zte/src/state.rs

612 lines
19 KiB
Rust

use crate::{
Args, Dir, Error,
highlight::{Highlighter, Highlights},
theme,
};
use slotmap::{HopSlotMap, new_key_type};
use std::{
io,
ops::Range,
path::{Path, PathBuf},
};
new_key_type! {
pub struct BufferId;
pub struct CursorId;
}
#[derive(Copy, Clone, Default)]
pub struct Cursor {
pub base: usize,
pub pos: usize,
// Used to 'remember' the desired column when skipping over shorter lines
desired_col: isize,
}
impl Cursor {
fn reset_desired_col(&mut self, text: &Text) {
self.desired_col = text.to_coord(self.pos)[0];
}
pub fn selection(&self) -> Option<Range<usize>> {
if self.base == self.pos {
None
} else {
Some(self.base.min(self.pos)..self.base.max(self.pos))
}
}
pub fn place_at(&mut self, pos: usize) {
self.base = pos;
self.pos = pos;
// TODO: Reset desired position
}
pub fn select(&mut self, range: Range<usize>) {
self.base = range.start;
self.pos = range.end;
// TODO: Reset desired position
}
}
#[derive(Default)]
pub struct Text {
chars: Vec<char>,
}
impl ToString for Text {
fn to_string(&self) -> String {
self.chars.iter().copied().collect()
}
}
impl Text {
// TODO: Remove this
pub fn chars(&self) -> &[char] {
&self.chars
}
pub fn to_coord(&self, pos: usize) -> [isize; 2] {
let mut n = 0;
let mut last_n = 0;
let mut i: usize = 0;
for line in self.lines() {
last_n = n;
i += 1;
if (n..n + line.len()).contains(&pos) {
break;
}
n += line.len();
}
[(pos - last_n) as isize, i.saturating_sub(1) as isize]
}
pub fn to_pos(&self, coord: [isize; 2]) -> usize {
if coord[1] < 0 {
return 0;
}
let mut pos = 0;
for (i, line) in self.lines().enumerate() {
if i as isize == coord[1] {
return pos + coord[0].clamp(0, line.len().saturating_sub(1) as isize) as usize;
} else {
pos += line.len();
}
}
pos.min(self.chars.len())
}
/// Return an iterator over the lines of the text.
///
/// Guarantees:
/// - If you sum the lengths of each line, it will be the same as the length (in characters) of the text
pub fn lines(&self) -> impl Iterator<Item = &[char]> {
let mut start = 0;
let mut i = 0;
let mut finished = false;
core::iter::from_fn(move || {
loop {
let Some(c) = self.chars.get(i) else {
return if finished {
None
} else {
let line = &self.chars[start..];
finished = true;
Some(line)
};
};
i += 1;
if *c == '\n' {
let line = &self.chars[start..i];
start = i;
return Some(line);
}
}
})
}
fn indent_of_line(&self, line: isize) -> &[char] {
let line_start = self.to_pos([0, line]);
let mut i = 0;
while self
.chars()
.get(line_start + i)
.map_or(false, |c| [' ', '\t'].contains(c))
{
i += 1;
}
self.chars().get(line_start..line_start + i).unwrap_or(&[])
}
}
#[derive(Default)]
pub struct Buffer {
pub unsaved: bool,
pub text: Text,
pub highlights: Option<Highlights>,
pub cursors: HopSlotMap<CursorId, Cursor>,
pub dir: Option<PathBuf>,
pub path: Option<PathBuf>,
}
impl Buffer {
pub fn from_file(path: PathBuf) -> Result<Self, Error> {
let (unsaved, dir, chars, s) = match std::fs::read_to_string(&path) {
Ok(s) => {
let mut path = path.canonicalize()?;
path.pop();
(false, Some(path), s.chars().collect(), s)
}
// If the file doesn't exist, create a new file
Err(err) if err.kind() == io::ErrorKind::NotFound => {
let dir = path
.parent()
.filter(|p| p.to_str() != Some(""))
.map(Path::to_owned)
.or_else(|| std::env::current_dir().ok());
(true, dir, Vec::new(), String::new())
}
Err(err) => return Err(err.into()),
};
Ok(Self {
unsaved,
highlights: Highlighter::from_file_name(&path).map(|h| h.highlight(&chars)),
text: Text { chars },
cursors: HopSlotMap::default(),
dir,
path: Some(path),
})
}
pub fn save(&mut self) -> Result<(), Error> {
if self.unsaved {
std::fs::write(
self.path.as_ref().expect("buffer must have path to save"),
self.text.to_string(),
)?;
self.unsaved = false;
}
Ok(())
}
pub fn name(&self) -> Option<String> {
Some(
match self.path.as_ref()?.file_name().and_then(|n| n.to_str()) {
Some(name) => format!("{}{name}", if self.unsaved { "* " } else { "" }),
None => "<error>".to_string(),
},
)
}
fn update_highlights(&mut self) {
self.highlights = self
.highlights
.take()
.map(|hl| hl.highlighter.highlight(self.text.chars()));
}
pub fn clear(&mut self) {
self.unsaved = true;
self.text.chars.clear();
self.update_highlights();
// Reset cursors
self.cursors.values_mut().for_each(|cursor| {
*cursor = Cursor::default();
});
}
pub fn goto_line_cursor(&mut self, cursor_id: CursorId, line: isize) {
let Some(cursor) = self.cursors.get_mut(cursor_id) else {
return;
};
cursor.pos = self.text.to_pos([0, line]);
cursor.reset_desired_col(&self.text);
cursor.base = cursor.pos;
}
pub fn select_token_cursor(&mut self, cursor_id: CursorId) {
let Some(cursor) = self.cursors.get_mut(cursor_id) else {
return;
};
if let Some(tok) = self
.highlights
.as_ref()
// Choose the longest token that the cursor is touching
.and_then(|hl| {
let a = hl.get_at(cursor.pos);
let b = hl.get_at(cursor.pos.saturating_sub(1));
a.zip(b)
.map(|(a, b)| {
if a.range.end - a.range.start > b.range.end - b.range.start {
a
} else {
b
}
})
.or(a)
.or(b)
})
{
cursor.select(tok.range.clone());
} else {
// TODO: Bell
}
}
pub fn select_all_cursor(&mut self, cursor_id: CursorId) {
let Some(cursor) = self.cursors.get_mut(cursor_id) else {
return;
};
cursor.base = 0;
cursor.pos = self.text.chars().len();
}
fn indent_at(&mut self, mut pos: usize, forward: bool) {
const TAB_ALIGN: usize = 4;
if forward {
let coord = self.text.to_coord(pos).map(|e| e.max(0) as usize);
let next_up = |x: usize, n: usize| (x / n + 1) * n;
let n = next_up(coord[0], TAB_ALIGN) - coord[0];
self.insert(pos, (0..n).map(|_| ' '));
} else {
// First, find the next non-space character in the line
while self.text.chars().get(pos) == Some(&' ') {
pos += 1;
}
// Find the desired column, and hence the number of spaces to remove
let coord = self.text.to_coord(pos).map(|e| e.max(0) as usize);
let next_down = |x: usize, n: usize| (x.saturating_sub(1) / n) * n;
let n = coord[0] - next_down(coord[0], TAB_ALIGN);
// Keep removing whitespace until we hit the desired column
for _ in 0..n {
pos = match pos.checked_sub(1) {
Some(pos) if self.text.chars().get(pos) == Some(&' ') => {
self.remove(pos..pos + 1);
pos
}
_ => break,
};
}
}
}
pub fn indent(&mut self, cursor_id: CursorId, forward: bool) {
let Some(cursor) = self.cursors.get_mut(cursor_id) else {
return;
};
if let Some(range) = cursor.selection() {
let line_range = self.text.to_coord(range.start)[1]..=self.text.to_coord(range.end)[1];
for line in line_range {
self.indent_at(self.text.to_pos([0, line]), forward);
}
} else {
let pos = cursor.pos;
self.indent_at(pos, forward);
}
}
pub fn move_cursor(
&mut self,
cursor_id: CursorId,
dir: Dir,
dist: [usize; 2],
retain_base: bool,
word: bool,
) {
let Some(cursor) = self.cursors.get_mut(cursor_id) else {
return;
};
match dir {
Dir::Left => {
cursor.pos = if !retain_base && cursor.base < cursor.pos {
cursor.base
} else if let (true, Some(mut pos)) = (word, cursor.pos.checked_sub(1)) {
let class = self.text.chars().get(pos).copied().map(classify);
loop {
pos = match pos.checked_sub(1) {
Some(pos)
if self.text.chars().get(pos).copied().map(classify) == class =>
{
pos
}
_ => break pos,
}
}
} else {
cursor.pos.saturating_sub(dist[0])
};
cursor.reset_desired_col(&self.text);
}
Dir::Right => {
cursor.pos = if !retain_base && cursor.base > cursor.pos {
cursor.base
} else if word {
let mut pos = cursor.pos;
let class = self.text.chars().get(pos).copied().map(classify);
loop {
pos = if self.text.chars().get(pos).copied().map(classify) == class {
pos + 1
} else {
break pos;
};
}
} else {
(cursor.pos + dist[0]).min(self.text.chars.len())
};
cursor.reset_desired_col(&self.text);
}
Dir::Up => {
let coord = self.text.to_coord(cursor.pos);
// Special case: pressing 'up' at the top of the screen resets the cursor to the beginning
if coord[1] <= 0 {
cursor.pos = 0;
cursor.reset_desired_col(&self.text);
} else {
cursor.pos = self
.text
.to_pos([cursor.desired_col, coord[1] - dist[1] as isize]);
}
}
Dir::Down => {
let coord = self.text.to_coord(cursor.pos);
cursor.pos = self
.text
.to_pos([cursor.desired_col, coord[1] + dist[1] as isize]);
}
};
if !retain_base {
cursor.base = cursor.pos;
}
}
pub fn insert(&mut self, pos: usize, chars: impl IntoIterator<Item = char>) {
self.unsaved = true;
let mut n = 0;
for c in chars {
self.text
.chars
.insert((pos + n).min(self.text.chars.len()), c);
n += 1;
}
self.update_highlights();
self.cursors.values_mut().for_each(|cursor| {
if cursor.base >= pos {
cursor.base += n;
}
if cursor.pos >= pos {
cursor.pos += n;
cursor.reset_desired_col(&self.text);
}
});
}
pub fn insert_after(&mut self, cursor_id: CursorId, chars: impl IntoIterator<Item = char>) {
let Some(cursor) = self.cursors.get(cursor_id) else {
return;
};
let old_cursor = *cursor;
self.insert(old_cursor.pos, chars);
let Some(cursor) = self.cursors.get_mut(cursor_id) else {
return;
};
*cursor = old_cursor;
}
pub fn enter(&mut self, cursor_id: CursorId, chars: impl IntoIterator<Item = char>) {
let Some(cursor) = self.cursors.get(cursor_id) else {
return;
};
if let Some(selection) = cursor.selection() {
self.remove(selection);
self.enter(cursor_id, chars);
} else {
self.insert(cursor.pos, chars);
}
}
// Assumes range is well-formed
pub fn remove(&mut self, range: Range<usize>) {
self.unsaved = true;
// TODO: Bell if false?
self.text.chars.drain(range.clone());
self.update_highlights();
self.cursors.values_mut().for_each(|cursor| {
if cursor.base >= range.start {
cursor.base = cursor
.base
.saturating_sub(range.end - range.start)
.max(range.start);
}
if cursor.pos >= range.start {
cursor.pos = cursor
.pos
.saturating_sub(range.end - range.start)
.max(range.start);
cursor.reset_desired_col(&self.text);
}
});
}
pub fn backspace(&mut self, cursor_id: CursorId) {
let Some(cursor) = self.cursors.get(cursor_id) else {
return;
};
let line_start = self.text.to_pos([0, self.text.to_coord(cursor.pos)[1]]);
if let Some(selection) = cursor.selection() {
self.remove(selection);
} else
/*if line_start != cursor.pos && (line_start..cursor.pos)
.all(|p| self.text.chars().get(p).map_or(false, |c| [' ', '\t'].contains(c)))
{
self.remove(line_start..cursor.pos);
self.backspace(cursor_id); // Remove the newline too
} else*/
if let Some(pos) = cursor.pos.checked_sub(1) {
// If a backspace is performed on a space, a deindent takes place instead
if self.text.chars().get(pos) == Some(&' ') {
self.indent_at(pos, false);
} else {
self.remove(pos..pos + 1);
}
}
}
pub fn delete(&mut self, cursor_id: CursorId) {
let Some(cursor) = self.cursors.get(cursor_id) else {
return;
};
if let Some(selection) = cursor.selection() {
self.remove(selection);
} else {
self.remove(cursor.pos..cursor.pos + 1);
}
}
pub fn newline(&mut self, cursor_id: CursorId) {
let Some(cursor) = self.cursors.get(cursor_id) else {
return;
};
let line = self.text.to_coord(cursor.pos)[1];
let line_start = self.text.to_pos([0, line]);
let prev_indent = self.text.indent_of_line(line).to_vec();
let next_indent = self.text.indent_of_line(line + 1).to_vec();
let (close_block, extra_indent, trailing_indent, base_indent) = if let Some(last_pos) =
cursor
.selection()
.map_or(cursor.pos, |s| s.start)
.checked_sub(1)
&& let Some(last_char) = self.text.chars().get(last_pos)
&& let Some((l, r)) = [('(', ')'), ('[', ']'), ('{', '}')]
.iter()
.find(|(l, _)| l == last_char)
&& let next_pos = cursor.selection().map_or(cursor.pos, |s| s.end)
&& let next_char = self
.text
.chars()
.get(next_pos..)
.unwrap_or(&[])
.iter()
.filter(|c| !c.is_ascii_whitespace())
.next()
{
let close_block = next_char != Some(r)
&& next_indent
.strip_prefix(&*prev_indent)
.map_or(true, |i| i.is_empty());
(
if close_block { Some(*r) } else { None },
true,
close_block || self.text.chars().get(next_pos) == Some(r),
prev_indent,
)
} else {
(None, false, false, prev_indent)
};
// Indent to same level as last line
self.enter(
cursor_id,
['\n'].into_iter().chain(base_indent.iter().copied()),
);
if let Some(r) = close_block {
self.insert_after(cursor_id, [r]);
}
if trailing_indent {
self.insert_after(cursor_id, core::iter::once('\n').chain(base_indent));
}
if extra_indent {
self.indent(cursor_id, true);
}
}
pub fn start_session(&mut self) -> CursorId {
self.cursors.insert(Cursor::default())
}
pub fn end_session(&mut self, cursor_id: CursorId) {
self.cursors.remove(cursor_id);
}
}
// CLassify the character by property
fn classify(c: char) -> u8 {
match c {
// c if c.is_ascii_whitespace() => 0,
c if c.is_alphanumeric() || c == '_' => 1,
_ => 2,
}
}
pub struct State {
pub buffers: HopSlotMap<BufferId, Buffer>,
pub tick: u64,
pub theme: theme::Theme,
}
impl TryFrom<Args> for State {
type Error = Error;
fn try_from(args: Args) -> Result<Self, Self::Error> {
let mut this = Self {
buffers: HopSlotMap::default(),
tick: 0,
theme: theme::Theme::default(),
};
if args.paths.is_empty() {
this.buffers.insert(Buffer::default());
} else {
for path in args.paths {
this.buffers.insert(Buffer::from_file(path)?);
}
}
Ok(this)
}
}
impl State {
pub fn open_or_get(&mut self, path: PathBuf) -> Result<BufferId, Error> {
let true_path = path.canonicalize()?;
if let Some((buffer_id, _)) = self.buffers.iter().find(|(_, b)| {
b.path.as_ref().and_then(|p| p.canonicalize().ok()).as_ref() == Some(&true_path)
}) {
Ok(buffer_id)
} else {
Ok(self.buffers.insert(Buffer::from_file(path)?))
}
}
pub fn tick(&mut self) {
self.tick += 1;
}
}