Working

internal/lsp/server.go

@@ -0,0 +1,109 @@
+package lsp
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+)
+
+type JsonRpcMessage struct {
+	Jsonrpc string          `json:"jsonrpc"`
+	Method  string          `json:"method,omitempty"`
+	Params  json.RawMessage `json:"params,omitempty"`
+	ID      interface{}     `json:"id,omitempty"`
+	Result  interface{}     `json:"result,omitempty"`
+	Error   *JsonRpcError   `json:"error,omitempty"`
+}
+
+type JsonRpcError struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+func RunServer() {
+	reader := bufio.NewReader(os.Stdin)
+	for {
+		msg, err := readMessage(reader)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			fmt.Fprintf(os.Stderr, "Error reading message: %v\n", err)
+			continue
+		}
+
+		handleMessage(msg)
+	}
+}
+
+func readMessage(reader *bufio.Reader) (*JsonRpcMessage, error) {
+	// LSP uses Content-Length header
+	var contentLength int
+	for {
+		line, err := reader.ReadString('\n')
+		if err != nil {
+			return nil, err
+		}
+		if line == "\r\n" {
+			break
+		}
+		if _, err := fmt.Sscanf(line, "Content-Length: %d", &contentLength); err == nil {
+			continue
+		}
+	}
+
+	body := make([]byte, contentLength)
+	_, err := io.ReadFull(reader, body)
+	if err != nil {
+		return nil, err
+	}
+
+	var msg JsonRpcMessage
+	err = json.Unmarshal(body, &msg)
+	return &msg, err
+}
+
+func handleMessage(msg *JsonRpcMessage) {
+	switch msg.Method {
+	case "initialize":
+		respond(msg.ID, map[string]interface{}{
+			"capabilities": map[string]interface{}{
+				"textDocumentSync": 1, // Full sync
+				"hoverProvider":    true,
+				"definitionProvider": true,
+				"referencesProvider": true,
+				"completionProvider": map[string]interface{}{
+					"triggerCharacters": []string{"=", ".", "{", "+", "$"},
+				},
+			},
+		})
+	case "initialized":
+		// Do nothing
+	case "shutdown":
+		respond(msg.ID, nil)
+	case "exit":
+		os.Exit(0)
+	case "textDocument/didOpen":
+		// Handle file open
+	case "textDocument/didChange":
+		// Handle file change
+	case "textDocument/hover":
+		// Handle hover
+	}
+}
+
+func respond(id interface{}, result interface{}) {
+	msg := JsonRpcMessage{
+		Jsonrpc: "2.0",
+		ID:      id,
+		Result:  result,
+	}
+	send(msg)
+}
+
+func send(msg interface{}) {
+	body, _ := json.Marshal(msg)
+	fmt.Printf("Content-Length: %d\r\n\r\n%s", len(body), body)
+}