Add a `Spinner`

1 files changed, 75 insertions, 0 deletions

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()
+    }
+}