import {BrowserCrypto} from './browser/crypto';
import {NodeCrypto} from './node/crypto';

export interface JwkCertificate {
  kty: string;
  alg: string;
  use?: string;
  kid: string;
  n: string;
  e: string;
}

export interface CryptoSigner {
  update(data: string): void;
  sign(key: string, outputFormat: string): string;
}

// Crypto interface will provide required crypto functions.
// Use `createCrypto()` factory function to create an instance
// of Crypto. It will either use Node.js `crypto` module, or
// use browser's SubtleCrypto interface. Since most of the
// SubtleCrypto methods return promises, we must make those
// methods return promises here as well, even though in Node.js
// they are synchronous.
export interface Crypto {
  sha256DigestBase64(str: string): Promise<string>;
  randomBytesBase64(n: number): string;
  verify(
    pubkey: string | JwkCertificate,
    data: string | Buffer,
    signature: string
  ): Promise<boolean>;
  sign(
    privateKey: string | JwkCertificate,
    data: string | Buffer
  ): Promise<string>;
  decodeBase64StringUtf8(base64: string): string;
  encodeBase64StringUtf8(text: string): string;
}

export function createCrypto(): Crypto {
  if (hasBrowserCrypto()) {
    return new BrowserCrypto();
  }
  return new NodeCrypto();
}

export function hasBrowserCrypto() {
  return (
    typeof window !== 'undefined' &&
    typeof window.crypto !== 'undefined' &&
    typeof window.crypto.subtle !== 'undefined'
  );
}