add initial lsp support

internal/lsp/protocol.go

@@ -0,0 +1,48 @@
+package lsp
+
+import (
+	"encoding/json"
+)
+
+// Message represents a JSON-RPC 2.0 message
+type Message struct {
+	JSONRPC string          `json:"jsonrpc"`
+	ID      int32           `json:"id,omitempty"`
+	Method  string          `json:"method,omitempty"`
+	Params  json.RawMessage `json:"params,omitempty"`
+	Result  json.RawMessage `json:"result,omitempty"`
+	Error   *ResponseError  `json:"error,omitempty"`
+}
+
+// ResponseError represents a JSON-RPC 2.0 error
+type ResponseError struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+func NewRequest(id int32, method string, params any) (*Message, error) {
+	paramsJSON, err := json.Marshal(params)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Message{
+		JSONRPC: "2.0",
+		ID:      id,
+		Method:  method,
+		Params:  paramsJSON,
+	}, nil
+}
+
+func NewNotification(method string, params any) (*Message, error) {
+	paramsJSON, err := json.Marshal(params)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Message{
+		JSONRPC: "2.0",
+		Method:  method,
+		Params:  paramsJSON,
+	}, nil
+}