Not template directives
        assert!(!is_template_directive_only("This is {{variable}} in text"));
        assert!(!is_template_directive_only("{{incomplete"));
        assert!(!is_template_directive_only("incomplete}}"));
        assert!(!is_template_directive_only(""));
        assert!(!is_template_directive_only("   "));
        assert!(!is_template_directive_only("Regular text"));
    }

    #[test]
    fn test_mixed_content_with_templates() {
        // Lines with mixed content should NOT be treated as template directives
        let content = "This has {{variable}} in the middle.";
        assert!(!is_template_directive_only(content));

        let content2 = "Start {{#something}} end";
        assert!(!is_template_directive_only(content2));
    }
}