285 lines
8.7 KiB
Rust
285 lines
8.7 KiB
Rust
/*
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* Copyright (c) 2023 Marceline Cramer
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*
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* This program is free software: you can redistribute it and/or modify it under
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* the terms of the GNU Affero General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see https://www.gnu.org/licenses/.
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*/
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use std::io::{stdin, stdout, Read, Write};
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use crossterm::{cursor, event, terminal, ExecutableCommand, Result};
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use event::{Event, KeyCode, KeyEvent};
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use ropey::Rope;
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struct Buffer {
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pub text: Rope,
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}
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impl Buffer {
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pub fn from_str(text: &str) -> Self {
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Self {
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text: Rope::from_str(text),
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}
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}
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pub fn draw(&self, out: &mut (impl ExecutableCommand + Write)) -> Result<u32> {
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let (cols, rows) = terminal::size()?;
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let lr_width = self.text.len_lines().ilog10() + 1;
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out.execute(cursor::MoveTo(0, 0))?;
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for (row, line) in (0..rows).zip(self.text.lines()) {
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write!(out, "{:width$} ", row, width = lr_width as usize)?;
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write!(out, "{}", line.as_str().unwrap_or("").trim_end())?;
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out.execute(cursor::MoveToNextLine(1))?;
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}
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Ok(lr_width + 1)
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}
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pub fn clamped_cursor(&self, cursor: Cursor) -> Cursor {
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Cursor {
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line: cursor.line,
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column: cursor
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.column
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.min(self.text.line(cursor.line).len_chars() - 1),
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}
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}
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pub fn cursor_to_char(&self, cursor: Cursor) -> usize {
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let cursor = self.clamped_cursor(cursor);
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self.text.line_to_char(cursor.line) + cursor.column
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}
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pub fn move_cursor(&self, cursor: &mut Cursor, direction: Direction, enable_linewrap: bool) {
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*cursor = self.clamped_cursor(*cursor);
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match direction {
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Direction::Left => {
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if cursor.column > 0 {
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cursor.column -= 1;
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} else if enable_linewrap && cursor.line > 0 {
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cursor.line -= 1;
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let line = self.text.line(cursor.line);
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cursor.column = line.len_chars() - 1;
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}
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}
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Direction::Down => {
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if cursor.line < self.text.len_lines() {
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cursor.line += 1;
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}
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}
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Direction::Up => {
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if cursor.line > 0 {
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cursor.line -= 1;
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}
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}
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Direction::Right => {
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let line = self.text.line(cursor.line);
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if cursor.column + 2 > line.len_chars() {
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if enable_linewrap && cursor.line < self.text.len_lines() {
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cursor.line += 1;
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cursor.column = 0;
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}
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} else {
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cursor.column += 1;
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}
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}
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}
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}
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}
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#[derive(Copy, Clone, Debug, Default)]
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struct Cursor {
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pub column: usize,
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pub line: usize,
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}
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#[derive(Copy, Clone, Debug, Default)]
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enum Mode {
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#[default]
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Normal,
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Command,
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Visual,
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Insert,
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}
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impl Mode {
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pub fn cursor_style(&self) -> cursor::SetCursorStyle {
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use cursor::SetCursorStyle as Style;
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match self {
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Mode::Normal => Style::SteadyBlock,
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Mode::Visual => Style::BlinkingBlock,
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Mode::Insert => Style::BlinkingBar,
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Mode::Command => Style::SteadyUnderScore,
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}
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}
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}
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#[derive(Copy, Clone, Debug)]
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enum Direction {
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Left,
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Down,
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Up,
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Right,
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}
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struct State {
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pub buffer: Buffer,
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pub cursor: Cursor,
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pub mode: Mode,
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pub quit: bool,
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}
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impl State {
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pub fn from_str(text: &str) -> Self {
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Self {
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buffer: Buffer::from_str(text),
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cursor: Cursor::default(),
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mode: Mode::default(),
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quit: false,
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}
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}
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pub fn draw(&self, out: &mut impl Write) -> Result<()> {
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out.execute(terminal::BeginSynchronizedUpdate)?;
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out.execute(terminal::Clear(terminal::ClearType::All))?;
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let lr_width = self.buffer.draw(out)?;
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let cursor = self.buffer.clamped_cursor(self.cursor);
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let (col, row) = (cursor.column as u16, cursor.line as u16);
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let col = col + lr_width as u16;
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out.execute(cursor::MoveTo(col, row))?;
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out.execute(self.mode.cursor_style())?;
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out.execute(terminal::EndSynchronizedUpdate)?;
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Ok(())
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}
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pub fn on_event(&mut self, event: Event) {
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match self.mode {
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Mode::Normal => self.on_normal_event(event),
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Mode::Command => self.on_command_event(event),
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Mode::Visual => self.on_visual_event(event),
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Mode::Insert => self.on_insert_event(event),
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}
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}
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fn on_normal_event(&mut self, event: Event) {
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match event {
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Event::Key(KeyEvent { code, .. }) => match code {
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KeyCode::Char('i') => {
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self.mode = Mode::Insert;
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}
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KeyCode::Char(':') => {
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self.mode = Mode::Command;
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}
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KeyCode::Char('v') => {
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self.mode = Mode::Visual;
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}
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KeyCode::Esc => {
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self.quit = true;
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}
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code => self.match_any_key(code),
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},
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_ => {}
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}
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}
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fn on_command_event(&mut self, event: Event) {
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match event {
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Event::Key(KeyEvent { code, .. }) => match code {
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KeyCode::Esc => {
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self.mode = Mode::Normal;
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}
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code => self.match_any_key(code),
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},
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_ => {}
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}
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}
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fn on_visual_event(&mut self, event: Event) {
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match event {
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Event::Key(KeyEvent { code, .. }) => match code {
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KeyCode::Esc => {
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self.mode = Mode::Normal;
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}
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code => self.match_any_key(code),
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},
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_ => {}
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}
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}
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fn on_insert_event(&mut self, event: Event) {
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match event {
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Event::Key(KeyEvent { code, .. }) => match code {
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KeyCode::Char(c) => {
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let index = self.buffer.cursor_to_char(self.cursor);
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self.buffer.text.insert_char(index, c);
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self.move_cursor(Direction::Right)
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}
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KeyCode::Backspace => {
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self.move_cursor(Direction::Left);
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let index = self.buffer.cursor_to_char(self.cursor);
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self.buffer.text.remove(index..=index);
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}
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KeyCode::Delete => {
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let index = self.buffer.cursor_to_char(self.cursor);
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self.buffer.text.remove(index..=index);
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}
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KeyCode::Enter => {
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let index = self.buffer.cursor_to_char(self.cursor);
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self.buffer.text.insert_char(index, '\n');
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self.cursor.line += 1;
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self.cursor.column = 0;
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}
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KeyCode::Esc => {
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self.mode = Mode::Normal;
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}
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code => self.match_any_key(code),
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},
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_ => {}
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}
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}
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fn match_any_key(&mut self, code: KeyCode) {
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match code {
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KeyCode::Esc => self.mode = Mode::Normal,
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KeyCode::Char('h') | KeyCode::Left => self.move_cursor(Direction::Left),
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KeyCode::Char('j') | KeyCode::Down => self.move_cursor(Direction::Down),
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KeyCode::Char('k') | KeyCode::Up => self.move_cursor(Direction::Up),
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KeyCode::Char('l') | KeyCode::Right => self.move_cursor(Direction::Right),
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_ => {}
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}
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}
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fn move_cursor(&mut self, direction: Direction) {
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self.buffer.move_cursor(&mut self.cursor, direction, true);
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}
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}
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fn main() -> Result<()> {
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let text = include_str!("main.rs");
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let mut state = State::from_str(text);
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let mut stdout = stdout();
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terminal::enable_raw_mode()?;
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stdout.execute(terminal::EnterAlternateScreen)?;
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while !state.quit {
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state.draw(&mut stdout)?;
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let event = event::read()?;
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state.on_event(event);
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}
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stdout.execute(terminal::LeaveAlternateScreen)?;
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Ok(())
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}
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