Merge pull request #4 from alt-art/load-spinner

Spinner to give feedback on load

Cargo.toml

@@ -19,4 +19,6 @@ reqwest = {version = "0.11"}
 serde = {version = "1", features = ["derive"]}
 serde_json = {version = "1"}
 tokio = {version = "1", features = ["full"]}
-human-panic = {version = "1.0"}
+human-panic = {version = "1.0"}
+crossterm = "0.27.0"
+futures = "0.3.28"

src/main.rs

@@ -1,10 +1,13 @@
 #![warn(clippy::all, clippy::pedantic, clippy::nursery, clippy::cargo)]
-#![allow(clippy::multiple_crate_versions)]
+#![allow(clippy::multiple_crate_versions, clippy::module_name_repetitions)]
 
 use human_panic::setup_panic;
 
 mod cli;
 mod web;
+mod spinner;
+
+use spinner::wrap_spinner;
 
 #[tokio::main]
 async fn main() {
@@ -16,7 +19,7 @@ async fn main() {
     } else if cmd == "-v" || cmd == "--version" {
         cli::print_version();
     } else {
-        let (url, lyrics) = web::get_lyrics(input.as_str()).await;
+        let (url, lyrics) = wrap_spinner(web::get_lyrics(input.as_str())).await.unwrap();
         bunt::println!("\n--------------------------");
         bunt::println!("{$yellow}{}{/$}", input);
         bunt::println!("--------------------------");

src/spinner.rs

@@ -0,0 +1,77 @@
+use crossterm::style::Print;
+use crossterm::terminal::ClearType;
+use crossterm::{cursor, execute, terminal};
+use futures::Future;
+use std::io::stderr;
+use tokio::sync::oneshot::{self, error::TryRecvError, Receiver, Sender};
+use tokio::task::JoinHandle;
+use tokio::time;
+
+const LOADING_SPINNER_DELAY: u64 = 40;
+const LOADING_SPINNER_DOTS: [&str; 56] = [
+    "⢀⠀", "⡀⠀", "⠄⠀", "⢂⠀", "⡂⠀", "⠅⠀", "⢃⠀", "⡃⠀", "⠍⠀", "⢋⠀", "⡋⠀", "⠍⠁", "⢋⠁", "⡋⠁", "⠍⠉", "⠋⠉",
+    "⠋⠉", "⠉⠙", "⠉⠙", "⠉⠩", "⠈⢙", "⠈⡙", "⢈⠩", "⡀⢙", "⠄⡙", "⢂⠩", "⡂⢘", "⠅⡘", "⢃⠨", "⡃⢐", "⠍⡐", "⢋⠠",
+    "⡋⢀", "⠍⡁", "⢋⠁", "⡋⠁", "⠍⠉", "⠋⠉", "⠋⠉", "⠉⠙", "⠉⠙", "⠉⠩", "⠈⢙", "⠈⡙", "⠈⠩", "⠀⢙", "⠀⡙", "⠀⠩",
+    "⠀⢘", "⠀⡘", "⠀⠨", "⠀⢐", "⠀⡐", "⠀⠠", "⠀⢀", "⠀⡀",
+];
+
+type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + Sync>>;
+
+pub struct Spinner {
+    tx: Sender<()>,
+    handle: JoinHandle<Result<()>>,
+}
+
+impl Spinner {
+    pub fn new() -> Self {
+        let (tx, rx) = oneshot::channel();
+        let handle = tokio::spawn(Self::spin(rx));
+        Self { tx, handle }
+    }
+
+    pub async fn stop(self) -> Result<()> {
+        self.tx.send(()).ok();
+        self.handle.await??;
+        Ok(())
+    }
+
+    async fn spin(mut rx: Receiver<()>) -> Result<()> {
+        let mut dots = LOADING_SPINNER_DOTS.iter().cycle();
+        terminal::enable_raw_mode()?;
+        execute!(
+            stderr(),
+            cursor::SavePosition,
+            cursor::Hide,
+            terminal::Clear(ClearType::CurrentLine),
+        )?;
+        let mut interval = time::interval(time::Duration::from_millis(LOADING_SPINNER_DELAY));
+        while rx.try_recv() == Err(TryRecvError::Empty) {
+            execute!(
+                stderr(),
+                cursor::MoveToColumn(1),
+                terminal::Clear(ClearType::CurrentLine),
+                Print(dots.next().unwrap())
+            )?;
+            interval.tick().await;
+        }
+        execute!(
+            stderr(),
+            terminal::Clear(ClearType::CurrentLine),
+            cursor::RestorePosition,
+            cursor::Show,
+        )?;
+        terminal::disable_raw_mode()?;
+        Ok(())
+    }
+}
+
+pub async fn wrap_spinner<F>(future: F) -> Result<F::Output>
+where
+    F: Future + Send,
+    F::Output: Send,
+{
+    let spinner = Spinner::new();
+    let result = future.await;
+    spinner.stop().await?;
+    Ok(result)
+}