yoi/crates/tui/src/input.rs

492 lines
15 KiB
Rust

//! Multi-line input buffer with paste placeholders.
//!
//! The buffer stores a sequence of [`Atom`]s — each either a single
//! character (including `\n`) or an atomic paste reference. The cursor
//! is an index in `0..=atoms.len()` marking the insertion point between
//! atoms. Paste atoms are indivisible: Backspace deletes the whole
//! placeholder, the cursor can't land "inside" one.
//!
//! Display form: paste atoms render as
//! `[Clipboard #N | X chars, Y lines]`. Submit form: paste atoms expand
//! back to their original captured content so the Pod sees the full
//! pasted text (without the placeholder label).
use ratatui::style::{Color, Style};
use ratatui::text::{Line, Span};
use unicode_width::UnicodeWidthChar;
#[derive(Debug, Clone)]
pub struct PasteRef {
pub id: u32,
pub chars: usize,
pub lines: usize,
pub content: String,
}
impl PasteRef {
pub fn label(&self) -> String {
format!(
"[Clipboard #{} | {} chars, {} lines]",
self.id, self.chars, self.lines
)
}
}
#[derive(Debug, Clone)]
pub enum Atom {
Char(char),
Paste(PasteRef),
}
pub struct InputBuffer {
atoms: Vec<Atom>,
/// Insertion point in `0..=atoms.len()`.
cursor: usize,
/// Monotonic counter reused across the TUI process lifetime.
next_paste_id: u32,
}
impl Default for InputBuffer {
fn default() -> Self {
Self {
atoms: Vec::new(),
cursor: 0,
next_paste_id: 1,
}
}
}
impl InputBuffer {
pub fn new() -> Self {
Self::default()
}
pub fn clear(&mut self) {
self.atoms.clear();
self.cursor = 0;
}
pub fn insert_char(&mut self, c: char) {
self.atoms.insert(self.cursor, Atom::Char(c));
self.cursor += 1;
}
pub fn insert_newline(&mut self) {
self.insert_char('\n');
}
pub fn insert_paste(&mut self, content: String) {
let id = self.next_paste_id;
self.next_paste_id = self.next_paste_id.wrapping_add(1);
let chars = content.chars().count();
let lines = content.lines().count().max(1);
self.atoms.insert(
self.cursor,
Atom::Paste(PasteRef {
id,
chars,
lines,
content,
}),
);
self.cursor += 1;
}
pub fn delete_before(&mut self) {
if self.cursor == 0 {
return;
}
self.cursor -= 1;
self.atoms.remove(self.cursor);
}
pub fn delete_after(&mut self) {
if self.cursor < self.atoms.len() {
self.atoms.remove(self.cursor);
}
}
pub fn move_left(&mut self) {
self.cursor = self.cursor.saturating_sub(1);
}
pub fn move_right(&mut self) {
self.cursor = (self.cursor + 1).min(self.atoms.len());
}
pub fn move_home(&mut self) {
while self.cursor > 0 {
if matches!(self.atoms[self.cursor - 1], Atom::Char('\n')) {
break;
}
self.cursor -= 1;
}
}
pub fn move_end(&mut self) {
while self.cursor < self.atoms.len() {
if matches!(self.atoms[self.cursor], Atom::Char('\n')) {
break;
}
self.cursor += 1;
}
}
/// Move one logical line up, preserving column (atom count from
/// current line start). No-op if already on the first line.
pub fn move_up(&mut self) {
let (line_start, col) = self.line_start_and_col();
if line_start == 0 {
return;
}
// `atoms[line_start - 1]` is the '\n' that opens the current
// line; find the previous line's start.
let prev_end = line_start - 1;
let mut prev_start = 0;
for i in (0..prev_end).rev() {
if matches!(self.atoms[i], Atom::Char('\n')) {
prev_start = i + 1;
break;
}
}
let prev_len = prev_end - prev_start;
self.cursor = prev_start + col.min(prev_len);
}
/// Move one logical line down, preserving column.
pub fn move_down(&mut self) {
let (line_start, col) = self.line_start_and_col();
// End of current line.
let mut cur_end = self.atoms.len();
for i in line_start..self.atoms.len() {
if matches!(self.atoms[i], Atom::Char('\n')) {
cur_end = i;
break;
}
}
if cur_end == self.atoms.len() {
return; // no next line
}
let next_start = cur_end + 1;
let mut next_end = self.atoms.len();
for i in next_start..self.atoms.len() {
if matches!(self.atoms[i], Atom::Char('\n')) {
next_end = i;
break;
}
}
let next_len = next_end - next_start;
self.cursor = next_start + col.min(next_len);
}
fn line_start_and_col(&self) -> (usize, usize) {
let mut start = 0;
for i in (0..self.cursor).rev() {
if matches!(self.atoms[i], Atom::Char('\n')) {
start = i + 1;
break;
}
}
(start, self.cursor - start)
}
/// Build the typed `Vec<Segment>` sent over the protocol. Adjacent
/// `Atom::Char`s are concatenated into a single `Segment::Text`;
/// each `Atom::Paste` becomes a standalone `Segment::Paste` so the
/// `[Clipboard #N | X chars, Y lines]` chip can be reconstructed by
/// any client subscribed to the resulting `Event::UserMessage`.
pub fn submit_segments(&self) -> Vec<protocol::Segment> {
let mut out = Vec::new();
let mut buf = String::new();
for a in &self.atoms {
match a {
Atom::Char(c) => buf.push(*c),
Atom::Paste(p) => {
if !buf.is_empty() {
out.push(protocol::Segment::text(std::mem::take(&mut buf)));
}
out.push(protocol::Segment::Paste {
id: p.id,
chars: p.chars as u32,
lines: p.lines as u32,
content: p.content.clone(),
});
}
}
}
if !buf.is_empty() {
out.push(protocol::Segment::text(buf));
}
out
}
/// Visible rendering wrapped to `content_width` display columns, plus
/// `(row, col)` of the cursor where `col` is a Unicode display column
/// within the wrapped layout.
pub fn render(&self, content_width: u16) -> InputRender {
let w = content_width.max(1) as usize;
let paste_style = Style::default().fg(Color::Magenta);
let text_style = Style::default();
// Row-builder state. `pending` + `pending_width` batch consecutive
// same-style chars into one Span per flush.
let mut rows: Vec<Vec<Span<'static>>> = vec![Vec::new()];
let mut row_width: usize = 0;
let mut pending = String::new();
let mut pending_width: usize = 0;
let mut pending_style = text_style;
let mut cursor_row: u16 = 0;
let mut cursor_col: u16 = 0;
let mut cursor_set = false;
// Record cursor once, at the point right before `atom` would be
// placed — accounting for a wrap that the atom itself will cause.
fn cursor_before(
leading_width: usize,
row_width: usize,
pending_width: usize,
content_w: usize,
cur_rows: usize,
) -> (u16, u16) {
let here = row_width + pending_width;
// If the atom's first-char width would overflow and the row
// isn't empty, the cursor sits at the start of the wrap row.
if leading_width > 0 && here + leading_width > content_w && here > 0 {
(cur_rows as u16, 0)
} else {
((cur_rows - 1) as u16, here as u16)
}
}
for (i, atom) in self.atoms.iter().enumerate() {
if !cursor_set && i == self.cursor {
let leading = match atom {
Atom::Char('\n') => 0,
Atom::Char(c) => UnicodeWidthChar::width(*c).unwrap_or(0),
Atom::Paste(p) => p
.label()
.chars()
.next()
.and_then(UnicodeWidthChar::width)
.unwrap_or(0),
};
let (r, c) = cursor_before(leading, row_width, pending_width, w, rows.len());
cursor_row = r;
cursor_col = c;
cursor_set = true;
}
match atom {
Atom::Char('\n') => {
flush_pending(
&mut pending,
&mut pending_width,
pending_style,
&mut rows,
&mut row_width,
);
rows.push(Vec::new());
row_width = 0;
}
Atom::Char(c) => {
let cw = UnicodeWidthChar::width(*c).unwrap_or(0);
if pending_style != text_style && !pending.is_empty() {
flush_pending(
&mut pending,
&mut pending_width,
pending_style,
&mut rows,
&mut row_width,
);
}
pending_style = text_style;
place_char(
*c,
cw,
&mut pending,
&mut pending_width,
pending_style,
&mut rows,
&mut row_width,
w,
);
}
Atom::Paste(p) => {
if pending_style != paste_style && !pending.is_empty() {
flush_pending(
&mut pending,
&mut pending_width,
pending_style,
&mut rows,
&mut row_width,
);
}
pending_style = paste_style;
for c in p.label().chars() {
let cw = UnicodeWidthChar::width(c).unwrap_or(0);
place_char(
c,
cw,
&mut pending,
&mut pending_width,
pending_style,
&mut rows,
&mut row_width,
w,
);
}
}
}
}
// Flush trailing pending chars.
flush_pending(
&mut pending,
&mut pending_width,
pending_style,
&mut rows,
&mut row_width,
);
// Cursor at end-of-buffer.
if !cursor_set && self.cursor == self.atoms.len() {
if row_width >= w && w > 0 {
// Last row is full — land the cursor on a fresh line so
// it stays visible instead of hanging off the right edge.
rows.push(Vec::new());
cursor_row = (rows.len() - 1) as u16;
cursor_col = 0;
} else {
cursor_row = (rows.len() - 1) as u16;
cursor_col = row_width as u16;
}
}
let lines: Vec<Line<'static>> = rows.into_iter().map(Line::from).collect();
InputRender {
lines,
cursor_row,
cursor_col,
}
}
}
/// Append a single char, wrapping to a new row first when it would
/// overflow `content_w`. The row is allowed to hold a single oversized
/// char (e.g. a wide CJK glyph on a 1-column layout) so we never loop.
fn place_char(
c: char,
cw: usize,
pending: &mut String,
pending_width: &mut usize,
style: Style,
rows: &mut Vec<Vec<Span<'static>>>,
row_width: &mut usize,
content_w: usize,
) {
let here = *row_width + *pending_width;
if here + cw > content_w && here > 0 {
flush_pending(pending, pending_width, style, rows, row_width);
rows.push(Vec::new());
*row_width = 0;
}
pending.push(c);
*pending_width += cw;
}
fn flush_pending(
pending: &mut String,
pending_width: &mut usize,
style: Style,
rows: &mut [Vec<Span<'static>>],
row_width: &mut usize,
) {
if pending.is_empty() {
return;
}
let taken = std::mem::take(pending);
*row_width += *pending_width;
*pending_width = 0;
if let Some(last) = rows.last_mut() {
last.push(Span::styled(taken, style));
}
}
pub struct InputRender {
pub lines: Vec<Line<'static>>,
pub cursor_row: u16,
pub cursor_col: u16,
}
#[cfg(test)]
mod submit_segments_tests {
use super::*;
use protocol::Segment;
#[test]
fn pure_text_collapses_to_one_text_segment() {
let mut buf = InputBuffer::new();
for c in "hello".chars() {
buf.insert_char(c);
}
let segs = buf.submit_segments();
assert_eq!(segs.len(), 1);
match &segs[0] {
Segment::Text { content } => assert_eq!(content, "hello"),
other => panic!("expected Text, got {other:?}"),
}
}
#[test]
fn paste_emits_separate_segment_with_metadata() {
let mut buf = InputBuffer::new();
for c in "see ".chars() {
buf.insert_char(c);
}
buf.insert_paste("line1\nline2".into());
for c in " end".chars() {
buf.insert_char(c);
}
let segs = buf.submit_segments();
assert_eq!(segs.len(), 3);
match &segs[0] {
Segment::Text { content } => assert_eq!(content, "see "),
other => panic!("expected Text, got {other:?}"),
}
match &segs[1] {
Segment::Paste {
chars,
lines,
content,
..
} => {
assert_eq!(content, "line1\nline2");
assert_eq!(*chars, "line1\nline2".chars().count() as u32);
assert_eq!(*lines, 2);
}
other => panic!("expected Paste, got {other:?}"),
}
match &segs[2] {
Segment::Text { content } => assert_eq!(content, " end"),
other => panic!("expected Text, got {other:?}"),
}
}
#[test]
fn empty_buffer_yields_empty_segments() {
let buf = InputBuffer::new();
assert!(buf.submit_segments().is_empty());
}
#[test]
fn leading_paste_does_not_emit_empty_text() {
let mut buf = InputBuffer::new();
buf.insert_paste("X".into());
let segs = buf.submit_segments();
assert_eq!(segs.len(), 1);
assert!(matches!(segs[0], Segment::Paste { .. }));
}
}