3 files changed, 98 insertions, 2 deletions

diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index faede58c..44f331ff 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -3,7 +3,7 @@ use crate::{
     compositor::{Component, Compositor, Context, EventResult},
     key,
     keymap::{self, Keymaps},
-    ui::Completion,
+    ui::{Completion, ProgressSpinners},
 };
 
 use helix_core::{
@@ -11,6 +11,7 @@ use helix_core::{
     syntax::{self, HighlightEvent},
     LineEnding, Position, Range,
 };
+use helix_lsp::LspProgressMap;
 use helix_view::{document::Mode, Document, Editor, Theme, View};
 use std::borrow::Cow;
 
@@ -31,6 +32,7 @@ pub struct EditorView {
     on_next_key: Option<Box<dyn FnOnce(&mut commands::Context, KeyEvent)>>,
     last_insert: (commands::Command, Vec<KeyEvent>),
     completion: Option<Completion>,
+    spinners: ProgressSpinners,
 }
 
 const OFFSET: u16 = 7; // 1 diagnostic + 5 linenr + 1 gutter
@@ -48,9 +50,15 @@ impl EditorView {
             on_next_key: None,
             last_insert: (commands::Command::normal_mode, Vec::new()),
             completion: None,
+            spinners: ProgressSpinners::default(),
         }
     }
 
+    pub fn spinners_mut(&mut self) -> &mut ProgressSpinners {
+        &mut self.spinners
+    }
+
+    #[allow(clippy::too_many_arguments)]
     pub fn render_view(
         &self,
         doc: &Document,
@@ -458,6 +466,7 @@ impl EditorView {
         );
     }
 
+    #[allow(clippy::too_many_arguments)]
     pub fn render_statusline(
         &self,
         doc: &Document,
@@ -476,6 +485,15 @@ impl EditorView {
             Mode::Select => "SEL",
             Mode::Normal => "NOR",
         };
+        let progress = doc
+            .language_server()
+            .and_then(|srv| {
+                self.spinners
+                    .get(srv.id())
+                    .and_then(|spinner| spinner.frame())
+            })
+            .unwrap_or("");
+
         let style = if is_focused {
             theme.get("ui.statusline")
         } else {
@@ -486,13 +504,14 @@ impl EditorView {
         if is_focused {
             surface.set_string(viewport.x + 1, viewport.y, mode, style);
         }
+        surface.set_string(viewport.x + 5, viewport.y, progress, style);
 
         if let Some(path) = doc.relative_path() {
             let path = path.to_string_lossy();
 
             let title = format!("{}{}", path, if doc.is_modified() { "[+]" } else { "" });
             surface.set_stringn(
-                viewport.x + 6,
+                viewport.x + 8,
                 viewport.y,
                 title,
                 viewport.width.saturating_sub(6) as usize,
diff --git a/helix-term/src/ui/mod.rs b/helix-term/src/ui/mod.rs
index e0177b7c..c062bffe 100644
--- a/helix-term/src/ui/mod.rs
+++ b/helix-term/src/ui/mod.rs
@@ -5,6 +5,7 @@ mod menu;
 mod picker;
 mod popup;
 mod prompt;
+mod spinner;
 mod text;
 
 pub use completion::Completion;
@@ -14,6 +15,7 @@ pub use menu::Menu;
 pub use picker::Picker;
 pub use popup::Popup;
 pub use prompt::{Prompt, PromptEvent};
+pub use spinner::{ProgressSpinners, Spinner};
 pub use text::Text;
 
 pub use tui::layout::Rect;
diff --git a/helix-term/src/ui/spinner.rs b/helix-term/src/ui/spinner.rs
new file mode 100644
index 00000000..e8a43b48
--- /dev/null
+++ b/helix-term/src/ui/spinner.rs
@@ -0,0 +1,75 @@
+use std::{collections::HashMap, time::SystemTime};
+
+#[derive(Default, Debug)]
+pub struct ProgressSpinners {
+    inner: HashMap<usize, Spinner>,
+}
+
+impl ProgressSpinners {
+    pub fn get(&self, id: usize) -> Option<&Spinner> {
+        self.inner.get(&id)
+    }
+
+    pub fn get_or_create(&mut self, id: usize) -> &mut Spinner {
+        self.inner.entry(id).or_insert_with(Spinner::default)
+    }
+}
+
+impl Default for Spinner {
+    fn default() -> Self {
+        Self::dots(80)
+    }
+}
+
+#[derive(Debug)]
+pub struct Spinner {
+    frames: Vec<&'static str>,
+    count: usize,
+    start: Option<SystemTime>,
+    interval: u64,
+}
+
+impl Spinner {
+    /// Creates a new spinner with `frames` and `interval`.
+    /// Expects the frames count and interval to be greater than 0.
+    pub fn new(frames: Vec<&'static str>, interval: u64) -> Self {
+        let count = frames.len();
+        assert!(count > 0);
+        assert!(interval > 0);
+
+        Self {
+            frames,
+            count,
+            interval,
+            start: None,
+        }
+    }
+
+    pub fn dots(interval: u64) -> Self {
+        Self::new(vec!["⣾", "⣽", "⣻", "⢿", "⡿", "⣟", "⣯", "⣷"], interval)
+    }
+
+    pub fn start(&mut self) {
+        self.start = Some(SystemTime::now());
+    }
+
+    pub fn frame(&self) -> Option<&str> {
+        let idx = (self
+            .start
+            .map(|time| SystemTime::now().duration_since(time))?
+            .ok()?
+            .as_millis()
+            / self.interval as u128) as usize
+            % self.count;
+
+        self.frames.get(idx).copied()
+    }
+
+    pub fn stop(&mut self) {
+        self.start = None;
+    }
+
+    pub fn is_stopped(&self) -> bool {
+        self.start.is_none()
+    }
+}