Add DeepSeek support (#23551)

- Added support for DeepSeek as a new language model provider in Zed
Assistant
- Implemented streaming API support for real-time responses from
DeepSeek models.
- Added a configuration UI for DeepSeek API key management and settings.
- Updated documentation with detailed setup instructions for DeepSeek
integration.
- Added DeepSeek-specific icons and model definitions for seamless
integration into the Zed UI.
- Integrated DeepSeek into the language model registry, making it
available alongside other providers like OpenAI and Anthropic.

Release Notes:

- Added support for DeepSeek to the Assistant.

---------

Co-authored-by: Marshall Bowers <git@maxdeviant.com>

crates/deepseek/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "deepseek"
+version = "0.1.0"
+edition.workspace = true
+publish.workspace = true
+license = "GPL-3.0-or-later"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/deepseek.rs"
+
+[features]
+default = []
+schemars = ["dep:schemars"]
+
+[dependencies]
+anyhow.workspace = true
+futures.workspace = true
+http_client.workspace = true
+schemars = { workspace = true, optional = true }
+serde.workspace = true
+serde_json.workspace = true

crates/deepseek/LICENSE-GPL

@@ -0,0 +1 @@
+../../LICENSE-GPL

crates/deepseek/src/deepseek.rs

@@ -0,0 +1,301 @@
+use anyhow::{anyhow, Result};
+use futures::{
+    io::BufReader,
+    stream::{BoxStream, StreamExt},
+    AsyncBufReadExt, AsyncReadExt,
+};
+use http_client::{AsyncBody, HttpClient, Method, Request as HttpRequest};
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+use std::convert::TryFrom;
+
+pub const DEEPSEEK_API_URL: &str = "https://api.deepseek.com";
+
+#[derive(Clone, Copy, Serialize, Deserialize, Debug, Eq, PartialEq)]
+#[serde(rename_all = "lowercase")]
+pub enum Role {
+    User,
+    Assistant,
+    System,
+    Tool,
+}
+
+impl TryFrom<String> for Role {
+    type Error = anyhow::Error;
+
+    fn try_from(value: String) -> Result<Self> {
+        match value.as_str() {
+            "user" => Ok(Self::User),
+            "assistant" => Ok(Self::Assistant),
+            "system" => Ok(Self::System),
+            "tool" => Ok(Self::Tool),
+            _ => Err(anyhow!("invalid role '{value}'")),
+        }
+    }
+}
+
+impl From<Role> for String {
+    fn from(val: Role) -> Self {
+        match val {
+            Role::User => "user".to_owned(),
+            Role::Assistant => "assistant".to_owned(),
+            Role::System => "system".to_owned(),
+            Role::Tool => "tool".to_owned(),
+        }
+    }
+}
+
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq)]
+pub enum Model {
+    #[serde(rename = "deepseek-chat")]
+    #[default]
+    Chat,
+    #[serde(rename = "deepseek-reasoner")]
+    Reasoner,
+    #[serde(rename = "custom")]
+    Custom {
+        name: String,
+        /// The name displayed in the UI, such as in the assistant panel model dropdown menu.
+        display_name: Option<String>,
+        max_tokens: usize,
+        max_output_tokens: Option<u32>,
+    },
+}
+
+impl Model {
+    pub fn from_id(id: &str) -> Result<Self> {
+        match id {
+            "deepseek-chat" => Ok(Self::Chat),
+            "deepseek-reasoner" => Ok(Self::Reasoner),
+            _ => Err(anyhow!("invalid model id")),
+        }
+    }
+
+    pub fn id(&self) -> &str {
+        match self {
+            Self::Chat => "deepseek-chat",
+            Self::Reasoner => "deepseek-reasoner",
+            Self::Custom { name, .. } => name,
+        }
+    }
+
+    pub fn display_name(&self) -> &str {
+        match self {
+            Self::Chat => "DeepSeek Chat",
+            Self::Reasoner => "DeepSeek Reasoner",
+            Self::Custom {
+                name, display_name, ..
+            } => display_name.as_ref().unwrap_or(name).as_str(),
+        }
+    }
+
+    pub fn max_token_count(&self) -> usize {
+        match self {
+            Self::Chat | Self::Reasoner => 64_000,
+            Self::Custom { max_tokens, .. } => *max_tokens,
+        }
+    }
+
+    pub fn max_output_tokens(&self) -> Option<u32> {
+        match self {
+            Self::Chat => Some(8_192),
+            Self::Reasoner => Some(8_192),
+            Self::Custom {
+                max_output_tokens, ..
+            } => *max_output_tokens,
+        }
+    }
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct Request {
+    pub model: String,
+    pub messages: Vec<RequestMessage>,
+    pub stream: bool,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub max_tokens: Option<u32>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub temperature: Option<f32>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub response_format: Option<ResponseFormat>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub tools: Vec<ToolDefinition>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum ResponseFormat {
+    Text,
+    #[serde(rename = "json_object")]
+    JsonObject,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum ToolDefinition {
+    Function { function: FunctionDefinition },
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct FunctionDefinition {
+    pub name: String,
+    pub description: Option<String>,
+    pub parameters: Option<Value>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
+#[serde(tag = "role", rename_all = "lowercase")]
+pub enum RequestMessage {
+    Assistant {
+        content: Option<String>,
+        #[serde(default, skip_serializing_if = "Vec::is_empty")]
+        tool_calls: Vec<ToolCall>,
+    },
+    User {
+        content: String,
+    },
+    System {
+        content: String,
+    },
+    Tool {
+        content: String,
+        tool_call_id: String,
+    },
+}
+
+#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
+pub struct ToolCall {
+    pub id: String,
+    #[serde(flatten)]
+    pub content: ToolCallContent,
+}
+
+#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
+#[serde(tag = "type", rename_all = "lowercase")]
+pub enum ToolCallContent {
+    Function { function: FunctionContent },
+}
+
+#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
+pub struct FunctionContent {
+    pub name: String,
+    pub arguments: String,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct Response {
+    pub id: String,
+    pub object: String,
+    pub created: u64,
+    pub model: String,
+    pub choices: Vec<Choice>,
+    pub usage: Usage,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub reasoning_content: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct Usage {
+    pub prompt_tokens: u32,
+    pub completion_tokens: u32,
+    pub total_tokens: u32,
+    #[serde(default)]
+    pub prompt_cache_hit_tokens: u32,
+    #[serde(default)]
+    pub prompt_cache_miss_tokens: u32,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct Choice {
+    pub index: u32,
+    pub message: RequestMessage,
+    pub finish_reason: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct StreamResponse {
+    pub id: String,
+    pub object: String,
+    pub created: u64,
+    pub model: String,
+    pub choices: Vec<StreamChoice>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct StreamChoice {
+    pub index: u32,
+    pub delta: StreamDelta,
+    pub finish_reason: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct StreamDelta {
+    pub role: Option<Role>,
+    pub content: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub tool_calls: Option<Vec<ToolCallChunk>>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub reasoning_content: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ToolCallChunk {
+    pub index: usize,
+    pub id: Option<String>,
+    pub function: Option<FunctionChunk>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct FunctionChunk {
+    pub name: Option<String>,
+    pub arguments: Option<String>,
+}
+
+pub async fn stream_completion(
+    client: &dyn HttpClient,
+    api_url: &str,
+    api_key: &str,
+    request: Request,
+) -> Result<BoxStream<'static, Result<StreamResponse>>> {
+    let uri = format!("{api_url}/v1/chat/completions");
+    let request_builder = HttpRequest::builder()
+        .method(Method::POST)
+        .uri(uri)
+        .header("Content-Type", "application/json")
+        .header("Authorization", format!("Bearer {}", api_key));
+
+    let request = request_builder.body(AsyncBody::from(serde_json::to_string(&request)?))?;
+    let mut response = client.send(request).await?;
+
+    if response.status().is_success() {
+        let reader = BufReader::new(response.into_body());
+        Ok(reader
+            .lines()
+            .filter_map(|line| async move {
+                match line {
+                    Ok(line) => {
+                        let line = line.strip_prefix("data: ")?;
+                        if line == "[DONE]" {
+                            None
+                        } else {
+                            match serde_json::from_str(line) {
+                                Ok(response) => Some(Ok(response)),
+                                Err(error) => Some(Err(anyhow!(error))),
+                            }
+                        }
+                    }
+                    Err(error) => Some(Err(anyhow!(error))),
+                }
+            })
+            .boxed())
+    } else {
+        let mut body = String::new();
+        response.body_mut().read_to_string(&mut body).await?;
+        Err(anyhow!(
+            "Failed to connect to DeepSeek API: {} {}",
+            response.status(),
+            body,
+        ))
+    }
+}