copilot: Add support for new models (#19968)

Closes #19963

This PR implements integration with the newly announced GitHub Copilot
LLM models, including:
- Claude 3.5 Sonnet
- o1-mini
- o1-preview

Release Notes:

- N/A

---------

Co-authored-by: Bennet Bo Fenner <bennet@zed.dev>

crates/copilot/src/copilot_chat.rs

@@ -35,14 +35,30 @@ pub enum Model {
     Gpt4,
     #[serde(alias = "gpt-3.5-turbo", rename = "gpt-3.5-turbo")]
     Gpt3_5Turbo,
+    #[serde(alias = "o1-preview", rename = "o1-preview-2024-09-12")]
+    O1Preview,
+    #[serde(alias = "o1-mini", rename = "o1-mini-2024-09-12")]
+    O1Mini,
+    #[serde(alias = "claude-3-5-sonnet", rename = "claude-3.5-sonnet")]
+    Claude3_5Sonnet,
 }
 
 impl Model {
+    pub fn uses_streaming(&self) -> bool {
+        match self {
+            Self::Gpt4o | Self::Gpt4 | Self::Gpt3_5Turbo | Self::Claude3_5Sonnet => true,
+            Self::O1Mini | Self::O1Preview => false,
+        }
+    }
+
     pub fn from_id(id: &str) -> Result<Self> {
         match id {
             "gpt-4o" => Ok(Self::Gpt4o),
             "gpt-4" => Ok(Self::Gpt4),
             "gpt-3.5-turbo" => Ok(Self::Gpt3_5Turbo),
+            "o1-preview" => Ok(Self::O1Preview),
+            "o1-mini" => Ok(Self::O1Mini),
+            "claude-3-5-sonnet" => Ok(Self::Claude3_5Sonnet),
             _ => Err(anyhow!("Invalid model id: {}", id)),
         }
     }
@@ -52,6 +68,9 @@ impl Model {
             Self::Gpt3_5Turbo => "gpt-3.5-turbo",
             Self::Gpt4 => "gpt-4",
             Self::Gpt4o => "gpt-4o",
+            Self::O1Mini => "o1-mini",
+            Self::O1Preview => "o1-preview",
+            Self::Claude3_5Sonnet => "claude-3-5-sonnet",
         }
     }
 
@@ -60,6 +79,9 @@ impl Model {
             Self::Gpt3_5Turbo => "GPT-3.5",
             Self::Gpt4 => "GPT-4",
             Self::Gpt4o => "GPT-4o",
+            Self::O1Mini => "o1-mini",
+            Self::O1Preview => "o1-preview",
+            Self::Claude3_5Sonnet => "Claude 3.5 Sonnet",
         }
     }
 
@@ -68,6 +90,9 @@ impl Model {
             Self::Gpt4o => 128000,
             Self::Gpt4 => 8192,
             Self::Gpt3_5Turbo => 16385,
+            Self::O1Mini => 128000,
+            Self::O1Preview => 128000,
+            Self::Claude3_5Sonnet => 200_000,
         }
     }
 }
@@ -87,7 +112,7 @@ impl Request {
         Self {
             intent: true,
             n: 1,
-            stream: true,
+            stream: model.uses_streaming(),
             temperature: 0.1,
             model,
             messages,
@@ -113,7 +138,8 @@ pub struct ResponseEvent {
 pub struct ResponseChoice {
     pub index: usize,
     pub finish_reason: Option<String>,
-    pub delta: ResponseDelta,
+    pub delta: Option<ResponseDelta>,
+    pub message: Option<ResponseDelta>,
 }
 
 #[derive(Debug, Deserialize)]
@@ -333,9 +359,23 @@ async fn stream_completion(
     if let Some(low_speed_timeout) = low_speed_timeout {
         request_builder = request_builder.read_timeout(low_speed_timeout);
     }
+    let is_streaming = request.stream;
+
     let request = request_builder.body(AsyncBody::from(serde_json::to_string(&request)?))?;
     let mut response = client.send(request).await?;
-    if response.status().is_success() {
+
+    if !response.status().is_success() {
+        let mut body = Vec::new();
+        response.body_mut().read_to_end(&mut body).await?;
+        let body_str = std::str::from_utf8(&body)?;
+        return Err(anyhow!(
+            "Failed to connect to API: {} {}",
+            response.status(),
+            body_str
+        ));
+    }
+
+    if is_streaming {
         let reader = BufReader::new(response.into_body());
         Ok(reader
             .lines()
@@ -367,19 +407,9 @@ async fn stream_completion(
     } else {
         let mut body = Vec::new();
         response.body_mut().read_to_end(&mut body).await?;
-
         let body_str = std::str::from_utf8(&body)?;
+        let response: ResponseEvent = serde_json::from_str(body_str)?;
 
-        match serde_json::from_str::<ResponseEvent>(body_str) {
-            Ok(_) => Err(anyhow!(
-                "Unexpected success response while expecting an error: {}",
-                body_str,
-            )),
-            Err(_) => Err(anyhow!(
-                "Failed to connect to API: {} {}",
-                response.status(),
-                body_str,
-            )),
-        }
+        Ok(futures::stream::once(async move { Ok(response) }).boxed())
     }
 }