use crate::Document; use crate::Row; use crate::Terminal; use std::env; use termion::color; use termion::event::Key; const STATUS_FG_COLOR: color::Rgb = color::Rgb(63, 63, 63); const STATUS_BG_COLOR: color::Rgb = color::Rgb(239, 239, 239); const VERSION: &str = env!("CARGO_PKG_VERSION"); #[derive(Default)] pub struct Position { pub x: usize, pub y: usize, } pub struct Editor { should_quit: bool, terminal: Terminal, cursor_position: Position, offset: Position, document: Document, } impl Editor { pub fn run(&mut self) { loop { if let Err(error) = self.refresh_screen() { die(error); } if self.should_quit { break; } if let Err(error) = self.process_keypress() { die(error); } } } pub fn default() -> Self { let args: Vec = env::args().collect(); let document = if args.len() > 1 { let file_name = &args[1]; Document::open(&file_name).unwrap_or_default() } else { Document::default() }; Self { should_quit: false, terminal: Terminal::default().expect("Failed to initialize terminal"), document, cursor_position: Position::default(), offset: Position::default(), } } fn refresh_screen(&self) -> Result<(), std::io::Error> { Terminal::cursor_hide(); Terminal::cursor_position(&Position::default()); if self.should_quit { Terminal::clear_screen(); println!("Goodbye.\r"); } else { self.draw_rows(); self.draw_status_bar(); self.draw_message_bar(); Terminal::cursor_position(&Position { x: self.cursor_position.x.saturating_sub(self.offset.x), y: self.cursor_position.y.saturating_sub(self.offset.y), }); } Terminal::cursor_show(); Terminal::flush() } fn draw_status_bar(&self) { let mut status; let width = self.terminal.size().width as usize; let mut file_name = "[No Name]".to_string(); if let Some(name) = &self.document.file_name { file_name = name.clone(); file_name.truncate(20); } status = format!("{} - {} lines", file_name, self.document.len()); let line_indicator = format!( "{}/{}", self.cursor_position.y.saturating_add(1), self.document.len() ); let len = status.len() + line_indicator.len(); if width > len { status.push_str(&" ".repeat(width - len)); } status = format!("{}{}", status, line_indicator); status.truncate(width); Terminal::set_bg_color(STATUS_BG_COLOR); Terminal::set_fg_color(STATUS_FG_COLOR); println!("{}\r", status); Terminal::reset_fg_color(); Terminal::reset_bg_color(); } fn draw_message_bar(&self) { Terminal::clear_current_line(); } fn process_keypress(&mut self) -> Result<(), std::io::Error> { let pressed_key = Terminal::read_key()?; match pressed_key { Key::Ctrl('q') => self.should_quit = true, Key::Up | Key::Down | Key::Left | Key::Right | Key::PageUp | Key::PageDown | Key::End | Key::Home => self.move_cursor(pressed_key), _ => (), } self.scroll(); Ok(()) } fn scroll(&mut self) { let Position { x, y } = self.cursor_position; let width = self.terminal.size().width as usize; let height = self.terminal.size().height as usize; let mut offset = &mut self.offset; if y < offset.y { offset.y = y; } else if y >= offset.y.saturating_add(height) { offset.y = y.saturating_sub(height).saturating_add(1); } if x < offset.x { offset.x = x; } else if x >= offset.x.saturating_add(width) { offset.x = x.saturating_sub(width).saturating_add(1); } } fn move_cursor(&mut self, key: Key) { let terminal_height = self.terminal.size().height as usize; let Position { mut y, mut x } = self.cursor_position; let height = self.document.len(); let mut width = if let Some(row) = self.document.row(y) { row.len() } else { 0 }; match key { Key::Up => y = y.saturating_sub(1), Key::Down => { if y < height { y = y.saturating_add(1); } }, Key::Left => { if x > 0 { x -= 1; } else if y > 0 { y -= 1; if let Some(row) = self.document.row(y) { x = row.len() } else { x = 0 } } }, Key::Right => { if x < width { x += 1; } else if y < height { y += 1; x = 0; } }, Key::PageUp => { y = if y > terminal_height { y - terminal_height } else { 0 } }, Key::PageDown => { y = if y.saturating_add(terminal_height) < height { y + terminal_height as usize } else { height } }, Key::Home => x = 0, Key::End => x = width, _ => (), } width = if let Some(row) = self.document.row(y) { row.len() } else { 0 }; if x > width { x = width; } self.cursor_position = Position { x, y } } fn draw_welcome_message(&self) { let mut welcome_message = format!("Hecto editor -- version {}", VERSION); let width = self.terminal.size().width as usize; let len = welcome_message.len(); let padding = width.saturating_sub(len) / 2; let spaces = " ".repeat(padding.saturating_sub(1)); welcome_message = format!("~{}{}", spaces, welcome_message); welcome_message.truncate(width); println!("{}\r", welcome_message); } pub fn draw_row(&self, row: &Row) { let width = self.terminal.size().width as usize; let start = self.offset.x; let end = self.offset.x + width; let row = row.render(start, end); println!("{}\r", row); } fn draw_rows(&self) { let height = self.terminal.size().height; for terminal_row in 0..height { Terminal::clear_current_line(); if let Some(row) = self.document.row(terminal_row as usize + self.offset.y) { self.draw_row(row); } else if self.document.is_empty() && terminal_row == height / 3 { self.draw_welcome_message(); } else { println!("~\r"); } } } } fn die(e: std::io::Error) { Terminal::clear_screen(); panic!(e); }