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import { getRuntimeKey } from '../../helper/adapter/index.ts'import { decodeBase64 } from '../encode.ts'import type { SignatureAlgorithm } from './jwa.ts'import { JwtAlgorithmNotImplemented } from './types.ts'import { CryptoKeyUsage } from './types.ts'import { utf8Encoder } from './utf8.ts'
// JSON Web Signature (JWS)// https://datatracker.ietf.org/doc/html/rfc7515
type KeyImporterAlgorithm = Parameters<typeof crypto.subtle.importKey>[2]type KeyAlgorithm =  | AlgorithmIdentifier  | RsaHashedImportParams  | (RsaPssParams & RsaHashedImportParams)  | (EcdsaParams & EcKeyImportParams)  | HmacImportParams
export type SignatureKey = string | JsonWebKey | CryptoKey
export async function signing(  privateKey: SignatureKey,  alg: SignatureAlgorithm,  data: BufferSource): Promise<ArrayBuffer> {  const algorithm = getKeyAlgorithm(alg)  const cryptoKey = await importPrivateKey(privateKey, algorithm)  return await crypto.subtle.sign(algorithm, cryptoKey, data)}
export async function verifying(  publicKey: SignatureKey,  alg: SignatureAlgorithm,  signature: BufferSource,  data: BufferSource): Promise<boolean> {  const algorithm = getKeyAlgorithm(alg)  const cryptoKey = await importPublicKey(publicKey, algorithm)  return await crypto.subtle.verify(algorithm, cryptoKey, signature, data)}
function pemToBinary(pem: string): Uint8Array {  return decodeBase64(pem.replace(/-+(BEGIN|END).*/g, '').replace(/\s/g, ''))}
async function importPrivateKey(key: SignatureKey, alg: KeyImporterAlgorithm): Promise<CryptoKey> {  if (!crypto.subtle || !crypto.subtle.importKey) {    throw new Error('`crypto.subtle.importKey` is undefined. JWT auth middleware requires it.')  }  if (isCryptoKey(key)) {    if (key.type !== 'private') {      throw new Error(`unexpected non private key: CryptoKey.type is ${key.type}`)    }    return key  }  const usages = [CryptoKeyUsage.Sign]  if (typeof key === 'object') {    // https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/importKey#json_web_key_import    return await crypto.subtle.importKey('jwk', key, alg, false, usages)  }  if (key.includes('PRIVATE')) {    // https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/importKey#pkcs_8_import    return await crypto.subtle.importKey('pkcs8', pemToBinary(key), alg, false, usages)  }  return await crypto.subtle.importKey('raw', utf8Encoder.encode(key), alg, false, usages)}
async function importPublicKey(key: SignatureKey, alg: KeyImporterAlgorithm): Promise<CryptoKey> {  if (!crypto.subtle || !crypto.subtle.importKey) {    throw new Error('`crypto.subtle.importKey` is undefined. JWT auth middleware requires it.')  }  if (isCryptoKey(key)) {    if (key.type === 'public' || key.type === 'secret') {      return key    }    key = await exportPublicJwkFrom(key)  }  if (typeof key === 'string' && key.includes('PRIVATE')) {    // https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/importKey#pkcs_8_import    const privateKey = await crypto.subtle.importKey('pkcs8', pemToBinary(key), alg, true, [      CryptoKeyUsage.Sign,    ])    key = await exportPublicJwkFrom(privateKey)  }  const usages = [CryptoKeyUsage.Verify]  if (typeof key === 'object') {    // https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/importKey#json_web_key_import    return await crypto.subtle.importKey('jwk', key, alg, false, usages)  }  if (key.includes('PUBLIC')) {    // https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/importKey#subjectpublickeyinfo_import    return await crypto.subtle.importKey('spki', pemToBinary(key), alg, false, usages)  }  return await crypto.subtle.importKey('raw', utf8Encoder.encode(key), alg, false, usages)}
// https://datatracker.ietf.org/doc/html/rfc7517async function exportPublicJwkFrom(privateKey: CryptoKey): Promise<JsonWebKey> {  if (privateKey.type !== 'private') {    throw new Error(`unexpected key type: ${privateKey.type}`)  }  if (!privateKey.extractable) {    throw new Error('unexpected private key is unextractable')  }  const jwk = await crypto.subtle.exportKey('jwk', privateKey)  const { kty } = jwk // common  const { alg, e, n } = jwk // rsa  const { crv, x, y } = jwk // elliptic-curve  return { kty, alg, e, n, crv, x, y, key_ops: [CryptoKeyUsage.Verify] }}
function getKeyAlgorithm(name: SignatureAlgorithm): KeyAlgorithm {  switch (name) {    case 'HS256':      return {        name: 'HMAC',        hash: {          name: 'SHA-256',        },      } satisfies HmacImportParams    case 'HS384':      return {        name: 'HMAC',        hash: {          name: 'SHA-384',        },      } satisfies HmacImportParams    case 'HS512':      return {        name: 'HMAC',        hash: {          name: 'SHA-512',        },      } satisfies HmacImportParams    case 'RS256':      return {        name: 'RSASSA-PKCS1-v1_5',        hash: {          name: 'SHA-256',        },      } satisfies RsaHashedImportParams    case 'RS384':      return {        name: 'RSASSA-PKCS1-v1_5',        hash: {          name: 'SHA-384',        },      } satisfies RsaHashedImportParams    case 'RS512':      return {        name: 'RSASSA-PKCS1-v1_5',        hash: {          name: 'SHA-512',        },      } satisfies RsaHashedImportParams    case 'PS256':      return {        name: 'RSA-PSS',        hash: {          name: 'SHA-256',        },        saltLength: 32, // 256 >> 3      } satisfies RsaPssParams & RsaHashedImportParams    case 'PS384':      return {        name: 'RSA-PSS',        hash: {          name: 'SHA-384',        },        saltLength: 48, // 384 >> 3      } satisfies RsaPssParams & RsaHashedImportParams    case 'PS512':      return {        name: 'RSA-PSS',        hash: {          name: 'SHA-512',        },        saltLength: 64, // 512 >> 3,      } satisfies RsaPssParams & RsaHashedImportParams    case 'ES256':      return {        name: 'ECDSA',        hash: {          name: 'SHA-256',        },        namedCurve: 'P-256',      } satisfies EcdsaParams & EcKeyImportParams    case 'ES384':      return {        name: 'ECDSA',        hash: {          name: 'SHA-384',        },        namedCurve: 'P-384',      } satisfies EcdsaParams & EcKeyImportParams    case 'ES512':      return {        name: 'ECDSA',        hash: {          name: 'SHA-512',        },        namedCurve: 'P-521',      } satisfies EcdsaParams & EcKeyImportParams    case 'EdDSA':      // Currently, supported only Safari and Deno, Node.js.      // See: https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/verify      return {        name: 'Ed25519',        namedCurve: 'Ed25519',      }    default:      throw new JwtAlgorithmNotImplemented(name)  }}
function isCryptoKey(key: SignatureKey): key is CryptoKey {  const runtime = getRuntimeKey()  // @ts-expect-error CryptoKey hasn't exported to global in node v18  if (runtime === 'node' && !!crypto.webcrypto) {    // @ts-expect-error CryptoKey hasn't exported to global in node v18    return key instanceof crypto.webcrypto.CryptoKey  }  return key instanceof CryptoKey}