import { randomId } from 'helpers/random-id';
// Frontend

type PasskeyUser = {
  id: string;
  email: string;
  firstName: string;
  lastName: string;
};

export function arrayBufferToBase64(buffer: ArrayBuffer) {
  const bytes = new Uint8Array(buffer);
  const binary = Array.from(bytes, (byte) => String.fromCharCode(byte)).join('');
  return window.btoa(binary);
}

export function getCredentialPayload(challenge: number[], user: PasskeyUser) {
  return {
    challenge: new Uint8Array(challenge),
    rp: {
      name: 'Pertento AI',
    },
    user: {
      id: Uint8Array.from(atob(btoa(user.id)), (c) => c.charCodeAt(0)),
      name: user.email,
      displayName: `${user.firstName} ${user.lastName}`,
    },
    pubKeyCredParams: [
      { type: 'public-key' as const, alg: -7 },
      { type: 'public-key' as const, alg: -257 },
    ],
  };
}

export function getSigninPayload(challenge: number[], credentialIds: string[]) {
  return {
    challenge: new Uint8Array(challenge),
    allowCredentials: credentialIds.map((id) => {
      const urlSafeId = id.replace(/-/g, '+').replace(/_/g, '/');
      const decodedId = atob(urlSafeId);
      return {
        type: 'public-key' as const,
        id: Uint8Array.from(decodedId, (c) => c.charCodeAt(0)),
      };
    }),
    userVerification: 'preferred' as const,
  };
}

// Backend

export function createChallenge() {
  const challenge = randomId();
  const hex = challenge.replace(/-/g, '');
  const array: number[] = new Array(hex.length / 2);
  for (let i = 0; i < hex.length; i += 2) {
    array[i / 2] = parseInt(hex.substr(i, 2), 16);
  }
  return array;
}

export const hexToString = (array: number[]) => array.map((byte) => byte.toString(16).padStart(2, '0')).join('');