Rename assistant2 to agent (#27887)

This PR renames the `assistant2` crate to `agent`.

Release Notes:

- N/A

crates/agent/src/terminal_codegen.rs

@@ -0,0 +1,194 @@
+use crate::inline_prompt_editor::CodegenStatus;
+use client::telemetry::Telemetry;
+use futures::{SinkExt, StreamExt, channel::mpsc};
+use gpui::{App, AppContext as _, Context, Entity, EventEmitter, Task};
+use language_model::{LanguageModelRegistry, LanguageModelRequest, report_assistant_event};
+use std::{sync::Arc, time::Instant};
+use telemetry_events::{AssistantEvent, AssistantKind, AssistantPhase};
+use terminal::Terminal;
+
+pub struct TerminalCodegen {
+    pub status: CodegenStatus,
+    pub telemetry: Option<Arc<Telemetry>>,
+    terminal: Entity<Terminal>,
+    generation: Task<()>,
+    pub message_id: Option<String>,
+    transaction: Option<TerminalTransaction>,
+}
+
+impl EventEmitter<CodegenEvent> for TerminalCodegen {}
+
+impl TerminalCodegen {
+    pub fn new(terminal: Entity<Terminal>, telemetry: Option<Arc<Telemetry>>) -> Self {
+        Self {
+            terminal,
+            telemetry,
+            status: CodegenStatus::Idle,
+            generation: Task::ready(()),
+            message_id: None,
+            transaction: None,
+        }
+    }
+
+    pub fn start(&mut self, prompt: LanguageModelRequest, cx: &mut Context<Self>) {
+        let Some(model) = LanguageModelRegistry::read_global(cx).active_model() else {
+            return;
+        };
+
+        let model_api_key = model.api_key(cx);
+        let http_client = cx.http_client();
+        let telemetry = self.telemetry.clone();
+        self.status = CodegenStatus::Pending;
+        self.transaction = Some(TerminalTransaction::start(self.terminal.clone()));
+        self.generation = cx.spawn(async move |this, cx| {
+            let model_telemetry_id = model.telemetry_id();
+            let model_provider_id = model.provider_id();
+            let response = model.stream_completion_text(prompt, &cx).await;
+            let generate = async {
+                let message_id = response
+                    .as_ref()
+                    .ok()
+                    .and_then(|response| response.message_id.clone());
+
+                let (mut hunks_tx, mut hunks_rx) = mpsc::channel(1);
+
+                let task = cx.background_spawn({
+                    let message_id = message_id.clone();
+                    let executor = cx.background_executor().clone();
+                    async move {
+                        let mut response_latency = None;
+                        let request_start = Instant::now();
+                        let task = async {
+                            let mut chunks = response?.stream;
+                            while let Some(chunk) = chunks.next().await {
+                                if response_latency.is_none() {
+                                    response_latency = Some(request_start.elapsed());
+                                }
+                                let chunk = chunk?;
+                                hunks_tx.send(chunk).await?;
+                            }
+
+                            anyhow::Ok(())
+                        };
+
+                        let result = task.await;
+
+                        let error_message = result.as_ref().err().map(|error| error.to_string());
+                        report_assistant_event(
+                            AssistantEvent {
+                                conversation_id: None,
+                                kind: AssistantKind::InlineTerminal,
+                                message_id,
+                                phase: AssistantPhase::Response,
+                                model: model_telemetry_id,
+                                model_provider: model_provider_id.to_string(),
+                                response_latency,
+                                error_message,
+                                language_name: None,
+                            },
+                            telemetry,
+                            http_client,
+                            model_api_key,
+                            &executor,
+                        );
+
+                        result?;
+                        anyhow::Ok(())
+                    }
+                });
+
+                this.update(cx, |this, _| {
+                    this.message_id = message_id;
+                })?;
+
+                while let Some(hunk) = hunks_rx.next().await {
+                    this.update(cx, |this, cx| {
+                        if let Some(transaction) = &mut this.transaction {
+                            transaction.push(hunk, cx);
+                            cx.notify();
+                        }
+                    })?;
+                }
+
+                task.await?;
+                anyhow::Ok(())
+            };
+
+            let result = generate.await;
+
+            this.update(cx, |this, cx| {
+                if let Err(error) = result {
+                    this.status = CodegenStatus::Error(error);
+                } else {
+                    this.status = CodegenStatus::Done;
+                }
+                cx.emit(CodegenEvent::Finished);
+                cx.notify();
+            })
+            .ok();
+        });
+        cx.notify();
+    }
+
+    pub fn stop(&mut self, cx: &mut Context<Self>) {
+        self.status = CodegenStatus::Done;
+        self.generation = Task::ready(());
+        cx.emit(CodegenEvent::Finished);
+        cx.notify();
+    }
+
+    pub fn complete(&mut self, cx: &mut Context<Self>) {
+        if let Some(transaction) = self.transaction.take() {
+            transaction.complete(cx);
+        }
+    }
+
+    pub fn undo(&mut self, cx: &mut Context<Self>) {
+        if let Some(transaction) = self.transaction.take() {
+            transaction.undo(cx);
+        }
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub enum CodegenEvent {
+    Finished,
+}
+
+#[cfg(not(target_os = "windows"))]
+pub const CLEAR_INPUT: &str = "\x15";
+#[cfg(target_os = "windows")]
+pub const CLEAR_INPUT: &str = "\x03";
+const CARRIAGE_RETURN: &str = "\x0d";
+
+struct TerminalTransaction {
+    terminal: Entity<Terminal>,
+}
+
+impl TerminalTransaction {
+    pub fn start(terminal: Entity<Terminal>) -> Self {
+        Self { terminal }
+    }
+
+    pub fn push(&mut self, hunk: String, cx: &mut App) {
+        // Ensure that the assistant cannot accidentally execute commands that are streamed into the terminal
+        let input = Self::sanitize_input(hunk);
+        self.terminal
+            .update(cx, |terminal, _| terminal.input(input));
+    }
+
+    pub fn undo(&self, cx: &mut App) {
+        self.terminal
+            .update(cx, |terminal, _| terminal.input(CLEAR_INPUT.to_string()));
+    }
+
+    pub fn complete(&self, cx: &mut App) {
+        self.terminal.update(cx, |terminal, _| {
+            terminal.input(CARRIAGE_RETURN.to_string())
+        });
+    }
+
+    fn sanitize_input(input: String) -> String {
+        input.replace(['\r', '\n'], "")
+    }
+}