debugger: Tidy up dropdown menus (#30679)

Before
![CleanShot 2025-05-14 at 13 22
44@2x](https://github.com/user-attachments/assets/c6c06c5c-571d-4913-a691-161f44bba27c)

After
![CleanShot 2025-05-14 at 13 22
17@2x](https://github.com/user-attachments/assets/0a25a053-81a3-4b96-8963-4b770b1e5b45)

Release Notes:

- N/A

crates/debugger_ui/src/dropdown_menus.rs

@@ -0,0 +1,186 @@
+use gpui::Entity;
+use project::debugger::session::{ThreadId, ThreadStatus};
+use ui::{ContextMenu, DropdownMenu, DropdownStyle, Indicator, prelude::*};
+
+use crate::{
+    debugger_panel::DebugPanel,
+    session::{DebugSession, running::RunningState},
+};
+
+impl DebugPanel {
+    fn dropdown_label(label: impl Into<SharedString>) -> Label {
+        Label::new(label).size(LabelSize::Small)
+    }
+
+    pub fn render_session_menu(
+        &mut self,
+        active_session: Option<Entity<DebugSession>>,
+        running_state: Option<Entity<RunningState>>,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) -> Option<impl IntoElement> {
+        if let Some(running_state) = running_state {
+            let sessions = self.sessions().clone();
+            let weak = cx.weak_entity();
+            let running_state = running_state.read(cx);
+            let label = if let Some(active_session) = active_session {
+                active_session.read(cx).session(cx).read(cx).label()
+            } else {
+                SharedString::new_static("Unknown Session")
+            };
+
+            let is_terminated = running_state.session().read(cx).is_terminated();
+            let session_state_indicator = {
+                if is_terminated {
+                    Some(Indicator::dot().color(Color::Error))
+                } else {
+                    match running_state.thread_status(cx).unwrap_or_default() {
+                        project::debugger::session::ThreadStatus::Stopped => {
+                            Some(Indicator::dot().color(Color::Conflict))
+                        }
+                        _ => Some(Indicator::dot().color(Color::Success)),
+                    }
+                }
+            };
+
+            let trigger = h_flex()
+                .gap_2()
+                .when_some(session_state_indicator, |this, indicator| {
+                    this.child(indicator)
+                })
+                .justify_between()
+                .child(
+                    DebugPanel::dropdown_label(label)
+                        .when(is_terminated, |this| this.strikethrough()),
+                )
+                .into_any_element();
+
+            Some(
+                DropdownMenu::new_with_element(
+                    "debugger-session-list",
+                    trigger,
+                    ContextMenu::build(window, cx, move |mut this, _, cx| {
+                        let context_menu = cx.weak_entity();
+                        for session in sessions.into_iter() {
+                            let weak_session = session.downgrade();
+                            let weak_session_id = weak_session.entity_id();
+
+                            this = this.custom_entry(
+                                {
+                                    let weak = weak.clone();
+                                    let context_menu = context_menu.clone();
+                                    move |_, cx| {
+                                        weak_session
+                                            .read_with(cx, |session, cx| {
+                                                let context_menu = context_menu.clone();
+                                                let id: SharedString = format!(
+                                                    "debug-session-{}",
+                                                    session.session_id(cx).0
+                                                )
+                                                .into();
+                                                h_flex()
+                                                    .w_full()
+                                                    .group(id.clone())
+                                                    .justify_between()
+                                                    .child(session.label_element(cx))
+                                                    .child(
+                                                        IconButton::new(
+                                                            "close-debug-session",
+                                                            IconName::Close,
+                                                        )
+                                                        .visible_on_hover(id.clone())
+                                                        .icon_size(IconSize::Small)
+                                                        .on_click({
+                                                            let weak = weak.clone();
+                                                            move |_, window, cx| {
+                                                                weak.update(cx, |panel, cx| {
+                                                                    panel.close_session(
+                                                                        weak_session_id,
+                                                                        window,
+                                                                        cx,
+                                                                    );
+                                                                })
+                                                                .ok();
+                                                                context_menu
+                                                                    .update(cx, |this, cx| {
+                                                                        this.cancel(
+                                                                            &Default::default(),
+                                                                            window,
+                                                                            cx,
+                                                                        );
+                                                                    })
+                                                                    .ok();
+                                                            }
+                                                        }),
+                                                    )
+                                                    .into_any_element()
+                                            })
+                                            .unwrap_or_else(|_| div().into_any_element())
+                                    }
+                                },
+                                {
+                                    let weak = weak.clone();
+                                    move |window, cx| {
+                                        weak.update(cx, |panel, cx| {
+                                            panel.activate_session(session.clone(), window, cx);
+                                        })
+                                        .ok();
+                                    }
+                                },
+                            );
+                        }
+                        this
+                    }),
+                )
+                .style(DropdownStyle::Ghost),
+            )
+        } else {
+            None
+        }
+    }
+
+    pub(crate) fn render_thread_dropdown(
+        &self,
+        running_state: &Entity<RunningState>,
+        threads: Vec<(dap::Thread, ThreadStatus)>,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) -> Option<DropdownMenu> {
+        let running_state = running_state.clone();
+        let running_state_read = running_state.read(cx);
+        let thread_id = running_state_read.thread_id();
+        let session = running_state_read.session();
+        let session_id = session.read(cx).session_id();
+        let session_terminated = session.read(cx).is_terminated();
+        let selected_thread_name = threads
+            .iter()
+            .find(|(thread, _)| thread_id.map(|id| id.0) == Some(thread.id))
+            .map(|(thread, _)| thread.name.clone());
+
+        if let Some(selected_thread_name) = selected_thread_name {
+            let trigger = DebugPanel::dropdown_label(selected_thread_name).into_any_element();
+            Some(
+                DropdownMenu::new_with_element(
+                    ("thread-list", session_id.0),
+                    trigger,
+                    ContextMenu::build_eager(window, cx, move |mut this, _, _| {
+                        for (thread, _) in threads {
+                            let running_state = running_state.clone();
+                            let thread_id = thread.id;
+                            this = this.entry(thread.name, None, move |window, cx| {
+                                running_state.update(cx, |running_state, cx| {
+                                    running_state.select_thread(ThreadId(thread_id), window, cx);
+                                });
+                            });
+                        }
+                        this
+                    }),
+                )
+                .disabled(session_terminated)
+                .style(DropdownStyle::Ghost),
+            )
+        } else {
+            None
+        }
+    }
+}