Mail · Reading: a message reader, a conversation, and quoted text

MailReader opens a message under its subject: the sender's picture,
name and address, who it went to, when it came, and Reply, Reply all
when it went to more than one, and Forward, each only with a handler;
then its words and its files, each downloadable. MailThreadView lays a
conversation oldest first: the newest stands open, the others fold to
a line of the sender, their first words and when, which a press, Enter
or Space opens. QuotedText folds words quoted from before behind a
small mark; open, they sit behind a rule. Long names give way at the
label width.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/mail/quoted.rs

@@ -0,0 +1,80 @@
+use gpui::{
+    AnyElement, App, ElementId, InteractiveElement, IntoElement, ParentElement, RenderOnce, Styled,
+    Window, div,
+};
+use smallvec::SmallVec;
+
+use crate::{
+    buttons::{ButtonVariant, IconButton},
+    layout::Collapsible,
+    primitives::IconName,
+    theme::{ActiveTheme, ControlSize},
+};
+
+/// Words quoted from an earlier message, folded behind "···" until it is pressed; open, they sit behind a rule. The fold is the text's own, logged.
+#[derive(IntoElement)]
+pub struct QuotedText {
+    id: ElementId,
+    body: SmallVec<[AnyElement; 2]>,
+}
+
+impl QuotedText {
+    pub fn new(id: impl Into<ElementId>) -> Self {
+        Self {
+            id: id.into(),
+            body: SmallVec::new(),
+        }
+    }
+}
+
+impl ParentElement for QuotedText {
+    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
+        self.body.extend(elements);
+    }
+}
+
+impl RenderOnce for QuotedText {
+    fn render(self, window: &mut Window, cx: &mut App) -> impl IntoElement {
+        let open = window.use_keyed_state((self.id.clone(), "open"), cx, |_, _| false);
+        let shown = *open.read(cx);
+        let theme = cx.theme();
+        let (id, named) = (self.id.clone(), self.id.clone());
+        div()
+            .flex()
+            .flex_col()
+            .gap_2()
+            .child(
+                div().flex().child(
+                    IconButton::new((self.id.clone(), "toggle"), IconName::Ellipsis)
+                        .variant(ButtonVariant::Subtle)
+                        .size(ControlSize::Sm)
+                        .tooltip(if shown {
+                            "Hide quoted text"
+                        } else {
+                            "Show quoted text"
+                        })
+                        .on_click(move |_, _, cx| {
+                            log::info!("quoted text {id}: {}", if shown { "hide" } else { "show" });
+                            open.update(cx, |open, cx| {
+                                *open = !*open;
+                                cx.notify();
+                            })
+                        }),
+                ),
+            )
+            .child(
+                Collapsible::new((self.id.clone(), "fold"), shown).child(
+                    div()
+                        .debug_selector(move || format!("quoted {named}"))
+                        .pl_3()
+                        .border_l_2()
+                        .border_color(theme.colors.border_strong)
+                        .text_color(theme.colors.fg_muted)
+                        .flex()
+                        .flex_col()
+                        .gap_2()
+                        .children(self.body),
+                ),
+            )
+    }
+}