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use ratatui::{
buffer::Buffer,
style::{Color, Style},
};
use syntect::easy::HighlightLines;
use syntect::util::LinesWithEndings;
use super::state::InteractiveState;
// Code block borders are outdented to the left of content so that the code text
// aligns with surrounding prose, and the border is purely decorative.
const CODE_BLOCK_BORDER_WIDTH: u16 = 2; // "│ " takes 2 columns
const CODE_BLOCK_BORDER_OUTDENT: i16 = -2; // Draw border 2 columns left of content
impl<'a> InteractiveState<'a> {
/// Render code block with syntax highlighting
pub(super) fn render_code_block(&mut self, lang: Option<&str>, code: &str, buf: &mut Buffer) {
let lang_display = match lang {
Some("no_run") | Some("should_panic") | Some("ignore") | Some("compile_fail")
| Some("edition2015") | Some("edition2018") | Some("edition2021")
| Some("edition2024") => "rust",
Some(l) => l,
None => "rust",
};
// Border is outdented (to the left of content) so code text aligns with surrounding text
let border_col = self
.layout
.indent
.saturating_add_signed(CODE_BLOCK_BORDER_OUTDENT);
let content_col = self.layout.indent; // Code content stays at indent
// Calculate code block dimensions accounting for content position
let available_width = self.layout.area.width.saturating_sub(content_col);
let max_line_width = code
.lines()
.map(|line| line.len())
.max()
.unwrap_or(0)
.min((available_width.saturating_sub(4)) as usize); // Leave room for border and padding
// Account for language label in border width: ╭───❬rust❭─╮
let lang_label = format!("❬{}❭", lang_display);
// Count actual display width (number of grapheme clusters, not bytes)
let label_display_width = lang_label.chars().count();
let min_border_for_label = label_display_width as u16 + 6; // label + some padding
let border_width = ((max_line_width + 4).max(min_border_for_label as usize))
.min(available_width as usize) as u16;
let border_style = self.theme.code_block_border_style;
// Top border with language label: ╭─────❬rust❭─╮
if self.layout.pos.y >= self.viewport.scroll_offset
&& self.layout.pos.y < self.viewport.scroll_offset + self.layout.area.height
{
self.write_text(
buf,
self.layout.pos.y,
border_col,
"╭",
self.layout.area,
border_style,
);
// Calculate position for language label (right side, with one dash before corner)
// Label ends at border_width - 2 (leaving space for ─╮)
let label_start =
border_col + border_width.saturating_sub(label_display_width as u16 + 2);
// Draw left dashes (up to label)
for i in 1..label_start.saturating_sub(border_col) {
self.write_text(
buf,
self.layout.pos.y,
border_col + i,
"─",
self.layout.area,
border_style,
);
}
// Draw language label
self.write_text(
buf,
self.layout.pos.y,
label_start,
&lang_label,
self.layout.area,
border_style,
);
// Draw dashes from end of label to corner
// The label takes label_display_width columns, so next position is label_start + label_display_width
let label_end_col = label_start + label_display_width as u16;
for i in label_end_col..border_col + border_width.saturating_sub(1) {
self.write_text(
buf,
self.layout.pos.y,
i,
"─",
self.layout.area,
border_style,
);
}
// Draw corner
self.write_text(
buf,
self.layout.pos.y,
border_col + border_width.saturating_sub(1),
"╮",
self.layout.area,
border_style,
);
}
self.layout.pos.y += 1;
// Render code content with side borders (no background color)
if let Some(syntax) = self
.render_context
.syntax_set()
.find_syntax_by_token(lang_display)
{
let theme = self.render_context.theme();
let mut highlighter = HighlightLines::new(syntax, theme);
for line in LinesWithEndings::from(code) {
if self.layout.pos.y >= self.viewport.scroll_offset
&& self.layout.pos.y < self.viewport.scroll_offset + self.layout.area.height
{
// Left border and padding
self.write_text(
buf,
self.layout.pos.y,
border_col,
"│ ",
self.layout.area,
border_style,
);
let mut col = content_col;
if let Ok(ranges) =
highlighter.highlight_line(line, self.render_context.syntax_set())
{
for (style, text) in ranges {
let fg = style.foreground;
let ratatui_style = Style::default().fg(Color::Rgb(fg.r, fg.g, fg.b));
let text = text.trim_end_matches('\n');
self.write_text(
buf,
self.layout.pos.y,
col,
text,
self.layout.area,
ratatui_style,
);
col += text.len() as u16;
}
} else {
self.write_text(
buf,
self.layout.pos.y,
content_col,
line.trim_end_matches('\n'),
self.layout.area,
Style::default(),
);
}
// Right border and padding
self.write_text(
buf,
self.layout.pos.y,
border_col + border_width.saturating_sub(2),
" │",
self.layout.area,
border_style,
);
}
self.layout.pos.y += 1;
}
} else {
for line in code.lines() {
if self.layout.pos.y >= self.viewport.scroll_offset
&& self.layout.pos.y < self.viewport.scroll_offset + self.layout.area.height
{
// Left border and padding
self.write_text(
buf,
self.layout.pos.y,
border_col,
"│ ",
self.layout.area,
border_style,
);
// Code content
self.write_text(
buf,
self.layout.pos.y,
content_col,
line,
self.layout.area,
Style::default(),
);
// Right border and padding
self.write_text(
buf,
self.layout.pos.y,
border_col + border_width.saturating_sub(2),
" │",
self.layout.area,
border_style,
);
}
self.layout.pos.y += 1;
}
}
// Bottom border: ╰─────╯
if self.layout.pos.y >= self.viewport.scroll_offset
&& self.layout.pos.y < self.viewport.scroll_offset + self.layout.area.height
{
self.write_text(
buf,
self.layout.pos.y,
border_col,
"╰",
self.layout.area,
border_style,
);
for i in 1..border_width.saturating_sub(1) {
self.write_text(
buf,
self.layout.pos.y,
border_col + i,
"─",
self.layout.area,
border_style,
);
}
self.write_text(
buf,
self.layout.pos.y,
border_col + border_width.saturating_sub(1),
"╯",
self.layout.area,
border_style,
);
}
self.layout.pos.y += 1;
}
}