import { bytesToHex, utf8ToBytes } from '@noble/hashes/utils'
import { installPkceS256, type PkceCryptoTarget } from '../src/lib/pkce-s256'

describe('PKCE S256 WebCrypto boundary', () => {
  test('installs a SHA-256 digest backed by the native CSPRNG target', async () => {
    const target: PkceCryptoTarget = {
      getRandomValues: <T extends ArrayBufferView>(array: T): T => array,
    }

    installPkceS256(target)

    const digest = await target.subtle?.digest?.('SHA-256', utf8ToBytes('abc'))
    expect(digest).toBeInstanceOf(ArrayBuffer)
    expect(bytesToHex(new Uint8Array(digest!))).toBe(
      'ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad',
    )
  })

  test('rejects digest algorithms outside the PKCE contract', async () => {
    const target: PkceCryptoTarget = {
      getRandomValues: <T extends ArrayBufferView>(array: T): T => array,
    }
    installPkceS256(target)

    await expect(target.subtle?.digest?.('SHA-1', new Uint8Array([1]))).rejects.toThrow(
      'pkce_digest_algorithm_unsupported',
    )
  })

  test('preserves a complete platform WebCrypto implementation', () => {
    const digest = jest.fn(async () => new ArrayBuffer(32))
    const target: PkceCryptoTarget = {
      getRandomValues: <T extends ArrayBufferView>(array: T): T => array,
      subtle: { digest },
    }

    installPkceS256(target)

    expect(target.subtle?.digest).toBe(digest)
  })

  test('fails closed when native random values are unavailable', () => {
    expect(() => installPkceS256({})).toThrow('pkce_native_csprng_unavailable')
  })
})