'use strict';

const {
  ObjectKeys,
  ObjectSetPrototypeOf,
} = primordials;

const kHashContextNode = 1;
const kHashContextWebCrypto = 2;
const kHashContextJwkRsa = 3;
const kHashContextJwkRsaPss = 4;
const kHashContextJwkRsaOaep = 5;
const kHashContextJwkHmac = 6;

// WebCrypto and JWK use a bunch of different names for the
// standard set of SHA-* digest algorithms... which is ... fun.
// Here we provide a utility for mapping between them in order
// make it easier in the code.

const kHashNames = {
  'sha1': {
    [kHashContextNode]: 'sha1',
    [kHashContextWebCrypto]: 'SHA-1',
    [kHashContextJwkRsa]: 'RS1',
    [kHashContextJwkRsaPss]: 'PS1',
    [kHashContextJwkRsaOaep]: 'RSA-OAEP',
    [kHashContextJwkHmac]: 'HS1',
  },
  'sha256': {
    [kHashContextNode]: 'sha256',
    [kHashContextWebCrypto]: 'SHA-256',
    [kHashContextJwkRsa]: 'RS256',
    [kHashContextJwkRsaPss]: 'PS256',
    [kHashContextJwkRsaOaep]: 'RSA-OAEP-256',
    [kHashContextJwkHmac]: 'HS256',
  },
  'sha384': {
    [kHashContextNode]: 'sha384',
    [kHashContextWebCrypto]: 'SHA-384',
    [kHashContextJwkRsa]: 'RS384',
    [kHashContextJwkRsaPss]: 'PS384',
    [kHashContextJwkRsaOaep]: 'RSA-OAEP-384',
    [kHashContextJwkHmac]: 'HS384',
  },
  'sha512': {
    [kHashContextNode]: 'sha512',
    [kHashContextWebCrypto]: 'SHA-512',
    [kHashContextJwkRsa]: 'RS512',
    [kHashContextJwkRsaPss]: 'PS512',
    [kHashContextJwkRsaOaep]: 'RSA-OAEP-512',
    [kHashContextJwkHmac]: 'HS512',
  },
  'shake128': {
    [kHashContextNode]: 'shake128',
    [kHashContextWebCrypto]: 'cSHAKE128',
  },
  'shake256': {
    [kHashContextNode]: 'shake256',
    [kHashContextWebCrypto]: 'cSHAKE256',
  },
  'sha3-256': {
    [kHashContextNode]: 'sha3-256',
    [kHashContextWebCrypto]: 'SHA3-256',
  },
  'sha3-384': {
    [kHashContextNode]: 'sha3-384',
    [kHashContextWebCrypto]: 'SHA3-384',
  },
  'sha3-512': {
    [kHashContextNode]: 'sha3-512',
    [kHashContextWebCrypto]: 'SHA3-512',
  },
};

// Both tables are indexed with computed keys, so a polluted %Object.prototype%
// key must not answer a miss. Detached here rather than declared
// `__proto__: null`: V8 puts that literal form in dictionary mode.
ObjectSetPrototypeOf(kHashNames, null);

{
  // Index the aliases
  const keys = ObjectKeys(kHashNames);
  for (let n = 0; n < keys.length; n++) {
    const entry = kHashNames[keys[n]];
    ObjectSetPrototypeOf(entry, null);
    const contexts = ObjectKeys(entry);
    for (let i = 0; i < contexts.length; i++) {
      const alias = entry[contexts[i]];
      if (kHashNames[alias] === undefined)
        kHashNames[alias] = entry;
    }
  }
}

function normalizeHashName(name, context = kHashContextNode) {
  return kHashNames[name]?.[context];
}


normalizeHashName.kContextNode = kHashContextNode;
normalizeHashName.kContextWebCrypto = kHashContextWebCrypto;
normalizeHashName.kContextJwkRsa = kHashContextJwkRsa;
normalizeHashName.kContextJwkRsaPss = kHashContextJwkRsaPss;
normalizeHashName.kContextJwkRsaOaep = kHashContextJwkRsaOaep;
normalizeHashName.kContextJwkHmac = kHashContextJwkHmac;

module.exports = normalizeHashName;