src/channels/chat-type.ts

export type NormalizedChatType = "direct" | "group" | "channel";

export function normalizeChatType(raw?: string): NormalizedChatType | undefined {
  const value = raw?.trim().toLowerCase();
  if (!value) {
    return undefined;
  }
  if (value === "direct" || value === "dm") {
    return "direct";
  }
  if (value === "group") {
    return "group";
  }
  if (value === "channel") {
    return "channel";
  }
  return undefined;
}