use crate::text_input::Value;
#[derive(Debug, Copy, Clone)]
pub struct Cursor {
state: State,
}
#[derive(Debug, Copy, Clone)]
pub enum State {
Index(usize),
Selection {
start: usize,
end: usize,
},
}
impl Default for Cursor {
fn default() -> Self {
Cursor {
state: State::Index(0),
}
}
}
impl Cursor {
pub fn state(&self, value: &Value) -> State {
match self.state {
State::Index(index) => State::Index(index.min(value.len())),
State::Selection { start, end } => {
let start = start.min(value.len());
let end = end.min(value.len());
if start == end {
State::Index(start)
} else {
State::Selection { start, end }
}
}
}
}
pub fn selection(&self, value: &Value) -> Option<(usize, usize)> {
match self.state(value) {
State::Selection { start, end } => {
Some((start.min(end), start.max(end)))
}
State::Index(_) => None,
}
}
pub(crate) fn move_to(&mut self, position: usize) {
self.state = State::Index(position);
}
pub(crate) fn move_right(&mut self, value: &Value) {
self.move_right_by_amount(value, 1);
}
pub(crate) fn move_right_by_words(&mut self, value: &Value) {
self.move_to(value.next_end_of_word(self.right(value)));
}
pub(crate) fn move_right_by_amount(
&mut self,
value: &Value,
amount: usize,
) {
match self.state(value) {
State::Index(index) => {
self.move_to(index.saturating_add(amount).min(value.len()));
}
State::Selection { start, end } => self.move_to(end.max(start)),
}
}
pub(crate) fn move_left(&mut self, value: &Value) {
match self.state(value) {
State::Index(index) if index > 0 => self.move_to(index - 1),
State::Selection { start, end } => self.move_to(start.min(end)),
State::Index(_) => self.move_to(0),
}
}
pub(crate) fn move_left_by_words(&mut self, value: &Value) {
self.move_to(value.previous_start_of_word(self.left(value)));
}
pub(crate) fn select_range(&mut self, start: usize, end: usize) {
if start == end {
self.state = State::Index(start);
} else {
self.state = State::Selection { start, end };
}
}
pub(crate) fn select_left(&mut self, value: &Value) {
match self.state(value) {
State::Index(index) if index > 0 => {
self.select_range(index, index - 1);
}
State::Selection { start, end } if end > 0 => {
self.select_range(start, end - 1);
}
_ => {}
}
}
pub(crate) fn select_right(&mut self, value: &Value) {
match self.state(value) {
State::Index(index) if index < value.len() => {
self.select_range(index, index + 1);
}
State::Selection { start, end } if end < value.len() => {
self.select_range(start, end + 1);
}
_ => {}
}
}
pub(crate) fn select_left_by_words(&mut self, value: &Value) {
match self.state(value) {
State::Index(index) => {
self.select_range(index, value.previous_start_of_word(index));
}
State::Selection { start, end } => {
self.select_range(start, value.previous_start_of_word(end));
}
}
}
pub(crate) fn select_right_by_words(&mut self, value: &Value) {
match self.state(value) {
State::Index(index) => {
self.select_range(index, value.next_end_of_word(index));
}
State::Selection { start, end } => {
self.select_range(start, value.next_end_of_word(end));
}
}
}
pub(crate) fn select_all(&mut self, value: &Value) {
self.select_range(0, value.len());
}
pub(crate) fn start(&self, value: &Value) -> usize {
let start = match self.state {
State::Index(index) => index,
State::Selection { start, .. } => start,
};
start.min(value.len())
}
pub(crate) fn end(&self, value: &Value) -> usize {
let end = match self.state {
State::Index(index) => index,
State::Selection { end, .. } => end,
};
end.min(value.len())
}
fn left(&self, value: &Value) -> usize {
match self.state(value) {
State::Index(index) => index,
State::Selection { start, end } => start.min(end),
}
}
fn right(&self, value: &Value) -> usize {
match self.state(value) {
State::Index(index) => index,
State::Selection { start, end } => start.max(end),
}
}
}