import type { SyncMessage } from './sync-types';

// Sync messages are JSON-encoded and then Noise NK encrypted. The encrypted
// binary is base64-encoded for transmission over the text-only WS server.
// This layer only handles the JSON ↔ SyncMessage boundary; the caller
// is responsible for the encrypt/decrypt step around it.

export function encodeSyncMessage(msg: SyncMessage): Uint8Array {
  return new TextEncoder().encode(JSON.stringify(msg));
}

export function decodeSyncMessage(data: Uint8Array): SyncMessage {
  const parsed = JSON.parse(new TextDecoder().decode(data));
  if (typeof parsed?.type !== 'string') throw new Error('invalid sync message');
  return parsed as SyncMessage;
}

// Base64 helpers for the WS text-frame transport layer.

export function bytesToBase64(bytes: Uint8Array): string {
  let binary = '';
  for (let i = 0; i < bytes.length; i++) binary += String.fromCharCode(bytes[i]);
  return btoa(binary);
}

export function base64ToBytes(b64: string): Uint8Array {
  const binary = atob(b64);
  const bytes = new Uint8Array(binary.length);
  for (let i = 0; i < binary.length; i++) bytes[i] = binary.charCodeAt(i);
  return bytes;
}