chat panel: Add timestamp in tooltip to edited message (#10444)

Hovering over the `(edited)` text inside a message displays a tooltip
with the timestamp of when the message was last edited:


![image](https://github.com/zed-industries/zed/assets/53836821/be6d68c2-7447-42bc-bd5e-7a9053b3c980)

---

Also removed the `fade_out` style for the `(edited)` text, as this was
causing tooltips to fade out as well:


![image](https://github.com/zed-industries/zed/assets/53836821/91d3cf6a-db58-4e1d-b257-663b2ce1aca4)

Instead it uses `theme().text_muted` now.


Release Notes:

- Hovering over an edited message now displays a tooltip revealing the
timestamp of the last edit.

crates/collab_ui/src/chat_panel.rs

@@ -531,6 +531,8 @@ impl ChatPanel {
                                 &self.languages,
                                 self.client.id(),
                                 &message,
+                                self.local_timezone,
+                                cx,
                             )
                         });
                         el.child(
@@ -744,6 +746,8 @@ impl ChatPanel {
         language_registry: &Arc<LanguageRegistry>,
         current_user_id: u64,
         message: &channel::ChannelMessage,
+        local_timezone: UtcOffset,
+        cx: &AppContext,
     ) -> RichText {
         let mentions = message
             .mentions
@@ -754,24 +758,39 @@ impl ChatPanel {
             })
             .collect::<Vec<_>>();
 
-        const MESSAGE_UPDATED: &str = " (edited)";
+        const MESSAGE_EDITED: &str = " (edited)";
 
         let mut body = message.body.clone();
 
         if message.edited_at.is_some() {
-            body.push_str(MESSAGE_UPDATED);
+            body.push_str(MESSAGE_EDITED);
         }
 
         let mut rich_text = rich_text::render_rich_text(body, &mentions, language_registry, None);
 
         if message.edited_at.is_some() {
+            let range = (rich_text.text.len() - MESSAGE_EDITED.len())..rich_text.text.len();
             rich_text.highlights.push((
-                (rich_text.text.len() - MESSAGE_UPDATED.len())..rich_text.text.len(),
+                range.clone(),
                 Highlight::Highlight(HighlightStyle {
-                    fade_out: Some(0.8),
+                    color: Some(cx.theme().colors().text_muted),
                     ..Default::default()
                 }),
             ));
+
+            if let Some(edit_timestamp) = message.edited_at {
+                let edit_timestamp_text = time_format::format_localized_timestamp(
+                    edit_timestamp,
+                    OffsetDateTime::now_utc(),
+                    local_timezone,
+                    time_format::TimestampFormat::Absolute,
+                );
+
+                rich_text.custom_ranges.push(range);
+                rich_text.set_tooltip_builder_for_custom_ranges(move |_, _, cx| {
+                    Some(Tooltip::text(edit_timestamp_text.clone(), cx))
+                })
+            }
         }
         rich_text
     }
@@ -1176,7 +1195,13 @@ mod tests {
             edited_at: None,
         };
 
-        let message = ChatPanel::render_markdown_with_mentions(&language_registry, 102, &message);
+        let message = ChatPanel::render_markdown_with_mentions(
+            &language_registry,
+            102,
+            &message,
+            UtcOffset::UTC,
+            cx,
+        );
 
         // Note that the "'" was replaced with ’ due to smart punctuation.
         let (body, ranges) = marked_text_ranges("«hi», «@abc», let’s «call» «@fgh»", false);
@@ -1224,7 +1249,13 @@ mod tests {
             edited_at: None,
         };
 
-        let message = ChatPanel::render_markdown_with_mentions(&language_registry, 102, &message);
+        let message = ChatPanel::render_markdown_with_mentions(
+            &language_registry,
+            102,
+            &message,
+            UtcOffset::UTC,
+            cx,
+        );
 
         // Note that the "'" was replaced with ’ due to smart punctuation.
         let (body, ranges) =
@@ -1265,7 +1296,13 @@ mod tests {
             edited_at: None,
         };
 
-        let message = ChatPanel::render_markdown_with_mentions(&language_registry, 102, &message);
+        let message = ChatPanel::render_markdown_with_mentions(
+            &language_registry,
+            102,
+            &message,
+            UtcOffset::UTC,
+            cx,
+        );
 
         // Note that the "'" was replaced with ’ due to smart punctuation.
         let (body, ranges) = marked_text_ranges(

crates/rich_text/src/rich_text.rs

@@ -1,7 +1,7 @@
 use futures::FutureExt;
 use gpui::{
-    AnyElement, ElementId, FontStyle, FontWeight, HighlightStyle, InteractiveText, IntoElement,
-    SharedString, StrikethroughStyle, StyledText, UnderlineStyle, WindowContext,
+    AnyElement, AnyView, ElementId, FontStyle, FontWeight, HighlightStyle, InteractiveText,
+    IntoElement, SharedString, StrikethroughStyle, StyledText, UnderlineStyle, WindowContext,
 };
 use language::{HighlightId, Language, LanguageRegistry};
 use std::{ops::Range, sync::Arc};
@@ -31,12 +31,16 @@ impl From<HighlightId> for Highlight {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Clone)]
 pub struct RichText {
     pub text: SharedString,
     pub highlights: Vec<(Range<usize>, Highlight)>,
     pub link_ranges: Vec<Range<usize>>,
     pub link_urls: Arc<[String]>,
+
+    pub custom_ranges: Vec<Range<usize>>,
+    custom_ranges_tooltip_fn:
+        Option<Arc<dyn Fn(usize, Range<usize>, &mut WindowContext) -> Option<AnyView>>>,
 }
 
 /// Allows one to specify extra links to the rendered markdown, which can be used
@@ -48,7 +52,14 @@ pub struct Mention {
 }
 
 impl RichText {
-    pub fn element(&self, id: ElementId, cx: &WindowContext) -> AnyElement {
+    pub fn set_tooltip_builder_for_custom_ranges(
+        &mut self,
+        f: impl Fn(usize, Range<usize>, &mut WindowContext) -> Option<AnyView> + 'static,
+    ) {
+        self.custom_ranges_tooltip_fn = Some(Arc::new(f));
+    }
+
+    pub fn element(&self, id: ElementId, cx: &mut WindowContext) -> AnyElement {
         let theme = cx.theme();
         let code_background = theme.colors().surface_background;
 
@@ -111,12 +122,21 @@ impl RichText {
         .tooltip({
             let link_ranges = self.link_ranges.clone();
             let link_urls = self.link_urls.clone();
+            let custom_tooltip_ranges = self.custom_ranges.clone();
+            let custom_tooltip_fn = self.custom_ranges_tooltip_fn.clone();
             move |idx, cx| {
                 for (ix, range) in link_ranges.iter().enumerate() {
                     if range.contains(&idx) {
                         return Some(LinkPreview::new(&link_urls[ix], cx));
                     }
                 }
+                for range in &custom_tooltip_ranges {
+                    if range.contains(&idx) {
+                        if let Some(f) = &custom_tooltip_fn {
+                            return f(idx, range.clone(), cx);
+                        }
+                    }
+                }
                 None
             }
         })
@@ -354,6 +374,8 @@ pub fn render_rich_text(
         link_urls: link_urls.into(),
         link_ranges,
         highlights,
+        custom_ranges: Vec::new(),
+        custom_ranges_tooltip_fn: None,
     }
 }