simple fixes

.replit

@@ -0,0 +1,20 @@
+run = "cargo run"
+hidden = ["target"]
+
+[packager]
+language = "rust"
+
+[packager.features]
+packageSearch = true
+
+[languages.rust]
+pattern = "**/*.rs"
+
+[languages.rust.languageServer]
+start = "rust-analyzer"
+
+[nix]
+channel = "stable-22_05"
+
+[gitHubImport]
+requiredFiles = [".replit", "replit.nix"]

docs/design/introduction.md

@@ -1,18 +0,0 @@
-# Introduction
-Velocity is a fast and hackable text editor made for programming. It is split into two main parts, the backend and the frontend.
-The backend, written in performant Rust, is the core of the editor and handles text manipulation, files, buffers, views, etc.
-The frontend, which can be written in any language, is the UI of the editor and handles rendering, keybinds, etc.
-
-## Editor
-The `struct Editor` is the main class of the backend. It contains the current state of the editor, the views, and the configuration.
-The `Editor` is the main way to interact with the backend, and is used by the frontend to manipulate the editor.
-
-## View
-The `struct View` defines a way of viewing a buffer, it contains information such as the current cursor locations, the scroll position, and the buffer
-
-## Buffer
-The `struct Buffer` contains the text of a file, and is the main way of interacting with the text. It contains a `Vec` of `Line`s, which contain a `Vec` of `char`s.
-Buffers can be `BufferKind::Read`, meaning the file is read-only, or `BufferKind::Write` allowing edits to be made to the file, or can be `BufferKind::Scratch` which are not associated with a file.
-
-## Line
-The `struct Line` contains a `Vec` of `char`s, and is the main way of interacting with the text. It contains a `Vec` of `Line`s, which contain a `Vec` of `char`s.

replit.nix

@@ -0,0 +1,9 @@
+{ pkgs }: {
+	deps = [
+		pkgs.rustc
+		pkgs.rustfmt
+		pkgs.cargo
+		pkgs.cargo-edit
+        pkgs.rust-analyzer
+	];
+}

src/core.rs

@@ -1,5 +0,0 @@
-pub mod editor;
-mod buffer;
-mod languages;
-mod config;
-mod files;

src/core/buffer.rs

@@ -1,61 +1,37 @@
-use std::error::Error;
-use crate::core::languages::Language;
-use crate::core::files;
+use std::path::PathBuf;
 
-enum BufferKind {
-    Read,
-    Write,
+#[derive(PartialEq)]
+pub enum BufferKind {
     Scratch,
+    Write,
+    Read,
 }
 
 impl BufferKind {
     pub fn as_str(&self) -> &str {
         match self {
-            BufferKind::Read => "read",
-            BufferKind::Write => "write",
-            BufferKind::Scratch => "*scratch*",
+            BufferKind::Scratch => "*Scratch*",
+            BufferKind::Write => "Write",
+            BufferKind::Read => "Read",
         }
     }
 }
 
-// An file that is open in the editor
-pub struct Buffer {
-    kind: BufferKind,
-    lines: Vec<String>,
-    filename: Option<String>,
-    language: Language,
+pub struct Buffer<'a> {
+    pub data: Vec<String>,
+    pub path: PathBuf,
+    pub kind: BufferKind,
+    pub name: &'a str,
 }
 
-impl Buffer {
-    pub fn new(path: Option<String>) -> Result<Self, Box<dyn Error>> {
-        // If the file exists, read it into the buffer
-        if let Some(path) = path {
-            // Read the file
-            let lines = files::read_file(path.clone())?;
-
-            // Get the language
-            let language = Language::get_language(&path);
-
-            // Check if the file is writeable
-            let kind = if std::path::Path::new(&path).is_file() {
-                BufferKind::Write
-            } else {
-                BufferKind::Read
-            };
-
-            Ok(Self {
-                kind,
-                lines,
-                filename: Some(path),
-                language,
-            })
-        } else {
-            Ok(Self {
-                kind: BufferKind::Scratch,
-                lines: Vec::new(),
-                filename: None,
-                language: Language::PlainText,
-            })
+impl<'a> Buffer<'a> {
+    pub fn new(path: PathBuf, name: &'a str, kind: BufferKind) -> Self {
+        // Return a buffer
+        Self {
+            data: vec![String::from("")],
+            path,
+            kind,
+            name,
         }
     }
-}
+}

src/core/config.rs

@@ -1,19 +0,0 @@
-const VERSION: Option<&str> = option_env!("CARGO_PKG_VERSION");
-
-pub struct Config {
-    name: &'static str,
-    version: &'static str,
-    logo: &'static str,
-    motto: &'static str,
-}
-
-impl Config {
-    pub fn new() -> Self {
-        Self {
-            name: "Velocity",
-            version: VERSION.unwrap_or("UNKNOWN"),
-            logo: "λ",
-            motto: "Hackable text editor for nerds.",
-        }
-    }
-}

src/core/editor.rs

@@ -1,22 +1,55 @@
+use std::path::PathBuf;
 use crate::core::buffer::Buffer;
-use crate::core::config::Config;
-use std::error::Error;
+use crate::core::buffer::BufferKind;
 
-pub struct Editor {
-    buffers: Vec<Buffer>,
-    config: Config,
+pub struct Config<'a> {
+    pub logo: &'a str,
+    pub friendly_name: &'a str,
 }
 
-impl Editor {
+impl<'a> Config<'a> {
     pub fn new() -> Self {
         Self {
-            buffers: Vec::new(),
-            config: Config::new(),
+            logo: "λ",
+            friendly_name: "Velocity",
         }
     }
+}
 
-    pub fn attach_file(&mut self) -> Result<(), Box<dyn Error>> {
-        self.buffers.push(Buffer::new(None)?);
-        Ok(())
+#[allow(dead_code)]
+pub enum Mode {
+    Normal,
+    Insert,
+    Select,
+    Command,
+}
+
+impl Mode {
+    pub fn as_str(&self) -> &str {
+        match self {
+            Mode::Normal => "NORMAL",
+            Mode::Insert => "INSERT",
+            Mode::Select => "SELECT",
+            Mode::Command => "COMMAND",
+        }
     }
-}
+}
+
+pub struct Editor<'a> {
+    pub config: Config<'a>,
+    pub buffer: Box<Buffer<'a>>,
+    pub cursors: Vec<i32>,
+    pub mode: Mode,
+}
+
+impl<'a> Editor<'a> {
+    pub fn new(path: PathBuf, buffer_name: &'a str) -> Self {
+        let buffer_kind = if path.to_str().unwrap().len() > 1 { BufferKind::Write } else { BufferKind::Scratch };
+        Editor {
+            config: Config::new(),
+            buffer: Box::new(Buffer::new(path, buffer_name, buffer_kind)),
+            cursors: Vec::from([0]),
+            mode: Mode::Normal,
+        }
+    }
+}

src/core/files.rs

@@ -1,9 +0,0 @@
-use std::error::Error;
-
-pub fn read_file(path: String) -> Result<Vec<String>, Box<dyn Error>> {
-    let contents: String = std::fs::read_to_string(path)?;
-    let lines: Vec<String> = contents.lines()
-        .map(|s| s.to_owned())
-        .collect();
-    Ok(lines)
-}

src/core/languages.rs

@@ -1,31 +0,0 @@
-pub enum Language {
-    Rust,
-    Python,
-    Markdown,
-    PlainText,
-}
-
-impl Language {
-    pub fn as_str(&self) -> &str {
-        match self {
-            Language::Rust => "rust",
-            Language::Python => "python",
-            Language::Markdown => "markdown",
-            Language::PlainText => "plain text",
-        }
-    }
-
-    pub fn get_language(filename: &str) -> Self {
-        let extension = std::path::Path::new(filename)
-            .extension()
-            .and_then(|s| s.to_str())
-            .unwrap_or("");
-
-        match extension {
-            "rs" => Language::Rust,
-            "py" => Language::Python,
-            "md" => Language::Markdown,
-            _ => Language::PlainText,
-        }
-    }
-}

src/core/mod.rs

@@ -0,0 +1,2 @@
+pub mod editor;
+pub mod buffer;

src/main.rs

@@ -1,6 +1,25 @@
 mod core;
+mod terminal;
+mod tui;
+use std::{env, path::PathBuf};
 
 fn main() {
-    let mut editor = core::editor::Editor::new();
-    editor.attach_file().unwrap();
-}
+    // Collect command line arguments
+    let args: Vec<String> = env::args().collect();
+
+    // Collect the file path
+    let file_path = if args.len() > 1 { PathBuf::from(&args[1]) } else { PathBuf::from("") };
+
+    // Collect the file name
+    let file_name = file_path.clone();
+    let file_name = if args.len() > 1 { file_name.file_name().unwrap().to_str().unwrap() } else { "" };
+
+    // Initalise a new editor
+    let velocity = core::editor::Editor::new(file_path, file_name);
+
+    // Initalise a screen
+    let mut screen = terminal::screen::Screen::new().unwrap();
+
+    // Begin velocity
+    tui::ui::start(&mut screen, velocity);
+}

src/terminal/mod.rs

@@ -0,0 +1 @@
+pub mod screen;

src/terminal/screen.rs

@@ -0,0 +1,154 @@
+use crossterm::cursor::{Hide, MoveTo, Show};
+use crossterm::style::Print;
+use crossterm::terminal;
+use crossterm::{execute, ErrorKind};
+use std::io::stdout;
+
+// Struct for holding coordinates
+#[derive(Copy, Clone)]
+pub struct Coords {
+    pub x: usize,
+    pub y: usize,
+}
+
+// Creating a coordinates from two values
+impl Coords {
+    pub fn from(x: usize, y: usize) -> Self {
+        Self { x, y }
+    }
+}
+
+// A cursor for writing to the terminal screen
+#[derive(Copy, Clone)]
+pub struct Cursor {
+    pub position: Coords,
+    pub hidden: bool,
+}
+
+// When a cursor is created
+impl Cursor {
+    pub fn new() -> Result<Self, ErrorKind> {
+        let mut cursor = Self {
+            position: Coords::from(0, 0),
+            hidden: true,
+        };
+        Cursor::move_to(&mut cursor, Coords::from(0, 0));
+        Cursor::hide(&mut cursor);
+        Ok(cursor)
+    }
+}
+
+// Cursor methods
+impl Cursor {
+    pub fn move_to(&mut self, position: Coords) {
+        // Set the new position of the cursor
+        self.position = position;
+
+        // Move the cursor to the desired posiition in the terminal
+        execute!(stdout(), MoveTo(position.x as u16, position.y as u16)).unwrap();
+    }
+
+    pub fn hide(&mut self) {
+        // Remember that the cursor is hidden
+        self.hidden = true;
+
+        // Hide the cursor from the terminal screen
+        execute!(stdout(), Hide).unwrap();
+    }
+
+    pub fn show(&mut self) {
+        // Remember that the cursor isn't hidden
+        self.hidden = false;
+
+        // Show the cursor to the terminal screen
+        execute!(stdout(), Show).unwrap();
+    }
+}
+
+// A struct for holding the size of the terminal
+pub struct Size {
+    pub width: usize,
+    pub height: usize,
+}
+
+// The terminal screen
+pub struct Screen {
+    pub size: Size,
+    pub cursor: Cursor,
+}
+
+// For when a new terminal screen is created
+impl Screen {
+    pub fn new() -> Result<Self, ErrorKind> {
+        // Get the size of the terminal
+        let size = terminal::size()?;
+
+        // Define a new terminal screen struct
+        let mut screen = Self {
+            size: Size {
+                width: size.0 as usize,
+                height: size.1 as usize,
+            },
+            cursor: Cursor::new().unwrap(),
+        };
+
+        // Empty the terminal screen
+        Screen::clear();
+
+        // Enter the terminal screen
+        screen.enter();
+
+        // Return a result containing the terminal
+        Ok(screen)
+    }
+}
+
+// Terminal functions and methods for managing the terminal
+impl Screen {
+    pub fn refresh(&mut self) -> Result<(), ErrorKind>{
+        // Clear the screen
+        Screen::clear();
+
+        // Update the screen dimensions
+        let size = terminal::size()?;
+        self.size.width = size.0 as usize;
+        self.size.height = size.1 as usize;
+
+        // Return Ok if was successful
+        Ok(())
+    }
+
+    pub fn enter(&mut self) {
+        // Hide the cursor
+        self.cursor.hide();
+
+        // Enter the terminal screen
+        terminal::enable_raw_mode().unwrap();
+        execute!(stdout(), terminal::EnterAlternateScreen).unwrap();
+    }
+
+    pub fn exit(&mut self) {
+        // Show the cursor
+        self.cursor.show();
+
+        // Exit the terminal screen
+        execute!(stdout(), terminal::LeaveAlternateScreen).unwrap();
+        terminal::disable_raw_mode().unwrap();
+    }
+
+    pub fn clear() {
+        // Clears the terminal screen
+        execute!(stdout(), terminal::Clear(terminal::ClearType::All)).unwrap();
+    }
+
+    pub fn write(text: &str) {
+        // Writes a line to a current cursor position
+        execute!(stdout(), Print(text)).unwrap();
+    }
+
+    pub fn write_at(&mut self, text: String, position: Coords) {
+        // Writes a line at a set of coordinates
+        self.cursor.move_to(position);
+        Screen::write(&text);
+    }
+}

src/tui/components/mod.rs

@@ -0,0 +1,2 @@
+pub mod statusbar;
+pub mod welcome;

src/tui/components/statusbar.rs

@@ -0,0 +1,63 @@
+use crossterm::style::Stylize;
+use crate::core::editor::Editor;
+use crate::terminal::screen::{Coords, Screen};
+use crate::tui::utils;
+
+pub fn draw(screen: &mut Screen, editor: &Editor) -> Result<(), ()> {
+    // Calculate where to draw the status bar
+    let status_height = screen.size.height - 2;
+
+    // Get the editor logo from the config
+    let editor_logo = &utils::with_spaces(editor.config.logo) as &str;
+    // Get the current mode into a string
+    let mode_string = &utils::with_spaces(editor.mode.as_str()) as &str;
+    // Get the current open file name
+    let file_name = &utils::with_spaces(editor.buffer.name) as &str;
+    // Get the current buffer kind
+    let buffer_kind = &utils::with_spaces(editor.buffer.kind.as_str()) as &str;
+
+    // Calculate the total length of all the status bar components
+    let total_length = editor_logo.len() + mode_string.len() + file_name.len() + buffer_kind.len() + 1;
+
+    // If the screen isn't wide enough, panic as we can't draw the status bar
+    if screen.size.width < total_length {
+        Err(())
+
+    } else {
+        // Write the editor logo
+        screen.write_at(
+            editor_logo.yellow().bold().reverse().to_string(),
+            Coords::from(0, status_height),
+        );
+
+        // Calculate where to write the current mode
+        let x = editor_logo.len() - 1;
+        // Write the current mode
+        screen.write_at(
+            mode_string.green().bold().reverse().to_string(),
+            Coords::from(x, status_height),
+        );
+
+        let x = x + mode_string.len();
+        // Draws the file name if it has a length, if not then it will draw the buffer type
+        if editor.buffer.name.len() > 0 {
+            screen.write_at(
+                file_name.magenta().bold().reverse().to_string(),
+                Coords::from(x, status_height),
+            );
+        } else {
+            screen.write_at(
+                buffer_kind.blue().bold().reverse().to_string(),
+                Coords::from(x, status_height),
+            );
+        }
+
+        let x = if editor.buffer.name.len() > 0 { x + file_name.len() } else { x + buffer_kind.len() };
+        screen.write_at(
+            " ".repeat(screen.size.width - x).reverse().to_string(),
+            Coords::from(x, status_height),
+        );
+
+        Ok(())
+    }
+}

src/tui/components/welcome.rs

@@ -0,0 +1,39 @@
+use crossterm::style::Stylize;
+use crate::core::editor::Editor;
+use crate::terminal::screen::{Coords, Screen};
+use crate::tui::utils;
+
+pub fn draw(screen: &mut Screen, editor: &Editor) {
+    // The welcome message
+    let title = format!("{} {}", editor.config.logo, editor.config.friendly_name);
+    let message: [&str; 5] = [
+        "Hackable text editor for nerds",
+        "",
+        "Type :help to open the README.md document",
+        "Type :o <file> to open a file and edit",
+        "Type :q! or <C-c> to quit the editor",
+    ];
+
+    // If the screen is big enough, we can draw
+    if screen.size.width > utils::longest_element_in_vec(message.to_vec()) && screen.size.height > message.len() + 4 {
+        // The starting y position in the centre of the screen
+        let mut y = (screen.size.height / 2) - (message.len() / 2) - 2;
+
+        // Calculate where to place the title
+        let x = utils::calc_centred_x(screen.size.width, title.len());
+
+        // Write the title to the screen
+        screen.write_at(title.yellow().to_string(), Coords::from(x, y));
+
+        for line in message {
+            // Each line has different width so requires a different x position to center it
+            let x = utils::calc_centred_x(screen.size.width, line.len()) ;
+
+            // For each line we move downwards so increment y
+            y += 1;
+
+            // Write the line to the screen at position (x, y)
+            screen.write_at(line.to_string(), Coords::from(x, y));
+        }
+    }
+}

src/tui/mod.rs

@@ -0,0 +1,3 @@
+pub mod ui;
+pub mod utils;
+mod components;

src/tui/ui.rs

@@ -0,0 +1,38 @@
+use crate::core::editor::Editor;
+use crate::core::buffer::BufferKind;
+use crate::terminal::screen::Screen;
+use crate::tui::components;
+use crossterm::event::{read, Event, KeyCode, KeyEvent, KeyModifiers};
+
+pub fn start(screen: &mut Screen, editor: Editor) {
+    // Main screen loop, runs until the program exits
+    loop {
+        // Refresh the screen
+        screen.refresh().unwrap();
+
+        // Draw the welcome message only if it is a scratch buffer
+        if editor.buffer.kind == BufferKind::Scratch {
+            components::welcome::draw(screen, &editor);
+        };
+
+        // Draw the status bar
+        components::statusbar::draw(screen, &editor).unwrap();
+
+        // Check for any key presses
+        match read().unwrap() {
+            Event::Key(KeyEvent {
+                code: KeyCode::Char('q'),
+                modifiers: KeyModifiers::CONTROL,
+                ..
+            }) => break,
+            Event::Key(KeyEvent {
+                code: KeyCode::Char('c'),
+                modifiers: KeyModifiers::CONTROL,
+                ..
+            }) => break,
+            _ => (),
+        }
+    }
+
+    screen.exit();
+}

src/tui/utils.rs

@@ -0,0 +1,14 @@
+// Surrounds a &str with spaces
+pub fn with_spaces(text: &str) -> String {
+    format!(" {} ", text)
+}
+
+// Calculates the starting x coordinate for centred text
+pub fn calc_centred_x(screen_width: usize, item_length: usize) -> usize {
+    (screen_width / 2) - (item_length / 2)
+}
+
+// Returns the longest element in a vector
+pub fn longest_element_in_vec(elements: Vec<&str>) -> usize {
+    elements.iter().max_by_key(|x: &&&str| x.len()).unwrap().len()
+}