Refactor llm package

internal/llm/client.go

@@ -7,20 +7,34 @@ import (
 	"time"
 )
 
-// Config holds the configuration for an LLM client.
+const (
+	// chatCompletionsPath is the endpoint for chat completion requests.
+	chatCompletionsPath = "/chat/completions"
+	// chatTemplateEnableThinking is the chat-template argument that selects
+	// whether a reasoning model emits reasoning tokens.
+	chatTemplateEnableThinking = "enable_thinking"
+	// defaultTimeout limits requests when Config.Timeout is empty.
+	defaultTimeout = 5 * time.Minute
+	// sseDone is the sentinel that terminates a chat completion stream.
+	sseDone = "[DONE]"
+)
+
+// Config configures a Client.
 type Config struct {
-	// Key is the API key for authentication.
+	// Key is sent as a bearer token. An empty key disables authentication.
 	Key string `yaml:"key"`
-	// SystemMessage is prepended to all conversations.
-	SystemMessage string `yaml:"system_message"`
-	// Timeout is the maximum duration for a query (e.g., "5m").
-	// Defaults to 5 minutes if empty.
+	// Provider is returned unchanged by Client.Provider. It is not sent to the
+	// inference endpoint.
+	Provider string `yaml:"provider"`
+	// Timeout limits each request, including reading a streaming response. It
+	// uses Go duration syntax and defaults to five minutes when empty.
 	Timeout string `yaml:"timeout"`
-	// URL is the base URL of the OpenAI-compatible API endpoint.
+	// URL is the endpoint root. Client appends /chat/completions or /models.
 	URL string `yaml:"url"`
 }
 
-// Validate checks that required configuration values are present and valid.
+// Validate reports whether Timeout is a Go duration, when set, and URL is
+// non-empty. It does not contact the endpoint.
 func (cfg Config) Validate() error {
 	if cfg.Timeout != "" {
 		if _, err := time.ParseDuration(cfg.Timeout); err != nil {
@@ -33,30 +47,27 @@ func (cfg Config) Validate() error {
 	return nil
 }
 
-// Client wraps an OpenAI-compatible client with tool execution support.
+// Client is an OpenAI-compatible inference client.
 type Client struct {
-	baseURL       string
-	httpc         *http.Client
-	key           string
-	log           *slog.Logger
-	registry      *Registry
-	systemMessage string
-	timeout       time.Duration
-	tools         []APITool
+	baseURL  string
+	httpc    *http.Client
+	key      string
+	log      *slog.Logger
+	provider string
+	timeout  time.Duration
 }
 
-// NewClient creates a new LLM client with the provided configuration.
-// The registry is optional; if nil, tool calling is disabled.
-func NewClient(
-	cfg Config,
-	registry *Registry,
-	log *slog.Logger,
-) (*Client, error) {
+// NewClient creates a client from cfg. If cfg.Timeout is empty, requests have a
+// five-minute timeout. log must be non-nil.
+func NewClient(cfg Config, log *slog.Logger) (*Client, error) {
 	if err := cfg.Validate(); err != nil {
 		return nil, fmt.Errorf("invalid config: %w", err)
 	}
+	if log == nil {
+		return nil, fmt.Errorf("missing logger")
+	}
 
-	timeout := 5 * time.Minute
+	timeout := defaultTimeout
 	if cfg.Timeout != "" {
 		d, err := time.ParseDuration(cfg.Timeout)
 		if err != nil {
@@ -65,18 +76,17 @@ func NewClient(
 		timeout = d
 	}
 
-	llm := &Client{
-		baseURL:       cfg.URL,
-		key:           cfg.Key,
-		log:           log,
-		systemMessage: cfg.SystemMessage,
-		registry:      registry,
-		httpc:         &http.Client{},
-		timeout:       timeout,
-	}
+	return &Client{
+		baseURL:  cfg.URL,
+		key:      cfg.Key,
+		log:      log,
+		provider: cfg.Provider,
+		httpc:    &http.Client{},
+		timeout:  timeout,
+	}, nil
+}
 
-	// Convert tools from registry.
-	llm.tools = registry.ToAPI()
-
-	return llm, nil
+// Provider returns the application-defined provider name supplied in Config.
+func (c *Client) Provider() string {
+	return c.provider
 }