1use std::{error::Error, fmt, path::Path, rc::Rc, sync::Arc};
 2
 3use agent_client_protocol::{self as acp};
 4use anyhow::Result;
 5use gpui::{AsyncApp, Entity, Task};
 6use language_model::LanguageModel;
 7use project::Project;
 8use ui::App;
 9
10use crate::AcpThread;
11
12/// Trait for agents that support listing, selecting, and querying language models.
13///
14/// This is an optional capability; agents indicate support via [AgentConnection::model_selector].
15pub trait ModelSelector: 'static {
16    /// Lists all available language models for this agent.
17    ///
18    /// # Parameters
19    /// - `cx`: The GPUI app context for async operations and global access.
20    ///
21    /// # Returns
22    /// A task resolving to the list of models or an error (e.g., if no models are configured).
23    fn list_models(&self, cx: &mut AsyncApp) -> Task<Result<Vec<Arc<dyn LanguageModel>>>>;
24
25    /// Selects a model for a specific session (thread).
26    ///
27    /// This sets the default model for future interactions in the session.
28    /// If the session doesn't exist or the model is invalid, it returns an error.
29    ///
30    /// # Parameters
31    /// - `session_id`: The ID of the session (thread) to apply the model to.
32    /// - `model`: The model to select (should be one from [list_models]).
33    /// - `cx`: The GPUI app context.
34    ///
35    /// # Returns
36    /// A task resolving to `Ok(())` on success or an error.
37    fn select_model(
38        &self,
39        session_id: acp::SessionId,
40        model: Arc<dyn LanguageModel>,
41        cx: &mut AsyncApp,
42    ) -> Task<Result<()>>;
43
44    /// Retrieves the currently selected model for a specific session (thread).
45    ///
46    /// # Parameters
47    /// - `session_id`: The ID of the session (thread) to query.
48    /// - `cx`: The GPUI app context.
49    ///
50    /// # Returns
51    /// A task resolving to the selected model (always set) or an error (e.g., session not found).
52    fn selected_model(
53        &self,
54        session_id: &acp::SessionId,
55        cx: &mut AsyncApp,
56    ) -> Task<Result<Arc<dyn LanguageModel>>>;
57}
58
59pub trait AgentConnection {
60    fn new_thread(
61        self: Rc<Self>,
62        project: Entity<Project>,
63        cwd: &Path,
64        cx: &mut AsyncApp,
65    ) -> Task<Result<Entity<AcpThread>>>;
66
67    fn auth_methods(&self) -> &[acp::AuthMethod];
68
69    fn authenticate(&self, method: acp::AuthMethodId, cx: &mut App) -> Task<Result<()>>;
70
71    fn prompt(&self, params: acp::PromptRequest, cx: &mut App)
72    -> Task<Result<acp::PromptResponse>>;
73
74    fn cancel(&self, session_id: &acp::SessionId, cx: &mut App);
75
76    /// Returns this agent as an [Rc<dyn ModelSelector>] if the model selection capability is supported.
77    ///
78    /// If the agent does not support model selection, returns [None].
79    /// This allows sharing the selector in UI components.
80    fn model_selector(&self) -> Option<Rc<dyn ModelSelector>> {
81        None // Default impl for agents that don't support it
82    }
83}
84
85#[derive(Debug)]
86pub struct AuthRequired;
87
88impl Error for AuthRequired {}
89impl fmt::Display for AuthRequired {
90    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
91        write!(f, "AuthRequired")
92    }
93}