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use crate::row::Row;
#[derive(Debug, Clone, Copy)]
pub enum UndoRedo {
Undo,
Redo,
}
#[derive(Debug)]
pub enum EditDiff {
InsertChar(usize, usize, char),
DeleteChar(usize, usize, char),
Insert(usize, usize, String),
Append(usize, String),
Truncate(usize, String),
Remove(usize, usize, String),
Newline,
InsertLine(usize, String),
DeleteLine(usize, String),
}
impl EditDiff {
pub fn apply(&self, rows: &mut Vec<Row>, which: UndoRedo) -> (usize, usize) {
// Returns cursor's next position (x, y)
use UndoRedo::*;
match *self {
EditDiff::InsertChar(x, y, c) => match which {
Redo => {
rows[y].insert_char(x, c);
(x + 1, y)
}
Undo => {
rows[y].remove_char(x);
(x, y)
}
},
EditDiff::DeleteChar(x, y, c) => match which {
Redo => {
rows[y].remove_char(x - 1);
(x - 1, y)
}
Undo => {
rows[y].insert_char(x - 1, c);
(x, y)
}
},
EditDiff::Append(y, ref s) => match which {
Redo => {
let len = rows[y].len();
rows[y].append(s);
(len, y)
}
Undo => {
let count = s.chars().count();
let len = rows[y].len();
rows[y].remove(len - count, len);
(rows[y].len(), y)
}
},
EditDiff::Truncate(y, ref s) => match which {
Redo => {
let count = s.chars().count();
let len = rows[y].len();
rows[y].truncate(len - count);
(len - count, y)
}
Undo => {
rows[y].append(s);
let x = rows[y].len() - s.chars().count();
(x, y)
}
},
EditDiff::Insert(x, y, ref s) => match which {
Redo => {
rows[y].insert_str(x, s);
(x + s.chars().count(), y)
}
Undo => {
rows[y].remove(x, s.chars().count());
(x, y)
}
},
EditDiff::Remove(x, y, ref s) => match which {
Redo => {
let next_x = x - s.chars().count();
rows[y].remove(next_x, x);
(next_x, y)
}
Undo => {
let count = s.chars().count();
rows[y].insert_str(x - count, s);
(x, y)
}
},
EditDiff::Newline => match which {
Redo => {
rows.push(Row::empty());
(0, rows.len() - 1)
}
Undo => {
debug_assert_eq!(rows[rows.len() - 1].buffer(), "");
rows.pop();
(0, rows.len())
}
},
EditDiff::InsertLine(y, ref s) => match which {
Redo => {
rows.insert(y, Row::new(s).unwrap());
(0, y)
}
Undo => {
rows.remove(y);
(rows[y - 1].len(), y - 1)
}
},
EditDiff::DeleteLine(y, ref s) => match which {
Redo => {
if y == rows.len() - 1 {
rows.pop();
} else {
rows.remove(y);
}
(rows[y - 1].len(), y - 1)
}
Undo => {
if y == rows.len() {
rows.push(Row::new(s).unwrap());
} else {
rows.insert(y, Row::new(s).unwrap());
}
(0, y)
}
},
}
}
}