Files
codex/codex-rs/tui/src/backtrack_helpers.rs
Ahmed Ibrahim d9b4e87cf8 refactor
2025-08-22 11:12:28 -07:00

98 lines
3.0 KiB
Rust

use ratatui::text::Line;
// Public helpers (most important first)
/// Convenience: compute the highlight range for the Nth last user message.
pub(crate) fn highlight_range_for_nth_last_user(
lines: &[Line<'_>],
n: usize,
) -> Option<(usize, usize)> {
let header = find_nth_last_user_header_index(lines, n)?;
Some(highlight_range_from_header(lines, header))
}
/// Compute the wrapped display-line offset before `header_idx`, for a given width.
pub(crate) fn wrapped_offset_before(lines: &[Line<'_>], header_idx: usize, width: u16) -> usize {
let before = &lines[0..header_idx];
crate::insert_history::word_wrap_lines(before, width).len()
}
/// Find the header index for the Nth last user message in the transcript.
/// Returns `None` if `n == 0` or there are fewer than `n` user messages.
pub(crate) fn find_nth_last_user_header_index(lines: &[Line<'_>], n: usize) -> Option<usize> {
if n == 0 {
return None;
}
let mut found = 0usize;
for (idx, line) in lines.iter().enumerate().rev() {
let content: String = line
.spans
.iter()
.map(|s| s.content.as_ref())
.collect::<Vec<_>>()
.join("");
if content.trim() == "user" {
found += 1;
if found == n {
return Some(idx);
}
}
}
None
}
/// Extract the text content of the Nth last user message.
/// The message body is considered to be the lines following the "user" header
/// until the first blank line.
pub(crate) fn nth_last_user_text(lines: &[Line<'_>], n: usize) -> Option<String> {
let header_idx = find_nth_last_user_header_index(lines, n)?;
extract_message_text_after_header(lines, header_idx)
}
// Private helpers
/// Extract message text starting after `header_idx` until the first blank line.
fn extract_message_text_after_header(lines: &[Line<'_>], header_idx: usize) -> Option<String> {
let start = header_idx + 1;
let mut out: Vec<String> = Vec::new();
for line in lines.iter().skip(start) {
let is_blank = line
.spans
.iter()
.all(|s| s.content.as_ref().trim().is_empty());
if is_blank {
break;
}
let text: String = line
.spans
.iter()
.map(|s| s.content.as_ref())
.collect::<Vec<_>>()
.join("");
out.push(text);
}
if out.is_empty() {
None
} else {
Some(out.join("\n"))
}
}
/// Given a header index, return the inclusive range for the message block
/// [header_idx, end) where end is the first blank line after the header or the
/// end of the transcript.
fn highlight_range_from_header(lines: &[Line<'_>], header_idx: usize) -> (usize, usize) {
let mut end = header_idx + 1;
while end < lines.len() {
let is_blank = lines[end]
.spans
.iter()
.all(|s| s.content.as_ref().trim().is_empty());
if is_blank {
break;
}
end += 1;
}
(header_idx, end)
}