Group chat token counts by thousands

src/app/view/chat.rs

@@ -427,9 +427,9 @@ fn generation_summary(stats: crate::app::generation::GenerationStats) -> Element
             text(format!(
                 "{} · {} input · {} cached · {} output",
                 format_duration(stats.duration_ms as f64 / 1_000.0),
-                stats.input_tokens,
-                stats.cached_tokens,
-                stats.output_tokens,
+                format_token_count(stats.input_tokens),
+                format_token_count(stats.cached_tokens),
+                format_token_count(stats.output_tokens),
             ))
             .size(11)
             .color(muted_text()),
@@ -441,6 +441,18 @@ fn generation_summary(stats: crate::app::generation::GenerationStats) -> Element
     .into()
 }
 
+fn format_token_count(value: u32) -> String {
+    let digits = value.to_string();
+    let mut output = String::with_capacity(digits.len() + digits.len() / 3);
+    for (index, digit) in digits.chars().enumerate() {
+        if index > 0 && (digits.len() - index).is_multiple_of(3) {
+            output.push(',');
+        }
+        output.push(digit);
+    }
+    output
+}
+
 fn tool_cards(cards: Vec<crate::agent::ToolCard>) -> Element<'static, Message> {
     let mut rows = column![].spacing(0);
     for (index, card) in cards.into_iter().enumerate() {
@@ -517,3 +529,16 @@ fn tool_cards(cards: Vec<crate::agent::ToolCard>) -> Element<'static, Message> {
         .style(preference_group_style)
         .into()
 }
+
+#[cfg(test)]
+mod tests {
+    use super::format_token_count;
+
+    #[test]
+    fn chat_divider_groups_token_counts_by_thousands() {
+        assert_eq!(format_token_count(0), "0");
+        assert_eq!(format_token_count(999), "999");
+        assert_eq!(format_token_count(1_000), "1,000");
+        assert_eq!(format_token_count(12_345_678), "12,345,678");
+    }
+}