// Copyright 2018-present AJ ONeal. All rights reserved
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
'use strict';
/* globals Promise */

require('@root/encoding/bytes');
var Enc = require('@root/encoding/base64');
var ACME = module.exports;
var Keypairs = require('@root/keypairs');
var CSR = require('@root/csr');
var sha2 = require('@root/keypairs/lib/node/sha2.js');
var http = require('./lib/node/http.js');

var native = require('./native.js');

ACME.formatPemChain = function formatPemChain(str) {
	return (
		str
			.trim()
			.replace(/[\r\n]+/g, '\n')
			.replace(/\-\n\-/g, '-\n\n-') + '\n'
	);
};
ACME.splitPemChain = function splitPemChain(str) {
	return str
		.trim()
		.split(/[\r\n]{2,}/g)
		.map(function(str) {
			return str + '\n';
		});
};

// http-01: GET https://example.org/.well-known/acme-challenge/{{token}} => {{keyAuth}}
// dns-01: TXT _acme-challenge.example.org. => "{{urlSafeBase64(sha256(keyAuth))}}"
ACME.challengePrefixes = {
	'http-01': '/.well-known/acme-challenge',
	'dns-01': '_acme-challenge'
};
ACME.challengeTests = {
	'http-01': function(me, auth) {
		var ch = auth.challenge;
		return me.http01(ch).then(function(keyAuth) {
			var err;

			// TODO limit the number of bytes that are allowed to be downloaded
			if (ch.keyAuthorization === (keyAuth || '').trim()) {
				return true;
			}

			err = new Error(
				'Error: Failed HTTP-01 Pre-Flight / Dry Run.\n' +
					"curl '" +
					ch.challengeUrl +
					"'\n" +
					"Expected: '" +
					ch.keyAuthorization +
					"'\n" +
					"Got: '" +
					keyAuth +
					"'\n" +
					'See https://git.coolaj86.com/coolaj86/acme-v2.js/issues/4'
			);
			err.code = 'E_FAIL_DRY_CHALLENGE';
			return Promise.reject(err);
		});
	},
	'dns-01': function(me, auth) {
		// remove leading *. on wildcard domains
		var ch = auth.challenge;
		return me.dns01(ch).then(function(ans) {
			var err;

			if (
				ans.answer.some(function(txt) {
					return ch.dnsAuthorization === txt.data[0];
				})
			) {
				return true;
			}

			err = new Error(
				'Error: Failed DNS-01 Pre-Flight Dry Run.\n' +
					"dig TXT '" +
					ch.dnsHost +
					"' does not return '" +
					ch.dnsAuthorization +
					"'\n" +
					'See https://git.coolaj86.com/coolaj86/acme-v2.js/issues/4'
			);
			err.code = 'E_FAIL_DRY_CHALLENGE';
			return Promise.reject(err);
		});
	}
};

ACME._directory = function(me) {
	// GET-as-GET ok
	// TODO cache the directory URL
	return me.request({ method: 'GET', url: me.directoryUrl, json: true });
};
ACME._getNonce = function(me) {
	// GET-as-GET, HEAD-as-HEAD ok
	var nonce;
	while (true) {
		nonce = me._nonces.shift();
		if (!nonce) {
			break;
		}
		if (Date.now() - nonce.createdAt > 15 * 60 * 1000) {
			nonce = null;
		} else {
			break;
		}
	}
	if (nonce) {
		return Promise.resolve(nonce.nonce);
	}
	return me
		.request({ method: 'HEAD', url: me._directoryUrls.newNonce })
		.then(function(resp) {
			return resp.headers['replay-nonce'];
		});
};
ACME._setNonce = function(me, nonce) {
	me._nonces.unshift({ nonce: nonce, createdAt: Date.now() });
};
// ACME RFC Section 7.3 Account Creation
/*
 {
   "protected": base64url({
     "alg": "ES256",
     "jwk": {...},
     "nonce": "6S8IqOGY7eL2lsGoTZYifg",
     "url": "https://example.com/acme/new-account"
   }),
   "payload": base64url({
     "termsOfServiceAgreed": true,
     "onlyReturnExisting": false,
     "contact": [
       "mailto:cert-admin@example.com",
       "mailto:admin@example.com"
     ]
   }),
   "signature": "RZPOnYoPs1PhjszF...-nh6X1qtOFPB519I"
 }
*/
ACME._registerAccount = function(me, options) {
	if (me.debug) {
		console.debug('[acme-v2] accounts.create');
	}

	return new Promise(function(resolve, reject) {
		function agree(tosUrl) {
			var err;
			if (me._tos !== tosUrl) {
				err = new Error(
					"You must agree to the ToS at '" + me._tos + "'"
				);
				err.code = 'E_AGREE_TOS';
				reject(err);
				return;
			}

			return ACME._importKeypair(me, options.accountKeypair).then(
				function(pair) {
					var contact;
					if (options.contact) {
						contact = options.contact.slice(0);
					} else if (options.subscriberEmail || options.email) {
						contact = [
							'mailto:' +
								(options.subscriberEmail || options.email)
						];
					}
					var accountRequest = {
						termsOfServiceAgreed: tosUrl === me._tos,
						onlyReturnExisting: false,
						contact: contact
					};
					var pExt;
					if (options.externalAccount) {
						pExt = me.Keypairs.signJws({
							// TODO is HMAC the standard, or is this arbitrary?
							secret: options.externalAccount.secret,
							protected: {
								alg: options.externalAccount.alg || 'HS256',
								kid: options.externalAccount.id,
								url: me._directoryUrls.newAccount
							},
							payload: Enc.strToBuf(JSON.stringify(pair.public))
						}).then(function(jws) {
							accountRequest.externalAccountBinding = jws;
							return accountRequest;
						});
					} else {
						pExt = Promise.resolve(accountRequest);
					}
					return pExt.then(function(accountRequest) {
						var payload = JSON.stringify(accountRequest);
						return ACME._jwsRequest(me, {
							options: options,
							url: me._directoryUrls.newAccount,
							protected: { kid: false, jwk: pair.public },
							payload: Enc.strToBuf(payload)
						})
							.then(function(resp) {
								var account = resp.body;

								if (
									resp.statusCode < 200 ||
									resp.statusCode >= 300
								) {
									if ('string' !== typeof account) {
										account = JSON.stringify(account);
									}
									throw new Error(
										'account error: ' +
											resp.statusCode +
											' ' +
											account +
											'\n' +
											JSON.stringify(accountRequest)
									);
								}

								var location = resp.headers.location;
								// the account id url
								options._kid = location;
								if (me.debug) {
									console.debug(
										'[DEBUG] new account location:'
									);
								}
								if (me.debug) {
									console.debug(location);
								}
								if (me.debug) {
									console.debug(resp);
								}

								/*
            {
              contact: ["mailto:jon@example.com"],
              orders: "https://some-url",
              status: 'valid'
            }
            */
								if (!account) {
									account = { _emptyResponse: true };
								}
								// https://git.coolaj86.com/coolaj86/acme-v2.js/issues/8
								if (!account.key) {
									account.key = {};
								}
								account.key.kid = options._kid;
								return account;
							})
							.then(resolve, reject);
					});
				}
			);
		}

		if (me.debug) {
			console.debug('[acme-v2] agreeToTerms');
		}
		if (1 === options.agreeToTerms.length) {
			// newer promise API
			return Promise.resolve(options.agreeToTerms(me._tos)).then(
				agree,
				reject
			);
		} else if (2 === options.agreeToTerms.length) {
			// backwards compat cb API
			return options.agreeToTerms(me._tos, function(err, tosUrl) {
				if (!err) {
					agree(tosUrl);
					return;
				}
				reject(err);
			});
		} else {
			reject(
				new Error(
					'agreeToTerms has incorrect function signature.' +
						' Should be fn(tos) { return Promise<tos>; }'
				)
			);
		}
	});
};
/*
 POST /acme/new-order HTTP/1.1
 Host: example.com
 Content-Type: application/jose+json

 {
   "protected": base64url({
     "alg": "ES256",
     "kid": "https://example.com/acme/acct/1",
     "nonce": "5XJ1L3lEkMG7tR6pA00clA",
     "url": "https://example.com/acme/new-order"
   }),
   "payload": base64url({
     "identifiers": [{"type:"dns","value":"example.com"}],
     "notBefore": "2016-01-01T00:00:00Z",
     "notAfter": "2016-01-08T00:00:00Z"
   }),
   "signature": "H6ZXtGjTZyUnPeKn...wEA4TklBdh3e454g"
 }
*/
ACME._getChallenges = function(me, options, authUrl) {
	if (me.debug) {
		console.debug('\n[DEBUG] getChallenges\n');
	}
	// TODO POST-as-GET

	return ACME._jwsRequest(me, {
		options: options,
		protected: {},
		payload: '',
		url: authUrl
	}).then(function(resp) {
		return resp.body;
	});
};
ACME._wait = function wait(ms) {
	return new Promise(function(resolve) {
		setTimeout(resolve, ms || 1100);
	});
};

ACME._testChallengeOptions = function() {
	var chToken = ACME._prnd(16);
	return [
		{
			type: 'http-01',
			status: 'pending',
			url: 'https://acme-staging-v02.example.com/0',
			token: 'test-' + chToken + '-0'
		},
		{
			type: 'dns-01',
			status: 'pending',
			url: 'https://acme-staging-v02.example.com/1',
			token: 'test-' + chToken + '-1',
			_wildcard: true
		},
		{
			type: 'tls-alpn-01',
			status: 'pending',
			url: 'https://acme-staging-v02.example.com/3',
			token: 'test-' + chToken + '-3'
		}
	];
};
ACME._testChallenges = function(me, options) {
	var CHECK_DELAY = 0;

	// memoized so that it doesn't run until it's first called
	var getThumbnail = function() {
		var thumbPromise = ACME._importKeypair(me, options.accountKeypair).then(
			function(pair) {
				return me.Keypairs.thumbprint({
					jwk: pair.public
				});
			}
		);
		getThumbnail = function() {
			return thumbPromise;
		};
		return thumbPromise;
	};

	return Promise.all(
		options.domains.map(function(identifierValue) {
			// TODO we really only need one to pass, not all to pass
			var challenges = ACME._testChallengeOptions();
			if (identifierValue.includes('*')) {
				challenges = challenges.filter(function(ch) {
					return ch._wildcard;
				});
			}

			var challenge = ACME._chooseChallenge(options, {
				challenges: challenges
			});
			if (!challenge) {
				// For example, wildcards require dns-01 and, if we don't have that, we have to bail
				var enabled = options.challengeTypes.join(', ') || 'none';
				var suitable =
					challenges
						.map(function(r) {
							return r.type;
						})
						.join(', ') || 'none';
				return Promise.reject(
					new Error(
						"None of the challenge types that you've enabled ( " +
							enabled +
							' )' +
							" are suitable for validating the domain you've selected (" +
							identifierValue +
							').' +
							' You must enable one of ( ' +
							suitable +
							' ).'
					)
				);
			}

			// TODO remove skipChallengeTest
			if (me.skipDryRun || me.skipChallengeTest) {
				return null;
			}

			if ('dns-01' === challenge.type) {
				// Give the nameservers a moment to propagate
				// TODO get this value from the plugin
				CHECK_DELAY = 7 * 1000;
			}

			return getThumbnail().then(function(accountKeyThumb) {
				var results = {
					identifier: {
						type: 'dns',
						value: identifierValue.replace(/^\*\./, '')
					},
					challenges: [challenge],
					expires: new Date(Date.now() + 60 * 1000).toISOString(),
					wildcard: identifierValue.includes('*.') || undefined
				};

				// The dry-run comes first in the spirit of "fail fast"
				// (and protecting against challenge failure rate limits)
				var dryrun = true;
				return ACME._challengeToAuth(
					me,
					options,
					accountKeyThumb,
					results,
					challenge,
					dryrun
				).then(function(auth) {
					if (!me._canUse[auth.type]) {
						return;
					}
					return ACME._setChallenge(me, options, auth).then(
						function() {
							return auth;
						}
					);
				});
			});
		})
	).then(function(auths) {
		auths = auths.filter(Boolean);
		if (!auths.length) {
			/*skip actual test*/ return;
		}
		return ACME._wait(CHECK_DELAY).then(function() {
			return Promise.all(
				auths.map(function(auth) {
					return ACME.challengeTests[auth.type](me, auth)
						.then(function(result) {
							// not a blocker
							ACME._removeChallenge(me, options, auth);
							return result;
						})
						.catch(function(err) {
							ACME._removeChallenge(me, options, auth);
							throw err;
						});
				})
			);
		});
	});
};
ACME._chooseChallenge = function(options, results) {
	// For each of the challenge types that we support
	var challenge;
	options.challengeTypes.some(function(chType) {
		// And for each of the challenge types that are allowed
		return results.challenges.some(function(ch) {
			// Check to see if there are any matches
			if (ch.type === chType) {
				challenge = ch;
				return true;
			}
		});
	});

	return challenge;
};
ACME._challengeToAuth = function(
	me,
	options,
	accountKeyThumb,
	request,
	challenge,
	dryrun
) {
	// we don't poison the dns cache with our dummy request
	var dnsPrefix = ACME.challengePrefixes['dns-01'];
	if (dryrun) {
		dnsPrefix = dnsPrefix.replace(
			'acme-challenge',
			'greenlock-dryrun-' + ACME._prnd(4)
		);
	}

	var auth = {};

	// straight copy from the new order response
	// { identifier, status, expires, challenges, wildcard }
	Object.keys(request).forEach(function(key) {
		auth[key] = request[key];
	});

	// copy from the challenge we've chosen
	// { type, status, url, token }
	// (note the duplicate status overwrites the one above, but they should be the same)
	Object.keys(challenge).forEach(function(key) {
		// don't confused devs with the id url
		auth[key] = challenge[key];
	});

	var zone = pluckZone(options.zonenames || [], auth.identifier.value);
	// batteries-included helpers
	auth.hostname = auth.identifier.value;
	// because I'm not 100% clear if the wildcard identifier does or doesn't have the leading *. in all cases
	auth.altname = ACME._untame(auth.identifier.value, auth.wildcard);
	// we must accept JWKs that we didn't generate and we can't guarantee
	// that they properly set kid to thumbnail (especially since ACME doesn't do this)
	// so we have to regenerate it every time we need it, which is quite often
	auth.thumbprint = accountKeyThumb;
	//   keyAuthorization = token || '.' || base64url(JWK_Thumbprint(accountKey))
	auth.keyAuthorization = challenge.token + '.' + auth.thumbprint;
	// conflicts with ACME challenge id url is already in use, so we call this challengeUrl instead
	// TODO auth.http01Url ?
	auth.challengeUrl =
		'http://' +
		auth.identifier.value +
		ACME.challengePrefixes['http-01'] +
		'/' +
		auth.token;
	auth.dnsHost = dnsPrefix + '.' + auth.hostname.replace('*.', '');

	// Always calculate dnsAuthorization because we
	// may need to present to the user for confirmation / instruction
	// _as part of_ the decision making process
	return sha2
		.sum(256, auth.keyAuthorization)
		.then(function(hash) {
			return Enc.bufToUrlBase64(new Uint8Array(hash));
		})
		.then(function(hash64) {
			auth.dnsAuthorization = hash64;
			if (zone) {
				auth.dnsZone = zone;
				auth.dnsPrefix = auth.dnsHost
					.replace(newZoneRegExp(zone), '')
					.replace(/\.$/, '');
			}

			// For backwards compat with the v2.7 plugins
			auth.challenge = auth;
			// TODO can we use just { challenge: auth }?
			// auth.request = ;

			// TODO get rid of no-challenge backwards compat challenge
			return {
				challenge: auth,
				request: function() {
					// TODO see https://git.rootprojects.org/root/acme.js/issues/###
					console.warn(
						"[warn] deprecated use of request on '" +
							auth.type +
							"' challenge object. Receive from challenger.init() instead."
					);
					me.request.apply(null, arguments);
				}
			};
		});
};

ACME._untame = function(name, wild) {
	if (wild) {
		name = '*.' + name.replace('*.', '');
	}
	return name;
};

// https://tools.ietf.org/html/draft-ietf-acme-acme-10#section-7.5.1
ACME._postChallenge = function(me, options, auth) {
	var RETRY_INTERVAL = me.retryInterval || 1000;
	var DEAUTH_INTERVAL = me.deauthWait || 10 * 1000;
	var MAX_POLL = me.retryPoll || 8;
	var MAX_PEND = me.retryPending || 4;
	var count = 0;
	var ch = auth.challenge;

	var altname = ACME._untame(ch.identifier.value, ch.wildcard);

	/*
   POST /acme/authz/1234 HTTP/1.1
   Host: example.com
   Content-Type: application/jose+json

   {
     "protected": base64url({
       "alg": "ES256",
       "kid": "https://example.com/acme/acct/1",
       "nonce": "xWCM9lGbIyCgue8di6ueWQ",
       "url": "https://example.com/acme/authz/1234"
     }),
     "payload": base64url({
       "status": "deactivated"
     }),
     "signature": "srX9Ji7Le9bjszhu...WTFdtujObzMtZcx4"
   }
   */
	function deactivate() {
		if (me.debug) {
			console.debug('[acme-v2.js] deactivate:');
		}
		return ACME._jwsRequest(me, {
			options: options,
			url: ch.url,
			protected: { kid: options._kid },
			payload: Enc.strToBuf(JSON.stringify({ status: 'deactivated' }))
		}).then(function(resp) {
			if (me.debug) {
				console.debug('deactivate challenge: resp.body:');
			}
			if (me.debug) {
				console.debug(resp.body);
			}
			return ACME._wait(DEAUTH_INTERVAL);
		});
	}

	function pollStatus() {
		if (count >= MAX_POLL) {
			return Promise.reject(
				new Error(
					"[acme-v2] stuck in bad pending/processing state for '" +
						altname +
						"'"
				)
			);
		}

		count += 1;

		if (me.debug) {
			console.debug('\n[DEBUG] statusChallenge\n');
		}
		// TODO POST-as-GET
		return me
			.request({ method: 'GET', url: ch.url, json: true })
			.then(function(resp) {
				if ('processing' === resp.body.status) {
					if (me.debug) {
						console.debug('poll: again', ch.url);
					}
					return ACME._wait(RETRY_INTERVAL).then(pollStatus);
				}

				// This state should never occur
				if ('pending' === resp.body.status) {
					if (count >= MAX_PEND) {
						return ACME._wait(RETRY_INTERVAL)
							.then(deactivate)
							.then(respondToChallenge);
					}
					if (me.debug) {
						console.debug('poll: again', ch.url);
					}
					return ACME._wait(RETRY_INTERVAL).then(respondToChallenge);
				}

				// REMOVE DNS records as soon as the state is non-processing
				try {
					ACME._removeChallenge(me, options, auth);
				} catch (e) {}

				if ('valid' === resp.body.status) {
					if (me.debug) {
						console.debug('poll: valid');
					}

					return resp.body;
				}

				var errmsg;
				if (!resp.body.status) {
					errmsg =
						"[acme-v2] (E_STATE_EMPTY) empty challenge state for '" +
						altname +
						"':";
				} else if ('invalid' === resp.body.status) {
					errmsg =
						"[acme-v2] (E_STATE_INVALID) challenge state for '" +
						altname +
						"': '" +
						//resp.body.status +
						JSON.stringify(resp.body) +
						"'";
				} else {
					errmsg =
						"[acme-v2] (E_STATE_UKN) challenge state for '" +
						altname +
						"': '" +
						resp.body.status +
						"'";
				}

				return Promise.reject(new Error(errmsg));
			});
	}

	function respondToChallenge() {
		if (me.debug) {
			console.debug('[acme-v2.js] responding to accept challenge:');
		}
		return ACME._jwsRequest(me, {
			options: options,
			url: ch.url,
			protected: { kid: options._kid },
			payload: Enc.strToBuf(JSON.stringify({}))
		}).then(function(resp) {
			if (me.debug) {
				console.debug('respond to challenge: resp.body:');
			}
			if (me.debug) {
				console.debug(resp.body);
			}
			return ACME._wait(RETRY_INTERVAL).then(pollStatus);
		});
	}

	return respondToChallenge();
};
ACME._setChallenge = function(me, options, auth) {
	var ch = auth.challenge;
	return Promise.resolve().then(function() {
		var challengers = options.challenges || {};
		var challenger = challengers[ch.type] && challengers[ch.type].set;
		if (!challenger) {
			throw new Error(
				"options.challenges did not have a valid entry for '" +
					ch.type +
					"'"
			);
		}
		if (1 === challenger.length) {
			return Promise.resolve(challenger(auth));
		} else if (2 === challenger.length) {
			return new Promise(function(resolve, reject) {
				challenger(auth, function(err) {
					if (err) {
						reject(err);
					} else {
						resolve();
					}
				});
			});
		} else {
			throw new Error(
				"Bad function signature for '" + ch.type + "' challenge.set()"
			);
		}
	});
};
ACME._finalizeOrder = function(me, options, validatedDomains) {
	if (me.debug) {
		console.debug('finalizeOrder:');
	}
	return ACME._generateCsrWeb64(me, options, validatedDomains).then(function(
		csr
	) {
		var body = { csr: csr };
		var payload = JSON.stringify(body);

		function pollCert() {
			if (me.debug) {
				console.debug('[acme-v2.js] pollCert:');
			}
			return ACME._jwsRequest(me, {
				options: options,
				url: options._finalize,
				protected: { kid: options._kid },
				payload: Enc.strToBuf(payload)
			}).then(function(resp) {
				if (me.debug) {
					console.debug('order finalized: resp.body:');
				}
				if (me.debug) {
					console.debug(resp.body);
				}

				// https://tools.ietf.org/html/draft-ietf-acme-acme-12#section-7.1.3
				// Possible values are: "pending" => ("invalid" || "ready") => "processing" => "valid"
				if ('valid' === resp.body.status) {
					options._expires = resp.body.expires;
					options._certificate = resp.body.certificate;

					return resp.body; // return order
				}

				if ('processing' === resp.body.status) {
					return ACME._wait().then(pollCert);
				}

				if (me.debug) {
					console.debug(
						'Error: bad status:\n' +
							JSON.stringify(resp.body, null, 2)
					);
				}

				if ('pending' === resp.body.status) {
					return Promise.reject(
						new Error(
							"Did not finalize order: status 'pending'." +
								' Best guess: You have not accepted at least one challenge for each domain:\n' +
								"Requested: '" +
								options.domains.join(', ') +
								"'\n" +
								"Validated: '" +
								validatedDomains.join(', ') +
								"'\n" +
								JSON.stringify(resp.body, null, 2)
						)
					);
				}

				if ('invalid' === resp.body.status) {
					return Promise.reject(
						new Error(
							"Did not finalize order: status 'invalid'." +
								' Best guess: One or more of the domain challenges could not be verified' +
								' (or the order was canceled).\n' +
								"Requested: '" +
								options.domains.join(', ') +
								"'\n" +
								"Validated: '" +
								validatedDomains.join(', ') +
								"'\n" +
								JSON.stringify(resp.body, null, 2)
						)
					);
				}

				if ('ready' === resp.body.status) {
					return Promise.reject(
						new Error(
							"Did not finalize order: status 'ready'." +
								" Hmmm... this state shouldn't be possible here. That was the last state." +
								" This one should at least be 'processing'.\n" +
								"Requested: '" +
								options.domains.join(', ') +
								"'\n" +
								"Validated: '" +
								validatedDomains.join(', ') +
								"'\n" +
								JSON.stringify(resp.body, null, 2) +
								'\n\n' +
								'Please open an issue at https://git.coolaj86.com/coolaj86/acme-v2.js'
						)
					);
				}

				return Promise.reject(
					new Error(
						"Didn't finalize order: Unhandled status '" +
							resp.body.status +
							"'." +
							' This is not one of the known statuses...\n' +
							"Requested: '" +
							options.domains.join(', ') +
							"'\n" +
							"Validated: '" +
							validatedDomains.join(', ') +
							"'\n" +
							JSON.stringify(resp.body, null, 2) +
							'\n\n' +
							'Please open an issue at https://git.coolaj86.com/coolaj86/acme-v2.js'
					)
				);
			});
		}

		return pollCert();
	});
};
// _kid
// registerAccount
// postChallenge
// finalizeOrder
// getCertificate
ACME._getCertificate = function(me, options) {
	if (me.debug) {
		console.debug('[acme-v2] DEBUG get cert 1');
	}

	// Lot's of error checking to inform the user of mistakes
	if (!(options.challengeTypes || []).length) {
		options.challengeTypes = Object.keys(options.challenges || {});
	}
	if (!options.challengeTypes.length) {
		options.challengeTypes = [options.challengeType].filter(Boolean);
	}
	if (options.challengeType) {
		options.challengeTypes.sort(function(a, b) {
			if (a === options.challengeType) {
				return -1;
			}
			if (b === options.challengeType) {
				return 1;
			}
			return 0;
		});
		if (options.challengeType !== options.challengeTypes[0]) {
			return Promise.reject(
				new Error(
					"options.challengeType is '" +
						options.challengeType +
						"'," +
						" which does not exist in the supplied types '" +
						options.challengeTypes.join(',') +
						"'"
				)
			);
		}
	}
	// TODO check that all challengeTypes are represented in challenges
	if (!options.challengeTypes.length) {
		return Promise.reject(
			new Error(
				'options.challengeTypes (string array) must be specified' +
					' (and in order of preferential priority).'
			)
		);
	}
	if (options.csr) {
		// TODO validate csr signature
		options._csr = me.CSR._info(options.csr);
		options.domains = options._csr.altnames;
		if (options._csr.subject !== options.domains[0]) {
			return Promise.reject(
				new Error(
					'certificate subject (commonName) does not match first altname (SAN)'
				)
			);
		}
	}
	if (!(options.domains && options.domains.length)) {
		return Promise.reject(
			new Error(
				'options.domains must be a list of string domain names,' +
					' with the first being the subject of the certificate (or options.subject must specified).'
			)
		);
	}

	// a cheap check to see if there are non-ascii characters in any of the domains
	var nonAsciiDomains = options.domains.some(function(d) {
		// IDN / unicode / utf-8 / punycode
		return Enc.strToBin(d) !== d;
	});
	if (nonAsciiDomains) {
		throw new Error(
			"please use the 'punycode' module to convert unicode domain names to punycode"
		);
	}

	// It's just fine if there's no account, we'll go get the key id we need via the existing key
	options._kid =
		options._kid ||
		options.accountKid ||
		(options.account &&
			(options.account.kid ||
				(options.account.key && options.account.key.kid)));
	if (!options._kid) {
		//return Promise.reject(new Error("must include KeyID"));
		// This is an idempotent request. It'll return the same account for the same public key.
		return ACME._registerAccount(me, options).then(function(account) {
			options._kid = account.key.kid;
			// start back from the top
			return ACME._getCertificate(me, options);
		});
	}

	// TODO Promise.all()?
	Object.keys(options.challenges).forEach(function(key) {
		var presenter = options.challenges[key];
		if ('function' === typeof presenter.init && !presenter._initialized) {
			presenter._initialized = true;
			return ACME._depInit(me, presenter);
		}
	});

	var promiseZones;
	if (options.challenges['dns-01']) {
		// a little bit of random to ensure that getZones()
		// actually returns the zones and not the hosts as zones
		var dnsHosts = options.domains.map(function(d) {
			var rnd = parseInt(
				Math.random()
					.toString()
					.slice(2),
				10
			)
				.toString(16)
				.slice(0, 4);
			return rnd + '.' + d;
		});
		promiseZones = ACME._getZones(
			me,
			options.challenges['dns-01'],
			dnsHosts
		);
	} else {
		promiseZones = Promise.resolve([]);
	}

	return promiseZones
		.then(function(zonenames) {
			options.zonenames = zonenames;
			// Do a little dry-run / self-test
			return ACME._testChallenges(me, options);
		})
		.then(function() {
			if (me.debug) {
				console.debug('[acme-v2] certificates.create');
			}
			var certOrder = {
				// raw wildcard syntax MUST be used here
				identifiers: options.domains
					.sort(function(a, b) {
						// the first in the list will be the subject of the certificate, I believe (and hope)
						if (!options.subject) {
							return 0;
						}
						if (options.subject === a) {
							return -1;
						}
						if (options.subject === b) {
							return 1;
						}
						return 0;
					})
					.map(function(hostname) {
						return {
							type: 'dns',
							value: hostname
						};
					})
				//, "notBefore": "2016-01-01T00:00:00Z"
				//, "notAfter": "2016-01-08T00:00:00Z"
			};

			var payload = JSON.stringify(certOrder);
			if (me.debug) {
				console.debug('\n[DEBUG] newOrder\n');
			}
			return ACME._jwsRequest(me, {
				options: options,
				url: me._directoryUrls.newOrder,
				protected: { kid: options._kid },
				payload: Enc.strToBuf(payload)
			}).then(function(resp) {
				var location = resp.headers.location;
				var setAuths;
				var validAuths = [];
				var auths = [];
				if (me.debug) {
					console.debug('[ordered]', location);
				} // the account id url
				if (me.debug) {
					console.debug(resp);
				}
				options._authorizations = resp.body.authorizations;
				options._order = location;
				options._finalize = resp.body.finalize;
				//if (me.debug) console.debug('[DEBUG] finalize:', options._finalize); return;

				if (!options._authorizations) {
					return Promise.reject(
						new Error(
							"[acme-v2.js] authorizations were not fetched for '" +
								options.domains.join() +
								"':\n" +
								JSON.stringify(resp.body)
						)
					);
				}
				if (me.debug) {
					console.debug('[acme-v2] POST newOrder has authorizations');
				}
				setAuths = options._authorizations.slice(0);

				var accountKeyThumb;
				function setThumbnail() {
					return ACME._importKeypair(me, options.accountKeypair).then(
						function(pair) {
							return me.Keypairs.thumbprint({
								jwk: pair.public
							}).then(function(_thumb) {
								accountKeyThumb = _thumb;
							});
						}
					);
				}

				function setNext() {
					var authUrl = setAuths.shift();
					if (!authUrl) {
						return;
					}

					return ACME._getChallenges(me, options, authUrl).then(
						function(results) {
							// var domain = options.domains[i]; // results.identifier.value

							// If it's already valid, we're golden it regardless
							if (
								results.challenges.some(function(ch) {
									return 'valid' === ch.status;
								})
							) {
								return setNext();
							}

							var challenge = ACME._chooseChallenge(
								options,
								results
							);
							if (!challenge) {
								// For example, wildcards require dns-01 and, if we don't have that, we have to bail
								return Promise.reject(
									new Error(
										"Server didn't offer any challenge we can handle for '" +
											options.domains.join() +
											"'."
									)
								);
							}

							return ACME._challengeToAuth(
								me,
								options,
								accountKeyThumb,
								results,
								challenge,
								false
							).then(function(auth) {
								auths.push(auth);
								return ACME._setChallenge(
									me,
									options,
									auth
								).then(setNext);
							});
						}
					);
				}

				function waitAll() {
					// TODO take the max wait of all challenge plugins and wait that long, or 1000ms
					var DELAY = me.setChallengeWait || 7000;
					if (true || me.debug) {
						console.debug(
							'\n[DEBUG] waitChallengeDelay %s\n',
							DELAY
						);
					}
					return ACME._wait(DELAY);
				}

				function checkNext() {
					var auth = auths.shift();
					if (!auth) {
						return;
					}

					var ch = auth.challenge;
					if (!me._canUse[ch.type] || me.skipChallengeTest) {
						// not so much "valid" as "not invalid"
						// but in this case we can't confirm either way
						validAuths.push(auth);
						return checkNext();
					}

					return ACME.challengeTests[ch.type](me, auth)
						.then(function() {
							validAuths.push(auth);
						})
						.then(checkNext);
				}

				function presentNext() {
					var auth = validAuths.shift();
					if (!auth) {
						return;
					}
					return ACME._postChallenge(me, options, auth).then(
						presentNext
					);
				}

				function finalizeOrder() {
					if (me.debug) {
						console.debug('[getCertificate] next.then');
					}
					var validatedDomains = certOrder.identifiers.map(function(
						ident
					) {
						return ident.value;
					});

					return ACME._finalizeOrder(me, options, validatedDomains);
				}

				function retrieveCerts(order) {
					if (me.debug) {
						console.debug('acme-v2: order was finalized');
					}
					// TODO POST-as-GET
					return me
						.request({
							method: 'GET',
							url: options._certificate,
							json: true
						})
						.then(function(resp) {
							if (me.debug) {
								console.debug(
									'acme-v2: csr submitted and cert received:'
								);
							}
							// https://github.com/certbot/certbot/issues/5721
							var certsarr = ACME.splitPemChain(
								ACME.formatPemChain(resp.body || '')
							);
							//  cert, chain, fullchain, privkey, /*TODO, subject, altnames, issuedAt, expiresAt */
							var certs = {
								expires: order.expires,
								identifiers: order.identifiers,
								//, authorizations: order.authorizations
								cert: certsarr.shift(),
								//, privkey: privkeyPem
								chain: certsarr.join('\n')
							};
							if (me.debug) {
								console.debug(certs);
							}
							return certs;
						});
				}

				// First we set each and every challenge
				// Then we ask for each challenge to be checked
				// Doing otherwise would potentially cause us to poison our own DNS cache with misses
				return setThumbnail()
					.then(setNext)
					.then(waitAll)
					.then(checkNext)
					.then(presentNext)
					.then(finalizeOrder)
					.then(retrieveCerts);
			});
		});
};

ACME._generateCsrWeb64 = function(me, options, validatedDomains) {
	var csr;
	if (options.csr) {
		csr = options.csr;
		// if der, convert to base64
		if ('string' !== typeof csr) {
			csr = Enc.bufToUrlBase64(csr);
		}
		// TODO PEM.parseBlock()
		// nix PEM headers, if any
		if ('-' === csr[0]) {
			csr = csr
				.split(/\n+/)
				.slice(1, -1)
				.join('');
		}
		csr = Enc.base64ToUrlBase64(csr.trim().replace(/\s+/g, ''));
		return Promise.resolve(csr);
	}

	return ACME._importKeypair(me, options.serverKeypair).then(function(pair) {
		return me.CSR.csr({
			jwk: pair.private,
			domains: validatedDomains,
			encoding: 'der'
		}).then(function(der) {
			return Enc.bufToUrlBase64(der);
		});
	});
};

ACME.create = function create(me) {
	if (!me) {
		me = {};
	}
	// me.debug = true;
	me.challengePrefixes = ACME.challengePrefixes;
	me.Keypairs = me.Keypairs || Keypairs;
	me.CSR = me.CSR || CSR;
	me._nonces = [];
	me._canUse = {};
	if (!me._baseUrl) {
		me._baseUrl = '';
	}
	//me.Keypairs = me.Keypairs || require('keypairs');
	//me.request = me.request || require('@root/request');
	if (!me.dns01) {
		me.dns01 = function(ch) {
			return native._dns01(me, ch);
		};
	}
	// backwards compat
	if (!me.dig) {
		me.dig = me.dns01;
	}
	if (!me.http01) {
		me.http01 = function(ch) {
			return native._http01(me, ch);
		};
	}

	if ('function' !== typeof me.request) {
		me.request = ACME._defaultRequest;
	}

	me.init = function(opts) {
		function fin(dir) {
			me._directoryUrls = dir;
			me._tos = dir.meta.termsOfService;
			return dir;
		}
		if (opts && opts.meta && opts.termsOfService) {
			return Promise.resolve(fin(opts));
		}
		if (!me.directoryUrl) {
			me.directoryUrl = opts;
		}
		if ('string' !== typeof me.directoryUrl) {
			throw new Error(
				'you must supply either the ACME directory url as a string or an object of the ACME urls'
			);
		}

		var p = Promise.resolve();
		if (!me.skipChallengeTest) {
			p = native._canCheck(me);
		}
		return p.then(function() {
			return ACME._directory(me).then(function(resp) {
				return fin(resp.body);
			});
		});
	};
	me.accounts = {
		create: function(options) {
			return ACME._registerAccount(me, options);
		}
	};
	me.certificates = {
		create: function(options) {
			return ACME._getCertificate(me, options);
		}
	};
	return me;
};

// Handle nonce, signing, and request altogether
ACME._jwsRequest = function(me, bigopts) {
	return ACME._getNonce(me).then(function(nonce) {
		bigopts.protected.nonce = nonce;
		bigopts.protected.url = bigopts.url;
		// protected.alg: added by Keypairs.signJws
		if (!bigopts.protected.jwk) {
			// protected.kid must be overwritten due to ACME's interpretation of the spec
			if (!bigopts.protected.kid) {
				bigopts.protected.kid = bigopts.options._kid;
			}
		}
		// this will shasum the thumbnail the 2nd time
		return me.Keypairs.signJws({
			jwk: bigopts.options.accountKeypair.privateKeyJwk,
			protected: bigopts.protected,
			payload: bigopts.payload
		}).then(function(jws) {
			if (me.debug) {
				console.debug('[acme-v2] ' + bigopts.url + ':');
			}
			if (me.debug) {
				console.debug(jws);
			}
			return ACME._request(me, { url: bigopts.url, json: jws });
		});
	});
};

// Handle some ACME-specific defaults
ACME._request = function(me, opts) {
	if (!opts.headers) {
		opts.headers = {};
	}
	if (opts.json && true !== opts.json) {
		opts.headers['Content-Type'] = 'application/jose+json';
		opts.body = JSON.stringify(opts.json);
		if (!opts.method) {
			opts.method = 'POST';
		}
	}
	return me.request(opts).then(function(resp) {
		resp = resp.toJSON();
		if (resp.headers['replay-nonce']) {
			ACME._setNonce(me, resp.headers['replay-nonce']);
		}
		return resp;
	});
};
// A very generic, swappable request lib
ACME._defaultRequest = function(opts) {
	// Note: normally we'd have to supply a User-Agent string, but not here in a browser
	if (!opts.headers) {
		opts.headers = {};
	}
	if (opts.json) {
		opts.headers.Accept = 'application/json';
		if (true !== opts.json) {
			opts.body = JSON.stringify(opts.json);
		}
	}
	if (!opts.method) {
		opts.method = 'GET';
		if (opts.body) {
			opts.method = 'POST';
		}
	}
	opts.cors = true;

	return http.request(opts);
};

ACME._importKeypair = function(me, kp) {
	var jwk = kp.privateKeyJwk;
	var p;
	if (jwk) {
		// nix the browser jwk extras
		jwk.key_ops = undefined;
		jwk.ext = undefined;
		p = Promise.resolve({
			private: jwk,
			public: me.Keypairs.neuter({ jwk: jwk })
		});
	} else {
		p = me.Keypairs.import({ pem: kp.privateKeyPem });
	}
	return p.then(function(pair) {
		kp.privateKeyJwk = pair.private;
		kp.publicKeyJwk = pair.public;
		if (pair.public.kid) {
			pair = JSON.parse(JSON.stringify(pair));
			delete pair.public.kid;
			delete pair.private.kid;
		}
		return pair;
	});
};

/*
TODO
Per-Order State Params
      _kty
      _alg
      _finalize
      _expires
      _certificate
      _order
      _authorizations
*/

ACME._toWebsafeBase64 = function(b64) {
	return b64
		.replace(/\+/g, '-')
		.replace(/\//g, '_')
		.replace(/=/g, '');
};

// In v8 this is crypto random, but we're just using it for pseudorandom
ACME._prnd = function(n) {
	var rnd = '';
	while (rnd.length / 2 < n) {
		var num = Math.random()
			.toString()
			.substr(2);
		if (num.length % 2) {
			num = '0' + num;
		}
		var pairs = num.match(/(..?)/g);
		rnd += pairs.map(ACME._toHex).join('');
	}
	return rnd.substr(0, n * 2);
};
ACME._toHex = function(pair) {
	return parseInt(pair, 10).toString(16);
};
ACME._removeChallenge = function(me, options, auth) {
	var challengers = options.challenges || {};
	var ch = auth.challenge;
	var removeChallenge = challengers[ch.type] && challengers[ch.type].remove;
	if (!removeChallenge) {
		throw new Error('challenge plugin is missing remove()');
	}
	if (1 === removeChallenge.length) {
		return Promise.resolve(removeChallenge(auth)).then(
			function() {},
			function(e) {
				console.error('Error during remove challenge:');
				console.error(e);
			}
		);
	} else if (2 === removeChallenge.length) {
		return new Promise(function(resolve) {
			removeChallenge(auth, function(err) {
				resolve();
				if (err) {
					console.error('Error during remove challenge:');
					console.error(err);
				}
				return err;
			});
		});
	} else {
		throw new Error(
			"Bad function signature for '" + auth.type + "' challenge.remove()"
		);
	}
};

ACME._depInit = function(me, presenter) {
	if ('function' !== typeof presenter.init) {
		return Promise.resolve(null);
	}
	return ACME._wrapCb(
		me,
		presenter,
		'init',
		{ type: '*', request: me.request },
		'null'
	);
};

ACME._getZones = function(me, presenter, dnsHosts) {
	if ('function' !== typeof presenter.zones) {
		presenter.zones = function() {
			return Promise.resolve([]);
		};
	}
	var challenge = {
		type: 'dns-01',
		dnsHosts: dnsHosts,
		request: me.request
	};
	return ACME._wrapCb(
		me,
		presenter,
		'zones',
		{ challenge: challenge },
		'an array of zone names'
	);
};

ACME._wrapCb = function(me, options, _name, args, _desc) {
	return new Promise(function(resolve, reject) {
		if (options[_name].length <= 1) {
			return Promise.resolve(options[_name](args))
				.then(resolve)
				.catch(reject);
		} else if (2 === options[_name].length) {
			options[_name](args, function(err, results) {
				if (err) {
					reject(err);
				} else {
					resolve(results);
				}
			});
		} else {
			throw new Error(
				'options.' + _name + ' should accept opts and Promise ' + _desc
			);
		}
	});
};

function newZoneRegExp(zonename) {
	// (^|\.)example\.com$
	// which matches:
	//  foo.example.com
	//  example.com
	// but not:
	//  fooexample.com
	return new RegExp('(^|\\.)' + zonename.replace(/\./g, '\\.') + '$');
}

function pluckZone(zonenames, dnsHost) {
	return zonenames
		.filter(function(zonename) {
			// the only character that needs to be escaped for regex
			// and is allowed in a domain name is '.'
			return newZoneRegExp(zonename).test(dnsHost);
		})
		.sort(function(a, b) {
			// longest match first
			return b.length - a.length;
		})[0];
}