Add basic text editor implementation to jvii

1 files changed, 567 insertions, 8 deletions

diff --git a/src/bin/jvii.rs b/src/bin/jvii.rs
index e7a20bb..9e1b444 100644
--- a/src/bin/jvii.rs
+++ b/src/bin/jvii.rs
@@ -1,3 +1,22 @@
+use std::env;
+use std::fs;
+use std::io::{self, Write};
+use std::path::PathBuf;
+
+use clap::{Parser, command};
+use crossterm::{
+    QueueableCommand,
+    cursor::MoveTo,
+    event::{self, Event, KeyCode, KeyEvent, KeyModifiers},
+    execute,
+    style::{self, Color, Print, SetForegroundColor},
+    terminal::{
+        self, Clear, ClearType, EnterAlternateScreen, LeaveAlternateScreen, disable_raw_mode,
+        enable_raw_mode,
+    },
+};
+use just_enough_vcs_cli::utils::display::display_width;
+
 #[derive(Parser, Debug)]
 #[command(
     disable_help_flag = true,
@@ -5,15 +24,555 @@
     disable_help_subcommand = true,
     help_template = "{all-args}"
 )]
-
 struct JustEnoughVcsInputer {
-    #[command(subcommand)]
-    command: JustEnoughVcsInputerCommand,
+    /// File to edit
+    file: Option<PathBuf>,
+}
+
+struct Editor {
+    content: Vec<String>,
+    cursor_x: usize,
+    cursor_y: usize,
+    selection_start: Option<(usize, usize)>,
+    is_selecting: bool,
+    file_path: PathBuf,
+    modified: bool,
+    terminal_size: (u16, u16),
+    should_exit: bool,
 }
 
-#[derive(Subcommand, Debug)]
-enum JustEnoughVcsInputerCommand {
-    /// Version information
-    #[command(alias = "--version", alias = "-v")]
-    Version(VersionArgs),
+impl Editor {
+    fn new(file_path: PathBuf) -> io::Result<Self> {
+        let content = if file_path.exists() {
+            fs::read_to_string(&file_path)?
+                .lines()
+                .map(|s| s.to_string())
+                .collect()
+        } else {
+            vec![String::new()]
+        };
+
+        let (width, height) = terminal::size().unwrap_or((80, 24));
+
+        Ok(Self {
+            content,
+            cursor_x: 0,
+            cursor_y: 0,
+            selection_start: None,
+            is_selecting: false,
+            file_path,
+            modified: false,
+            terminal_size: (width, height),
+            should_exit: false,
+        })
+    }
+
+    fn show_message(&mut self, message: &str, stdout: &mut io::Stdout) -> io::Result<()> {
+        let (width, height) = self.terminal_size;
+        let message_line = height - 2;
+
+        // Save current cursor position
+        stdout.queue(MoveTo(0, message_line))?;
+        stdout.queue(Clear(ClearType::CurrentLine))?;
+
+        stdout.queue(SetForegroundColor(Color::Yellow))?;
+        stdout.queue(style::SetBackgroundColor(Color::DarkBlue))?;
+        let display_message = if display_width(message) > width as usize {
+            // Find the maximum number of characters that fit within width
+            let mut _chars_count = 0;
+            let mut current_width = 0;
+            let mut byte_pos = 0;
+            for c in message.chars() {
+                let char_width = if c.is_ascii() { 1 } else { 2 };
+                if current_width + char_width > width as usize {
+                    break;
+                }
+                current_width += char_width;
+                _chars_count += 1;
+                byte_pos += c.len_utf8();
+            }
+            &message[..byte_pos]
+        } else {
+            &message
+        };
+        stdout.queue(Print(display_message))?;
+        stdout.queue(style::ResetColor)?;
+
+        // Restore cursor position - calculate display position
+        let start_line = if self.cursor_y >= (height - 2) as usize {
+            self.cursor_y.saturating_sub((height - 2) as usize)
+        } else {
+            0
+        };
+        let cursor_screen_y = self.cursor_y.saturating_sub(start_line) as u16;
+
+        // Calculate cursor x position based on display width
+        let line = &self.content[self.cursor_y];
+        let mut cursor_display_x = 0;
+        let mut chars_processed = 0;
+
+        for c in line.chars() {
+            if chars_processed >= self.cursor_x {
+                break;
+            }
+            cursor_display_x += if c.is_ascii() { 1 } else { 2 };
+            chars_processed += 1;
+        }
+
+        let cursor_screen_x = cursor_display_x.min(width as usize) as u16;
+        stdout.queue(MoveTo(cursor_screen_x, cursor_screen_y))?;
+
+        stdout.flush()?;
+        Ok(())
+    }
+
+    fn save(&mut self) -> io::Result<()> {
+        let content = self.content.join("\n");
+        fs::write(&self.file_path, content)?;
+        self.modified = false;
+        Ok(())
+    }
+
+    fn move_cursor(&mut self, dx: i32, dy: i32) {
+        let new_y = (self.cursor_y as i32 + dy).max(0) as usize;
+        let new_y = new_y.min(self.content.len().saturating_sub(1));
+
+        if new_y != self.cursor_y {
+            self.cursor_y = new_y;
+            // Limit cursor_x to number of characters in the line
+            self.cursor_x = self
+                .cursor_x
+                .min(self.content[self.cursor_y].chars().count());
+        } else if dx != 0 {
+            let new_x = (self.cursor_x as i32 + dx).max(0) as usize;
+            // Limit to number of characters in the line
+            self.cursor_x = new_x.min(self.content[self.cursor_y].chars().count());
+        }
+    }
+
+    fn insert_char(&mut self, c: char) {
+        if self.cursor_y >= self.content.len() {
+            self.content.push(String::new());
+        }
+
+        let line = &mut self.content[self.cursor_y];
+
+        // Convert character position to byte position
+        let byte_pos = if self.cursor_x == 0 {
+            0
+        } else {
+            line.char_indices()
+                .nth(self.cursor_x - 1)
+                .map(|(i, _)| i + line.chars().nth(self.cursor_x - 1).unwrap().len_utf8())
+                .unwrap_or(line.len())
+        };
+
+        if byte_pos <= line.len() {
+            line.insert(byte_pos, c);
+            self.cursor_x += 1;
+            self.modified = true;
+        }
+    }
+
+    fn delete_char(&mut self) {
+        if self.cursor_x > 0 && self.cursor_y < self.content.len() {
+            let line = &mut self.content[self.cursor_y];
+
+            // Convert character position to byte position for removal
+            let byte_pos = if self.cursor_x == 1 {
+                0
+            } else {
+                line.char_indices()
+                    .nth(self.cursor_x - 2)
+                    .map(|(i, _)| i + line.chars().nth(self.cursor_x - 2).unwrap().len_utf8())
+                    .unwrap_or(line.len())
+            };
+
+            // Find the character to remove
+            if let Some(c) = line.chars().nth(self.cursor_x - 1) {
+                let char_len = c.len_utf8();
+                line.drain(byte_pos..byte_pos + char_len);
+                self.cursor_x -= 1;
+                self.modified = true;
+            }
+        } else if self.cursor_x == 0 && self.cursor_y > 0 {
+            // Merge with previous line
+            let current_line = self.content.remove(self.cursor_y);
+            self.cursor_y -= 1;
+            // Set cursor to end of previous line (in characters)
+            self.cursor_x = self.content[self.cursor_y].chars().count();
+            self.content[self.cursor_y].push_str(&current_line);
+            self.modified = true;
+        }
+    }
+
+    fn new_line(&mut self) {
+        if self.cursor_y >= self.content.len() {
+            self.content.push(String::new());
+            self.cursor_y = self.content.len() - 1;
+            self.cursor_x = 0;
+        } else {
+            let line = self.content[self.cursor_y].clone();
+
+            // Convert character position to byte position for splitting
+            let byte_pos = if self.cursor_x == 0 {
+                0
+            } else {
+                line.char_indices()
+                    .nth(self.cursor_x - 1)
+                    .map(|(i, _)| i + line.chars().nth(self.cursor_x - 1).unwrap().len_utf8())
+                    .unwrap_or(line.len())
+            };
+
+            let (left, right) = line.split_at(byte_pos);
+
+            self.content[self.cursor_y] = left.to_string();
+            self.content.insert(self.cursor_y + 1, right.to_string());
+
+            self.cursor_y += 1;
+            self.cursor_x = 0;
+        }
+        self.modified = true;
+    }
+
+    fn render(&self, stdout: &mut io::Stdout) -> io::Result<()> {
+        // Clear screen
+        stdout.queue(Clear(ClearType::All))?;
+
+        // Calculate visible range
+        let (width, height) = self.terminal_size;
+        let start_line = if self.cursor_y >= (height - 2) as usize {
+            self.cursor_y.saturating_sub((height - 2) as usize)
+        } else {
+            0
+        };
+
+        let end_line = (start_line + (height - 2) as usize).min(self.content.len());
+
+        // Render content
+        for (i, line) in self.content[start_line..end_line].iter().enumerate() {
+            stdout.queue(MoveTo(0, i as u16))?;
+
+            // Truncate line if too long based on display width
+            let display_line = if display_width(line) > width as usize {
+                // Find the maximum number of characters that fit within width
+                let mut current_width = 0;
+                let mut byte_pos = 0;
+                for c in line.chars() {
+                    let char_width = if c.is_ascii() { 1 } else { 2 };
+                    if current_width + char_width > width as usize {
+                        break;
+                    }
+                    current_width += char_width;
+                    byte_pos += c.len_utf8();
+                }
+                &line[..byte_pos]
+            } else {
+                line
+            };
+
+            stdout.queue(Print(display_line))?;
+        }
+
+        // Render status bar
+        let status_line = height - 1;
+        stdout.queue(MoveTo(0, status_line))?;
+        stdout.queue(Clear(ClearType::CurrentLine))?;
+
+        let status = format!(
+            "{} - {} lines{}",
+            self.file_path.display(),
+            self.content.len(),
+            if self.modified { " *" } else { "" }
+        );
+
+        stdout.queue(SetForegroundColor(Color::White))?;
+        stdout.queue(style::SetBackgroundColor(Color::DarkBlue))?;
+        let display_status = if display_width(&status) > width as usize {
+            // Find the maximum number of characters that fit within width
+            let mut current_width = 0;
+            let mut byte_pos = 0;
+            for c in status.chars() {
+                let char_width = if c.is_ascii() { 1 } else { 2 };
+                if current_width + char_width > width as usize {
+                    break;
+                }
+                current_width += char_width;
+                byte_pos += c.len_utf8();
+            }
+            &status[..byte_pos]
+        } else {
+            &status
+        };
+        stdout.queue(Print(display_status))?;
+
+        // Reset colors
+        stdout.queue(style::ResetColor)?;
+
+        // Position cursor - calculate display position based on display width
+        let cursor_screen_y = self.cursor_y.saturating_sub(start_line) as u16;
+
+        // Calculate cursor x position based on display width of characters before cursor
+        let line = &self.content[self.cursor_y];
+        let mut cursor_display_x = 0;
+        let mut chars_processed = 0;
+
+        for c in line.chars() {
+            if chars_processed >= self.cursor_x {
+                break;
+            }
+            cursor_display_x += if c.is_ascii() { 1 } else { 2 };
+            chars_processed += 1;
+        }
+
+        let cursor_screen_x = cursor_display_x.min(width as usize) as u16;
+
+        stdout.queue(MoveTo(cursor_screen_x, cursor_screen_y))?;
+
+        stdout.flush()?;
+        Ok(())
+    }
+
+    fn run(&mut self) -> io::Result<()> {
+        let mut stdout = io::stdout();
+
+        // Setup terminal with error handling
+        if let Err(e) = enable_raw_mode() {
+            eprintln!("Failed to enable raw mode: {}", e);
+            return Err(e);
+        }
+
+        if let Err(e) = execute!(stdout, EnterAlternateScreen) {
+            disable_raw_mode().ok();
+            eprintln!("Failed to enter alternate screen: {}", e);
+            return Err(e);
+        }
+
+        // Initial render
+        if let Err(e) = self.render(&mut stdout) {
+            self.cleanup_terminal(&mut stdout)?;
+            return Err(e);
+        }
+
+        // Event loop
+        let result = loop {
+            match event::read() {
+                Ok(Event::Key(key_event)) => {
+                    if let Err(e) = self.handle_key_event(key_event, &mut stdout) {
+                        break Err(e);
+                    }
+
+                    if self.should_exit {
+                        break Ok(());
+                    }
+                }
+                Ok(Event::Resize(width, height)) => {
+                    self.terminal_size = (width, height);
+                    if let Err(e) = self.render(&mut stdout) {
+                        break Err(e);
+                    }
+                }
+                Ok(_) => {}
+                Err(e) => {
+                    break Err(e);
+                }
+            }
+        };
+
+        // Cleanup terminal
+        self.cleanup_terminal(&mut stdout)?;
+        result
+    }
+
+    fn cleanup_terminal(&self, stdout: &mut io::Stdout) -> io::Result<()> {
+        execute!(stdout, LeaveAlternateScreen)?;
+        disable_raw_mode()?;
+        Ok(())
+    }
+
+    fn handle_key_event(&mut self, key_event: KeyEvent, stdout: &mut io::Stdout) -> io::Result<()> {
+        match key_event.code {
+            KeyCode::Char('s') if key_event.modifiers.contains(KeyModifiers::CONTROL) => {
+                if let Err(e) = self.save() {
+                    eprintln!("Failed to save file: {}", e);
+                    // Continue editing even if save fails
+                } else {
+                    self.show_message("File saved successfully", stdout)?;
+                }
+            }
+            KeyCode::Char(c) => {
+                if key_event.modifiers.contains(KeyModifiers::SHIFT) {
+                    self.is_selecting = true;
+                    if self.selection_start.is_none() {
+                        self.selection_start = Some((self.cursor_x, self.cursor_y));
+                    }
+                } else {
+                    self.is_selecting = false;
+                    self.selection_start = None;
+                }
+
+                // Handle special characters
+                match c {
+                    '\n' | '\r' => self.new_line(),
+                    _ => self.insert_char(c),
+                }
+            }
+            KeyCode::Backspace => {
+                self.delete_char();
+                self.is_selecting = false;
+                self.selection_start = None;
+            }
+            KeyCode::Enter => {
+                self.new_line();
+                self.is_selecting = false;
+                self.selection_start = None;
+            }
+            KeyCode::Left => {
+                if key_event.modifiers.contains(KeyModifiers::SHIFT) {
+                    self.is_selecting = true;
+                    if self.selection_start.is_none() {
+                        self.selection_start = Some((self.cursor_x, self.cursor_y));
+                    }
+                } else {
+                    self.is_selecting = false;
+                    self.selection_start = None;
+                }
+                self.move_cursor(-1, 0);
+            }
+            KeyCode::Right => {
+                if key_event.modifiers.contains(KeyModifiers::SHIFT) {
+                    self.is_selecting = true;
+                    if self.selection_start.is_none() {
+                        self.selection_start = Some((self.cursor_x, self.cursor_y));
+                    }
+                } else {
+                    self.is_selecting = false;
+                    self.selection_start = None;
+                }
+                self.move_cursor(1, 0);
+            }
+            KeyCode::Up => {
+                if key_event.modifiers.contains(KeyModifiers::SHIFT) {
+                    self.is_selecting = true;
+                    if self.selection_start.is_none() {
+                        self.selection_start = Some((self.cursor_x, self.cursor_y));
+                    }
+                } else {
+                    self.is_selecting = false;
+                    self.selection_start = None;
+                }
+                self.move_cursor(0, -1);
+            }
+            KeyCode::Down => {
+                if key_event.modifiers.contains(KeyModifiers::SHIFT) {
+                    self.is_selecting = true;
+                    if self.selection_start.is_none() {
+                        self.selection_start = Some((self.cursor_x, self.cursor_y));
+                    }
+                } else {
+                    self.is_selecting = false;
+                    self.selection_start = None;
+                }
+                self.move_cursor(0, 1);
+            }
+            KeyCode::Esc => {
+                if self.modified {
+                    self.show_message(
+                        "Unsaved changes! Press Ctrl+S to save or Esc again to exit",
+                        stdout,
+                    )?;
+                    // Don't exit immediately, wait for second Esc
+                } else {
+                    self.should_exit = true;
+                }
+            }
+            _ => {}
+        }
+
+        if let Err(e) = self.render(stdout) {
+            eprintln!("Render error: {}", e);
+            return Err(e);
+        }
+        Ok(())
+    }
+}
+
+#[tokio::main]
+async fn main() {
+    let args = JustEnoughVcsInputer::parse();
+
+    // Check if a file argument was provided
+    let file_path = match args.file {
+        Some(path) => path,
+        None => {
+            eprintln!("Error: No file path provided");
+            std::process::exit(1);
+        }
+    };
+
+    // Perform precheck
+    match precheck(file_path) {
+        Ok(full_path) => {
+            if let Err(e) = open_editor(full_path).await {
+                eprintln!("Editor error: {}", e);
+                std::process::exit(1);
+            }
+        }
+        Err(e) => {
+            eprintln!("File error: {}", e);
+            std::process::exit(1);
+        }
+    }
+}
+
+fn precheck(file_path: PathBuf) -> Result<PathBuf, std::io::Error> {
+    // Get the current directory
+    let current_dir = env::current_dir()?;
+
+    // Build the full path
+    let full_path = if file_path.is_absolute() {
+        file_path
+    } else {
+        current_dir.join(&file_path)
+    };
+
+    // Create file if it doesn't exist
+    if !full_path.exists() {
+        // Create parent directories if needed
+        if let Some(parent) = full_path.parent() {
+            fs::create_dir_all(parent)?;
+        }
+        // Create empty file
+        fs::write(&full_path, "")?;
+    }
+
+    // Check if it's a file (or we just created it as a file)
+    if !full_path.is_file() {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::InvalidInput,
+            format!("Path is not a file: {}", full_path.display()),
+        ));
+    }
+
+    Ok(full_path)
+}
+
+async fn open_editor(file: PathBuf) -> io::Result<()> {
+    match Editor::new(file) {
+        Ok(mut editor) => {
+            let result = editor.run();
+
+            // Always try to cleanup terminal even if there was an error
+            if let Err(e) = result {
+                eprintln!("Editor error: {}", e);
+                return Err(e);
+            }
+
+            Ok(())
+        }
+        Err(e) => {
+            eprintln!("Failed to initialize editor: {}", e);
+            Err(e)
+        }
+    }
 }