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import { isCloudflareWorkers } from './env.ts'import crypto from './webcrypto.ts'import type { JWKImportFunction } from './interfaces.d.ts'import { JOSENotSupported } from '../util/errors.ts'import type { JWK } from '../types.d.ts'import { decode as base64url } from './base64url.ts'
function subtleMapping(jwk: JWK): {  algorithm: RsaHashedImportParams | EcKeyAlgorithm | Algorithm  keyUsages: KeyUsage[]} {  let algorithm: RsaHashedImportParams | EcKeyAlgorithm | Algorithm  let keyUsages: KeyUsage[]
  switch (jwk.kty) {    case 'oct': {      switch (jwk.alg) {        case 'HS256':        case 'HS384':        case 'HS512':          algorithm = { name: 'HMAC', hash: `SHA-${jwk.alg.slice(-3)}` }          keyUsages = ['sign', 'verify']          break        case 'A128CBC-HS256':        case 'A192CBC-HS384':        case 'A256CBC-HS512':          throw new JOSENotSupported(`${jwk.alg} keys cannot be imported as CryptoKey instances`)        case 'A128GCM':        case 'A192GCM':        case 'A256GCM':        case 'A128GCMKW':        case 'A192GCMKW':        case 'A256GCMKW':          algorithm = { name: 'AES-GCM' }          keyUsages = ['encrypt', 'decrypt']          break        case 'A128KW':        case 'A192KW':        case 'A256KW':          algorithm = { name: 'AES-KW' }          keyUsages = ['wrapKey', 'unwrapKey']          break        case 'PBES2-HS256+A128KW':        case 'PBES2-HS384+A192KW':        case 'PBES2-HS512+A256KW':          algorithm = { name: 'PBKDF2' }          keyUsages = ['deriveBits']          break        default:          throw new JOSENotSupported('Invalid or unsupported JWK "alg" (Algorithm) Parameter value')      }      break    }    case 'RSA': {      switch (jwk.alg) {        case 'PS256':        case 'PS384':        case 'PS512':          algorithm = { name: 'RSA-PSS', hash: `SHA-${jwk.alg.slice(-3)}` }          keyUsages = jwk.d ? ['sign'] : ['verify']          break        case 'RS256':        case 'RS384':        case 'RS512':          algorithm = { name: 'RSASSA-PKCS1-v1_5', hash: `SHA-${jwk.alg.slice(-3)}` }          keyUsages = jwk.d ? ['sign'] : ['verify']          break        case 'RSA-OAEP':        case 'RSA-OAEP-256':        case 'RSA-OAEP-384':        case 'RSA-OAEP-512':          algorithm = {            name: 'RSA-OAEP',            hash: `SHA-${parseInt(jwk.alg.slice(-3), 10) || 1}`,          }          keyUsages = jwk.d ? ['decrypt', 'unwrapKey'] : ['encrypt', 'wrapKey']          break        default:          throw new JOSENotSupported('Invalid or unsupported JWK "alg" (Algorithm) Parameter value')      }      break    }    case 'EC': {      switch (jwk.alg) {        case 'ES256':          algorithm = { name: 'ECDSA', namedCurve: 'P-256' }          keyUsages = jwk.d ? ['sign'] : ['verify']          break        case 'ES384':          algorithm = { name: 'ECDSA', namedCurve: 'P-384' }          keyUsages = jwk.d ? ['sign'] : ['verify']          break        case 'ES512':          algorithm = { name: 'ECDSA', namedCurve: 'P-521' }          keyUsages = jwk.d ? ['sign'] : ['verify']          break        case 'ECDH-ES':        case 'ECDH-ES+A128KW':        case 'ECDH-ES+A192KW':        case 'ECDH-ES+A256KW':          algorithm = { name: 'ECDH', namedCurve: jwk.crv! }          keyUsages = jwk.d ? ['deriveBits'] : []          break        default:          throw new JOSENotSupported('Invalid or unsupported JWK "alg" (Algorithm) Parameter value')      }      break    }    case isCloudflareWorkers() && 'OKP':      if (jwk.alg !== 'EdDSA') {        throw new JOSENotSupported('Invalid or unsupported JWK "alg" (Algorithm) Parameter value')      }      switch (jwk.crv) {        case 'Ed25519':          algorithm = { name: 'NODE-ED25519', namedCurve: 'NODE-ED25519' }          keyUsages = jwk.d ? ['sign'] : ['verify']          break        default:          throw new JOSENotSupported(            'Invalid or unsupported JWK "crv" (Subtype of Key Pair) Parameter value',          )      }      break    default:      throw new JOSENotSupported('Invalid or unsupported JWK "kty" (Key Type) Parameter value')  }
  return { algorithm, keyUsages }}
const parse: JWKImportFunction = async (jwk: JWK): Promise<CryptoKey> => {  const { algorithm, keyUsages } = subtleMapping(jwk)  const rest: [RsaHashedImportParams | EcKeyAlgorithm | Algorithm, boolean, KeyUsage[]] = [    algorithm,    jwk.ext ?? false,    <KeyUsage[]>jwk.key_ops ?? keyUsages,  ]
  if (algorithm.name === 'PBKDF2') {    return crypto.subtle.importKey('raw', base64url(jwk.k!), ...rest)  }
  const keyData: JWK = { ...jwk }  delete keyData.alg  return crypto.subtle.importKey('jwk', keyData, ...rest)}export default parse