Can't use Ratatui for the watch mode :(

src/main.rs

@@ -1,11 +1,11 @@
-use crate::consts::{DEFAULT_OUT, WELCOME};
+use crate::consts::WELCOME;
 use crate::embedded::{WriteStrategy, EMBEDDED_FILES};
 use crate::exercise::{Exercise, ExerciseList};
 use crate::run::run;
-use crate::tui::tui;
 use crate::verify::verify;
 use anyhow::{bail, Context, Result};
 use clap::{Parser, Subcommand};
+use state::State;
 use std::io::Write;
 use std::path::Path;
 use std::process::exit;
@@ -17,8 +17,8 @@ mod exercise;
 mod init;
 mod run;
 mod state;
-mod tui;
 mod verify;
+mod watch;
 
 /// Rustlings is a collection of small exercises to get you used to writing and reading Rust code
 #[derive(Parser)]
@@ -75,10 +75,6 @@ enum Subcommands {
 fn main() -> Result<()> {
     let args = Args::parse();
 
-    if args.command.is_none() {
-        println!("\n{WELCOME}\n");
-    }
-
     which::which("cargo").context(
         "Failed to find `cargo`.
 Did you already install Rust?
@@ -97,16 +93,20 @@ Then run `rustlings` for further instructions on getting started."
         return Ok(());
     } else if !Path::new("exercises").is_dir() {
         println!(
-            "\nThe `exercises` directory wasn't found in the current directory.
+            "
+{WELCOME}
+
+The `exercises` directory wasn't found in the current directory.
 If you are just starting with Rustlings, run the command `rustlings init` to initialize it."
         );
         exit(1);
     }
 
+    let state = State::read_or_default(&exercises);
+
     match args.command {
         None | Some(Subcommands::Watch) => {
-            println!("{DEFAULT_OUT}\n");
-            tui(&exercises)?;
+            watch::watch(&state, &exercises)?;
         }
         // `Init` is handled above.
         Some(Subcommands::Init) => (),
@@ -199,7 +199,7 @@ If you are just starting with Rustlings, run the command `rustlings init` to ini
             let exercise = find_exercise(&name, &exercises)?;
             println!("{}", exercise.hint);
         }
-        Some(Subcommands::Verify) => match verify(&exercises, (0, exercises.len()))? {
+        Some(Subcommands::Verify) => match verify(&exercises, 0)? {
             VerifyState::AllExercisesDone => println!("All exercises done!"),
             VerifyState::Failed(exercise) => bail!("Exercise {exercise} failed"),
         },

src/tui.rs

@@ -1,92 +0,0 @@
-use anyhow::Result;
-use crossterm::{
-    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
-    ExecutableCommand,
-};
-use notify_debouncer_mini::{new_debouncer, notify::RecursiveMode, DebouncedEventKind};
-use ratatui::{backend::CrosstermBackend, Terminal};
-use std::{
-    io::stdout,
-    path::Path,
-    sync::mpsc::{channel, RecvTimeoutError},
-    time::Duration,
-};
-
-use crate::{
-    exercise::Exercise,
-    verify::{verify, VerifyState},
-};
-
-fn watch(exercises: &[Exercise]) -> Result<()> {
-    let (tx, rx) = channel();
-
-    let mut debouncer = new_debouncer(Duration::from_secs(1), tx)?;
-    debouncer
-        .watcher()
-        .watch(Path::new("exercises"), RecursiveMode::Recursive)?;
-
-    let mut failed_exercise_hint = match verify(exercises, (0, exercises.len()))? {
-        VerifyState::AllExercisesDone => return Ok(()),
-        VerifyState::Failed(exercise) => Some(&exercise.hint),
-    };
-
-    let mut pending_exercises = Vec::with_capacity(exercises.len());
-    loop {
-        match rx.recv_timeout(Duration::from_secs(1)) {
-            Ok(event) => match event {
-                Ok(events) => {
-                    for event in events {
-                        if event.kind == DebouncedEventKind::Any
-                            && event.path.extension().is_some_and(|ext| ext == "rs")
-                        {
-                            pending_exercises.extend(exercises.iter().filter(|exercise| {
-                                !exercise.looks_done().unwrap_or(false)
-                                    || event.path.ends_with(&exercise.path)
-                            }));
-                            let num_done = exercises.len() - pending_exercises.len();
-
-                            match verify(
-                                pending_exercises.iter().copied(),
-                                (num_done, exercises.len()),
-                            )? {
-                                VerifyState::AllExercisesDone => return Ok(()),
-                                VerifyState::Failed(exercise) => {
-                                    failed_exercise_hint = Some(&exercise.hint);
-                                }
-                            }
-
-                            pending_exercises.clear();
-                        }
-                    }
-                }
-                Err(e) => println!("watch error: {e:?}"),
-            },
-            Err(RecvTimeoutError::Timeout) => {
-                // the timeout expired, just check the `should_quit` variable below then loop again
-            }
-            Err(e) => println!("watch error: {e:?}"),
-        }
-
-        // TODO: Check if we need to exit
-    }
-}
-
-pub fn tui(exercises: &[Exercise]) -> Result<()> {
-    let mut stdout = stdout().lock();
-    stdout.execute(EnterAlternateScreen)?;
-    enable_raw_mode()?;
-    let mut terminal = Terminal::new(CrosstermBackend::new(&mut stdout))?;
-    terminal.clear()?;
-
-    watch(exercises)?;
-
-    drop(terminal);
-    stdout.execute(LeaveAlternateScreen)?;
-    disable_raw_mode()?;
-
-    // TODO
-    println!("We hope you're enjoying learning about Rust!");
-    println!("If you want to continue working on the exercises at a later point, you can simply run `rustlings watch` again");
-
-    Ok(())
-}

src/watch.rs

@@ -0,0 +1,240 @@
+use anyhow::Result;
+use crossterm::{
+    style::{Attribute, ContentStyle, Stylize},
+    terminal::{Clear, ClearType},
+    ExecutableCommand,
+};
+use notify_debouncer_mini::{
+    new_debouncer, notify::RecursiveMode, DebounceEventResult, DebouncedEventKind,
+};
+use std::{
+    fmt::Write as _,
+    io::{self, BufRead, StdoutLock, Write},
+    path::Path,
+    sync::mpsc::{channel, sync_channel, Receiver},
+    thread,
+    time::Duration,
+};
+
+use crate::{
+    exercise::{self, Exercise},
+    state::State,
+};
+
+enum Event {
+    Hint,
+    Clear,
+    Quit,
+}
+
+struct WatchState<'a> {
+    writer: StdoutLock<'a>,
+    rx: Receiver<DebounceEventResult>,
+    exercises: &'a [Exercise],
+    exercise: &'a Exercise,
+    current_exercise_ind: usize,
+    stdout: Option<Vec<u8>>,
+    stderr: Option<Vec<u8>>,
+    message: Option<String>,
+    prompt: Vec<u8>,
+}
+
+impl<'a> WatchState<'a> {
+    fn run_exercise(&mut self) -> Result<bool> {
+        let output = self.exercise.run()?;
+
+        if !output.status.success() {
+            self.stdout = Some(output.stdout);
+            self.stderr = Some(output.stderr);
+            return Ok(false);
+        }
+
+        if let exercise::State::Pending(context) = self.exercise.state()? {
+            let mut message = format!(
+                "
+You can keep working on this exercise or jump into the next one by removing the {} comment:
+
+",
+                "`I AM NOT DONE`".bold(),
+            );
+
+            for context_line in context {
+                let formatted_line = if context_line.important {
+                    context_line.line.bold()
+                } else {
+                    context_line.line.stylize()
+                };
+
+                writeln!(
+                    message,
+                    "{:>2} {}  {}",
+                    ContentStyle {
+                        foreground_color: Some(crossterm::style::Color::Blue),
+                        background_color: None,
+                        underline_color: None,
+                        attributes: Attribute::Bold.into()
+                    }
+                    .apply(context_line.number),
+                    "|".blue(),
+                    formatted_line,
+                )?;
+            }
+
+            self.stdout = Some(output.stdout);
+            self.message = Some(message);
+            return Ok(false);
+        }
+
+        Ok(true)
+    }
+
+    fn try_recv_event(&mut self) -> Result<()> {
+        let Ok(events) = self.rx.recv_timeout(Duration::from_millis(100)) else {
+            return Ok(());
+        };
+
+        if let Some(current_exercise_ind) = events?
+            .iter()
+            .filter_map(|event| {
+                if event.kind != DebouncedEventKind::Any
+                    || !event.path.extension().is_some_and(|ext| ext == "rs")
+                {
+                    return None;
+                }
+
+                self.exercises
+                    .iter()
+                    .position(|exercise| event.path.ends_with(&exercise.path))
+            })
+            .min()
+        {
+            self.current_exercise_ind = current_exercise_ind;
+        } else {
+            return Ok(());
+        };
+
+        while self.current_exercise_ind < self.exercises.len() {
+            self.exercise = &self.exercises[self.current_exercise_ind];
+            if !self.run_exercise()? {
+                break;
+            }
+
+            self.current_exercise_ind += 1;
+        }
+
+        Ok(())
+    }
+
+    fn prompt(&mut self) -> io::Result<()> {
+        self.writer.write_all(&self.prompt)?;
+        self.writer.flush()
+    }
+
+    fn render(&mut self) -> Result<()> {
+        self.writer.execute(Clear(ClearType::All))?;
+
+        if let Some(stdout) = &self.stdout {
+            self.writer.write_all(stdout)?;
+        }
+
+        if let Some(stderr) = &self.stderr {
+            self.writer.write_all(stderr)?;
+        }
+
+        if let Some(message) = &self.message {
+            self.writer.write_all(message.as_bytes())?;
+        }
+
+        self.prompt()?;
+
+        Ok(())
+    }
+}
+
+pub fn watch(state: &State, exercises: &[Exercise]) -> Result<()> {
+    let (tx, rx) = channel();
+    let mut debouncer = new_debouncer(Duration::from_secs(1), tx)?;
+    debouncer
+        .watcher()
+        .watch(Path::new("exercises"), RecursiveMode::Recursive)?;
+
+    let current_exercise_ind = state.progress.iter().position(|done| *done).unwrap_or(0);
+
+    let exercise = &exercises[current_exercise_ind];
+
+    let writer = io::stdout().lock();
+
+    let mut watch_state = WatchState {
+        writer,
+        rx,
+        exercises,
+        exercise,
+        current_exercise_ind,
+        stdout: None,
+        stderr: None,
+        message: None,
+        prompt: format!(
+            "\n\n{}int/{}lear/{}uit? ",
+            "h".bold(),
+            "c".bold(),
+            "q".bold()
+        )
+        .into_bytes(),
+    };
+
+    watch_state.run_exercise()?;
+    watch_state.render()?;
+
+    let (tx, rx) = sync_channel(0);
+    thread::spawn(move || {
+        let mut stdin = io::stdin().lock();
+        let mut stdin_buf = String::with_capacity(8);
+
+        loop {
+            stdin.read_line(&mut stdin_buf).unwrap();
+
+            let event = match stdin_buf.trim() {
+                "h" | "hint" => Some(Event::Hint),
+                "c" | "clear" => Some(Event::Clear),
+                "q" | "quit" => Some(Event::Quit),
+                _ => None,
+            };
+
+            stdin_buf.clear();
+
+            if tx.send(event).is_err() {
+                break;
+            };
+        }
+    });
+
+    loop {
+        watch_state.try_recv_event()?;
+
+        if let Ok(event) = rx.try_recv() {
+            match event {
+                Some(Event::Hint) => {
+                    watch_state
+                        .writer
+                        .write_all(watch_state.exercise.hint.as_bytes())?;
+                    watch_state.prompt()?;
+                }
+                Some(Event::Clear) => {
+                    watch_state.render()?;
+                }
+                Some(Event::Quit) => break,
+                None => {
+                    watch_state.writer.write_all(b"Invalid command")?;
+                    watch_state.prompt()?;
+                }
+            }
+        }
+    }
+
+    watch_state.writer.write_all(b"
+We hope you're enjoying learning Rust!
+If you want to continue working on the exercises at a later point, you can simply run `rustlings` again.
+")?;
+
+    Ok(())
+}