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use crate::ui::span::SpanKind;
use ratatui::{style::Style, text::Span};
use unicode_segmentation::UnicodeSegmentation;
use unicode_width::UnicodeWidthStr;
/// Wrap spans to the provided width while preserving styles and word boundaries.
/// Shared between markdown rendering and range computation so downstream
/// consumers stay in sync. A continuation indent width can be supplied to
/// account for prefixes added after wrapping (e.g., hanging indents).
pub(crate) fn wrap_spans_to_width_generic_shared(
spans: &[(Span<'static>, SpanKind)],
max_width: usize,
continuation_indent_width: usize,
) -> Vec<Vec<(Span<'static>, SpanKind)>> {
const MAX_UNBREAKABLE_LENGTH: usize = 30;
if spans.is_empty() {
return vec![Vec::new()];
}
let mut wrapped_lines = Vec::new();
let mut current_line: Vec<(Span<'static>, SpanKind)> = Vec::new();
let mut current_width = 0usize;
let continuation_width = max_width
.saturating_sub(continuation_indent_width)
.max(1 /* prevent zero width */);
let mut line_limit = max_width;
// Break incoming spans into owned (text, style) parts
let mut parts: Vec<(String, Style, SpanKind)> = spans
.iter()
.map(|(s, kind)| (s.content.to_string(), s.style, kind.clone()))
.collect();
for (mut text, style, kind) in parts.drain(..) {
while !text.is_empty() {
let mut chars_to_fit = 0usize;
let mut width_so_far = 0usize;
let mut last_break_pos: Option<(usize, usize)> = None;
for (grapheme_start, grapheme) in text.grapheme_indices(true) {
let grapheme_end = grapheme_start + grapheme.len();
let gw = UnicodeWidthStr::width(grapheme);
if current_width + width_so_far + gw <= line_limit {
width_so_far += gw;
chars_to_fit = grapheme_end;
if grapheme.chars().all(|c| c.is_whitespace()) {
last_break_pos = Some((grapheme_end, width_so_far));
}
} else {
break;
}
}
if chars_to_fit == 0 {
// Nothing fits on this line
if !current_line.is_empty() {
// Look back at the previous span to find natural word boundary.
// When styled text (code, emphasis) fills the line and the next span
// starts with whitespace/punctuation, we want to recognize that as
// a word boundary between the spans, not as content of the next span.
if let Some((_last_span, _)) = current_line.last() {
// Extract any leading punctuation to keep with previous line.
// Trim any whitespace. Never lose characters.
// Examples: ") today" → extract ")", trim " ", wrap "today"
// "))) more" → extract ")))", trim " ", wrap "more"
// " useful" → trim " ", wrap "useful"
// " )" → trim " ", wrap ")" (standalone, don't backtrack)
let mut punct_start = None; // Where punctuation begins (None if not found)
let mut punct_end = 0;
let mut ws_end = 0;
for (idx, ch) in text.char_indices() {
if punct_start.is_none() {
if ch.is_whitespace() {
ws_end = idx + ch.len_utf8();
} else if !ch.is_alphanumeric() && ch != '_' {
// Found first punctuation character
punct_start = Some(idx);
punct_end = idx + ch.len_utf8();
ws_end = punct_end;
} else {
// Hit word character, stop
break;
}
} else {
// We already found punctuation, continue scanning
if ch.is_whitespace() {
ws_end = idx + ch.len_utf8();
} else if !ch.is_alphanumeric() && ch != '_' {
// Found additional punctuation character
punct_end = idx + ch.len_utf8();
ws_end = punct_end;
} else {
// Hit word character, stop
break;
}
}
}
// Check if punctuation fits on current line
if punct_end > 0 {
let punct_width = UnicodeWidthStr::width(&text[..punct_end]);
if current_width + punct_width <= line_limit {
// Punctuation fits, add it to current line and trim trailing space
let punct_text = text[..punct_end].to_string();
current_line.push((Span::styled(punct_text, style), kind.clone()));
// Note: current_width update not needed - will be reset when wrapping
text = text[ws_end..].to_string();
if text.is_empty() {
// After processing boundary characters, nothing remains
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
continue;
}
} else if punct_start == Some(0) {
// Punctuation doesn't fit AND it's directly adjacent (no leading space).
// Before backtracking, check if we'd make progress:
// If styled span + punctuation won't fit on a new line, don't backtrack.
let punct_width = UnicodeWidthStr::width(&text[..punct_end]);
let last_span_width = current_line
.last()
.map(|(span, _)| UnicodeWidthStr::width(span.content.as_ref()))
.unwrap_or(0);
// Only backtrack if styled word + punctuation will fit on continuation line
if last_span_width + punct_width <= continuation_width {
// Backtrack: pop styled span, wrap current line, then add styled span
// to next line followed by current text. This preserves the styling.
if let Some((last_span, last_kind)) = current_line.pop() {
// Wrap the current line (without the styled span)
wrapped_lines.push(std::mem::take(&mut current_line));
// Start new line with the styled span (preserving its style/kind)
current_line.push((last_span, last_kind));
current_width = UnicodeWidthStr::width(
current_line[0].0.content.as_ref(),
);
line_limit = continuation_width;
// Restart the while loop to reprocess current text on the new line
continue;
}
}
// else: backtracking won't help, let normal wrapping handle it
} else if punct_start.is_some() {
// Punctuation doesn't fit but "stands alone" (has leading space).
// Trim the leading space and let punctuation wrap normally.
text = text.trim_start().to_string();
}
} else if ws_end > 0 {
// Just whitespace, trim it
text = text[ws_end..].to_string();
if text.is_empty() {
// After trimming whitespace, nothing remains
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
continue;
}
}
}
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
continue;
} else {
// Consider unbreakable word
let next_word_end = text.find(char::is_whitespace).unwrap_or(text.len());
let next_word = &text[..next_word_end];
let ww = UnicodeWidthStr::width(next_word);
if ww <= MAX_UNBREAKABLE_LENGTH {
current_line
.push((Span::styled(next_word.to_string(), style), kind.clone()));
current_width += ww;
if next_word_end < text.len() {
text = text[next_word_end..].to_string();
} else {
break;
}
} else {
// Hard break the very long token
let mut forced_width = 0usize;
let mut forced_end = 0usize;
for (grapheme_start, grapheme) in text.grapheme_indices(true) {
let grapheme_end = grapheme_start + grapheme.len();
let gw = UnicodeWidthStr::width(grapheme);
if forced_width + gw > line_limit {
if forced_end == 0 {
forced_end = grapheme_end;
forced_width += gw;
}
break;
}
forced_width += gw;
forced_end = grapheme_end;
}
if forced_end == 0 {
forced_end = text.len();
forced_width = UnicodeWidthStr::width(text.as_str());
}
let chunk = text[..forced_end].to_string();
current_line.push((Span::styled(chunk, style), kind.clone()));
current_width = forced_width;
text = text[forced_end..].to_string();
if !text.is_empty() {
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
}
}
}
} else if chars_to_fit >= text.len() {
current_line.push((Span::styled(text.clone(), style), kind.clone()));
current_width += width_so_far;
break;
} else {
let (break_pos, _bw) = last_break_pos.unwrap_or((chars_to_fit, width_so_far));
if last_break_pos.is_none() && current_width > 0 {
// No natural break inside the incoming span; start it on the next line so
// multi-word links and long tokens stay intact.
// BUT FIRST: apply lookahead to find word boundaries between spans.
if let Some((_last_span, _)) = current_line.last() {
// Extract any leading punctuation to keep with previous line.
// Trim any whitespace. Never lose characters.
// " )" → trim " ", wrap ")" (standalone, don't backtrack)
// "))) more" → extract ")))", wrap "more"
let mut punct_start = None; // Where punctuation begins (None if not found)
let mut punct_end = 0;
let mut ws_end = 0;
for (idx, ch) in text.char_indices() {
if punct_start.is_none() {
if ch.is_whitespace() {
ws_end = idx + ch.len_utf8();
} else if !ch.is_alphanumeric() && ch != '_' {
// Found first punctuation character
punct_start = Some(idx);
punct_end = idx + ch.len_utf8();
ws_end = punct_end;
} else {
// Hit word character, stop
break;
}
} else {
// We already found punctuation, continue scanning
if ch.is_whitespace() {
ws_end = idx + ch.len_utf8();
} else if !ch.is_alphanumeric() && ch != '_' {
// Found additional punctuation character
punct_end = idx + ch.len_utf8();
ws_end = punct_end;
} else {
// Hit word character, stop
break;
}
}
}
// Check if punctuation fits on current line
if punct_end > 0 {
let punct_width = UnicodeWidthStr::width(&text[..punct_end]);
if current_width + punct_width <= line_limit {
// Punctuation fits, add it to current line and trim trailing space
let punct_text = text[..punct_end].to_string();
current_line.push((Span::styled(punct_text, style), kind.clone()));
// Note: current_width update not needed - will be reset when wrapping
text = text[ws_end..].to_string();
if text.is_empty() {
// After processing boundary characters, nothing remains
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
continue;
}
} else if punct_start == Some(0) {
// Punctuation doesn't fit AND it's directly adjacent (no leading space).
// Before backtracking, check if we'd make progress:
// If styled span + punctuation won't fit on a new line, don't backtrack.
let punct_width = UnicodeWidthStr::width(&text[..punct_end]);
let last_span_width = current_line
.last()
.map(|(span, _)| UnicodeWidthStr::width(span.content.as_ref()))
.unwrap_or(0);
// Only backtrack if styled word + punctuation will fit on continuation line
if last_span_width + punct_width <= continuation_width {
// Backtrack: pop styled span, wrap current line, then add styled span
// to next line followed by current text. This preserves the styling.
if let Some((last_span, last_kind)) = current_line.pop() {
// Wrap the current line (without the styled span)
wrapped_lines.push(std::mem::take(&mut current_line));
// Start new line with the styled span (preserving its style/kind)
current_line.push((last_span, last_kind));
current_width = UnicodeWidthStr::width(
current_line[0].0.content.as_ref(),
);
line_limit = continuation_width;
// Restart the while loop to reprocess current text on the new line
continue;
}
}
// else: backtracking won't help, let normal wrapping handle it
} else if punct_start.is_some() {
// Punctuation doesn't fit but "stands alone" (has leading space).
// Trim the leading space and let punctuation wrap normally.
text = text.trim_start().to_string();
}
} else if ws_end > 0 {
// Just whitespace, trim it
text = text[ws_end..].to_string();
if text.is_empty() {
// After trimming whitespace, nothing remains
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
continue;
}
}
}
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
continue;
}
let left = text[..break_pos].trim_end();
if !left.is_empty() {
let left_width = UnicodeWidthStr::width(left);
if current_width > 0 && current_width + left_width > line_limit {
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
}
if left_width > 0 {
current_line.push((Span::styled(left.to_string(), style), kind.clone()));
current_width += left_width;
}
}
text = text[break_pos..].trim_start().to_string();
if !text.is_empty() {
wrapped_lines.push(std::mem::take(&mut current_line));
current_width = 0;
line_limit = continuation_width;
}
}
}
}
if !current_line.is_empty() {
wrapped_lines.push(current_line);
}
if wrapped_lines.is_empty() {
vec![Vec::new()]
} else {
wrapped_lines
}
}
#[cfg(test)]
mod tests {
use super::wrap_spans_to_width_generic_shared;
use crate::ui::span::SpanKind;
use ratatui::text::Span;
#[test]
fn wrap_splits_at_spaces() {
let spans = vec![(Span::raw("word boundary test"), SpanKind::Text)];
let wrapped = wrap_spans_to_width_generic_shared(&spans, 6, 0);
let lines: Vec<String> = wrapped
.into_iter()
.map(|line| {
line.iter()
.map(|(s, _)| s.content.as_ref())
.collect::<String>()
})
.filter(|s| !s.is_empty())
.collect();
assert_eq!(lines, vec!["word", "bounda", "ry", "test"]);
}
#[test]
fn wrap_preserves_zwj_clusters() {
let spans = vec![(Span::raw("👩💻👩💻"), SpanKind::Text)];
let wrapped = wrap_spans_to_width_generic_shared(&spans, 2, 0);
let lines: Vec<String> = wrapped
.into_iter()
.map(|line| {
line.iter()
.map(|(s, _)| s.content.as_ref())
.collect::<String>()
})
.filter(|s| !s.is_empty())
.collect();
assert_eq!(lines, vec!["👩💻", "👩💻"]);
}
#[test]
fn wrap_preserves_skin_tone_modifiers() {
let spans = vec![(Span::raw("👍🏽👍🏽"), SpanKind::Text)];
let wrapped = wrap_spans_to_width_generic_shared(&spans, 2, 0);
let lines: Vec<String> = wrapped
.into_iter()
.map(|line| {
line.iter()
.map(|(s, _)| s.content.as_ref())
.collect::<String>()
})
.filter(|s| !s.is_empty())
.collect();
assert_eq!(lines, vec!["👍🏽", "👍🏽"]);
}
}