import { isoCBOR } from "./iso/index.ts";

/**
 * Convert an AttestationObject buffer to a proper object
 *
 * @param base64AttestationObject Attestation Object buffer
 */
export function decodeAttestationObject(
  attestationObject: Uint8Array,
): AttestationObject {
  return _decodeAttestationObjectInternals.stubThis(
    isoCBOR.decodeFirst<AttestationObject>(attestationObject),
  );
}

export type AttestationFormat =
  | "fido-u2f"
  | "packed"
  | "android-safetynet"
  | "android-key"
  | "tpm"
  | "apple"
  | "none";

export type AttestationObject = {
  get(key: "fmt"): AttestationFormat;
  get(key: "attStmt"): AttestationStatement;
  get(key: "authData"): Uint8Array;
};

/**
 * `AttestationStatement` will be an instance of `Map`, but these keys help make finite the list of
 * possible values within it.
 */
export type AttestationStatement = {
  get(key: "sig"): Uint8Array | undefined;
  get(key: "x5c"): Uint8Array[] | undefined;
  get(key: "response"): Uint8Array | undefined;
  get(key: "alg"): number | undefined;
  get(key: "ver"): string | undefined;
  get(key: "certInfo"): Uint8Array | undefined;
  get(key: "pubArea"): Uint8Array | undefined;
  // `Map` properties
  readonly size: number;
};

// Make it possible to stub the return value during testing
export const _decodeAttestationObjectInternals = {
  stubThis: (value: AttestationObject) => value,
};