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use std::{cmp, ops::Range};
use super::{CharIndex, TextStorage, TextStorageMut};
#[derive(Clone, Debug, PartialEq)]
pub struct Cursor {
/// Char range under cursor, aligned to extended grapheme clusters.
range: Range<CharIndex>,
/// The start of a selection if in select mode, ending at `range.start` or
/// `range.end`, depending on direction. Aligned to extended grapheme
/// clusters.
selection: Option<CharIndex>,
visual_horizontal_offset: Option<usize>,
}
impl Default for Cursor {
fn default() -> Self {
Self {
range: CharIndex(0)..CharIndex(1),
visual_horizontal_offset: None,
selection: None,
}
}
}
impl Cursor {
pub fn new() -> Self {
Self::default()
}
#[cfg(test)]
pub fn end_of_buffer<'a>(text: impl TextStorage<'a>) -> Self {
Self {
range: text.prev_grapheme_boundary(text.len_chars())..text.len_chars(),
visual_horizontal_offset: None,
selection: None,
}
}
pub fn range(&self) -> &Range<CharIndex> {
&self.range
}
pub fn selection(&self) -> Range<CharIndex> {
match self.selection {
Some(selection) if selection > self.range.start => self.range.start..selection,
Some(selection) if selection < self.range.start => selection..self.range.start,
_ => self.range.clone(),
}
}
pub fn begin_selection(&mut self) {
self.selection = Some(self.range.start)
}
pub fn clear_selection(&mut self) {
self.selection = None;
}
pub fn select_all<'a>(&mut self, text: &impl TextStorage<'a>) {
self.move_to_start_of_buffer(text);
self.selection = Some(text.len_chars());
}
// pub fn move_up(&mut self, text: impl TextStorage) {
// let current_line_index = text.char_to_line(self.range.start);
// if current_line_index.0 == 0 {
// return;
// }
// self.move_vertically(text, current_line_index, current_line_index - 1);
// }
// pub fn move_up_n(&mut self, text: &impl TextStorage, n: usize) {
// for _ in 0..n {
// self.move_up(text);
// }
// }
// pub fn move_down(&mut self, text: impl TextStorage) {
// let current_line_index = text.char_to_line(self.range.start);
// if current_line_index >= text.len_lines() {
// return;
// }
// self.move_vertically(text, current_line_index.0, current_line_index.0 + 1);
// }
// pub fn move_down_n(&mut self, text: impl TextStorage, n: usize) {
// for _ in 0..n {
// self.move_down(text);
// }
// }
pub fn move_left<'a>(&mut self, text: &impl TextStorage<'a>) {
let previous_grapheme_start = text.prev_grapheme_boundary(self.range.start);
if previous_grapheme_start == CharIndex(0) && self.range.start == CharIndex(0) {
return;
}
self.range = previous_grapheme_start..self.range.start;
self.visual_horizontal_offset = None;
}
pub fn move_right<'a>(&mut self, text: &impl TextStorage<'a>) {
let grapheme_start = self.range.end;
let grapheme_end = text.next_grapheme_boundary(grapheme_start);
if grapheme_start != grapheme_end {
self.range = grapheme_start..grapheme_end;
}
self.visual_horizontal_offset = None;
}
pub fn move_right_n<'a>(&mut self, text: &impl TextStorage<'a>, n: usize) {
for _ in 0..n {
self.move_right(text);
}
}
pub fn move_to_start_of_line<'a>(&mut self, text: &impl TextStorage<'a>) {
let line_index = text.char_to_line(self.range.start);
let char_index = text.line_to_char(line_index);
self.range = char_index..text.next_grapheme_boundary(char_index);
self.visual_horizontal_offset = None;
}
pub fn move_to_end_of_line<'a>(&mut self, text: &'a impl TextStorage<'a>) {
self.range = {
let line_index = text.char_to_line(
cmp::min(text.len_chars().0.saturating_sub(1), self.range.start.0).into(),
);
let line_length = text.line(line_index).len_chars();
let char_index = text.line_to_char(line_index);
(char_index + line_length).saturating_sub(1.into())..char_index + line_length
};
self.visual_horizontal_offset = None;
}
pub fn move_to_start_of_buffer<'a>(&mut self, text: &impl TextStorage<'a>) {
self.range = CharIndex(0)..text.next_grapheme_boundary(CharIndex(0));
self.visual_horizontal_offset = None;
}
pub fn move_to_end_of_buffer<'a>(&mut self, text: &impl TextStorage<'a>) {
self.range = text.prev_grapheme_boundary(text.len_chars())..text.len_chars();
self.visual_horizontal_offset = None;
}
pub fn insert_char<'a>(&mut self, text: &mut impl TextStorageMut<'a>, character: char) {
text.insert_char(self.range.start, character);
ensure_trailing_newline_with_content(text);
}
pub fn insert_chars<'a>(
&mut self,
text: &mut impl TextStorageMut<'a>,
characters: impl Iterator<Item = char>,
) {
characters.enumerate().for_each(|(offset, character)| {
text.insert_char(self.range.start + offset.into(), character);
});
ensure_trailing_newline_with_content(text);
}
// // pub fn insert_slice<StorageT>(&mut self, text: &mut StorageT, slice: StorageT::Slice)
// // where
// // StorageT: TextStorage,
// // {
// // let mut cursor_start = self.range.start;
// // for chunk in slice.chunks() {
// // text.insert(cursor_start.0, chunk);
// // cursor_start.0 += chunk.chars().count();
// // }
// // // TODO: make sure cursor start is aligned to grapheme boundary
// // self.range = cursor_start..next_grapheme_boundary(&text.slice(..), cursor_start);
// // }
pub fn delete<'a>(&mut self, text: &mut impl TextStorageMut<'a>) {
if text.len_chars() == 0.into()
|| self.range.start == text.len_chars().saturating_sub(1.into())
{
return;
}
text.remove(self.range.start.0..self.range.end.0);
let grapheme_start = self.range.start;
let grapheme_end = text.next_grapheme_boundary(self.range.start);
if grapheme_start < grapheme_end {
self.range = grapheme_start..grapheme_end
} else {
self.range = CharIndex(0)..CharIndex(1)
}
ensure_trailing_newline_with_content(text);
}
pub fn delete_line<'a>(&mut self, text: &mut impl TextStorageMut<'a>) {
if text.len_chars() == 0.into() {
return;
}
// Delete line
let line_index = text.char_to_line(self.range.start);
let delete_range_start = text.line_to_char(line_index);
let delete_range_end = text.line_to_char(line_index + 1.into());
text.remove(delete_range_start.0..delete_range_end.0);
// Update cursor position
let grapheme_start = text.line_to_char(cmp::min(
line_index,
text.len_lines().saturating_sub(2.into()),
));
let grapheme_end = text.next_grapheme_boundary(grapheme_start);
if grapheme_start != grapheme_end {
self.range = grapheme_start..grapheme_end
} else {
self.range = CharIndex(0)..CharIndex(1)
}
}
// pub fn delete_selection(&mut self, text: &mut impl TextStorage) {
// // Delete selection
// let selection = self.selection();
// text.remove(selection.start.0..selection.end.0);
// // Update cursor position
// let grapheme_start = cmp::min(
// self.range.start,
// prev_grapheme_boundary(&text.slice(..), CharIndex(text.len_chars())),
// );
// let grapheme_end = next_grapheme_boundary(&text.slice(..), grapheme_start);
// if grapheme_start != grapheme_end {
// self.range = grapheme_start..grapheme_end
// } else {
// self.range = CharIndex(0)..CharIndex(1)
// }
// self.clear_selection();
// self.visual_horizontal_offset = None;
// }
pub fn backspace<'a>(&mut self, text: &mut impl TextStorageMut<'a>) {
if self.range.start.0 > 0 {
self.move_left(text);
self.delete(text)
}
}
pub fn sync<'a>(
&mut self,
current_text: &'a impl TextStorage<'a>,
new_text: &'a impl TextStorage<'a>,
) {
let current_line = current_text.char_to_line(self.range.start);
let current_line_offset = self.range.start - current_text.line_to_char(current_line);
let new_line = cmp::min(current_line, new_text.len_lines().saturating_sub(1.into()));
let new_line_offset = cmp::min(
current_line_offset,
new_text.line(new_line).len_chars().saturating_sub(1.into()),
);
let grapheme_end =
new_text.next_grapheme_boundary(new_text.line_to_char(new_line) + new_line_offset);
let grapheme_start = new_text.prev_grapheme_boundary(grapheme_end);
self.range = if grapheme_start != grapheme_end {
grapheme_start..grapheme_end
} else {
CharIndex(0)..CharIndex(1)
};
self.visual_horizontal_offset = None;
self.selection = None;
}
// fn move_vertically(
// &mut self,
// text: impl TextStorage,
// current_line_index: LineIndex,
// new_line_index: LineIndex,
// ) {
// if new_line_index >= text.len_lines() {
// return;
// }
// let current_line_start = text.line_to_char(current_line_index).0;
// let cursor_range_start = self.range.start.0;
// // Should be grapheme width, not len
// let current_visual_x = self.visual_horizontal_offset.get_or_insert_with(|| {
// text.slice(current_line_start..cursor_range_start)
// .len_graphemes()
// });
// let new_line = text.line(new_line_index);
// let mut graphemes = new_line.graphemes();
// let mut new_visual_x = 0;
// while let Some(grapheme) = graphemes.next() {
// // Should be grapheme width, not len
// let width = grapheme.len_graphemes();
// if new_visual_x + width > *current_visual_x {
// break;
// }
// new_visual_x += width;
// }
// let new_line_offset = CharIndex(
// text.byte_to_char(text.line_to_byte(new_line_index) + graphemes.cursor.cur_cursor()),
// );
// self.range = if new_visual_x <= *current_visual_x {
// let grapheme_start = prev_grapheme_boundary(&text.slice(..), new_line_offset);
// let grapheme_end = next_grapheme_boundary(&text.slice(..), grapheme_start);
// grapheme_start..grapheme_end
// } else {
// let grapheme_end = next_grapheme_boundary(&text.slice(..), new_line_offset);
// let grapheme_start = prev_grapheme_boundary(&text.slice(..), grapheme_end);
// grapheme_start..grapheme_end
// }
// }
}
pub(crate) fn ensure_trailing_newline_with_content<'a>(text: &mut impl TextStorageMut<'a>) {
if text.len_chars() == 0.into() || text.char(text.len_chars() - 1.into()) != '\n' {
text.insert_char(text.len_chars(), '\n');
}
}