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rumdl_lib/rules/
md013_line_length.rs

1/// Rule MD013: Line length
2///
3/// See [docs/md013.md](../../docs/md013.md) for full documentation, configuration, and examples.
4use crate::rule::{LintError, LintResult, LintWarning, Rule, RuleCategory, Severity};
5use crate::rule_config_serde::RuleConfig;
6use crate::utils::mkdocs_admonitions;
7use crate::utils::mkdocs_attr_list::is_standalone_attr_list;
8use crate::utils::mkdocs_snippets::is_snippet_block_delimiter;
9use crate::utils::mkdocs_tabs;
10use crate::utils::range_utils::LineIndex;
11use crate::utils::range_utils::calculate_excess_range;
12use crate::utils::regex_cache::{IMAGE_REF_PATTERN, LINK_REF_PATTERN, URL_PATTERN};
13use crate::utils::table_utils::TableUtils;
14use crate::utils::text_reflow::{
15    BlockquoteLineData, ReflowLengthMode, blockquote_continuation_style, dominant_blockquote_prefix,
16    reflow_blockquote_content, split_into_sentences,
17};
18use pulldown_cmark::LinkType;
19use toml;
20
21mod block_builder;
22mod helpers;
23pub mod md013_config;
24use crate::utils::is_template_directive_only;
25use block_builder::{Block, BlockBuilder};
26use helpers::{
27    extract_list_marker_and_content, has_hard_break, is_github_alert_marker, is_horizontal_rule, is_html_only_line,
28    is_list_item, is_standalone_link_or_image_line, is_unwrappable_line, split_into_segments,
29    trim_preserving_hard_break,
30};
31pub use md013_config::MD013Config;
32use md013_config::{LengthMode, ReflowMode};
33
34#[cfg(test)]
35mod tests;
36use unicode_width::UnicodeWidthStr;
37
38#[derive(Clone, Default)]
39pub struct MD013LineLength {
40    pub(crate) config: MD013Config,
41}
42
43/// Blockquote paragraph line collected for reflow, with original line index for range computation.
44struct CollectedBlockquoteLine {
45    line_idx: usize,
46    data: BlockquoteLineData,
47}
48
49impl MD013LineLength {
50    pub fn new(line_length: usize, code_blocks: bool, tables: bool, headings: bool, strict: bool) -> Self {
51        Self {
52            config: MD013Config {
53                line_length: crate::types::LineLength::new(line_length),
54                code_blocks,
55                code_spans: true,
56                tables,
57                headings,
58                paragraphs: true,  // Default to true for backwards compatibility
59                blockquotes: true, // Default to true for backwards compatibility
60                strict,
61                stern: false,
62                heading_line_length: None,
63                code_block_line_length: None,
64                reflow: false,
65                reflow_mode: ReflowMode::default(),
66                length_mode: LengthMode::default(),
67                abbreviations: Vec::new(),
68                require_sentence_capital: true,
69            },
70        }
71    }
72
73    pub fn from_config_struct(config: MD013Config) -> Self {
74        Self { config }
75    }
76
77    /// Return a clone with code block checking disabled.
78    /// Used for doc comment linting where code blocks are Rust code managed by rustfmt.
79    pub fn with_code_blocks_disabled(&self) -> Self {
80        let mut clone = self.clone();
81        clone.config.code_blocks = false;
82        clone
83    }
84
85    /// Convert MD013 LengthMode to text_reflow ReflowLengthMode
86    fn reflow_length_mode(&self) -> ReflowLengthMode {
87        match self.config.length_mode {
88            LengthMode::Chars => ReflowLengthMode::Chars,
89            LengthMode::Visual => ReflowLengthMode::Visual,
90            LengthMode::Bytes => ReflowLengthMode::Bytes,
91        }
92    }
93
94    fn should_ignore_line(
95        &self,
96        line: &str,
97        _lines: &[&str],
98        current_line: usize,
99        ctx: &crate::lint_context::LintContext,
100    ) -> bool {
101        if self.config.strict {
102            return false;
103        }
104
105        // Quick check for common patterns before expensive regex
106        let trimmed = line.trim();
107
108        // Only skip if the entire line is a URL (quick check first)
109        if (trimmed.starts_with("http://") || trimmed.starts_with("https://")) && URL_PATTERN.is_match(trimmed) {
110            return true;
111        }
112
113        // Only skip if the entire line is an image reference (quick check first)
114        if trimmed.starts_with("![") && trimmed.ends_with(']') && IMAGE_REF_PATTERN.is_match(trimmed) {
115            return true;
116        }
117
118        // Note: link reference definitions are handled as always-exempt (even in strict mode)
119        // in the main check loop, so they don't need to be checked here.
120
121        // Code blocks with long strings (only check if in code block)
122        if ctx.line_info(current_line + 1).is_some_and(|info| info.in_code_block)
123            && !trimmed.is_empty()
124            && !line.contains(' ')
125            && !line.contains('\t')
126        {
127            return true;
128        }
129
130        false
131    }
132
133    /// Check if rule should skip based on provided config (used for inline config support)
134    fn should_skip_with_config(&self, ctx: &crate::lint_context::LintContext, config: &MD013Config) -> bool {
135        // Skip if content is empty
136        if ctx.content.is_empty() {
137            return true;
138        }
139
140        // For sentence-per-line, semantic-line-breaks, or normalize mode, never skip based on line length
141        if config.reflow
142            && (config.reflow_mode == ReflowMode::SentencePerLine
143                || config.reflow_mode == ReflowMode::SemanticLineBreaks
144                || config.reflow_mode == ReflowMode::Normalize)
145        {
146            return false;
147        }
148
149        // Use the smallest applicable budget across line/heading/code-block
150        // contexts so a stricter context-specific limit doesn't get masked by
151        // the document-wide budget.
152        let min_limit = config.min_effective_line_length();
153        if min_limit.is_unlimited() {
154            return true;
155        }
156        let min_limit_bytes = min_limit.get();
157
158        // Quick check: if total content is shorter than the smallest line limit,
159        // definitely skip.
160        if ctx.content.len() <= min_limit_bytes {
161            return true;
162        }
163
164        // Skip if no line exceeds the smallest applicable limit.
165        !ctx.lines.iter().any(|line| line.byte_len > min_limit_bytes)
166    }
167
168    fn normalize_mode_needs_reflow<'a, I>(&self, lines: I, config: &MD013Config) -> bool
169    where
170        I: IntoIterator<Item = &'a str>,
171    {
172        let mut line_count = 0;
173        let check_length = !config.line_length.is_unlimited();
174
175        for line in lines {
176            line_count += 1;
177            if check_length && self.calculate_effective_length(line) > config.line_length.get() {
178                return true;
179            }
180        }
181
182        line_count > 1
183    }
184}
185
186impl Rule for MD013LineLength {
187    fn name(&self) -> &'static str {
188        "MD013"
189    }
190
191    fn description(&self) -> &'static str {
192        "Line length should not be excessive"
193    }
194
195    fn check(&self, ctx: &crate::lint_context::LintContext) -> LintResult {
196        // Use pre-parsed inline config from LintContext
197        let config_override = ctx.inline_config().get_rule_config("MD013");
198
199        // Apply configuration override if present
200        let effective_config = if let Some(json_config) = config_override {
201            if let Some(obj) = json_config.as_object() {
202                let mut config = self.config.clone();
203                if let Some(line_length) = obj.get("line_length").and_then(serde_json::Value::as_u64) {
204                    config.line_length = crate::types::LineLength::new(line_length as usize);
205                }
206                if let Some(code_blocks) = obj.get("code_blocks").and_then(serde_json::Value::as_bool) {
207                    config.code_blocks = code_blocks;
208                }
209                if let Some(code_spans) = obj.get("code_spans").and_then(serde_json::Value::as_bool) {
210                    config.code_spans = code_spans;
211                }
212                if let Some(tables) = obj.get("tables").and_then(serde_json::Value::as_bool) {
213                    config.tables = tables;
214                }
215                if let Some(headings) = obj.get("headings").and_then(serde_json::Value::as_bool) {
216                    config.headings = headings;
217                }
218                if let Some(blockquotes) = obj.get("blockquotes").and_then(serde_json::Value::as_bool) {
219                    config.blockquotes = blockquotes;
220                }
221                if let Some(strict) = obj.get("strict").and_then(serde_json::Value::as_bool) {
222                    config.strict = strict;
223                }
224                if let Some(reflow) = obj.get("reflow").and_then(serde_json::Value::as_bool) {
225                    config.reflow = reflow;
226                }
227                if let Some(reflow_mode) = obj.get("reflow_mode").and_then(|v| v.as_str()) {
228                    config.reflow_mode = match reflow_mode {
229                        "default" => ReflowMode::Default,
230                        "normalize" => ReflowMode::Normalize,
231                        "sentence-per-line" => ReflowMode::SentencePerLine,
232                        "semantic-line-breaks" => ReflowMode::SemanticLineBreaks,
233                        _ => ReflowMode::default(),
234                    };
235                }
236                config
237            } else {
238                self.config.clone()
239            }
240        } else {
241            self.config.clone()
242        };
243
244        // Fast early return using should_skip with EFFECTIVE config (after inline overrides)
245        // But don't skip if we're in reflow mode with Normalize or SentencePerLine
246        if self.should_skip_with_config(ctx, &effective_config)
247            && !(effective_config.reflow
248                && (effective_config.reflow_mode == ReflowMode::Normalize
249                    || effective_config.reflow_mode == ReflowMode::SentencePerLine
250                    || effective_config.reflow_mode == ReflowMode::SemanticLineBreaks))
251        {
252            return Ok(Vec::new());
253        }
254
255        // Direct implementation without DocumentStructure
256        let mut warnings = Vec::new();
257
258        // Special handling: line_length = 0 means "no line length limit"
259        // Skip all line length checks, but still allow reflow if enabled
260        let skip_length_checks = effective_config.line_length.is_unlimited();
261
262        // Pre-filter lines that could be problematic to avoid processing all lines.
263        // Use the smallest applicable budget across line/heading/code-block contexts
264        // so candidates aren't dropped when a stricter context-specific budget applies.
265        let prefilter_limit = effective_config.min_effective_line_length();
266        let prefilter_skip = prefilter_limit.is_unlimited();
267        let mut candidate_lines = Vec::new();
268        if !skip_length_checks && !prefilter_skip {
269            for (line_idx, line_info) in ctx.lines.iter().enumerate() {
270                // Skip front matter - it should never be linted
271                if line_info.in_front_matter {
272                    continue;
273                }
274
275                // Quick length check first
276                if line_info.byte_len > prefilter_limit.get() {
277                    candidate_lines.push(line_idx);
278                }
279            }
280        }
281
282        // If no candidate lines and not in normalize or sentence-per-line mode, early return
283        if candidate_lines.is_empty()
284            && !(effective_config.reflow
285                && (effective_config.reflow_mode == ReflowMode::Normalize
286                    || effective_config.reflow_mode == ReflowMode::SentencePerLine
287                    || effective_config.reflow_mode == ReflowMode::SemanticLineBreaks))
288        {
289            return Ok(warnings);
290        }
291
292        let lines = ctx.raw_lines();
293
294        // Create a quick lookup set for heading lines
295        // We need this for both the heading skip check AND the paragraphs check
296        let heading_lines_set: std::collections::HashSet<usize> = ctx
297            .lines
298            .iter()
299            .enumerate()
300            .filter(|(_, line)| line.heading.is_some())
301            .map(|(idx, _)| idx + 1)
302            .collect();
303
304        // Use pre-computed table blocks from context
305        // We need this for both the table skip check AND the paragraphs check
306        let table_blocks = &ctx.table_blocks;
307        let mut table_lines_set = std::collections::HashSet::new();
308        for table in table_blocks {
309            table_lines_set.insert(table.header_line + 1);
310            table_lines_set.insert(table.delimiter_line + 1);
311            for &line in &table.content_lines {
312                table_lines_set.insert(line + 1);
313            }
314        }
315
316        // Process candidate lines for line length checks
317        'line_loop: for &line_idx in &candidate_lines {
318            let line_number = line_idx + 1;
319            let line = lines[line_idx];
320
321            // Calculate actual line length (used in warning messages)
322            let effective_length = self.calculate_effective_length(line);
323
324            // Pick the context-specific limit: heading > code-block > paragraph.
325            // Headings dominate over code-block context if a setext underline ever
326            // overlaps a fenced range (defensive — these are mutually exclusive in
327            // practice, but the explicit ordering documents intent).
328            let is_heading_line = heading_lines_set.contains(&line_number);
329            let in_code_block = ctx.line_info(line_number).is_some_and(|info| info.in_code_block);
330            let line_limit = if is_heading_line {
331                effective_config.effective_heading_line_length().get()
332            } else if in_code_block {
333                effective_config.effective_code_block_line_length().get()
334            } else {
335                effective_config.line_length.get()
336            };
337
338            // A context-specific limit of 0 means "unlimited for this context".
339            if line_limit == 0 {
340                continue;
341            }
342
343            // Stern mode: like default, but the trailing-token forgiveness is
344            // disabled — a line with whitespace that exceeds the limit is a
345            // violation even if the excess is the final token. The "unwrappable"
346            // line exemption (single token, optionally prefixed by # or >) is
347            // still honored. Strict overrides stern entirely.
348            if effective_config.stern && !effective_config.strict && is_unwrappable_line(line) {
349                continue;
350            }
351
352            // Trailing-token forgiveness: only in default mode (not strict, not stern).
353            // If the line only exceeds the limit because of a long token at the end
354            // (URL, link chain, identifier), it passes. This matches markdownlint's
355            // behavior: line.replace(/\S*$/u, "#")
356            let check_length = if effective_config.strict || effective_config.stern {
357                effective_length
358            } else {
359                match line.rfind(char::is_whitespace) {
360                    Some(pos) => {
361                        let ws_char = line[pos..].chars().next().unwrap();
362                        let prefix_end = pos + ws_char.len_utf8();
363                        self.calculate_string_length(&line[..prefix_end]) + 1
364                    }
365                    None => 1, // No whitespace — entire line is a single token
366                }
367            };
368
369            // Skip lines where the check length is within the limit
370            if check_length <= line_limit {
371                continue;
372            }
373
374            // Semantic link understanding: suppress when excess comes entirely from inline URLs
375            if !effective_config.strict {
376                let text_only_length = self.calculate_text_only_length(effective_length, line_number, ctx);
377                if text_only_length <= line_limit {
378                    continue;
379                }
380            }
381
382            // Inline code spans cannot be wrapped, so reflow cannot shorten a line
383            // whose excess length is one. When code-span checking is disabled,
384            // suppress a violation that would fit once inline code spans are excluded.
385            if !effective_config.code_spans {
386                let code_span_width: usize = ctx
387                    .code_spans()
388                    .iter()
389                    .filter(|span| span.line == line_number && span.end_line == line_number)
390                    .map(|span| self.calculate_string_length(&ctx.content[span.byte_offset..span.byte_end]))
391                    .sum();
392                if effective_length.saturating_sub(code_span_width) <= line_limit {
393                    continue;
394                }
395            }
396
397            // Skip mkdocstrings and pymdown blocks (already handled by LintContext)
398            if ctx.lines[line_idx].in_mkdocstrings || ctx.lines[line_idx].in_pymdown_block {
399                continue;
400            }
401
402            // Skip MyST comments (% comment) — structural lines, not prose
403            if ctx.lines[line_idx].is_myst_comment {
404                continue;
405            }
406
407            // Link reference definitions are always exempt, even in strict mode.
408            // There's no way to shorten them without breaking the URL.
409            // Also check after stripping list markers, since list items may
410            // contain link ref defs as their content.
411            {
412                let trimmed = line.trim();
413                if trimmed.starts_with('[') && trimmed.contains("]:") && LINK_REF_PATTERN.is_match(trimmed) {
414                    continue;
415                }
416                if is_list_item(trimmed) {
417                    let (_, content) = extract_list_marker_and_content(trimmed);
418                    let content_trimmed = content.trim();
419                    if content_trimmed.starts_with('[')
420                        && content_trimmed.contains("]:")
421                        && LINK_REF_PATTERN.is_match(content_trimmed)
422                    {
423                        continue;
424                    }
425                }
426            }
427
428            // Skip various block types efficiently
429            if !effective_config.strict {
430                // Lines whose only content is a link/image are exempt.
431                // After stripping list markers, blockquote markers, and emphasis,
432                // if only a link or image remains, there is no way to shorten it.
433                if is_standalone_link_or_image_line(line) {
434                    continue;
435                }
436
437                // Lines consisting entirely of HTML tags are exempt.
438                // Badge lines, images with attributes, and similar inline HTML
439                // are long due to URLs in attributes and can't be meaningfully shortened.
440                if is_html_only_line(line) {
441                    continue;
442                }
443
444                // Skip setext heading underlines
445                if !line.trim().is_empty() && line.trim().chars().all(|c| c == '=' || c == '-') {
446                    continue;
447                }
448
449                // Skip block elements according to config flags
450                // The flags mean: true = check these elements, false = skip these elements
451                // So we skip when the flag is FALSE and the line is in that element type
452                if (!effective_config.headings && heading_lines_set.contains(&line_number))
453                    || (!effective_config.code_blocks
454                        && ctx.line_info(line_number).is_some_and(|info| info.in_code_block))
455                    || (!effective_config.tables && table_lines_set.contains(&line_number))
456                    || ctx.line_info(line_number).is_some_and(|info| info.in_html_block)
457                    || ctx.line_info(line_number).is_some_and(|info| info.in_html_comment)
458                    || ctx.line_info(line_number).is_some_and(|info| info.in_esm_block)
459                    || ctx.line_info(line_number).is_some_and(|info| info.in_jsx_expression)
460                    || ctx.line_info(line_number).is_some_and(|info| info.in_jsx_block)
461                    || ctx.line_info(line_number).is_some_and(|info| info.in_mdx_comment)
462                    || ctx.line_info(line_number).is_some_and(|info| info.in_pymdown_block)
463                {
464                    continue;
465                }
466
467                // Check if this is a paragraph/regular text line
468                // If paragraphs = false, skip lines that are NOT in special blocks
469                // Blockquote content is treated as paragraph text, so it's not
470                // included in the special blocks list here.
471                if !effective_config.paragraphs {
472                    let is_special_block = heading_lines_set.contains(&line_number)
473                        || ctx.line_info(line_number).is_some_and(|info| info.in_code_block)
474                        || table_lines_set.contains(&line_number)
475                        || ctx.line_info(line_number).is_some_and(|info| info.in_html_block)
476                        || ctx.line_info(line_number).is_some_and(|info| info.in_html_comment)
477                        || ctx.line_info(line_number).is_some_and(|info| info.in_esm_block)
478                        || ctx.line_info(line_number).is_some_and(|info| info.in_jsx_expression)
479                        || ctx.line_info(line_number).is_some_and(|info| info.in_jsx_block)
480                        || ctx.line_info(line_number).is_some_and(|info| info.in_mdx_comment)
481                        || ctx
482                            .line_info(line_number)
483                            .is_some_and(super::super::lint_context::types::LineInfo::in_mkdocs_container);
484
485                    // Skip regular paragraph text when paragraphs = false
486                    if !is_special_block {
487                        continue;
488                    }
489                }
490
491                // Skip blockquote lines when blockquotes = false.
492                // Also skip lazy continuation lines that belong to a blockquote
493                // (lines without `>` prefix that follow a blockquote line).
494                if !effective_config.blockquotes {
495                    if ctx.lines[line_number - 1].blockquote.is_some() {
496                        continue;
497                    }
498                    // Check for lazy continuation: scan backwards through
499                    // non-blank lines to find if this paragraph started with
500                    // a blockquote marker
501                    if !line.trim().is_empty() {
502                        let mut scan = line_number.saturating_sub(2);
503                        loop {
504                            if ctx.lines[scan].blockquote.is_some() {
505                                // Found a blockquote ancestor — this is a lazy continuation
506                                continue 'line_loop;
507                            }
508                            if lines[scan].trim().is_empty() || scan == 0 {
509                                break;
510                            }
511                            scan -= 1;
512                        }
513                    }
514                }
515
516                // Skip lines that are only a URL, image ref, or link ref
517                if self.should_ignore_line(line, lines, line_idx, ctx) {
518                    continue;
519                }
520            }
521
522            // In sentence-per-line mode, check if this is a single long sentence
523            // If so, emit a warning without a fix (user must manually rephrase)
524            if effective_config.reflow_mode == ReflowMode::SentencePerLine {
525                let sentences = split_into_sentences(line.trim());
526                if sentences.len() == 1 {
527                    // Single sentence that's too long - warn but don't auto-fix
528                    let message = format!("Line length {effective_length} exceeds {line_limit} characters");
529
530                    let (start_line, start_col, end_line, end_col) =
531                        calculate_excess_range(line_number, line, line_limit);
532
533                    warnings.push(LintWarning {
534                        rule_name: Some(self.name().to_string()),
535                        message,
536                        line: start_line,
537                        column: start_col,
538                        end_line,
539                        end_column: end_col,
540                        severity: Severity::Warning,
541                        fix: None, // No auto-fix for long single sentences
542                    });
543                    continue;
544                }
545                // Multiple sentences will be handled by paragraph-based reflow
546                continue;
547            }
548
549            // In semantic-line-breaks mode, skip per-line checks —
550            // all reflow is handled at the paragraph level with cascading splits
551            if effective_config.reflow_mode == ReflowMode::SemanticLineBreaks {
552                continue;
553            }
554
555            // Don't provide fix for individual lines when reflow is enabled
556            // Paragraph-based fixes will be handled separately
557            let fix = None;
558
559            let message = format!("Line length {effective_length} exceeds {line_limit} characters");
560
561            // Calculate precise character range for the excess portion
562            let (start_line, start_col, end_line, end_col) = calculate_excess_range(line_number, line, line_limit);
563
564            warnings.push(LintWarning {
565                rule_name: Some(self.name().to_string()),
566                message,
567                line: start_line,
568                column: start_col,
569                end_line,
570                end_column: end_col,
571                severity: Severity::Warning,
572                fix,
573            });
574        }
575
576        // If reflow is enabled, generate paragraph-based fixes
577        if effective_config.reflow {
578            let paragraph_warnings = self.generate_paragraph_fixes(ctx, &effective_config, lines);
579            // Merge paragraph warnings with line warnings, removing duplicates
580            for pw in paragraph_warnings {
581                // Remove any line warnings that overlap with this paragraph
582                warnings.retain(|w| w.line < pw.line || w.line > pw.end_line);
583                warnings.push(pw);
584            }
585        }
586
587        Ok(warnings)
588    }
589
590    fn fix(&self, ctx: &crate::lint_context::LintContext) -> Result<String, LintError> {
591        // For CLI usage, apply fixes from warnings
592        // LSP will use the warning-based fixes directly
593        let warnings = self.check(ctx)?;
594        let warnings =
595            crate::utils::fix_utils::filter_warnings_by_inline_config(warnings, ctx.inline_config(), self.name());
596
597        // If there are no fixes, return content unchanged
598        if !warnings.iter().any(|w| w.fix.is_some()) {
599            return Ok(ctx.content.to_string());
600        }
601
602        // Apply warning-based fixes
603        crate::utils::fix_utils::apply_warning_fixes(ctx.content, &warnings)
604            .map_err(|e| LintError::FixFailed(format!("Failed to apply fixes: {e}")))
605    }
606
607    fn as_any(&self) -> &dyn std::any::Any {
608        self
609    }
610
611    fn category(&self) -> RuleCategory {
612        RuleCategory::Whitespace
613    }
614
615    fn should_skip(&self, ctx: &crate::lint_context::LintContext) -> bool {
616        self.should_skip_with_config(ctx, &self.config)
617    }
618
619    fn default_config_section(&self) -> Option<(String, toml::Value)> {
620        let table = crate::rule_config_serde::config_schema_table(&MD013Config::default())?;
621        if table.is_empty() {
622            None
623        } else {
624            Some((MD013Config::RULE_NAME.to_string(), toml::Value::Table(table)))
625        }
626    }
627
628    fn config_aliases(&self) -> Option<std::collections::HashMap<String, String>> {
629        let mut aliases = std::collections::HashMap::new();
630        aliases.insert("enable_reflow".to_string(), "reflow".to_string());
631        aliases.insert("strict_sentences".to_string(), "require-sentence-capital".to_string());
632        aliases.insert("strict-sentences".to_string(), "require-sentence-capital".to_string());
633        Some(aliases)
634    }
635
636    fn from_config(config: &crate::config::Config) -> Box<dyn Rule>
637    where
638        Self: Sized,
639    {
640        let mut rule_config = crate::rule_config_serde::load_rule_config::<MD013Config>(config);
641        // Use global line_length if rule-specific config still has default value
642        if rule_config.line_length.get() == 80 {
643            rule_config.line_length = config.global.line_length;
644        }
645        Box::new(Self::from_config_struct(rule_config))
646    }
647}
648
649impl MD013LineLength {
650    /// True when `line_num` (1-based) sits inside a structure whose lines must be
651    /// preserved verbatim (code block, front matter, HTML/JSX/MDX block, MkDocs
652    /// container, div marker, ...). Used to keep blockquote reflow from touching
653    /// quoted-looking text embedded in such structures.
654    fn line_in_verbatim_context(&self, line_num: usize, ctx: &crate::lint_context::LintContext) -> bool {
655        ctx.line_info(line_num).is_some_and(|info| {
656            info.in_code_block
657                || info.in_front_matter
658                || info.in_html_block
659                || info.in_html_comment
660                || info.in_esm_block
661                || info.in_jsx_expression
662                || info.in_jsx_block
663                || info.in_mdx_comment
664                || info.in_mkdocstrings
665                || info.in_pymdown_block
666                || info.in_mkdocs_container()
667                || info.is_div_marker
668        })
669    }
670
671    fn is_blockquote_content_boundary(
672        &self,
673        content: &str,
674        line_num: usize,
675        ctx: &crate::lint_context::LintContext,
676    ) -> bool {
677        let trimmed = content.trim();
678
679        trimmed.is_empty()
680            || self.line_in_verbatim_context(line_num, ctx)
681            || trimmed.starts_with('#')
682            || trimmed.starts_with("```")
683            || trimmed.starts_with("~~~")
684            || trimmed.starts_with('>')
685            || TableUtils::is_potential_table_row(content)
686            || is_list_item(trimmed)
687            || is_horizontal_rule(content)
688            || (trimmed.starts_with('[') && content.contains("]:"))
689            || is_template_directive_only(content)
690            || is_standalone_attr_list(content)
691            || is_snippet_block_delimiter(content)
692            || is_github_alert_marker(trimmed)
693            || is_html_only_line(content)
694    }
695
696    fn generate_blockquote_paragraph_fix(
697        &self,
698        ctx: &crate::lint_context::LintContext,
699        config: &MD013Config,
700        lines: &[&str],
701        line_index: &LineIndex,
702        start_idx: usize,
703        line_ending: &str,
704    ) -> (Option<LintWarning>, usize) {
705        let Some(start_bq) = ctx.lines.get(start_idx).and_then(|line| line.blockquote.as_deref()) else {
706            return (None, start_idx + 1);
707        };
708        let target_level = start_bq.nesting_level;
709
710        let mut collected: Vec<CollectedBlockquoteLine> = Vec::new();
711        let mut i = start_idx;
712
713        while i < lines.len() {
714            if !collected.is_empty() && has_hard_break(&collected[collected.len() - 1].data.content) {
715                break;
716            }
717
718            let line_num = i + 1;
719            if line_num > ctx.lines.len() {
720                break;
721            }
722
723            if lines[i].trim().is_empty() {
724                break;
725            }
726
727            let line_bq = ctx.lines[i].blockquote.as_deref();
728            if let Some(bq) = line_bq {
729                if bq.nesting_level != target_level {
730                    break;
731                }
732
733                if self.is_blockquote_content_boundary(&bq.content, line_num, ctx) {
734                    break;
735                }
736
737                collected.push(CollectedBlockquoteLine {
738                    line_idx: i,
739                    data: BlockquoteLineData::explicit(trim_preserving_hard_break(&bq.content), bq.prefix.clone()),
740                });
741                i += 1;
742                continue;
743            }
744
745            let lazy_content = lines[i].trim_start();
746            if self.is_blockquote_content_boundary(lazy_content, line_num, ctx) {
747                break;
748            }
749
750            collected.push(CollectedBlockquoteLine {
751                line_idx: i,
752                data: BlockquoteLineData::lazy(trim_preserving_hard_break(lazy_content)),
753            });
754            i += 1;
755        }
756
757        if collected.is_empty() {
758            return (None, start_idx + 1);
759        }
760
761        let next_idx = i;
762        let paragraph_start = collected[0].line_idx;
763        let end_line = collected[collected.len() - 1].line_idx;
764        let line_data: Vec<BlockquoteLineData> = collected.iter().map(|l| l.data.clone()).collect();
765        let paragraph_text = line_data
766            .iter()
767            .map(|d| d.content.as_str())
768            .collect::<Vec<_>>()
769            .join(" ");
770
771        let contains_definition_list = line_data
772            .iter()
773            .any(|d| crate::utils::is_definition_list_item(&d.content));
774        if contains_definition_list {
775            return (None, next_idx);
776        }
777
778        let contains_snippets = line_data.iter().any(|d| is_snippet_block_delimiter(&d.content));
779        if contains_snippets {
780            return (None, next_idx);
781        }
782
783        let needs_reflow = match config.reflow_mode {
784            ReflowMode::Normalize => {
785                self.normalize_mode_needs_reflow(line_data.iter().map(|d| d.content.as_str()), config)
786            }
787            ReflowMode::SentencePerLine => {
788                let sentences = split_into_sentences(&paragraph_text);
789                sentences.len() > 1 || line_data.len() > 1
790            }
791            ReflowMode::SemanticLineBreaks => {
792                let sentences = split_into_sentences(&paragraph_text);
793                sentences.len() > 1
794                    || line_data.len() > 1
795                    || collected
796                        .iter()
797                        .any(|l| self.calculate_effective_length(lines[l.line_idx]) > config.line_length.get())
798            }
799            ReflowMode::Default => collected
800                .iter()
801                .any(|l| self.calculate_effective_length(lines[l.line_idx]) > config.line_length.get()),
802        };
803
804        if !needs_reflow {
805            return (None, next_idx);
806        }
807
808        let fallback_prefix = start_bq.prefix.clone();
809        let explicit_prefix = dominant_blockquote_prefix(&line_data, &fallback_prefix);
810        let continuation_style = blockquote_continuation_style(&line_data);
811
812        let reflow_line_length = if config.line_length.is_unlimited() {
813            usize::MAX
814        } else {
815            config
816                .line_length
817                .get()
818                .saturating_sub(self.calculate_string_length(&explicit_prefix))
819                .max(1)
820        };
821
822        let reflow_options = crate::utils::text_reflow::ReflowOptions {
823            line_length: reflow_line_length,
824            break_on_sentences: true,
825            preserve_breaks: false,
826            sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
827            semantic_line_breaks: config.reflow_mode == ReflowMode::SemanticLineBreaks,
828            abbreviations: config.abbreviations_for_reflow(),
829            length_mode: self.reflow_length_mode(),
830            attr_lists: ctx.flavor.supports_attr_lists(),
831            myst_roles: ctx.flavor.supports_myst_roles(),
832            require_sentence_capital: config.require_sentence_capital,
833            max_list_continuation_indent: if ctx.flavor.requires_strict_list_indent() {
834                Some(4)
835            } else {
836                None
837            },
838        };
839
840        let reflowed_with_style =
841            reflow_blockquote_content(&line_data, &explicit_prefix, continuation_style, &reflow_options);
842
843        if reflowed_with_style.is_empty() {
844            return (None, next_idx);
845        }
846
847        let reflowed_text = reflowed_with_style.join(line_ending);
848
849        let start_range = line_index.whole_line_range(paragraph_start + 1);
850        let end_range = if end_line == lines.len() - 1 && !ctx.content.ends_with('\n') {
851            line_index.line_text_range(end_line + 1, 1, lines[end_line].len() + 1)
852        } else {
853            line_index.whole_line_range(end_line + 1)
854        };
855        let byte_range = start_range.start..end_range.end;
856
857        let replacement = if end_line < lines.len() - 1 || ctx.content.ends_with('\n') {
858            format!("{reflowed_text}{line_ending}")
859        } else {
860            reflowed_text
861        };
862
863        let original_text = &ctx.content[byte_range.clone()];
864        if original_text == replacement {
865            return (None, next_idx);
866        }
867
868        let (warning_line, warning_end_line) = match config.reflow_mode {
869            ReflowMode::Normalize => (paragraph_start + 1, end_line + 1),
870            ReflowMode::SentencePerLine | ReflowMode::SemanticLineBreaks => (paragraph_start + 1, end_line + 1),
871            ReflowMode::Default => {
872                let violating_line = collected
873                    .iter()
874                    .find(|line| self.calculate_effective_length(lines[line.line_idx]) > config.line_length.get())
875                    .map_or(paragraph_start + 1, |line| line.line_idx + 1);
876                (violating_line, violating_line)
877            }
878        };
879
880        let warning = LintWarning {
881            rule_name: Some(self.name().to_string()),
882            message: match config.reflow_mode {
883                ReflowMode::Normalize => format!(
884                    "Paragraph could be normalized to use line length of {} characters",
885                    config.line_length.get()
886                ),
887                ReflowMode::SentencePerLine => {
888                    let num_sentences = split_into_sentences(&paragraph_text).len();
889                    if line_data.len() == 1 {
890                        format!("Line contains {num_sentences} sentences (one sentence per line required)")
891                    } else {
892                        let num_lines = line_data.len();
893                        format!(
894                            "Paragraph should have one sentence per line (found {num_sentences} sentences across {num_lines} lines)"
895                        )
896                    }
897                }
898                ReflowMode::SemanticLineBreaks => {
899                    let num_sentences = split_into_sentences(&paragraph_text).len();
900                    format!("Paragraph should use semantic line breaks ({num_sentences} sentences)")
901                }
902                ReflowMode::Default => format!("Line length exceeds {} characters", config.line_length.get()),
903            },
904            line: warning_line,
905            column: 1,
906            end_line: warning_end_line,
907            end_column: lines[warning_end_line.saturating_sub(1)].chars().count() + 1,
908            severity: Severity::Warning,
909            fix: Some(crate::rule::Fix::new(byte_range, replacement)),
910        };
911
912        (Some(warning), next_idx)
913    }
914
915    /// Reflow a single list item that lives inside a blockquote.
916    ///
917    /// The blockquote paragraph reflow treats a list marker as a content boundary,
918    /// so `> - long item ...` is never wrapped even though the identical top-level
919    /// item is. This handles that case: it collects one tight, prose-only list item
920    /// at the starting blockquote level, reflows the item body to the configured
921    /// width, and re-emits it with the blockquote prefix preserved and continuation
922    /// lines aligned under the list content.
923    ///
924    /// Sibling and nested list items end collection and are reflowed independently
925    /// by the caller's outer loop (a nested item carries its indent folded into the
926    /// blockquote prefix, so it reflows correctly on its own). Items that are not
927    /// simple tight prose - those embedding a code block, table, fence, or hard
928    /// break - are left untouched (`None`) and the cursor still advances past the
929    /// whole item so its inner lines are never reprocessed as loose prose.
930    fn generate_blockquote_list_item_fix(
931        &self,
932        ctx: &crate::lint_context::LintContext,
933        config: &MD013Config,
934        lines: &[&str],
935        line_index: &LineIndex,
936        start_idx: usize,
937        line_ending: &str,
938    ) -> (Option<LintWarning>, usize) {
939        use crate::utils::blockquote::effective_indent_in_blockquote;
940
941        let Some(start_bq) = ctx.lines.get(start_idx).and_then(|line| line.blockquote.as_deref()) else {
942            return (None, start_idx + 1);
943        };
944
945        // A `>`-prefixed line can be marked as a blockquote even inside a fenced code
946        // block (or other verbatim structure); such content must never be reflowed.
947        if self.line_in_verbatim_context(start_idx + 1, ctx) {
948            return (None, start_idx + 1);
949        }
950
951        let target_level = start_bq.nesting_level;
952
953        // The marker line carries the canonical blockquote prefix: its content begins
954        // with the list marker, so no list indent has been folded into the prefix.
955        let bq_prefix = start_bq.prefix.clone();
956
957        let (marker, first_body) = extract_list_marker_and_content(&start_bq.content);
958        if marker.is_empty() {
959            return (None, start_idx + 1);
960        }
961        let marker_width = marker.chars().count();
962
963        // Continuation lines of a checkbox item align under the bullet+checkbox, but
964        // are recognized from the bullet width, matching the top-level list reflow.
965        let base_marker_width = ["[ ] ", "[x] ", "[X] "]
966            .iter()
967            .find_map(|cb| marker.find(*cb))
968            .unwrap_or(marker_width);
969
970        // Collect the item: the marker line plus its tight prose continuation lines.
971        // `end_idx` always tracks the last consumed line so the cursor advances past
972        // the entire item, even when it turns out to be too complex to reflow safely.
973        let first_piece = trim_preserving_hard_break(&first_body);
974        let mut simple = !has_hard_break(&first_piece);
975        let mut body_pieces: Vec<String> = vec![first_piece];
976        let mut end_idx = start_idx;
977        let mut i = start_idx + 1;
978
979        while i < lines.len() {
980            let Some(bq) = ctx.lines[i].blockquote.as_deref() else {
981                // A blank line ends the item.
982                if lines[i].trim().is_empty() {
983                    break;
984                }
985                // A lazy continuation (no `>` marker) is too ambiguous to reflow
986                // safely. Consume the whole lazy run into this item's span and leave
987                // the item untouched, so the caller does not reflow the continuation
988                // in isolation and leave the marker line partially fixed.
989                simple = false;
990                while i < lines.len() && ctx.lines[i].blockquote.is_none() && !lines[i].trim().is_empty() {
991                    end_idx = i;
992                    i += 1;
993                }
994                break;
995            };
996            if bq.nesting_level != target_level {
997                break;
998            }
999
1000            let content = bq.content.as_str();
1001            if content.trim().is_empty() {
1002                // Blank quoted line ends the tight paragraph. A following indented
1003                // paragraph (loose item) is reflowed on its own by the prose path.
1004                break;
1005            }
1006
1007            let eff_indent = effective_indent_in_blockquote(lines[i], target_level, 0);
1008            if eff_indent < base_marker_width {
1009                // Dedented: a sibling list item or text outside this item. Stop here
1010                // and let the outer loop classify it.
1011                break;
1012            }
1013            if is_list_item(content) {
1014                // A nested list item: its own item, handled independently.
1015                break;
1016            }
1017
1018            // An embedded structure (code block, table, fence, nested quote, ...)
1019            // means the item is not simple prose: keep consuming so the cursor clears
1020            // the whole structure, but do not produce a fix.
1021            if self.is_blockquote_content_boundary(content, i + 1, ctx) {
1022                simple = false;
1023            }
1024
1025            let piece = trim_preserving_hard_break(content);
1026            if has_hard_break(&piece) {
1027                simple = false;
1028            }
1029            body_pieces.push(piece);
1030            end_idx = i;
1031            i += 1;
1032        }
1033
1034        let next_idx = end_idx + 1;
1035
1036        if !simple {
1037            return (None, next_idx);
1038        }
1039
1040        let exceeds_limit =
1041            || (start_idx..=end_idx).any(|idx| self.calculate_effective_length(lines[idx]) > config.line_length.get());
1042        let body_text = body_pieces.join(" ");
1043        let body_text = body_text.trim();
1044
1045        // Some bodies cannot be shortened and must stay verbatim, matching the
1046        // exemptions the top-level list reflow applies: link reference definitions
1047        // always, and (in non-strict mode) standalone links/images and HTML-only
1048        // lines. Reflowing a link reference definition would split it after the
1049        // colon/URL and break the definition.
1050        let is_link_ref_def =
1051            body_text.starts_with('[') && body_text.contains("]:") && LINK_REF_PATTERN.is_match(body_text);
1052        let raw_marker_line = lines[start_idx];
1053        let body_is_unwrappable = is_link_ref_def
1054            || (!config.strict && is_standalone_link_or_image_line(raw_marker_line))
1055            || (!config.strict && is_html_only_line(raw_marker_line));
1056        if body_is_unwrappable {
1057            return (None, next_idx);
1058        }
1059
1060        let needs_reflow = match config.reflow_mode {
1061            ReflowMode::Normalize => body_pieces.len() > 1 || exceeds_limit(),
1062            ReflowMode::Default => exceeds_limit(),
1063            ReflowMode::SentencePerLine => split_into_sentences(body_text).len() > 1 || body_pieces.len() > 1,
1064            ReflowMode::SemanticLineBreaks => split_into_sentences(body_text).len() > 1 || exceeds_limit(),
1065        };
1066        if !needs_reflow {
1067            return (None, next_idx);
1068        }
1069
1070        let prefix_width = self.calculate_string_length(&bq_prefix) + self.calculate_string_length(&marker);
1071        let reflow_line_length = if config.line_length.is_unlimited() {
1072            usize::MAX
1073        } else {
1074            config.line_length.get().saturating_sub(prefix_width).max(1)
1075        };
1076
1077        let reflow_options = crate::utils::text_reflow::ReflowOptions {
1078            line_length: reflow_line_length,
1079            break_on_sentences: true,
1080            preserve_breaks: false,
1081            sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
1082            semantic_line_breaks: config.reflow_mode == ReflowMode::SemanticLineBreaks,
1083            abbreviations: config.abbreviations_for_reflow(),
1084            length_mode: self.reflow_length_mode(),
1085            attr_lists: ctx.flavor.supports_attr_lists(),
1086            myst_roles: ctx.flavor.supports_myst_roles(),
1087            require_sentence_capital: config.require_sentence_capital,
1088            max_list_continuation_indent: if ctx.flavor.requires_strict_list_indent() {
1089                Some(4)
1090            } else {
1091                None
1092            },
1093        };
1094
1095        let reflowed = crate::utils::text_reflow::reflow_line(body_text, &reflow_options);
1096        if reflowed.is_empty() {
1097            return (None, next_idx);
1098        }
1099
1100        let continuation_indent = " ".repeat(marker_width);
1101        let reflowed_text = reflowed
1102            .iter()
1103            .enumerate()
1104            .map(|(idx, line)| {
1105                if idx == 0 {
1106                    format!("{bq_prefix}{marker}{line}")
1107                } else {
1108                    format!("{bq_prefix}{continuation_indent}{line}")
1109                }
1110            })
1111            .collect::<Vec<_>>()
1112            .join(line_ending);
1113
1114        let start_range = line_index.whole_line_range(start_idx + 1);
1115        let end_range = if end_idx == lines.len() - 1 && !ctx.content.ends_with('\n') {
1116            line_index.line_text_range(end_idx + 1, 1, lines[end_idx].len() + 1)
1117        } else {
1118            line_index.whole_line_range(end_idx + 1)
1119        };
1120        let byte_range = start_range.start..end_range.end;
1121
1122        let replacement = if end_idx < lines.len() - 1 || ctx.content.ends_with('\n') {
1123            format!("{reflowed_text}{line_ending}")
1124        } else {
1125            reflowed_text
1126        };
1127
1128        let original_text = &ctx.content[byte_range.clone()];
1129        if original_text == replacement {
1130            return (None, next_idx);
1131        }
1132
1133        let message = match config.reflow_mode {
1134            ReflowMode::Normalize => format!(
1135                "Paragraph could be normalized to use line length of {} characters",
1136                config.line_length.get()
1137            ),
1138            ReflowMode::SentencePerLine => {
1139                let num_sentences = split_into_sentences(body_text).len();
1140                format!("List item should have one sentence per line (found {num_sentences} sentences)")
1141            }
1142            ReflowMode::SemanticLineBreaks => {
1143                let num_sentences = split_into_sentences(body_text).len();
1144                format!("List item should use semantic line breaks ({num_sentences} sentences)")
1145            }
1146            ReflowMode::Default => format!("Line length exceeds {} characters", config.line_length.get()),
1147        };
1148
1149        let warning = LintWarning {
1150            rule_name: Some(self.name().to_string()),
1151            message,
1152            line: start_idx + 1,
1153            column: 1,
1154            end_line: end_idx + 1,
1155            end_column: lines[end_idx].chars().count() + 1,
1156            severity: Severity::Warning,
1157            fix: Some(crate::rule::Fix::new(byte_range, replacement)),
1158        };
1159
1160        (Some(warning), next_idx)
1161    }
1162
1163    /// Generate paragraph-based fixes
1164    fn generate_paragraph_fixes(
1165        &self,
1166        ctx: &crate::lint_context::LintContext,
1167        config: &MD013Config,
1168        lines: &[&str],
1169    ) -> Vec<LintWarning> {
1170        let mut warnings = Vec::new();
1171        let line_index = LineIndex::new(ctx.content);
1172
1173        // Detect the content's line ending style to preserve it in replacements.
1174        // The LSP receives content from editors which may use CRLF (Windows).
1175        // Replacements must match the original line endings to avoid false positives.
1176        let line_ending = crate::utils::line_ending::detect_line_ending(ctx.content);
1177
1178        let mut i = 0;
1179        while i < lines.len() {
1180            let line_num = i + 1;
1181
1182            // Handle blockquote paragraphs with style-preserving reflow.
1183            // Skip blockquotes when blockquotes=false or paragraphs=false
1184            if line_num > 0 && line_num <= ctx.lines.len() && ctx.lines[line_num - 1].blockquote.is_some() {
1185                if !config.blockquotes || !config.paragraphs {
1186                    // Skip past all blockquote lines (explicit and lazy continuations).
1187                    // A lazy continuation is a non-blank line without `>` that follows
1188                    // a blockquote line and isn't a structural element.
1189                    let mut saw_explicit_bq = false;
1190                    while i < lines.len() && i < ctx.lines.len() {
1191                        if ctx.lines[i].blockquote.is_some() {
1192                            saw_explicit_bq = true;
1193                            i += 1;
1194                        } else if saw_explicit_bq
1195                            && !lines[i].trim().is_empty()
1196                            && !lines[i].trim_start().starts_with('#')
1197                            && !lines[i].trim_start().starts_with('>')
1198                        {
1199                            // Lazy continuation of preceding blockquote
1200                            i += 1;
1201                        } else {
1202                            break;
1203                        }
1204                    }
1205                    continue;
1206                }
1207                // A list item inside the blockquote needs list-aware reflow (marker +
1208                // continuation indent); plain prose goes through the paragraph path.
1209                let is_bq_list_item = ctx.lines[i]
1210                    .blockquote
1211                    .as_deref()
1212                    .is_some_and(|bq| is_list_item(&bq.content));
1213                let (warning, next_idx) = if is_bq_list_item {
1214                    self.generate_blockquote_list_item_fix(ctx, config, lines, &line_index, i, line_ending)
1215                } else {
1216                    self.generate_blockquote_paragraph_fix(ctx, config, lines, &line_index, i, line_ending)
1217                };
1218                if let Some(warning) = warning {
1219                    warnings.push(warning);
1220                }
1221                i = next_idx;
1222                continue;
1223            }
1224
1225            // Skip special structures (but NOT MkDocs containers - those get special handling)
1226            let should_skip_due_to_line_info = ctx.line_info(line_num).is_some_and(|info| {
1227                info.in_code_block
1228                    || info.in_front_matter
1229                    || info.in_html_block
1230                    || info.in_html_comment
1231                    || info.in_esm_block
1232                    || info.in_jsx_expression
1233                    || info.in_jsx_block
1234                    || info.in_mdx_comment
1235                    || info.in_mkdocstrings
1236                    || info.in_pymdown_block
1237            });
1238
1239            // Skip link reference definitions but NOT footnote definitions.
1240            // Footnote definitions (`[^id]: prose`) contain reflowable text,
1241            // while link reference definitions (`[ref]: URL`) contain URLs
1242            // that cannot be shortened.
1243            let is_link_ref_def =
1244                lines[i].trim().starts_with('[') && !lines[i].trim().starts_with("[^") && lines[i].contains("]:");
1245
1246            if should_skip_due_to_line_info
1247                || lines[i].trim().starts_with('#')
1248                || TableUtils::is_potential_table_row(lines[i])
1249                || lines[i].trim().is_empty()
1250                || is_horizontal_rule(lines[i])
1251                || is_template_directive_only(lines[i])
1252                || is_link_ref_def
1253                || ctx.line_info(line_num).is_some_and(|info| info.is_div_marker)
1254                || is_html_only_line(lines[i])
1255            {
1256                i += 1;
1257                continue;
1258            }
1259
1260            // Handle footnote definitions: `[^id]: prose text that can be reflowed`
1261            // Supports multi-paragraph footnotes with code blocks, blockquotes,
1262            // tables, and lists preserved verbatim.
1263            // Validate structure: must start with `[^`, contain `]:`, and the ID
1264            // must not contain `[` or `]` (prevents false matches on nested brackets)
1265            if lines[i].trim().starts_with("[^") && lines[i].contains("]:") && {
1266                let after_caret = &lines[i].trim()[2..];
1267                after_caret
1268                    .find("]:")
1269                    .is_some_and(|pos| pos > 0 && !after_caret[..pos].contains(['[', ']']))
1270            } {
1271                let footnote_start = i;
1272                let line = lines[i];
1273
1274                // Extract the prefix `[^id]:`
1275                let Some(colon_pos) = line.find("]:") else {
1276                    i += 1;
1277                    continue;
1278                };
1279                let prefix_end = colon_pos + 2;
1280                let prefix = &line[..prefix_end];
1281
1282                // Content starts after `]: ` (with optional space)
1283                let content_start = if line[prefix_end..].starts_with(' ') {
1284                    prefix_end + 1
1285                } else {
1286                    prefix_end
1287                };
1288                let first_content = &line[content_start..];
1289
1290                // CommonMark footnotes use 4-space continuation indent
1291                const FN_INDENT: usize = 4;
1292
1293                // --- Line classification for footnote content ---
1294                #[derive(Debug, Clone)]
1295                enum FnLineType {
1296                    Content(String),
1297                    Verbatim(String, usize), // preserved text, original indent
1298                    Empty,
1299                }
1300
1301                // Helper: compute visual indent (tabs = 4 spaces)
1302                let visual_indent = |s: &str| -> usize {
1303                    s.chars()
1304                        .take_while(|c| c.is_whitespace())
1305                        .map(|c| if c == '\t' { 4 } else { 1 })
1306                        .sum::<usize>()
1307                };
1308
1309                // Helper: check if a trimmed line is a fence marker (homogeneous chars)
1310                let is_fence = |s: &str| -> bool {
1311                    let t = s.trim();
1312                    let fence_char = t.chars().next();
1313                    matches!(fence_char, Some('`') | Some('~'))
1314                        && t.chars().take_while(|&c| c == fence_char.unwrap()).count() >= 3
1315                };
1316
1317                // Helper: check if a trimmed line is a setext underline
1318                let is_setext_underline = |s: &str| -> bool {
1319                    let t = s.trim();
1320                    !t.is_empty()
1321                        && (t.chars().all(|c| c == '=' || c == ' ') || t.chars().all(|c| c == '-' || c == ' '))
1322                        && t.contains(['=', '-'])
1323                };
1324
1325                // Deferred body: `[^id]:\n    content` — first line has no content,
1326                // actual content starts on the next indented line
1327                let deferred_body = first_content.trim().is_empty();
1328
1329                // Collect all lines belonging to this footnote definition
1330                let mut fn_lines: Vec<FnLineType> = Vec::new();
1331                if !deferred_body {
1332                    fn_lines.push(FnLineType::Content(first_content.to_string()));
1333                }
1334                let mut last_consumed = i;
1335                i += 1;
1336
1337                // Strip only the footnote continuation indent, preserving
1338                // internal indentation (e.g., code block body indent)
1339                let strip_fn_indent = |s: &str| -> String {
1340                    let mut chars = s.chars();
1341                    let mut stripped = 0;
1342                    while stripped < FN_INDENT {
1343                        match chars.next() {
1344                            Some('\t') => stripped += 4,
1345                            Some(c) if c.is_whitespace() => stripped += 1,
1346                            _ => break,
1347                        }
1348                    }
1349                    chars.as_str().to_string()
1350                };
1351
1352                let mut in_fenced_code = false;
1353                let mut consecutive_blanks = 0u32;
1354
1355                while i < lines.len() {
1356                    let next = lines[i];
1357                    let next_trimmed = next.trim();
1358
1359                    // Blank line handling
1360                    if next_trimmed.is_empty() {
1361                        consecutive_blanks += 1;
1362                        // 2+ consecutive blanks terminate the footnote
1363                        if consecutive_blanks >= 2 {
1364                            break;
1365                        }
1366
1367                        // Inside a fenced code block, blank lines are part of the code
1368                        if in_fenced_code {
1369                            consecutive_blanks = 0; // Don't count blanks inside code blocks
1370                            fn_lines.push(FnLineType::Verbatim(String::new(), 0));
1371                            last_consumed = i;
1372                            i += 1;
1373                            continue;
1374                        }
1375
1376                        // Peek ahead: if next non-blank line is indented >= FN_INDENT,
1377                        // this blank is an internal paragraph separator
1378                        if i + 1 < lines.len() {
1379                            let peek = lines[i + 1];
1380                            let peek_indent = visual_indent(peek);
1381                            if !peek.trim().is_empty() && peek_indent >= FN_INDENT {
1382                                fn_lines.push(FnLineType::Empty);
1383                                last_consumed = i;
1384                                i += 1;
1385                                continue;
1386                            }
1387                        }
1388                        // No valid continuation after blank — end of footnote
1389                        break;
1390                    }
1391
1392                    consecutive_blanks = 0;
1393                    let indent = visual_indent(next);
1394
1395                    // Not indented enough — end of footnote
1396                    if indent < FN_INDENT {
1397                        break;
1398                    }
1399
1400                    // Inside a fenced code block: everything is verbatim until closing fence
1401                    if in_fenced_code {
1402                        fn_lines.push(FnLineType::Verbatim(strip_fn_indent(next), indent));
1403                        if is_fence(next_trimmed) {
1404                            in_fenced_code = false;
1405                        }
1406                        last_consumed = i;
1407                        i += 1;
1408                        continue;
1409                    }
1410
1411                    // Fence opener — start verbatim code block
1412                    if is_fence(next_trimmed) {
1413                        in_fenced_code = true;
1414                        fn_lines.push(FnLineType::Verbatim(strip_fn_indent(next), indent));
1415                        last_consumed = i;
1416                        i += 1;
1417                        continue;
1418                    }
1419
1420                    // Indented code block: indent >= FN_INDENT + 4 (= 8 spaces)
1421                    if indent >= FN_INDENT + 4 {
1422                        fn_lines.push(FnLineType::Verbatim(strip_fn_indent(next), indent));
1423                        last_consumed = i;
1424                        i += 1;
1425                        continue;
1426                    }
1427
1428                    // Structural content that must be preserved verbatim
1429                    if next_trimmed.starts_with('#')
1430                        || is_list_item(next_trimmed)
1431                        || next_trimmed.starts_with('>')
1432                        || TableUtils::is_potential_table_row(next_trimmed)
1433                        || is_setext_underline(next_trimmed)
1434                        || is_horizontal_rule(next_trimmed)
1435                        || crate::utils::mkdocs_footnotes::is_footnote_definition(next_trimmed)
1436                    {
1437                        // Preserve verbatim: blockquotes, tables, lists, setext
1438                        // underlines, and horizontal rules inside the footnote
1439                        if next_trimmed.starts_with('>')
1440                            || TableUtils::is_potential_table_row(next_trimmed)
1441                            || is_list_item(next_trimmed)
1442                            || is_setext_underline(next_trimmed)
1443                            || is_horizontal_rule(next_trimmed)
1444                        {
1445                            fn_lines.push(FnLineType::Verbatim(strip_fn_indent(next), indent));
1446                            last_consumed = i;
1447                            i += 1;
1448                            continue;
1449                        }
1450                        // Headings, new footnote defs, link refs — end the footnote
1451                        break;
1452                    }
1453
1454                    // Link reference definitions inside footnotes are not reflowable
1455                    if next_trimmed.starts_with('[')
1456                        && !next_trimmed.starts_with("[^")
1457                        && next_trimmed.contains("]:")
1458                        && LINK_REF_PATTERN.is_match(next_trimmed)
1459                    {
1460                        fn_lines.push(FnLineType::Verbatim(strip_fn_indent(next), indent));
1461                        last_consumed = i;
1462                        i += 1;
1463                        continue;
1464                    }
1465
1466                    // HTML-only lines inside footnotes are not reflowable
1467                    if is_html_only_line(next_trimmed) {
1468                        fn_lines.push(FnLineType::Verbatim(strip_fn_indent(next), indent));
1469                        last_consumed = i;
1470                        i += 1;
1471                        continue;
1472                    }
1473
1474                    // Regular prose content
1475                    fn_lines.push(FnLineType::Content(next_trimmed.to_string()));
1476                    last_consumed = i;
1477                    i += 1;
1478                }
1479
1480                // Nothing collected or only empty lines
1481                if fn_lines.iter().all(|l| matches!(l, FnLineType::Empty)) || fn_lines.is_empty() {
1482                    continue;
1483                }
1484
1485                // --- Group into blocks ---
1486                #[derive(Debug)]
1487                enum FnBlock {
1488                    Paragraph(Vec<String>),
1489                    Verbatim(Vec<(String, usize)>), // (content, indent) preserved as-is
1490                }
1491
1492                let mut blocks: Vec<FnBlock> = Vec::new();
1493                let mut current_para: Vec<String> = Vec::new();
1494                let mut current_verbatim: Vec<(String, usize)> = Vec::new();
1495
1496                for fl in &fn_lines {
1497                    match fl {
1498                        FnLineType::Content(s) => {
1499                            if !current_verbatim.is_empty() {
1500                                blocks.push(FnBlock::Verbatim(std::mem::take(&mut current_verbatim)));
1501                            }
1502                            current_para.push(s.clone());
1503                        }
1504                        FnLineType::Verbatim(s, indent) => {
1505                            if !current_para.is_empty() {
1506                                blocks.push(FnBlock::Paragraph(std::mem::take(&mut current_para)));
1507                            }
1508                            current_verbatim.push((s.clone(), *indent));
1509                        }
1510                        FnLineType::Empty => {
1511                            if !current_para.is_empty() {
1512                                blocks.push(FnBlock::Paragraph(std::mem::take(&mut current_para)));
1513                            }
1514                            if !current_verbatim.is_empty() {
1515                                blocks.push(FnBlock::Verbatim(std::mem::take(&mut current_verbatim)));
1516                            }
1517                        }
1518                    }
1519                }
1520                if !current_para.is_empty() {
1521                    blocks.push(FnBlock::Paragraph(current_para));
1522                }
1523                if !current_verbatim.is_empty() {
1524                    blocks.push(FnBlock::Verbatim(current_verbatim));
1525                }
1526
1527                // --- Reflow paragraphs and reconstruct ---
1528                let prefix_display_width = prefix.chars().count() + 1; // +1 for space
1529                let reflow_line_length = if config.line_length.is_unlimited() {
1530                    usize::MAX
1531                } else {
1532                    config
1533                        .line_length
1534                        .get()
1535                        .saturating_sub(FN_INDENT.max(prefix_display_width))
1536                        .max(20)
1537                };
1538                let reflow_options = crate::utils::text_reflow::ReflowOptions {
1539                    line_length: reflow_line_length,
1540                    break_on_sentences: true,
1541                    preserve_breaks: false,
1542                    sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
1543                    semantic_line_breaks: config.reflow_mode == ReflowMode::SemanticLineBreaks,
1544                    abbreviations: config.abbreviations_for_reflow(),
1545                    length_mode: self.reflow_length_mode(),
1546                    attr_lists: ctx.flavor.supports_attr_lists(),
1547                    myst_roles: ctx.flavor.supports_myst_roles(),
1548                    require_sentence_capital: config.require_sentence_capital,
1549                    max_list_continuation_indent: None,
1550                };
1551
1552                let indent_str = " ".repeat(FN_INDENT);
1553                let mut result_lines: Vec<String> = Vec::new();
1554                let mut is_first_block = true;
1555
1556                for block in &blocks {
1557                    match block {
1558                        FnBlock::Paragraph(para_lines) => {
1559                            let paragraph_text = para_lines.join(" ");
1560                            let paragraph_text = paragraph_text.trim();
1561                            if paragraph_text.is_empty() {
1562                                continue;
1563                            }
1564
1565                            let reflowed = crate::utils::text_reflow::reflow_line(paragraph_text, &reflow_options);
1566                            if reflowed.is_empty() {
1567                                continue;
1568                            }
1569
1570                            // Blank line separator between blocks
1571                            if !result_lines.is_empty() {
1572                                result_lines.push(String::new());
1573                            }
1574
1575                            for (idx, rline) in reflowed.iter().enumerate() {
1576                                if is_first_block && idx == 0 {
1577                                    result_lines.push(format!("{prefix} {rline}"));
1578                                } else {
1579                                    result_lines.push(format!("{indent_str}{rline}"));
1580                                }
1581                            }
1582                            is_first_block = false;
1583                        }
1584                        FnBlock::Verbatim(verb_lines) => {
1585                            // Blank line separator between blocks
1586                            if !result_lines.is_empty() {
1587                                result_lines.push(String::new());
1588                            }
1589
1590                            if is_first_block {
1591                                // Verbatim as first block in a deferred-body footnote
1592                                if deferred_body {
1593                                    result_lines.push(prefix.to_string());
1594                                }
1595                                is_first_block = false;
1596                            }
1597                            for (content, _orig_indent) in verb_lines {
1598                                result_lines.push(format!("{indent_str}{content}"));
1599                            }
1600                        }
1601                    }
1602                }
1603
1604                // If nothing was produced, skip
1605                if result_lines.is_empty() {
1606                    continue;
1607                }
1608
1609                let reflowed_text = result_lines.join(line_ending);
1610
1611                // Calculate byte range using last_consumed
1612                let start_range = line_index.whole_line_range(footnote_start + 1);
1613                let end_range = if last_consumed == lines.len() - 1 && !ctx.content.ends_with('\n') {
1614                    line_index.line_text_range(last_consumed + 1, 1, lines[last_consumed].len() + 1)
1615                } else {
1616                    line_index.whole_line_range(last_consumed + 1)
1617                };
1618                let byte_range = start_range.start..end_range.end;
1619
1620                let replacement = if last_consumed < lines.len() - 1 || ctx.content.ends_with('\n') {
1621                    format!("{reflowed_text}{line_ending}")
1622                } else {
1623                    reflowed_text
1624                };
1625
1626                let original_text = &ctx.content[byte_range.clone()];
1627                let max_length = (footnote_start..=last_consumed)
1628                    .map(|idx| self.calculate_effective_length(lines[idx]))
1629                    .max()
1630                    .unwrap_or(0);
1631                let line_limit = if config.line_length.is_unlimited() {
1632                    usize::MAX
1633                } else {
1634                    config.line_length.get()
1635                };
1636                if original_text != replacement && max_length > line_limit {
1637                    warnings.push(LintWarning {
1638                        rule_name: Some(self.name().to_string()),
1639                        message: format!(
1640                            "Line length {} exceeds {} characters",
1641                            max_length,
1642                            config.line_length.get()
1643                        ),
1644                        line: footnote_start + 1,
1645                        column: 1,
1646                        end_line: last_consumed + 1,
1647                        end_column: lines[last_consumed].chars().count() + 1,
1648                        severity: Severity::Warning,
1649                        fix: Some(crate::rule::Fix::new(byte_range, replacement)),
1650                    });
1651                }
1652                continue;
1653            }
1654
1655            // Handle MkDocs container content (admonitions and tabs) with indent-preserving reflow
1656            if ctx
1657                .line_info(line_num)
1658                .is_some_and(super::super::lint_context::types::LineInfo::in_mkdocs_container)
1659            {
1660                // Skip admonition/tab marker lines — only reflow their indented content
1661                let current_line = lines[i];
1662                if mkdocs_admonitions::is_admonition_start(current_line) || mkdocs_tabs::is_tab_marker(current_line) {
1663                    i += 1;
1664                    continue;
1665                }
1666
1667                let container_start = i;
1668
1669                // Detect the actual indent level from the first content line
1670                // (supports nested admonitions with 8+ spaces)
1671                let first_line = lines[i];
1672                let base_indent_len = first_line.len() - first_line.trim_start().len();
1673                let base_indent: String = " ".repeat(base_indent_len);
1674
1675                // Collect consecutive MkDocs container paragraph lines
1676                let mut container_lines: Vec<&str> = Vec::new();
1677                while i < lines.len() {
1678                    let current_line_num = i + 1;
1679                    let line_info = ctx.line_info(current_line_num);
1680
1681                    // Stop if we leave the MkDocs container
1682                    if !line_info.is_some_and(super::super::lint_context::types::LineInfo::in_mkdocs_container) {
1683                        break;
1684                    }
1685
1686                    let line = lines[i];
1687
1688                    // Stop at paragraph boundaries within the container
1689                    if line.trim().is_empty() {
1690                        break;
1691                    }
1692
1693                    // Skip list items, code blocks, headings, HTML-only lines within containers
1694                    if is_list_item(line.trim())
1695                        || line.trim().starts_with("```")
1696                        || line.trim().starts_with("~~~")
1697                        || line.trim().starts_with('#')
1698                        || is_html_only_line(line)
1699                    {
1700                        break;
1701                    }
1702
1703                    container_lines.push(line);
1704                    i += 1;
1705                }
1706
1707                if container_lines.is_empty() {
1708                    // Must advance i to avoid infinite loop when we encounter
1709                    // non-paragraph content (code block, list, heading, empty line)
1710                    // at the start of an MkDocs container
1711                    i += 1;
1712                    continue;
1713                }
1714
1715                // Strip the base indent from each line and join for reflow
1716                let stripped_lines: Vec<&str> = container_lines
1717                    .iter()
1718                    .map(|line| {
1719                        if line.starts_with(&base_indent) {
1720                            &line[base_indent_len..]
1721                        } else {
1722                            line.trim_start()
1723                        }
1724                    })
1725                    .collect();
1726                let paragraph_text = stripped_lines.join(" ");
1727
1728                // Check if reflow is needed
1729                let needs_reflow = match config.reflow_mode {
1730                    ReflowMode::Normalize => self.normalize_mode_needs_reflow(container_lines.iter().copied(), config),
1731                    ReflowMode::SentencePerLine => {
1732                        let sentences = split_into_sentences(&paragraph_text);
1733                        sentences.len() > 1 || container_lines.len() > 1
1734                    }
1735                    ReflowMode::SemanticLineBreaks => {
1736                        let sentences = split_into_sentences(&paragraph_text);
1737                        sentences.len() > 1
1738                            || container_lines.len() > 1
1739                            || container_lines
1740                                .iter()
1741                                .any(|line| self.calculate_effective_length(line) > config.line_length.get())
1742                    }
1743                    ReflowMode::Default => container_lines
1744                        .iter()
1745                        .any(|line| self.calculate_effective_length(line) > config.line_length.get()),
1746                };
1747
1748                if !needs_reflow {
1749                    continue;
1750                }
1751
1752                // Calculate byte range for this container paragraph
1753                let start_range = line_index.whole_line_range(container_start + 1);
1754                let end_line = container_start + container_lines.len() - 1;
1755                let end_range = if end_line == lines.len() - 1 && !ctx.content.ends_with('\n') {
1756                    line_index.line_text_range(end_line + 1, 1, lines[end_line].len() + 1)
1757                } else {
1758                    line_index.whole_line_range(end_line + 1)
1759                };
1760                let byte_range = start_range.start..end_range.end;
1761
1762                // Reflow with adjusted line length (accounting for the 4-space indent)
1763                let reflow_line_length = if config.line_length.is_unlimited() {
1764                    usize::MAX
1765                } else {
1766                    config.line_length.get().saturating_sub(base_indent_len).max(1)
1767                };
1768                let reflow_options = crate::utils::text_reflow::ReflowOptions {
1769                    line_length: reflow_line_length,
1770                    break_on_sentences: true,
1771                    preserve_breaks: false,
1772                    sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
1773                    semantic_line_breaks: config.reflow_mode == ReflowMode::SemanticLineBreaks,
1774                    abbreviations: config.abbreviations_for_reflow(),
1775                    length_mode: self.reflow_length_mode(),
1776                    attr_lists: ctx.flavor.supports_attr_lists(),
1777                    myst_roles: ctx.flavor.supports_myst_roles(),
1778                    require_sentence_capital: config.require_sentence_capital,
1779                    max_list_continuation_indent: if ctx.flavor.requires_strict_list_indent() {
1780                        Some(4)
1781                    } else {
1782                        None
1783                    },
1784                };
1785                let reflowed = crate::utils::text_reflow::reflow_line(&paragraph_text, &reflow_options);
1786
1787                // Re-add the 4-space indent to each reflowed line
1788                let reflowed_with_indent: Vec<String> =
1789                    reflowed.iter().map(|line| format!("{base_indent}{line}")).collect();
1790                let reflowed_text = reflowed_with_indent.join(line_ending);
1791
1792                // Preserve trailing newline
1793                let replacement = if end_line < lines.len() - 1 || ctx.content.ends_with('\n') {
1794                    format!("{reflowed_text}{line_ending}")
1795                } else {
1796                    reflowed_text
1797                };
1798
1799                // Only generate a warning if the replacement is different
1800                let original_text = &ctx.content[byte_range.clone()];
1801                if original_text != replacement {
1802                    warnings.push(LintWarning {
1803                        rule_name: Some(self.name().to_string()),
1804                        message: format!(
1805                            "Line length {} exceeds {} characters (in MkDocs container)",
1806                            container_lines.iter().map(|l| l.len()).max().unwrap_or(0),
1807                            config.line_length.get()
1808                        ),
1809                        line: container_start + 1,
1810                        column: 1,
1811                        end_line: end_line + 1,
1812                        end_column: lines[end_line].chars().count() + 1,
1813                        severity: Severity::Warning,
1814                        fix: Some(crate::rule::Fix::new(byte_range, replacement)),
1815                    });
1816                }
1817                continue;
1818            }
1819
1820            // Helper function to detect semantic line markers
1821            let is_semantic_line = |content: &str| -> bool {
1822                let trimmed = content.trim_start();
1823                let semantic_markers = [
1824                    "NOTE:",
1825                    "WARNING:",
1826                    "IMPORTANT:",
1827                    "CAUTION:",
1828                    "TIP:",
1829                    "DANGER:",
1830                    "HINT:",
1831                    "INFO:",
1832                ];
1833                semantic_markers.iter().any(|marker| trimmed.starts_with(marker))
1834            };
1835
1836            // Helper function to detect fence markers (opening or closing)
1837            let is_fence_marker = |content: &str| -> bool {
1838                let trimmed = content.trim_start();
1839                trimmed.starts_with("```") || trimmed.starts_with("~~~")
1840            };
1841
1842            // Check if this is a list item - handle it specially
1843            let trimmed = lines[i].trim();
1844            if is_list_item(trimmed) {
1845                // Collect the entire list item including continuation lines
1846                let list_start = i;
1847                let (marker, first_content) = extract_list_marker_and_content(lines[i]);
1848                let marker_len = marker.len();
1849
1850                // Checkbox ([ ]/[x]/[X]) is inline content, not part of the list marker.
1851                // Use the base bullet/number marker width for continuation recognition
1852                // so that continuation lines at 2+ spaces are collected for "- [ ] " items.
1853                let base_marker_len = if marker.contains("[ ] ") || marker.contains("[x] ") || marker.contains("[X] ") {
1854                    marker.find('[').unwrap_or(marker_len)
1855                } else {
1856                    marker_len
1857                };
1858
1859                // MkDocs flavor requires at least 4 spaces for list continuation
1860                // after a blank line (multi-paragraph list items). For non-blank
1861                // continuation (lines directly following the marker line), use
1862                // the natural marker width so that 2-space indent is recognized.
1863                let item_indent = ctx.lines[i].indent;
1864                let min_continuation_indent = if ctx.flavor.requires_strict_list_indent() {
1865                    // Use 4-space relative indent from the list item's nesting level
1866                    item_indent + (base_marker_len - item_indent).max(4)
1867                } else {
1868                    marker_len
1869                };
1870                let content_continuation_indent = base_marker_len;
1871
1872                // Track lines and their types (content, code block, fence, nested list)
1873                #[derive(Clone)]
1874                enum LineType {
1875                    Content(String),
1876                    CodeBlock(String, usize),         // content and original indent
1877                    SemanticLine(String), // Lines starting with NOTE:, WARNING:, etc that should stay separate
1878                    SnippetLine(String),  // MkDocs Snippets delimiters (-8<-) that must stay on their own line
1879                    DivMarker(String),    // Quarto/Pandoc div markers (::: opening or closing)
1880                    AdmonitionHeader(String, usize), // header text (e.g. "!!! note") and original indent
1881                    AdmonitionContent(String, usize), // body content text and original indent
1882                    Table(String, usize), // GFM table row, preserved verbatim with original indent
1883                    Empty,
1884                }
1885
1886                let mut list_item_lines: Vec<LineType> = vec![LineType::Content(first_content)];
1887                i += 1;
1888
1889                // Collect continuation lines using ctx.lines for metadata
1890                while i < lines.len() {
1891                    let line_info = &ctx.lines[i];
1892
1893                    // Use pre-computed is_blank from ctx
1894                    if line_info.is_blank {
1895                        // Empty line - check if next line is indented (part of list item)
1896                        if i + 1 < lines.len() {
1897                            let next_info = &ctx.lines[i + 1];
1898
1899                            // Check if next line is indented enough to be continuation
1900                            if !next_info.is_blank && next_info.indent >= min_continuation_indent {
1901                                // This blank line is between paragraphs/blocks in the list item
1902                                list_item_lines.push(LineType::Empty);
1903                                i += 1;
1904                                continue;
1905                            }
1906                        }
1907                        // No indented line after blank, end of list item
1908                        break;
1909                    }
1910
1911                    // Use pre-computed indent from ctx
1912                    let indent = line_info.indent;
1913
1914                    // Valid continuation must be indented at least content_continuation_indent.
1915                    // For non-blank continuation, use marker_len (e.g. 2 for "- ").
1916                    // MkDocs strict 4-space requirement applies only after blank lines.
1917                    if indent >= content_continuation_indent {
1918                        let trimmed = line_info.content(ctx.content).trim();
1919
1920                        // Check for MkDocs admonition lines inside list items BEFORE
1921                        // checking in_code_block. Lines inside code blocks within
1922                        // admonitions have both in_admonition and in_code_block set;
1923                        // admonition membership takes priority so the entire admonition
1924                        // structure (including embedded code blocks) is preserved.
1925                        if line_info.in_admonition {
1926                            let raw_content = line_info.content(ctx.content);
1927                            if mkdocs_admonitions::is_admonition_start(raw_content) {
1928                                let header_text = raw_content[indent..].trim_end().to_string();
1929                                list_item_lines.push(LineType::AdmonitionHeader(header_text, indent));
1930                            } else {
1931                                let body_text = raw_content[indent..].trim_end().to_string();
1932                                list_item_lines.push(LineType::AdmonitionContent(body_text, indent));
1933                            }
1934                            i += 1;
1935                            continue;
1936                        }
1937
1938                        // Use pre-computed in_code_block from ctx
1939                        if line_info.in_code_block {
1940                            list_item_lines.push(LineType::CodeBlock(
1941                                line_info.content(ctx.content)[indent..].to_string(),
1942                                indent,
1943                            ));
1944                            i += 1;
1945                            continue;
1946                        }
1947
1948                        // Check if this is a SIBLING list item (breaks parent)
1949                        // Nested lists are indented >= marker_len and are PART of the parent item
1950                        // Siblings are at indent < marker_len (at or before parent marker)
1951                        if is_list_item(trimmed) && indent < marker_len {
1952                            // This is a sibling item at same or higher level - end parent item
1953                            break;
1954                        }
1955
1956                        // Nested list items are always processed independently
1957                        // by the outer loop, so break when we encounter one.
1958                        // If a blank line was collected before this, uncollect it
1959                        // so the outer loop preserves the blank between parent and nested.
1960                        if is_list_item(trimmed) && indent >= marker_len {
1961                            if matches!(list_item_lines.last(), Some(LineType::Empty)) {
1962                                list_item_lines.pop();
1963                                i -= 1;
1964                            }
1965                            break;
1966                        }
1967
1968                        // Normal continuation vs indented code block.
1969                        // Use min_continuation_indent for the threshold since
1970                        // code blocks start 4 spaces beyond the expected content
1971                        // level (which is min_continuation_indent for MkDocs).
1972                        if indent <= min_continuation_indent + 3 {
1973                            // Extract content (remove indentation and trailing whitespace)
1974                            // Preserve hard breaks (2 trailing spaces) while removing excessive whitespace
1975                            // See: https://github.com/rvben/rumdl/issues/76
1976                            let content = trim_preserving_hard_break(&line_info.content(ctx.content)[indent..]);
1977
1978                            // Check if this is a div marker (::: opening or closing)
1979                            // These must be preserved on their own line, not merged into paragraphs
1980                            if line_info.is_div_marker {
1981                                list_item_lines.push(LineType::DivMarker(content));
1982                            }
1983                            // Check if this is a fence marker (opening or closing)
1984                            // These should be treated as code block lines, not paragraph content
1985                            else if is_fence_marker(&content) {
1986                                list_item_lines.push(LineType::CodeBlock(content, indent));
1987                            }
1988                            // Check if this is a semantic line (NOTE:, WARNING:, etc.)
1989                            else if is_semantic_line(&content) {
1990                                list_item_lines.push(LineType::SemanticLine(content));
1991                            }
1992                            // Check if this is a snippet block delimiter (-8<- or --8<--)
1993                            // These must be preserved on their own lines for MkDocs Snippets extension
1994                            else if is_snippet_block_delimiter(&content) {
1995                                list_item_lines.push(LineType::SnippetLine(content));
1996                            }
1997                            // Check if this is a GFM table row. Tables nested inside list
1998                            // items must be preserved verbatim — joining them with prose
1999                            // breaks the column structure.
2000                            //
2001                            // `is_potential_table_row` is intentionally permissive at the
2002                            // row level: any line with `|` and 2+ cells qualifies. To avoid
2003                            // misclassifying prose continuation lines that contain a literal
2004                            // pipe (e.g. "use grep | sort to ..."), require one of:
2005                            //   - the row is pipe-bordered (`| ... |`), the canonical form
2006                            //     for tables nested in lists; or
2007                            //   - the next line is a delimiter row (this is a header); or
2008                            //   - the previous classified line was already a Table (this is
2009                            //     a continuation row).
2010                            else if TableUtils::is_potential_table_row(&content) && {
2011                                let pipe_bordered = content.trim().starts_with('|') && content.trim().ends_with('|');
2012                                let next_is_delim = ctx
2013                                    .lines
2014                                    .get(i + 1)
2015                                    .is_some_and(|next| TableUtils::is_delimiter_row(next.content(ctx.content)));
2016                                let prev_was_table = matches!(list_item_lines.last(), Some(LineType::Table(..)));
2017                                pipe_bordered || next_is_delim || prev_was_table
2018                            } {
2019                                list_item_lines.push(LineType::Table(content, indent));
2020                            } else {
2021                                list_item_lines.push(LineType::Content(content));
2022                            }
2023                            i += 1;
2024                        } else {
2025                            // indent >= min_continuation_indent + 4: indented code block
2026                            list_item_lines.push(LineType::CodeBlock(
2027                                line_info.content(ctx.content)[indent..].to_string(),
2028                                indent,
2029                            ));
2030                            i += 1;
2031                        }
2032                    } else {
2033                        // Not indented enough, end of list item
2034                        break;
2035                    }
2036                }
2037
2038                // Determine the output continuation indent.
2039                // Normalize/Default modes canonicalize to min_continuation_indent
2040                // (fixing over-indented continuation). Semantic/SentencePerLine
2041                // modes preserve the user's actual indent since they only fix
2042                // line breaking, not indentation.
2043                let indent_size = match config.reflow_mode {
2044                    ReflowMode::SemanticLineBreaks | ReflowMode::SentencePerLine => {
2045                        // Find indent of the first plain text continuation line,
2046                        // skipping the marker line (index 0), nested list items,
2047                        // code blocks, and blank lines.
2048                        list_item_lines
2049                            .iter()
2050                            .enumerate()
2051                            .skip(1)
2052                            .find_map(|(k, lt)| {
2053                                if matches!(lt, LineType::Content(_)) {
2054                                    Some(ctx.lines[list_start + k].indent)
2055                                } else {
2056                                    None
2057                                }
2058                            })
2059                            .unwrap_or(min_continuation_indent)
2060                    }
2061                    _ => min_continuation_indent,
2062                };
2063                // For checkbox items in mkdocs flavor, enforce minimum indent so
2064                // continuation lines use the structural list indent (4), not the
2065                // content-aligned indent (6) which Python-Markdown doesn't support
2066                let has_checkbox = base_marker_len < marker_len;
2067                let indent_size = if has_checkbox && ctx.flavor.requires_strict_list_indent() {
2068                    indent_size.max(min_continuation_indent)
2069                } else {
2070                    indent_size
2071                };
2072                let expected_indent = " ".repeat(indent_size);
2073
2074                // Split list_item_lines into blocks (paragraphs, code blocks, nested lists, semantic lines, and HTML blocks)
2075                let mut builder = BlockBuilder::new();
2076                for line in &list_item_lines {
2077                    match line {
2078                        LineType::Empty => builder.feed_blank_line(),
2079                        LineType::Content(content) => builder.feed_content(content),
2080                        LineType::CodeBlock(content, indent) => builder.feed_code_line(content, *indent),
2081                        LineType::SemanticLine(content) => builder.feed_semantic_line(content),
2082                        LineType::SnippetLine(content) => builder.feed_snippet_line(content),
2083                        LineType::DivMarker(content) => builder.feed_div_marker(content),
2084                        LineType::AdmonitionHeader(header_text, indent) => {
2085                            builder.feed_admonition_header(header_text, *indent)
2086                        }
2087                        LineType::AdmonitionContent(content, indent) => {
2088                            builder.feed_admonition_content(content, *indent)
2089                        }
2090                        LineType::Table(content, indent) => builder.feed_table_line(content, *indent),
2091                    }
2092                }
2093                let blocks = builder.finalize();
2094
2095                // Helper: check if a line (raw source or stripped content) is exempt
2096                // from line-length checks. Link reference definitions are always exempt;
2097                // standalone link/image lines are exempt when strict mode is off.
2098                // Also checks content after stripping list markers, since list item
2099                // continuation lines may contain link ref defs.
2100                let is_exempt_line = |raw_line: &str| -> bool {
2101                    let trimmed = raw_line.trim();
2102                    // Link reference definitions: always exempt
2103                    if trimmed.starts_with('[') && trimmed.contains("]:") && LINK_REF_PATTERN.is_match(trimmed) {
2104                        return true;
2105                    }
2106                    // Also check after stripping list markers (for list item content)
2107                    if is_list_item(trimmed) {
2108                        let (_, content) = extract_list_marker_and_content(trimmed);
2109                        let content_trimmed = content.trim();
2110                        if content_trimmed.starts_with('[')
2111                            && content_trimmed.contains("]:")
2112                            && LINK_REF_PATTERN.is_match(content_trimmed)
2113                        {
2114                            return true;
2115                        }
2116                    }
2117                    // Standalone link/image lines: exempt when not strict
2118                    if !config.strict && is_standalone_link_or_image_line(raw_line) {
2119                        return true;
2120                    }
2121                    // HTML-only lines: exempt when not strict
2122                    if !config.strict && is_html_only_line(raw_line) {
2123                        return true;
2124                    }
2125                    false
2126                };
2127
2128                // Check if reflowing is needed (only for content paragraphs, not code blocks or nested lists)
2129                // Exclude link reference definitions and standalone link lines from content
2130                // so they don't pollute combined_content or trigger false reflow.
2131                let content_lines: Vec<String> = list_item_lines
2132                    .iter()
2133                    .filter_map(|line| {
2134                        if let LineType::Content(s) = line {
2135                            if is_exempt_line(s) {
2136                                return None;
2137                            }
2138                            Some(s.clone())
2139                        } else {
2140                            None
2141                        }
2142                    })
2143                    .collect();
2144
2145                // Check if we need to reflow this list item
2146                // We check the combined content to see if it exceeds length limits
2147                let combined_content = content_lines.join(" ").trim().to_string();
2148
2149                // Helper to check if we should reflow in normalize mode
2150                let should_normalize = || {
2151                    // Don't normalize if the list item only contains nested lists, code blocks, or semantic lines
2152                    // DO normalize if it has plain text content that spans multiple lines
2153                    let has_code_blocks = blocks.iter().any(|b| matches!(b, Block::Code { .. }));
2154                    let has_semantic_lines = blocks.iter().any(|b| matches!(b, Block::SemanticLine(_)));
2155                    let has_snippet_lines = blocks.iter().any(|b| matches!(b, Block::SnippetLine(_)));
2156                    let has_div_markers = blocks.iter().any(|b| matches!(b, Block::DivMarker(_)));
2157                    let has_admonitions = blocks.iter().any(|b| matches!(b, Block::Admonition { .. }));
2158                    let has_tables = blocks.iter().any(|b| matches!(b, Block::Table { .. }));
2159                    let has_paragraphs = blocks.iter().any(|b| matches!(b, Block::Paragraph(_)));
2160
2161                    // If we have structural blocks but no paragraphs, don't normalize
2162                    if (has_code_blocks
2163                        || has_semantic_lines
2164                        || has_snippet_lines
2165                        || has_div_markers
2166                        || has_admonitions
2167                        || has_tables)
2168                        && !has_paragraphs
2169                    {
2170                        return false;
2171                    }
2172
2173                    // If we have paragraphs, check if they span multiple lines or there are multiple blocks
2174                    if has_paragraphs {
2175                        // Count only paragraphs that contain at least one non-exempt line.
2176                        // Paragraphs consisting entirely of link ref defs or standalone links
2177                        // should not trigger normalization.
2178                        let paragraph_count = blocks
2179                            .iter()
2180                            .filter(|b| {
2181                                if let Block::Paragraph(para_lines) = b {
2182                                    !para_lines.iter().all(|line| is_exempt_line(line))
2183                                } else {
2184                                    false
2185                                }
2186                            })
2187                            .count();
2188                        if paragraph_count > 1 {
2189                            // Multiple non-exempt paragraph blocks should be normalized
2190                            return true;
2191                        }
2192
2193                        // Single paragraph block: normalize if it has multiple content lines
2194                        if content_lines.len() > 1 {
2195                            return true;
2196                        }
2197                    }
2198
2199                    false
2200                };
2201
2202                let needs_reflow = match config.reflow_mode {
2203                    ReflowMode::Normalize => {
2204                        // Only reflow if:
2205                        // 1. Any non-exempt paragraph, when joined, exceeds the limit, OR
2206                        // 2. Any admonition content line exceeds the limit, OR
2207                        // 3. The list item should be normalized (has multi-line plain text)
2208                        let any_paragraph_exceeds = blocks.iter().any(|block| match block {
2209                            Block::Paragraph(para_lines) => {
2210                                if para_lines.iter().all(|line| is_exempt_line(line)) {
2211                                    return false;
2212                                }
2213                                let joined = para_lines.join(" ");
2214                                let with_marker = format!("{}{}", " ".repeat(indent_size), joined.trim());
2215                                self.calculate_effective_length(&with_marker) > config.line_length.get()
2216                            }
2217                            Block::Admonition {
2218                                content_lines,
2219                                header_indent,
2220                                ..
2221                            } => content_lines.iter().any(|(content, indent)| {
2222                                if content.is_empty() {
2223                                    return false;
2224                                }
2225                                let with_indent = format!("{}{}", " ".repeat(*indent.max(header_indent)), content);
2226                                self.calculate_effective_length(&with_indent) > config.line_length.get()
2227                            }),
2228                            _ => false,
2229                        });
2230                        if any_paragraph_exceeds {
2231                            true
2232                        } else {
2233                            should_normalize()
2234                        }
2235                    }
2236                    ReflowMode::SentencePerLine => {
2237                        // Check if list item has multiple sentences
2238                        let sentences = split_into_sentences(&combined_content);
2239                        sentences.len() > 1
2240                    }
2241                    ReflowMode::SemanticLineBreaks => {
2242                        let sentences = split_into_sentences(&combined_content);
2243                        sentences.len() > 1
2244                            || (list_start..i).any(|line_idx| {
2245                                let line = lines[line_idx];
2246                                let trimmed = line.trim();
2247                                if trimmed.is_empty() || is_exempt_line(line) {
2248                                    return false;
2249                                }
2250                                self.calculate_effective_length(line) > config.line_length.get()
2251                            })
2252                    }
2253                    ReflowMode::Default => {
2254                        // In default mode, only reflow if any individual non-exempt line exceeds limit
2255                        (list_start..i).any(|line_idx| {
2256                            let line = lines[line_idx];
2257                            let trimmed = line.trim();
2258                            // Skip blank lines and exempt lines
2259                            if trimmed.is_empty() || is_exempt_line(line) {
2260                                return false;
2261                            }
2262                            self.calculate_effective_length(line) > config.line_length.get()
2263                        })
2264                    }
2265                };
2266
2267                if needs_reflow {
2268                    let start_range = line_index.whole_line_range(list_start + 1);
2269                    let end_line = i - 1;
2270                    let end_range = if end_line == lines.len() - 1 && !ctx.content.ends_with('\n') {
2271                        line_index.line_text_range(end_line + 1, 1, lines[end_line].len() + 1)
2272                    } else {
2273                        line_index.whole_line_range(end_line + 1)
2274                    };
2275                    let byte_range = start_range.start..end_range.end;
2276
2277                    // Reflow each block (paragraphs only, preserve code blocks)
2278                    // When line_length = 0 (no limit), use a very large value for reflow
2279                    let reflow_line_length = if config.line_length.is_unlimited() {
2280                        usize::MAX
2281                    } else {
2282                        config.line_length.get().saturating_sub(indent_size).max(1)
2283                    };
2284                    let reflow_options = crate::utils::text_reflow::ReflowOptions {
2285                        line_length: reflow_line_length,
2286                        break_on_sentences: true,
2287                        preserve_breaks: false,
2288                        sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
2289                        semantic_line_breaks: config.reflow_mode == ReflowMode::SemanticLineBreaks,
2290                        abbreviations: config.abbreviations_for_reflow(),
2291                        length_mode: self.reflow_length_mode(),
2292                        attr_lists: ctx.flavor.supports_attr_lists(),
2293                        myst_roles: ctx.flavor.supports_myst_roles(),
2294                        require_sentence_capital: config.require_sentence_capital,
2295                        max_list_continuation_indent: if ctx.flavor.requires_strict_list_indent() {
2296                            Some(4)
2297                        } else {
2298                            None
2299                        },
2300                    };
2301
2302                    let mut result: Vec<String> = Vec::new();
2303                    let mut is_first_block = true;
2304
2305                    for (block_idx, block) in blocks.iter().enumerate() {
2306                        match block {
2307                            Block::Paragraph(para_lines) => {
2308                                // If every line in this paragraph is exempt (link ref defs,
2309                                // standalone links), preserve the paragraph verbatim instead
2310                                // of reflowing it. Reflowing would corrupt link ref defs.
2311                                let all_exempt = para_lines.iter().all(|line| is_exempt_line(line));
2312
2313                                if all_exempt {
2314                                    for (idx, line) in para_lines.iter().enumerate() {
2315                                        if is_first_block && idx == 0 {
2316                                            result.push(format!("{marker}{line}"));
2317                                            is_first_block = false;
2318                                        } else {
2319                                            result.push(format!("{expected_indent}{line}"));
2320                                        }
2321                                    }
2322                                } else {
2323                                    // Split the paragraph into segments at hard break boundaries
2324                                    // Each segment can be reflowed independently
2325                                    let segments = split_into_segments(para_lines);
2326
2327                                    for (segment_idx, segment) in segments.iter().enumerate() {
2328                                        // Check if this segment ends with a hard break and what type
2329                                        let hard_break_type = segment.last().and_then(|line| {
2330                                            let line = line.strip_suffix('\r').unwrap_or(line);
2331                                            if line.ends_with('\\') {
2332                                                Some("\\")
2333                                            } else if line.ends_with("  ") {
2334                                                Some("  ")
2335                                            } else {
2336                                                None
2337                                            }
2338                                        });
2339
2340                                        // Join and reflow the segment (removing the hard break marker for processing)
2341                                        let segment_for_reflow: Vec<String> = segment
2342                                            .iter()
2343                                            .map(|line| {
2344                                                // Strip hard break marker (2 spaces or backslash) for reflow processing
2345                                                if line.ends_with('\\') {
2346                                                    line[..line.len() - 1].trim_end().to_string()
2347                                                } else if line.ends_with("  ") {
2348                                                    line[..line.len() - 2].trim_end().to_string()
2349                                                } else {
2350                                                    line.clone()
2351                                                }
2352                                            })
2353                                            .collect();
2354
2355                                        let segment_text = segment_for_reflow.join(" ").trim().to_string();
2356                                        if !segment_text.is_empty() {
2357                                            let reflowed =
2358                                                crate::utils::text_reflow::reflow_line(&segment_text, &reflow_options);
2359
2360                                            if is_first_block && segment_idx == 0 {
2361                                                // First segment of first block starts with marker
2362                                                result.push(format!("{marker}{}", reflowed[0]));
2363                                                for line in reflowed.iter().skip(1) {
2364                                                    result.push(format!("{expected_indent}{line}"));
2365                                                }
2366                                                is_first_block = false;
2367                                            } else {
2368                                                // Subsequent segments
2369                                                for line in reflowed {
2370                                                    result.push(format!("{expected_indent}{line}"));
2371                                                }
2372                                            }
2373
2374                                            // If this segment had a hard break, add it back to the last line
2375                                            // Preserve the original hard break format (backslash or two spaces)
2376                                            if let Some(break_marker) = hard_break_type
2377                                                && let Some(last_line) = result.last_mut()
2378                                            {
2379                                                last_line.push_str(break_marker);
2380                                            }
2381                                        }
2382                                    }
2383                                }
2384
2385                                // Add blank line after paragraph block if there's a next block.
2386                                // Check if next block is a code block that doesn't want a preceding blank.
2387                                // Also don't add blank lines before snippet lines (they should stay tight).
2388                                // Only add if not already ending with one (avoids double blanks).
2389                                if block_idx < blocks.len() - 1 {
2390                                    let next_block = &blocks[block_idx + 1];
2391                                    let should_add_blank = match next_block {
2392                                        Block::Code {
2393                                            has_preceding_blank, ..
2394                                        } => *has_preceding_blank,
2395                                        Block::Table {
2396                                            has_preceding_blank, ..
2397                                        } => *has_preceding_blank,
2398                                        Block::SnippetLine(_) | Block::DivMarker(_) => false,
2399                                        _ => true, // For all other blocks, add blank line
2400                                    };
2401                                    if should_add_blank && result.last().is_none_or(|s: &String| !s.is_empty()) {
2402                                        result.push(String::new());
2403                                    }
2404                                }
2405                            }
2406                            Block::Code {
2407                                lines: code_lines,
2408                                has_preceding_blank: _,
2409                            } => {
2410                                // Preserve code blocks as-is with original indentation
2411                                // NOTE: Blank line before code block is handled by the previous block
2412                                // (see paragraph block's logic above)
2413
2414                                for (idx, (content, orig_indent)) in code_lines.iter().enumerate() {
2415                                    if is_first_block && idx == 0 {
2416                                        // First line of first block gets marker
2417                                        result.push(format!(
2418                                            "{marker}{}",
2419                                            " ".repeat(orig_indent - marker_len) + content
2420                                        ));
2421                                        is_first_block = false;
2422                                    } else if content.is_empty() {
2423                                        result.push(String::new());
2424                                    } else {
2425                                        result.push(format!("{}{}", " ".repeat(*orig_indent), content));
2426                                    }
2427                                }
2428                            }
2429                            Block::SemanticLine(content) => {
2430                                // Preserve semantic lines (NOTE:, WARNING:, etc.) as-is on their own line.
2431                                // Only add blank before if not already ending with one.
2432                                if !is_first_block && result.last().is_none_or(|s: &String| !s.is_empty()) {
2433                                    result.push(String::new());
2434                                }
2435
2436                                if is_first_block {
2437                                    // First block starts with marker
2438                                    result.push(format!("{marker}{content}"));
2439                                    is_first_block = false;
2440                                } else {
2441                                    // Subsequent blocks use expected indent
2442                                    result.push(format!("{expected_indent}{content}"));
2443                                }
2444
2445                                // Add blank line after semantic line if there's a next block.
2446                                // Only add if not already ending with one.
2447                                if block_idx < blocks.len() - 1 {
2448                                    let next_block = &blocks[block_idx + 1];
2449                                    let should_add_blank = match next_block {
2450                                        Block::Code {
2451                                            has_preceding_blank, ..
2452                                        } => *has_preceding_blank,
2453                                        Block::Table {
2454                                            has_preceding_blank, ..
2455                                        } => *has_preceding_blank,
2456                                        Block::SnippetLine(_) | Block::DivMarker(_) => false,
2457                                        _ => true, // For all other blocks, add blank line
2458                                    };
2459                                    if should_add_blank && result.last().is_none_or(|s: &String| !s.is_empty()) {
2460                                        result.push(String::new());
2461                                    }
2462                                }
2463                            }
2464                            Block::SnippetLine(content) => {
2465                                // Preserve snippet delimiters (-8<-) as-is on their own line
2466                                // Unlike semantic lines, snippet lines don't add extra blank lines
2467                                if is_first_block {
2468                                    // First block starts with marker
2469                                    result.push(format!("{marker}{content}"));
2470                                    is_first_block = false;
2471                                } else {
2472                                    // Subsequent blocks use expected indent
2473                                    result.push(format!("{expected_indent}{content}"));
2474                                }
2475                                // No blank lines added before or after snippet delimiters
2476                            }
2477                            Block::DivMarker(content) => {
2478                                // Preserve div markers (::: opening or closing) as-is on their own line
2479                                if is_first_block {
2480                                    result.push(format!("{marker}{content}"));
2481                                    is_first_block = false;
2482                                } else {
2483                                    result.push(format!("{expected_indent}{content}"));
2484                                }
2485                            }
2486                            Block::Html {
2487                                lines: html_lines,
2488                                has_preceding_blank: _,
2489                            } => {
2490                                // Preserve HTML blocks exactly as-is with original indentation
2491                                // NOTE: Blank line before HTML block is handled by the previous block
2492
2493                                for (idx, line) in html_lines.iter().enumerate() {
2494                                    if is_first_block && idx == 0 {
2495                                        // First line of first block gets marker
2496                                        result.push(format!("{marker}{line}"));
2497                                        is_first_block = false;
2498                                    } else if line.is_empty() {
2499                                        // Preserve blank lines inside HTML blocks
2500                                        result.push(String::new());
2501                                    } else {
2502                                        // Preserve lines with their original content (already includes indentation)
2503                                        result.push(format!("{expected_indent}{line}"));
2504                                    }
2505                                }
2506
2507                                // Add blank line after HTML block if there's a next block.
2508                                // Only add if not already ending with one (avoids double blanks
2509                                // when the HTML block itself contained a trailing blank line).
2510                                if block_idx < blocks.len() - 1 {
2511                                    let next_block = &blocks[block_idx + 1];
2512                                    let should_add_blank = match next_block {
2513                                        Block::Code {
2514                                            has_preceding_blank, ..
2515                                        } => *has_preceding_blank,
2516                                        Block::Html {
2517                                            has_preceding_blank, ..
2518                                        } => *has_preceding_blank,
2519                                        Block::Table {
2520                                            has_preceding_blank, ..
2521                                        } => *has_preceding_blank,
2522                                        Block::SnippetLine(_) | Block::DivMarker(_) => false,
2523                                        _ => true, // For all other blocks, add blank line
2524                                    };
2525                                    if should_add_blank && result.last().is_none_or(|s: &String| !s.is_empty()) {
2526                                        result.push(String::new());
2527                                    }
2528                                }
2529                            }
2530                            Block::Table {
2531                                lines: table_lines,
2532                                has_preceding_blank: _,
2533                            } => {
2534                                // Preserve table rows verbatim with their original indentation.
2535                                // Reflowing rows would corrupt column alignment and inject `|`
2536                                // characters mid-paragraph (issue #590).
2537                                // The leading blank line is emitted by the previous block.
2538                                for (idx, (content, orig_indent)) in table_lines.iter().enumerate() {
2539                                    if is_first_block && idx == 0 {
2540                                        // First line of first block gets the list marker
2541                                        result.push(format!(
2542                                            "{marker}{}",
2543                                            " ".repeat(orig_indent.saturating_sub(marker_len)) + content
2544                                        ));
2545                                        is_first_block = false;
2546                                    } else {
2547                                        result.push(format!("{}{}", " ".repeat(*orig_indent), content));
2548                                    }
2549                                }
2550
2551                                // Add blank line after table block if there's a next block.
2552                                if block_idx < blocks.len() - 1 {
2553                                    let next_block = &blocks[block_idx + 1];
2554                                    let should_add_blank = match next_block {
2555                                        Block::Code {
2556                                            has_preceding_blank, ..
2557                                        } => *has_preceding_blank,
2558                                        Block::Html {
2559                                            has_preceding_blank, ..
2560                                        } => *has_preceding_blank,
2561                                        Block::Table {
2562                                            has_preceding_blank, ..
2563                                        } => *has_preceding_blank,
2564                                        Block::SnippetLine(_) | Block::DivMarker(_) => false,
2565                                        _ => true,
2566                                    };
2567                                    if should_add_blank && result.last().is_none_or(|s: &String| !s.is_empty()) {
2568                                        result.push(String::new());
2569                                    }
2570                                }
2571                            }
2572                            Block::Admonition {
2573                                header,
2574                                header_indent,
2575                                content_lines: admon_lines,
2576                            } => {
2577                                // Reconstruct admonition block with header at original indent
2578                                // and body content reflowed to fit within the line length limit
2579
2580                                // Add blank line before admonition if not first block
2581                                if !is_first_block && result.last().is_none_or(|s: &String| !s.is_empty()) {
2582                                    result.push(String::new());
2583                                }
2584
2585                                // Output the header at its original indent
2586                                let header_indent_str = " ".repeat(*header_indent);
2587                                if is_first_block {
2588                                    result.push(format!(
2589                                        "{marker}{}",
2590                                        " ".repeat(header_indent.saturating_sub(marker_len)) + header
2591                                    ));
2592                                    is_first_block = false;
2593                                } else {
2594                                    result.push(format!("{header_indent_str}{header}"));
2595                                }
2596
2597                                // Derive body indent from the first non-empty content line's
2598                                // stored indent, falling back to header_indent + 4 for
2599                                // empty-body admonitions
2600                                let body_indent = admon_lines
2601                                    .iter()
2602                                    .find(|(content, _)| !content.is_empty())
2603                                    .map_or(header_indent + 4, |(_, indent)| *indent);
2604                                let body_indent_str = " ".repeat(body_indent);
2605
2606                                // Segment body content into code blocks (verbatim) and
2607                                // text paragraphs (reflowable), separated by blank lines.
2608                                // Code lines store (content, orig_indent) to reconstruct
2609                                // internal indentation relative to body_indent.
2610                                enum AdmonSegment {
2611                                    Text(Vec<String>),
2612                                    Code(Vec<(String, usize)>),
2613                                }
2614
2615                                let mut segments: Vec<AdmonSegment> = Vec::new();
2616                                let mut current_text: Vec<String> = Vec::new();
2617                                let mut current_code: Vec<(String, usize)> = Vec::new();
2618                                let mut in_admon_code = false;
2619                                // Track the opening fence character so closing fences
2620                                // must match (backticks close backticks, tildes close tildes)
2621                                let mut fence_char: char = '`';
2622
2623                                // Opening fences: ``` or ~~~ followed by optional info string
2624                                let get_opening_fence = |s: &str| -> Option<(char, usize)> {
2625                                    let t = s.trim_start();
2626                                    if t.starts_with("```") {
2627                                        Some(('`', t.bytes().take_while(|&b| b == b'`').count()))
2628                                    } else if t.starts_with("~~~") {
2629                                        Some(('~', t.bytes().take_while(|&b| b == b'~').count()))
2630                                    } else {
2631                                        None
2632                                    }
2633                                };
2634                                // Closing fences: ONLY fence chars + optional trailing spaces
2635                                let get_closing_fence = |s: &str| -> Option<(char, usize)> {
2636                                    let t = s.trim();
2637                                    if t.starts_with("```") && t.bytes().all(|b| b == b'`') {
2638                                        Some(('`', t.len()))
2639                                    } else if t.starts_with("~~~") && t.bytes().all(|b| b == b'~') {
2640                                        Some(('~', t.len()))
2641                                    } else {
2642                                        None
2643                                    }
2644                                };
2645                                let mut fence_len: usize = 3;
2646
2647                                for (content, orig_indent) in admon_lines {
2648                                    if in_admon_code {
2649                                        // Closing fence must use the same character, be
2650                                        // at least as long, and have no info string
2651                                        if let Some((ch, len)) = get_closing_fence(content)
2652                                            && ch == fence_char
2653                                            && len >= fence_len
2654                                        {
2655                                            current_code.push((content.clone(), *orig_indent));
2656                                            in_admon_code = false;
2657                                            segments.push(AdmonSegment::Code(std::mem::take(&mut current_code)));
2658                                            continue;
2659                                        }
2660                                        current_code.push((content.clone(), *orig_indent));
2661                                    } else if let Some((ch, len)) = get_opening_fence(content) {
2662                                        if !current_text.is_empty() {
2663                                            segments.push(AdmonSegment::Text(std::mem::take(&mut current_text)));
2664                                        }
2665                                        in_admon_code = true;
2666                                        fence_char = ch;
2667                                        fence_len = len;
2668                                        current_code.push((content.clone(), *orig_indent));
2669                                    } else if content.is_empty() {
2670                                        if !current_text.is_empty() {
2671                                            segments.push(AdmonSegment::Text(std::mem::take(&mut current_text)));
2672                                        }
2673                                    } else {
2674                                        current_text.push(content.clone());
2675                                    }
2676                                }
2677                                if in_admon_code && !current_code.is_empty() {
2678                                    segments.push(AdmonSegment::Code(std::mem::take(&mut current_code)));
2679                                }
2680                                if !current_text.is_empty() {
2681                                    segments.push(AdmonSegment::Text(std::mem::take(&mut current_text)));
2682                                }
2683
2684                                // Build reflow options once for all text segments
2685                                let admon_reflow_length = if config.line_length.is_unlimited() {
2686                                    usize::MAX
2687                                } else {
2688                                    config.line_length.get().saturating_sub(body_indent).max(1)
2689                                };
2690
2691                                let admon_reflow_options = crate::utils::text_reflow::ReflowOptions {
2692                                    line_length: admon_reflow_length,
2693                                    break_on_sentences: true,
2694                                    preserve_breaks: false,
2695                                    sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
2696                                    semantic_line_breaks: config.reflow_mode == ReflowMode::SemanticLineBreaks,
2697                                    abbreviations: config.abbreviations_for_reflow(),
2698                                    length_mode: self.reflow_length_mode(),
2699                                    attr_lists: ctx.flavor.supports_attr_lists(),
2700                                    myst_roles: ctx.flavor.supports_myst_roles(),
2701                                    require_sentence_capital: config.require_sentence_capital,
2702                                    max_list_continuation_indent: if ctx.flavor.requires_strict_list_indent() {
2703                                        Some(4)
2704                                    } else {
2705                                        None
2706                                    },
2707                                };
2708
2709                                // Output each segment
2710                                for segment in &segments {
2711                                    // Blank line before each segment (after the header or previous segment)
2712                                    result.push(String::new());
2713
2714                                    match segment {
2715                                        AdmonSegment::Code(lines) => {
2716                                            for (line, orig_indent) in lines {
2717                                                if line.is_empty() {
2718                                                    // Preserve blank lines inside code blocks
2719                                                    result.push(String::new());
2720                                                } else {
2721                                                    // Reconstruct with body_indent + any extra
2722                                                    // indentation the line had beyond body_indent
2723                                                    let extra = orig_indent.saturating_sub(body_indent);
2724                                                    let indent_str = " ".repeat(body_indent + extra);
2725                                                    result.push(format!("{indent_str}{line}"));
2726                                                }
2727                                            }
2728                                        }
2729                                        AdmonSegment::Text(lines) => {
2730                                            let paragraph_text = lines.join(" ").trim().to_string();
2731                                            if paragraph_text.is_empty() {
2732                                                continue;
2733                                            }
2734                                            let reflowed = crate::utils::text_reflow::reflow_line(
2735                                                &paragraph_text,
2736                                                &admon_reflow_options,
2737                                            );
2738                                            for line in &reflowed {
2739                                                result.push(format!("{body_indent_str}{line}"));
2740                                            }
2741                                        }
2742                                    }
2743                                }
2744
2745                                // Add blank line after admonition if there's a next block
2746                                if block_idx < blocks.len() - 1 {
2747                                    let next_block = &blocks[block_idx + 1];
2748                                    let should_add_blank = match next_block {
2749                                        Block::Code {
2750                                            has_preceding_blank, ..
2751                                        } => *has_preceding_blank,
2752                                        Block::Table {
2753                                            has_preceding_blank, ..
2754                                        } => *has_preceding_blank,
2755                                        Block::SnippetLine(_) | Block::DivMarker(_) => false,
2756                                        _ => true,
2757                                    };
2758                                    if should_add_blank && result.last().is_none_or(|s: &String| !s.is_empty()) {
2759                                        result.push(String::new());
2760                                    }
2761                                }
2762                            }
2763                        }
2764                    }
2765
2766                    let reflowed_text = result.join(line_ending);
2767
2768                    // Preserve trailing newline
2769                    let replacement = if end_line < lines.len() - 1 || ctx.content.ends_with('\n') {
2770                        format!("{reflowed_text}{line_ending}")
2771                    } else {
2772                        reflowed_text
2773                    };
2774
2775                    // Get the original text to compare
2776                    let original_text = &ctx.content[byte_range.clone()];
2777
2778                    // Physical-line-length scan, shared by the Normalize-mode gate and its
2779                    // message. The list-item reflow preserves code blocks, HTML blocks,
2780                    // admonition headers, fence markers, semantic markers, and snippet/div
2781                    // markers verbatim; only paragraph content and admonition bodies are
2782                    // restructured. Only those lines drive the length warning, so that
2783                    // preserved-but-overlong content does not keep the paragraph-level
2784                    // warning alive when the reflow would not fix that line.
2785                    let should_count_for_length = |line_idx: usize| -> bool {
2786                        let line = lines[line_idx];
2787                        let trimmed = line.trim();
2788                        if trimmed.is_empty() || is_exempt_line(line) {
2789                            return false;
2790                        }
2791                        let info = &ctx.lines[line_idx];
2792                        if info.in_code_block || info.in_html_block {
2793                            return false;
2794                        }
2795                        if info.in_admonition && mkdocs_admonitions::is_admonition_start(line) {
2796                            return false;
2797                        }
2798                        if is_fence_marker(line) || is_semantic_line(line) {
2799                            return false;
2800                        }
2801                        if is_snippet_block_delimiter(line) {
2802                            return false;
2803                        }
2804                        if line.trim_start().starts_with(":::") {
2805                            return false;
2806                        }
2807                        true
2808                    };
2809                    let max_physical_length = (list_start..i)
2810                        .filter(|&idx| should_count_for_length(idx))
2811                        .map(|idx| self.calculate_effective_length(lines[idx]))
2812                        .max()
2813                        .unwrap_or(0);
2814                    // `line-length = 0` means "no limit", so no physical line can be
2815                    // "over"; the message below then describes a structural join rather
2816                    // than a length violation.
2817                    let any_paragraph_line_over =
2818                        !config.line_length.is_unlimited() && max_physical_length > config.line_length.get();
2819
2820                    // Normalize mode reflows list-item prose just like paragraphs:
2821                    // joining continuation lines and re-wrapping to `line-length`.
2822                    // `prose_changed` is true only when the reflow alters the words or
2823                    // line breaks, not when it would merely re-indent continuation
2824                    // lines or trim trailing whitespace. Comparing the texts with each
2825                    // line's leading and trailing whitespace removed isolates "did the
2826                    // words/line breaks change" from "did the surrounding whitespace
2827                    // change". Continuation indentation is MD077's responsibility and
2828                    // trailing whitespace is MD009's; an MD013 warning for either would
2829                    // both duplicate those rules and resurface a persistent advisory on
2830                    // already-fitting items that users disable MD013 fixing to avoid.
2831                    let prose_changed = {
2832                        let stripped = |text: &str| text.lines().map(str::trim).collect::<Vec<_>>().join("\n");
2833                        stripped(original_text) != stripped(&replacement)
2834                    };
2835                    // Warn when the reflow rewraps prose (the normalize feature for
2836                    // list items), or when a physical line genuinely exceeds the limit
2837                    // and the reflow can change something (a true length violation,
2838                    // even if all that changes is the continuation indent). A line that
2839                    // is already optimal in both respects produces no warning.
2840                    let gate_ok = prose_changed || (any_paragraph_line_over && original_text != replacement);
2841                    if gate_ok {
2842                        // Generate an appropriate message based on why reflow is needed
2843                        let message = match config.reflow_mode {
2844                            ReflowMode::SentencePerLine => {
2845                                let num_sentences = split_into_sentences(&combined_content).len();
2846                                let num_lines = content_lines.len();
2847                                if num_lines == 1 {
2848                                    // Single line with multiple sentences
2849                                    format!("Line contains {num_sentences} sentences (one sentence per line required)")
2850                                } else {
2851                                    // Multiple lines - could be split sentences or mixed
2852                                    format!(
2853                                        "Paragraph should have one sentence per line (found {num_sentences} sentences across {num_lines} lines)"
2854                                    )
2855                                }
2856                            }
2857                            ReflowMode::SemanticLineBreaks => {
2858                                let num_sentences = split_into_sentences(&combined_content).len();
2859                                format!("Paragraph should use semantic line breaks ({num_sentences} sentences)")
2860                            }
2861                            ReflowMode::Normalize => {
2862                                // When a physical line genuinely exceeds the limit, report
2863                                // it as a length violation. Otherwise the reflow is a
2864                                // structural normalization (joining/re-wrapping multi-line
2865                                // content that already fits), mirroring the paragraph path.
2866                                if any_paragraph_line_over {
2867                                    format!(
2868                                        "Line length {} exceeds {} characters",
2869                                        max_physical_length,
2870                                        config.line_length.get()
2871                                    )
2872                                } else {
2873                                    format!(
2874                                        "List item could be normalized to use line length of {} characters",
2875                                        config.line_length.get()
2876                                    )
2877                                }
2878                            }
2879                            ReflowMode::Default => {
2880                                // Report the actual longest non-exempt line, not the combined content
2881                                let max_length = (list_start..i)
2882                                    .filter(|&line_idx| {
2883                                        let line = lines[line_idx];
2884                                        let trimmed = line.trim();
2885                                        !trimmed.is_empty() && !is_exempt_line(line)
2886                                    })
2887                                    .map(|line_idx| self.calculate_effective_length(lines[line_idx]))
2888                                    .max()
2889                                    .unwrap_or(0);
2890                                format!(
2891                                    "Line length {} exceeds {} characters",
2892                                    max_length,
2893                                    config.line_length.get()
2894                                )
2895                            }
2896                        };
2897
2898                        warnings.push(LintWarning {
2899                            rule_name: Some(self.name().to_string()),
2900                            message,
2901                            line: list_start + 1,
2902                            column: 1,
2903                            end_line: end_line + 1,
2904                            end_column: lines[end_line].chars().count() + 1,
2905                            severity: Severity::Warning,
2906                            fix: Some(crate::rule::Fix::new(byte_range, replacement)),
2907                        });
2908                    }
2909                }
2910                continue;
2911            }
2912
2913            // Found start of a paragraph - collect all lines in it
2914            let paragraph_start = i;
2915            let mut paragraph_lines = vec![lines[i]];
2916            i += 1;
2917
2918            while i < lines.len() {
2919                let next_line = lines[i];
2920                let next_line_num = i + 1;
2921                let next_trimmed = next_line.trim();
2922
2923                // Stop at paragraph boundaries
2924                if next_trimmed.is_empty()
2925                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_code_block)
2926                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_front_matter)
2927                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_html_block)
2928                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_html_comment)
2929                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_esm_block)
2930                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_jsx_expression)
2931                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_jsx_block)
2932                    || ctx.line_info(next_line_num).is_some_and(|info| info.in_mdx_comment)
2933                    || ctx
2934                        .line_info(next_line_num)
2935                        .is_some_and(super::super::lint_context::types::LineInfo::in_mkdocs_container)
2936                    || (next_line_num > 0
2937                        && next_line_num <= ctx.lines.len()
2938                        && ctx.lines[next_line_num - 1].blockquote.is_some())
2939                    || next_trimmed.starts_with('#')
2940                    || TableUtils::is_potential_table_row(next_line)
2941                    || is_list_item(next_trimmed)
2942                    || is_horizontal_rule(next_line)
2943                    || (next_trimmed.starts_with('[') && next_line.contains("]:"))
2944                    || is_template_directive_only(next_line)
2945                    || is_standalone_attr_list(next_line)
2946                    || is_snippet_block_delimiter(next_line)
2947                    || ctx.line_info(next_line_num).is_some_and(|info| info.is_div_marker)
2948                    || is_html_only_line(next_line)
2949                {
2950                    break;
2951                }
2952
2953                // Check if the previous line ends with a hard break (2+ spaces or backslash)
2954                if i > 0 && has_hard_break(lines[i - 1]) {
2955                    // Don't include lines after hard breaks in the same paragraph
2956                    break;
2957                }
2958
2959                paragraph_lines.push(next_line);
2960                i += 1;
2961            }
2962
2963            // Compute the common leading indent of all non-empty paragraph lines,
2964            // but only when those lines are structurally inside a list block.
2965            // Indented continuation lines that follow a nested list arrive here
2966            // with their structural indentation intact (e.g. 2 spaces for a
2967            // top-level list item). Stripping the indent before reflow and
2968            // re-applying it afterward prevents the fixer from moving those
2969            // lines to column 0.
2970            //
2971            // The list-block guard is essential: top-level paragraphs that happen
2972            // to start with spaces (insignificant in Markdown) must NOT have those
2973            // spaces preserved or injected by the fixer.
2974            let common_indent: String = if ctx.is_in_list_block(paragraph_start + 1) {
2975                let min_len = paragraph_lines
2976                    .iter()
2977                    .filter(|l| !l.trim().is_empty())
2978                    .map(|l| l.len() - l.trim_start().len())
2979                    .min()
2980                    .unwrap_or(0);
2981                paragraph_lines
2982                    .iter()
2983                    .find(|l| !l.trim().is_empty())
2984                    .map(|l| l[..min_len].to_string())
2985                    .unwrap_or_default()
2986            } else {
2987                String::new()
2988            };
2989
2990            // Combine paragraph lines into a single string for processing.
2991            // This must be done BEFORE the needs_reflow check for sentence-per-line mode.
2992            let paragraph_text = if common_indent.is_empty() {
2993                paragraph_lines.join(" ")
2994            } else {
2995                paragraph_lines
2996                    .iter()
2997                    .map(|l| {
2998                        if l.starts_with(common_indent.as_str()) {
2999                            &l[common_indent.len()..]
3000                        } else {
3001                            l.trim_start()
3002                        }
3003                    })
3004                    .collect::<Vec<_>>()
3005                    .join(" ")
3006            };
3007
3008            // Skip reflowing if this paragraph contains definition list items
3009            // Definition lists are multi-line structures that should not be joined
3010            let contains_definition_list = paragraph_lines
3011                .iter()
3012                .any(|line| crate::utils::is_definition_list_item(line));
3013
3014            if contains_definition_list {
3015                // Don't reflow definition lists - skip this paragraph
3016                i = paragraph_start + paragraph_lines.len();
3017                continue;
3018            }
3019
3020            // Skip reflowing if this paragraph contains MkDocs Snippets markers
3021            // Snippets blocks (-8<- ... -8<-) should be preserved exactly
3022            let contains_snippets = paragraph_lines.iter().any(|line| is_snippet_block_delimiter(line));
3023
3024            if contains_snippets {
3025                // Don't reflow Snippets blocks - skip this paragraph
3026                i = paragraph_start + paragraph_lines.len();
3027                continue;
3028            }
3029
3030            // Check if this paragraph needs reflowing
3031            let needs_reflow = match config.reflow_mode {
3032                ReflowMode::Normalize => self.normalize_mode_needs_reflow(paragraph_lines.iter().copied(), config),
3033                ReflowMode::SentencePerLine => {
3034                    // In sentence-per-line mode, check if the JOINED paragraph has multiple sentences
3035                    // Note: we check the joined text because sentences can span multiple lines
3036                    let sentences = split_into_sentences(&paragraph_text);
3037
3038                    // Always reflow if multiple sentences on one line
3039                    if sentences.len() > 1 {
3040                        true
3041                    } else if paragraph_lines.len() > 1 {
3042                        // For single-sentence paragraphs spanning multiple lines:
3043                        // Reflow if they COULD fit on one line (respecting line-length constraint)
3044                        if config.line_length.is_unlimited() {
3045                            // No line-length constraint - always join single sentences
3046                            true
3047                        } else {
3048                            // Only join if it fits within line-length.
3049                            // paragraph_text has the common indent stripped, so add it
3050                            // back to get the true output length before comparing.
3051                            let effective_length =
3052                                self.calculate_effective_length(&paragraph_text) + common_indent.len();
3053                            effective_length <= config.line_length.get()
3054                        }
3055                    } else {
3056                        false
3057                    }
3058                }
3059                ReflowMode::SemanticLineBreaks => {
3060                    let sentences = split_into_sentences(&paragraph_text);
3061                    // Reflow if multiple sentences, multiple lines, or any line exceeds limit
3062                    sentences.len() > 1
3063                        || paragraph_lines.len() > 1
3064                        || paragraph_lines
3065                            .iter()
3066                            .any(|line| self.calculate_effective_length(line) > config.line_length.get())
3067                }
3068                ReflowMode::Default => {
3069                    // In default mode, only reflow if lines exceed limit
3070                    paragraph_lines
3071                        .iter()
3072                        .any(|line| self.calculate_effective_length(line) > config.line_length.get())
3073                }
3074            };
3075
3076            if needs_reflow {
3077                // Calculate byte range for this paragraph
3078                // Use whole_line_range for each line and combine
3079                let start_range = line_index.whole_line_range(paragraph_start + 1);
3080                let end_line = paragraph_start + paragraph_lines.len() - 1;
3081
3082                // For the last line, we want to preserve any trailing newline
3083                let end_range = if end_line == lines.len() - 1 && !ctx.content.ends_with('\n') {
3084                    // Last line without trailing newline - use line_text_range
3085                    line_index.line_text_range(end_line + 1, 1, lines[end_line].len() + 1)
3086                } else {
3087                    // Not the last line or has trailing newline - use whole_line_range
3088                    line_index.whole_line_range(end_line + 1)
3089                };
3090
3091                let byte_range = start_range.start..end_range.end;
3092
3093                // Check if the paragraph ends with a hard break and what type
3094                let hard_break_type = paragraph_lines.last().and_then(|line| {
3095                    let line = line.strip_suffix('\r').unwrap_or(line);
3096                    if line.ends_with('\\') {
3097                        Some("\\")
3098                    } else if line.ends_with("  ") {
3099                        Some("  ")
3100                    } else {
3101                        None
3102                    }
3103                });
3104
3105                // Reflow the paragraph
3106                // When line_length = 0 (no limit), use a very large value for reflow
3107                let reflow_line_length = if config.line_length.is_unlimited() {
3108                    usize::MAX
3109                } else {
3110                    config.line_length.get()
3111                };
3112                let reflow_options = crate::utils::text_reflow::ReflowOptions {
3113                    line_length: reflow_line_length,
3114                    break_on_sentences: true,
3115                    preserve_breaks: false,
3116                    sentence_per_line: config.reflow_mode == ReflowMode::SentencePerLine,
3117                    semantic_line_breaks: config.reflow_mode == ReflowMode::SemanticLineBreaks,
3118                    abbreviations: config.abbreviations_for_reflow(),
3119                    length_mode: self.reflow_length_mode(),
3120                    attr_lists: ctx.flavor.supports_attr_lists(),
3121                    myst_roles: ctx.flavor.supports_myst_roles(),
3122                    require_sentence_capital: config.require_sentence_capital,
3123                    max_list_continuation_indent: if ctx.flavor.requires_strict_list_indent() {
3124                        Some(4)
3125                    } else {
3126                        None
3127                    },
3128                };
3129                let mut reflowed = crate::utils::text_reflow::reflow_line(&paragraph_text, &reflow_options);
3130
3131                // Re-apply the common indent to each non-empty reflowed line so
3132                // that the replacement preserves the original structural indentation.
3133                if !common_indent.is_empty() {
3134                    for line in &mut reflowed {
3135                        if !line.is_empty() {
3136                            *line = format!("{common_indent}{line}");
3137                        }
3138                    }
3139                }
3140
3141                // If the original paragraph ended with a hard break, preserve it
3142                // Preserve the original hard break format (backslash or two spaces)
3143                if let Some(break_marker) = hard_break_type
3144                    && !reflowed.is_empty()
3145                {
3146                    let last_idx = reflowed.len() - 1;
3147                    if !has_hard_break(&reflowed[last_idx]) {
3148                        reflowed[last_idx].push_str(break_marker);
3149                    }
3150                }
3151
3152                let reflowed_text = reflowed.join(line_ending);
3153
3154                // Preserve trailing newline if the original paragraph had one
3155                let replacement = if end_line < lines.len() - 1 || ctx.content.ends_with('\n') {
3156                    format!("{reflowed_text}{line_ending}")
3157                } else {
3158                    reflowed_text
3159                };
3160
3161                // Get the original text to compare
3162                let original_text = &ctx.content[byte_range.clone()];
3163
3164                // Only generate a warning if the replacement is different from the original
3165                if original_text != replacement {
3166                    // Create warning with actual fix
3167                    // In default mode, report the specific line that violates
3168                    // In normalize mode, report the whole paragraph
3169                    // In sentence-per-line mode, report the entire paragraph
3170                    let (warning_line, warning_end_line) = match config.reflow_mode {
3171                        ReflowMode::Normalize => (paragraph_start + 1, end_line + 1),
3172                        ReflowMode::SentencePerLine | ReflowMode::SemanticLineBreaks => {
3173                            // Highlight the entire paragraph that needs reformatting
3174                            (paragraph_start + 1, paragraph_start + paragraph_lines.len())
3175                        }
3176                        ReflowMode::Default => {
3177                            // Find the first line that exceeds the limit
3178                            let mut violating_line = paragraph_start;
3179                            for (idx, line) in paragraph_lines.iter().enumerate() {
3180                                if self.calculate_effective_length(line) > config.line_length.get() {
3181                                    violating_line = paragraph_start + idx;
3182                                    break;
3183                                }
3184                            }
3185                            (violating_line + 1, violating_line + 1)
3186                        }
3187                    };
3188
3189                    warnings.push(LintWarning {
3190                        rule_name: Some(self.name().to_string()),
3191                        message: match config.reflow_mode {
3192                            ReflowMode::Normalize => format!(
3193                                "Paragraph could be normalized to use line length of {} characters",
3194                                config.line_length.get()
3195                            ),
3196                            ReflowMode::SentencePerLine => {
3197                                let num_sentences = split_into_sentences(&paragraph_text).len();
3198                                if paragraph_lines.len() == 1 {
3199                                    // Single line with multiple sentences
3200                                    format!("Line contains {num_sentences} sentences (one sentence per line required)")
3201                                } else {
3202                                    let num_lines = paragraph_lines.len();
3203                                    // Multiple lines - could be split sentences or mixed
3204                                    format!("Paragraph should have one sentence per line (found {num_sentences} sentences across {num_lines} lines)")
3205                                }
3206                            },
3207                            ReflowMode::SemanticLineBreaks => {
3208                                let num_sentences = split_into_sentences(&paragraph_text).len();
3209                                format!(
3210                                    "Paragraph should use semantic line breaks ({num_sentences} sentences)"
3211                                )
3212                            },
3213                            ReflowMode::Default => format!("Line length exceeds {} characters", config.line_length.get()),
3214                        },
3215                        line: warning_line,
3216                        column: 1,
3217                        end_line: warning_end_line,
3218                        end_column: lines[warning_end_line.saturating_sub(1)].chars().count() + 1,
3219                        severity: Severity::Warning,
3220                        fix: Some(crate::rule::Fix::new(byte_range, replacement)),
3221                    });
3222                }
3223            }
3224        }
3225
3226        warnings
3227    }
3228
3229    /// Calculate string length based on the configured length mode
3230    fn calculate_string_length(&self, s: &str) -> usize {
3231        match self.config.length_mode {
3232            LengthMode::Chars => s.chars().count(),
3233            LengthMode::Visual => s.width(),
3234            LengthMode::Bytes => s.len(),
3235        }
3236    }
3237
3238    /// Calculate effective line length
3239    ///
3240    /// Returns the actual display length of the line using the configured length mode.
3241    fn calculate_effective_length(&self, line: &str) -> usize {
3242        self.calculate_string_length(line)
3243    }
3244
3245    /// Calculate line length with inline link/image URLs removed.
3246    ///
3247    /// For each inline link `[text](url)` or image `![alt](url)` on the line,
3248    /// computes the "savings" from removing the URL portion (keeping only `[text]`
3249    /// or `![alt]`). Returns `effective_length - total_savings`.
3250    ///
3251    /// Handles nested constructs (e.g., `[![img](url)](url)`) by only counting the
3252    /// outermost construct to avoid double-counting.
3253    fn calculate_text_only_length(
3254        &self,
3255        effective_length: usize,
3256        line_number: usize,
3257        ctx: &crate::lint_context::LintContext,
3258    ) -> usize {
3259        let line_range = ctx.line_index.line_content_range(line_number);
3260        let line_byte_end = line_range.end;
3261
3262        // Collect inline links/images on this line: (byte_offset, byte_end, text_only_display_len)
3263        let mut constructs: Vec<(usize, usize, usize)> = Vec::new();
3264
3265        // Binary search: links are sorted by byte_offset, so link.line is non-decreasing
3266        let link_start = ctx.links.partition_point(|l| l.line < line_number);
3267        for link in &ctx.links[link_start..] {
3268            if link.line != line_number {
3269                break;
3270            }
3271            if link.is_reference {
3272                continue;
3273            }
3274            if !matches!(link.link_type, LinkType::Inline) {
3275                continue;
3276            }
3277            if link.byte_end > line_byte_end {
3278                continue;
3279            }
3280            let text_only_len = 2 + self.calculate_string_length(&link.text);
3281            constructs.push((link.byte_offset, link.byte_end, text_only_len));
3282        }
3283
3284        let img_start = ctx.images.partition_point(|i| i.line < line_number);
3285        for image in &ctx.images[img_start..] {
3286            if image.line != line_number {
3287                break;
3288            }
3289            if image.is_reference {
3290                continue;
3291            }
3292            if !matches!(image.link_type, LinkType::Inline) {
3293                continue;
3294            }
3295            if image.byte_end > line_byte_end {
3296                continue;
3297            }
3298            let text_only_len = 3 + self.calculate_string_length(&image.alt_text);
3299            constructs.push((image.byte_offset, image.byte_end, text_only_len));
3300        }
3301
3302        if constructs.is_empty() {
3303            return effective_length;
3304        }
3305
3306        // Sort by byte offset to handle overlapping/nested constructs
3307        constructs.sort_by_key(|&(start, _, _)| start);
3308
3309        let mut total_savings: usize = 0;
3310        let mut last_end: usize = 0;
3311
3312        for (start, end, text_only_len) in &constructs {
3313            // Skip constructs nested inside a previously counted one
3314            if *start < last_end {
3315                continue;
3316            }
3317            // Full construct length in configured length mode
3318            let full_source = &ctx.content[*start..*end];
3319            let full_len = self.calculate_string_length(full_source);
3320            total_savings += full_len.saturating_sub(*text_only_len);
3321            last_end = *end;
3322        }
3323
3324        effective_length.saturating_sub(total_savings)
3325    }
3326}