use std::sync::Arc;

use async_trait::async_trait;

use crate::{
    Result,
    llm::ChatStream,
    mcp::{McpToolCall, McpToolDescriptor, McpToolResponse},
    types::{ChatRequest, ChatResponse, ModelInfo},
};

/// Object-safe facade for interacting with LLM backends.
#[async_trait]
pub trait LlmClient: Send + Sync {
    /// List the models exposed by this client.
    async fn list_models(&self) -> Result<Vec<ModelInfo>>;

    /// Issue a one-shot chat request and wait for the complete response.
    async fn send_chat(&self, request: ChatRequest) -> Result<ChatResponse>;

    /// Stream chat responses incrementally.
    async fn stream_chat(&self, request: ChatRequest) -> Result<ChatStream>;

    /// Enumerate tools exposed by the backing provider.
    async fn list_tools(&self) -> Result<Vec<McpToolDescriptor>>;

    /// Invoke a tool exposed by the provider.
    async fn call_tool(&self, call: McpToolCall) -> Result<McpToolResponse>;
}

/// Convenience alias for trait-object clients.
pub type DynLlmClient = Arc<dyn LlmClient>;