'use strict';
/*global Promise*/
var crypto = require('crypto');

module.exports.create = function() {
	throw new Error(
		'acme-challenge-test is a test fixture for acme-challenge-* plugins, not a plugin itself'
	);
};

// ignore all of this, it's just to normalize Promise vs node-style callback thunk vs synchronous
function promiseCheckAndCatch(obj, name) {
	var promisify = require('util').promisify;
	// don't loose this-ness, just in case that's important
	var fn = obj[name].bind(obj);
	var promiser;

	// function signature must match, or an error will be thrown
	if (1 === fn.length) {
		// wrap so that synchronous errors are caught (alsa handles synchronous results)
		promiser = function(opts) {
			return Promise.resolve().then(function() {
				return fn(opts);
			});
		};
	} else if (2 === fn.length) {
		// wrap as a promise
		promiser = promisify(fn);
	} else {
		return Promise.reject(
			new Error(
				"'challenge." +
					name +
					"' should accept either one argument, the options," +
					' and return a Promise or accept two arguments, the options and a node-style callback thunk'
			)
		);
	}

	function shouldntBeNull(result) {
		if ('undefined' === typeof result) {
			throw new Error(
				"'challenge.'" +
					name +
					"' should never return `undefined`. Please explicitly return null" +
					" (or fix the place where a value should have been returned but wasn't)."
			);
		}
		return result;
	}

	return function(opts) {
		return promiser(opts).then(shouldntBeNull);
	};
}

function mapAsync(els, doer) {
	els = els.slice(0);
	var results = [];
	function next() {
		var el = els.shift();
		if (!el) {
			return results;
		}
		return doer(el).then(function(result) {
			results.push(result);
			return next();
		});
	}
	return next();
}

// Here's the meat, where the tests are happening:
function testEach(type, domains, challenger) {
	var chr = wrapChallenger(challenger);
	var all = domains.map(function(d) {
		return { domain: d };
	});
	var rnd = crypto.randomBytes(2).toString('hex');

	return mapAsync(all, function(opts) {
		console.info("TEST '%s'", opts.domain);
		opts.challenge = fakeChallenge(type, opts.domain, rnd);
		var ch = opts.challenge;
		if ('http-01' === ch.type && ch.wildname) {
			throw new Error('http-01 cannot be used for wildcard domains');
		}

		// The first time we just check it against itself
		// this will cause the prompt to appear
		return chr.set(opts).then(function() {
			// this will cause the final completion message to appear
			// _test is used by the manual cli reference implementations
			var query = { type: ch.type, /*debug*/ status: ch.status, _test: true };
			if ('http-01' === ch.type) {
				query.identifier = ch.identifier;
				query.token = ch.token;
				// For testing only
				query.url = ch.challengeUrl;
			} else if ('dns-01' === ch.type) {
				query.identifier = { type: 'dns', value: ch.dnsHost };
				// For testing only
				query.altname = ch.altname;
				// there should only be two possible TXT records per challenge domain:
				// one for the bare domain, and the other if and only if there's a wildcard
				query.wildcard = ch.wildcard;
				query.dnsAuthorization = ch.dnsAuthorization;
			} else {
				query = JSON.parse(JSON.stringify(ch));
				query.comment = 'unknown challenge type, supplying everything';
			}
			opts.query = query;
			return opts;
		});
	})
		.then(function(all) {
			return mapAsync(all, function(opts) {
				var ch = opts.challenge;
				return chr.get({ challenge: opts.query }).then(function(secret) {
					if ('string' === typeof secret) {
						console.info(
							'secret was passed as a string, which works historically, but should be an object instead:'
						);
						console.info('{ "keyAuthorization": "' + secret + '" }');
						console.info('or');
						// TODO this should be "keyAuthorizationDigest"
						console.info('{ "dnsAuthorization": "' + secret + '" }');
						console.info(
							'This is to help keep acme / greenlock (and associated plugins) future-proof for new challenge types'
						);
					}
					// historically 'secret' has been a string, but I'd like it to transition to be an object.
					// to make it backwards compatible in v2.7 to change it,
					// so I'm not sure that we really need to.
					if ('http-01' === ch.type) {
						secret = secret.keyAuthorization || secret;
						if (ch.keyAuthorization !== secret) {
							throw new Error(
								"http-01 challenge.get() returned '" +
									secret +
									"', which does not match the keyAuthorization" +
									" saved with challenge.set(), which was '" +
									ch.keyAuthorization +
									"'"
							);
						}
					} else if ('dns-01' === ch.type) {
						secret = secret.dnsAuthorization || secret;
						if (ch.dnsAuthorization !== secret) {
							throw new Error(
								"dns-01 challenge.get() returned '" +
									secret +
									"', which does not match the dnsAuthorization" +
									" (keyAuthDigest) saved with challenge.set(), which was '" +
									ch.dnsAuthorization +
									"'"
							);
						}
					} else {
						if ('tls-alpn-01' === ch.type) {
							console.warn(
								"'tls-alpn-01' support is in development" +
									" (or developed and we haven't update this yet). Please contact us."
							);
						} else {
							console.warn(
								"We don't know how to test '" +
									ch.type +
									"'... are you sure that's a thing?"
							);
						}
						secret = secret.keyAuthorization || secret;
						if (ch.keyAuthorization !== secret) {
							console.warn(
								"The returned value doesn't match keyAuthorization",
								ch.keyAuthorization,
								secret
							);
						}
					}
				});
			});
		})
		.then(function() {
			return mapAsync(all, function(opts) {
				return chr.remove(opts).then(function() {
					return chr.get(opts).then(function(result) {
						if (result) {
							throw new Error(
								'challenge.remove() should have made it not possible for challenge.get() to return a value'
							);
						}
						if (null !== result) {
							throw new Error(
								'challenge.get() should return null when the value is not set'
							);
						}
						console.info("PASS '%s'", opts.domain);
					});
				});
			});
		})
		.then(function() {
			console.info('All soft tests: PASS');
			console.warn(
				'Hard tests (actually checking http URLs and dns records) is implemented in acme-v2.'
			);
			console.warn(
				"We'll copy them over here as well, but that's a TODO for next week."
			);
		});
}

function testZone(type, zone, challenger) {
	var domains = [zone, 'foo.' + zone];
	if ('dns-01' === type) {
		domains.push('*.foo.' + zone);
	}
	return testEach(type, domains, challenger);
}

function wrapChallenger(challenger) {
	var set = promiseCheckAndCatch(challenger, 'set');
	if ('function' !== typeof challenger.get) {
		throw new Error(
			"'challenge.get' should be implemented for the sake of testing." +
				' It should be implemented as the internal method for fetching the challenge' +
				' (i.e. reading from a database, file system or API, not return internal),' +
				' not the external check (the http call, dns query, etc), which will already be done as part of this test.'
		);
	}
	var get = promiseCheckAndCatch(challenger, 'get');
	var remove = promiseCheckAndCatch(challenger, 'remove');

	return { set: set, get: get, remove: remove };
}

function fakeChallenge(type, altname, rnd) {
	var expires = new Date(Date.now() + 10 * 60 * 1000).toISOString();
	var token = crypto.randomBytes(8).toString('hex');
	var thumb = crypto.randomBytes(16).toString('hex');
	var keyAuth = token + '.' + crypto.randomBytes(16).toString('hex');
	var dnsAuth = crypto
		.createHash('sha256')
		.update(keyAuth)
		.digest('base64')
		.replace(/\+/g, '-')
		.replace(/\//g, '_')
		.replace(/=/g, '');

	var challenge = {
		type: type,
		identifier: { type: 'dns', value: null }, // completed below
		wildcard: false, // completed below
		status: 'pending',
		expires: expires,
		token: token,
		thumbprint: thumb,
		keyAuthorization: keyAuth,
		url: null, // completed below
		dnsHost: '_' + rnd.slice(0, 2) + '-acme-challenge-' + rnd.slice(2) + '.', // completed below
		dnsAuthorization: dnsAuth,
		altname: altname,
		_test: true // used by CLI referenced implementations
	};
	if ('*.' === altname.slice(0, 2)) {
		challenge.wildcard = true;
		altname = altname.slice(2);
	}
	challenge.identifier.value = altname;
	challenge.url =
		'http://' + altname + '/.well-known/acme-challenge/' + challenge.token;
	challenge.dnsHost += altname;

	return challenge;
}

function testRecord(type, altname, challenger) {
	return testEach(type, [altname], challenger);
}

module.exports.testRecord = testRecord;
module.exports.testZone = testZone;
module.exports.test = testZone;