acp: Rename assistant::QuoteSelection and support it in agent2 threads (#36628)

Release Notes:

- N/A

crates/agent_ui/src/acp/message_editor.rs

@@ -1,6 +1,6 @@
 use crate::{
     acp::completion_provider::ContextPickerCompletionProvider,
-    context_picker::fetch_context_picker::fetch_url_content,
+    context_picker::{ContextPickerAction, fetch_context_picker::fetch_url_content},
 };
 use acp_thread::{MentionUri, selection_name};
 use agent_client_protocol as acp;
@@ -27,7 +27,7 @@ use gpui::{
 };
 use language::{Buffer, Language};
 use language_model::LanguageModelImage;
-use project::{Project, ProjectPath, Worktree};
+use project::{CompletionIntent, Project, ProjectItem, ProjectPath, Worktree};
 use prompt_store::PromptStore;
 use rope::Point;
 use settings::Settings;
@@ -561,21 +561,24 @@ impl MessageEditor {
             let range = snapshot.anchor_after(offset + range_to_fold.start)
                 ..snapshot.anchor_after(offset + range_to_fold.end);
 
-            let path = buffer
-                .read(cx)
-                .file()
-                .map_or(PathBuf::from("untitled"), |file| file.path().to_path_buf());
+            // TODO support selections from buffers with no path
+            let Some(project_path) = buffer.read(cx).project_path(cx) else {
+                continue;
+            };
+            let Some(abs_path) = self.project.read(cx).absolute_path(&project_path, cx) else {
+                continue;
+            };
             let snapshot = buffer.read(cx).snapshot();
 
             let point_range = selection_range.to_point(&snapshot);
             let line_range = point_range.start.row..point_range.end.row;
 
             let uri = MentionUri::Selection {
-                path: path.clone(),
+                path: abs_path.clone(),
                 line_range: line_range.clone(),
             };
             let crease = crate::context_picker::crease_for_mention(
-                selection_name(&path, &line_range).into(),
+                selection_name(&abs_path, &line_range).into(),
                 uri.icon_path(cx),
                 range,
                 self.editor.downgrade(),
@@ -587,8 +590,7 @@ impl MessageEditor {
                 crease_ids.first().copied().unwrap()
             });
 
-            self.mention_set
-                .insert_uri(crease_id, MentionUri::Selection { path, line_range });
+            self.mention_set.insert_uri(crease_id, uri);
         }
     }
 
@@ -948,6 +950,38 @@ impl MessageEditor {
         .detach();
     }
 
+    pub fn insert_selections(&mut self, window: &mut Window, cx: &mut Context<Self>) {
+        let buffer = self.editor.read(cx).buffer().clone();
+        let Some(buffer) = buffer.read(cx).as_singleton() else {
+            return;
+        };
+        let anchor = buffer.update(cx, |buffer, _cx| buffer.anchor_before(buffer.len()));
+        let Some(workspace) = self.workspace.upgrade() else {
+            return;
+        };
+        let Some(completion) = ContextPickerCompletionProvider::completion_for_action(
+            ContextPickerAction::AddSelections,
+            anchor..anchor,
+            cx.weak_entity(),
+            &workspace,
+            cx,
+        ) else {
+            return;
+        };
+        self.editor.update(cx, |message_editor, cx| {
+            message_editor.edit(
+                [(
+                    multi_buffer::Anchor::max()..multi_buffer::Anchor::max(),
+                    completion.new_text,
+                )],
+                cx,
+            );
+        });
+        if let Some(confirm) = completion.confirm {
+            confirm(CompletionIntent::Complete, window, cx);
+        }
+    }
+
     pub fn set_read_only(&mut self, read_only: bool, cx: &mut Context<Self>) {
         self.editor.update(cx, |message_editor, cx| {
             message_editor.set_read_only(read_only);