/**
 * @license MIT <https://opensource.org/licenses/MIT>
 * @copyright Michael Hart 2024
 */
const encoder = new TextEncoder();
const HOST_SERVICES = {
  appstream2: 'appstream',
  cloudhsmv2: 'cloudhsm',
  email: 'ses',
  marketplace: 'aws-marketplace',
  mobile: 'AWSMobileHubService',
  pinpoint: 'mobiletargeting',
  queue: 'sqs',
  'git-codecommit': 'codecommit',
  'mturk-requester-sandbox': 'mturk-requester',
  'personalize-runtime': 'personalize',
};
const UNSIGNABLE_HEADERS = new Set([
  'authorization',
  'content-type',
  'content-length',
  'user-agent',
  'presigned-expires',
  'expect',
  'x-amzn-trace-id',
  'range',
  'connection',
]);
class AwsClient {
  constructor({ accessKeyId, secretAccessKey, sessionToken, service, region, cache, retries, initRetryMs }) {
    if (accessKeyId == null) throw new TypeError('accessKeyId is a required option')
    if (secretAccessKey == null) throw new TypeError('secretAccessKey is a required option')
    this.accessKeyId = accessKeyId;
    this.secretAccessKey = secretAccessKey;
    this.sessionToken = sessionToken;
    this.service = service;
    this.region = region;
    this.cache = cache || new Map();
    this.retries = retries != null ? retries : 10;
    this.initRetryMs = initRetryMs || 50;
  }
  async sign(input, init) {
    if (input instanceof Request) {
      const { method, url, headers, body } = input;
      init = Object.assign({ method, url, headers }, init);
      if (init.body == null && headers.has('Content-Type')) {
        init.body = body != null && headers.has('X-Amz-Content-Sha256') ? body : await input.clone().arrayBuffer();
      }
      input = url;
    }
    const signer = new AwsV4Signer(Object.assign({ url: input.toString() }, init, this, init && init.aws));
    const signed = Object.assign({}, init, await signer.sign());
    delete signed.aws;
    try {
      return new Request(signed.url.toString(), signed)
    } catch (e) {
      if (e instanceof TypeError) {
        return new Request(signed.url.toString(), Object.assign({ duplex: 'half' }, signed))
      }
      throw e
    }
  }
  async fetch(input, init) {
    for (let i = 0; i <= this.retries; i++) {
      const fetched = fetch(await this.sign(input, init));
      if (i === this.retries) {
        return fetched
      }
      const res = await fetched;
      if (res.status < 500 && res.status !== 429) {
        return res
      }
      await new Promise(resolve => setTimeout(resolve, Math.random() * this.initRetryMs * Math.pow(2, i)));
    }
    throw new Error('An unknown error occurred, ensure retries is not negative')
  }
}
class AwsV4Signer {
  constructor({ method, url, headers, body, accessKeyId, secretAccessKey, sessionToken, service, region, cache, datetime, signQuery, appendSessionToken, allHeaders, singleEncode }) {
    if (url == null) throw new TypeError('url is a required option')
    if (accessKeyId == null) throw new TypeError('accessKeyId is a required option')
    if (secretAccessKey == null) throw new TypeError('secretAccessKey is a required option')
    this.method = method || (body ? 'POST' : 'GET');
    this.url = new URL(url);
    this.headers = new Headers(headers || {});
    this.body = body;
    this.accessKeyId = accessKeyId;
    this.secretAccessKey = secretAccessKey;
    this.sessionToken = sessionToken;
    let guessedService, guessedRegion;
    if (!service || !region) {
[guessedService, guessedRegion] = guessServiceRegion(this.url, this.headers);
    }
    this.service = service || guessedService || '';
    this.region = region || guessedRegion || 'us-east-1';
    this.cache = cache || new Map();
    this.datetime = datetime || new Date().toISOString().replace(/[:-]|\.\d{3}/g, '');
    this.signQuery = signQuery;
    this.appendSessionToken = appendSessionToken || this.service === 'iotdevicegateway';
    this.headers.delete('Host');
    if (this.service === 's3' && !this.signQuery && !this.headers.has('X-Amz-Content-Sha256')) {
      this.headers.set('X-Amz-Content-Sha256', 'UNSIGNED-PAYLOAD');
    }
    const params = this.signQuery ? this.url.searchParams : this.headers;
    params.set('X-Amz-Date', this.datetime);
    if (this.sessionToken && !this.appendSessionToken) {
      params.set('X-Amz-Security-Token', this.sessionToken);
    }
    this.signableHeaders = ['host', ...this.headers.keys()]
      .filter(header => allHeaders || !UNSIGNABLE_HEADERS.has(header))
      .sort();
    this.signedHeaders = this.signableHeaders.join(';');
    this.canonicalHeaders = this.signableHeaders
      .map(header => header + ':' + (header === 'host' ? this.url.host : (this.headers.get(header) || '').replace(/\s+/g, ' ')))
      .join('\n');
    this.credentialString = [this.datetime.slice(0, 8), this.region, this.service, 'aws4_request'].join('/');
    if (this.signQuery) {
      if (this.service === 's3' && !params.has('X-Amz-Expires')) {
        params.set('X-Amz-Expires', '86400');
      }
      params.set('X-Amz-Algorithm', 'AWS4-HMAC-SHA256');
      params.set('X-Amz-Credential', this.accessKeyId + '/' + this.credentialString);
      params.set('X-Amz-SignedHeaders', this.signedHeaders);
    }
    if (this.service === 's3') {
      try {
        this.encodedPath = decodeURIComponent(this.url.pathname.replace(/\+/g, ' '));
      } catch (e) {
        this.encodedPath = this.url.pathname;
      }
    } else {
      this.encodedPath = this.url.pathname.replace(/\/+/g, '/');
    }
    if (!singleEncode) {
      this.encodedPath = encodeURIComponent(this.encodedPath).replace(/%2F/g, '/');
    }
    this.encodedPath = encodeRfc3986(this.encodedPath);
    const seenKeys = new Set();
    this.encodedSearch = [...this.url.searchParams]
      .filter(([k]) => {
        if (!k) return false
        if (this.service === 's3') {
          if (seenKeys.has(k)) return false
          seenKeys.add(k);
        }
        return true
      })
      .map(pair => pair.map(p => encodeRfc3986(encodeURIComponent(p))))
      .sort(([k1, v1], [k2, v2]) => k1 < k2 ? -1 : k1 > k2 ? 1 : v1 < v2 ? -1 : v1 > v2 ? 1 : 0)
      .map(pair => pair.join('='))
      .join('&');
  }
  async sign() {
    if (this.signQuery) {
      this.url.searchParams.set('X-Amz-Signature', await this.signature());
      if (this.sessionToken && this.appendSessionToken) {
        this.url.searchParams.set('X-Amz-Security-Token', this.sessionToken);
      }
    } else {
      this.headers.set('Authorization', await this.authHeader());
    }
    return {
      method: this.method,
      url: this.url,
      headers: this.headers,
      body: this.body,
    }
  }
  async authHeader() {
    return [
      'AWS4-HMAC-SHA256 Credential=' + this.accessKeyId + '/' + this.credentialString,
      'SignedHeaders=' + this.signedHeaders,
      'Signature=' + (await this.signature()),
    ].join(', ')
  }
  async signature() {
    const date = this.datetime.slice(0, 8);
    const cacheKey = [this.secretAccessKey, date, this.region, this.service].join();
    let kCredentials = this.cache.get(cacheKey);
    if (!kCredentials) {
      const kDate = await hmac('AWS4' + this.secretAccessKey, date);
      const kRegion = await hmac(kDate, this.region);
      const kService = await hmac(kRegion, this.service);
      kCredentials = await hmac(kService, 'aws4_request');
      this.cache.set(cacheKey, kCredentials);
    }
    return buf2hex(await hmac(kCredentials, await this.stringToSign()))
  }
  async stringToSign() {
    return [
      'AWS4-HMAC-SHA256',
      this.datetime,
      this.credentialString,
      buf2hex(await hash(await this.canonicalString())),
    ].join('\n')
  }
  async canonicalString() {
    return [
      this.method.toUpperCase(),
      this.encodedPath,
      this.encodedSearch,
      this.canonicalHeaders + '\n',
      this.signedHeaders,
      await this.hexBodyHash(),
    ].join('\n')
  }
  async hexBodyHash() {
    let hashHeader = this.headers.get('X-Amz-Content-Sha256') || (this.service === 's3' && this.signQuery ? 'UNSIGNED-PAYLOAD' : null);
    if (hashHeader == null) {
      if (this.body && typeof this.body !== 'string' && !('byteLength' in this.body)) {
        throw new Error('body must be a string, ArrayBuffer or ArrayBufferView, unless you include the X-Amz-Content-Sha256 header')
      }
      hashHeader = buf2hex(await hash(this.body || ''));
    }
    return hashHeader
  }
}
async function hmac(key, string) {
  const cryptoKey = await crypto.subtle.importKey(
    'raw',
    typeof key === 'string' ? encoder.encode(key) : key,
    { name: 'HMAC', hash: { name: 'SHA-256' } },
    false,
    ['sign'],
  );
  return crypto.subtle.sign('HMAC', cryptoKey, encoder.encode(string))
}
async function hash(content) {
  return crypto.subtle.digest('SHA-256', typeof content === 'string' ? encoder.encode(content) : content)
}
const HEX_CHARS = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'];
function buf2hex(arrayBuffer) {
  const buffer = new Uint8Array(arrayBuffer);
  let out = '';
  for (let idx = 0; idx < buffer.length; idx++) {
    const n = buffer[idx];
    out += HEX_CHARS[(n >>> 4) & 0xF];
    out += HEX_CHARS[n & 0xF];
  }
  return out
}
function encodeRfc3986(urlEncodedStr) {
  return urlEncodedStr.replace(/[!'()*]/g, c => '%' + c.charCodeAt(0).toString(16).toUpperCase())
}
function guessServiceRegion(url, headers) {
  const { hostname, pathname } = url;
  if (hostname.endsWith('.on.aws')) {
    const match = hostname.match(/^[^.]{1,63}\.lambda-url\.([^.]{1,63})\.on\.aws$/);
    return match != null ? ['lambda', match[1] || ''] : ['', '']
  }
  if (hostname.endsWith('.r2.cloudflarestorage.com')) {
    return ['s3', 'auto']
  }
  if (hostname.endsWith('.backblazeb2.com')) {
    const match = hostname.match(/^(?:[^.]{1,63}\.)?s3\.([^.]{1,63})\.backblazeb2\.com$/);
    return match != null ? ['s3', match[1] || ''] : ['', '']
  }
  const match = hostname.replace('dualstack.', '').match(/([^.]{1,63})\.(?:([^.]{0,63})\.)?amazonaws\.com(?:\.cn)?$/);
  let service = (match && match[1]) || '';
  let region = match && match[2];
  if (region === 'us-gov') {
    region = 'us-gov-west-1';
  } else if (region === 's3' || region === 's3-accelerate') {
    region = 'us-east-1';
    service = 's3';
  } else if (service === 'iot') {
    if (hostname.startsWith('iot.')) {
      service = 'execute-api';
    } else if (hostname.startsWith('data.jobs.iot.')) {
      service = 'iot-jobs-data';
    } else {
      service = pathname === '/mqtt' ? 'iotdevicegateway' : 'iotdata';
    }
  } else if (service === 'autoscaling') {
    const targetPrefix = (headers.get('X-Amz-Target') || '').split('.')[0];
    if (targetPrefix === 'AnyScaleFrontendService') {
      service = 'application-autoscaling';
    } else if (targetPrefix === 'AnyScaleScalingPlannerFrontendService') {
      service = 'autoscaling-plans';
    }
  } else if (region == null && service.startsWith('s3-')) {
    region = service.slice(3).replace(/^fips-|^external-1/, '');
    service = 's3';
  } else if (service.endsWith('-fips')) {
    service = service.slice(0, -5);
  } else if (region && /-\d$/.test(service) && !/-\d$/.test(region)) {
[service, region] = [region, service];
  }
  return [HOST_SERVICES[service] || service, region || '']
}

export { AwsClient, AwsV4Signer };