import type { MCPServerConfig, ServerType } from "./types.js";

/**
 * Returns the transport type for an MCP server configuration.
 * If type is omitted, defaults to "stdio". Throws if type is invalid.
 */
export function getServerType(config: MCPServerConfig): ServerType {
  if (!("type" in config) || config.type === undefined) {
    return "stdio";
  }
  const type = config.type;
  if (type === "stdio") {
    return "stdio";
  }
  if (type === "sse") {
    return "sse";
  }
  if (type === "streamable-http") {
    return "streamable-http";
  }
  throw new Error(
    `Invalid server type: ${type}. Valid types are: stdio, sse, streamable-http`,
  );
}