'use strict';

exports = module.exports = {
    setUserCertificate, // per location certificate
    setFallbackCertificate, // per domain certificate

    generateFallbackCertificate,

    validateCertificate,

    getCertificatePath, // resolved cert path
    ensureCertificate,

    checkCerts,

    // the 'configure' functions ensure a certificate and generate nginx config
    configureApp,
    unconfigureApp,

    // these only generate nginx config
    writeDefaultConfig,
    writeDashboardConfig,
    writeAppConfigs,

    removeAppConfigs,
    restoreFallbackCertificates,

    // exported for testing
    _getAcmeApiOptions: getAcmeApiOptions
};

const acme2 = require('./acme2.js'),
    apps = require('./apps.js'),
    assert = require('assert'),
    blobs = require('./blobs.js'),
    BoxError = require('./boxerror.js'),
    constants = require('./constants.js'),
    crypto = require('crypto'),
    debug = require('debug')('box:reverseproxy'),
    directoryServer = require('./directoryserver.js'),
    dns = require('./dns.js'),
    domains = require('./domains.js'),
    ejs = require('ejs'),
    eventlog = require('./eventlog.js'),
    fs = require('fs'),
    mail = require('./mail.js'),
    os = require('os'),
    path = require('path'),
    paths = require('./paths.js'),
    safe = require('safetydance'),
    settings = require('./settings.js'),
    shell = require('./shell.js'),
    sysinfo = require('./sysinfo.js'),
    users = require('./users.js'),
    util = require('util');

const NGINX_APPCONFIG_EJS = fs.readFileSync(__dirname + '/nginxconfig.ejs', { encoding: 'utf8' });
const RESTART_SERVICE_CMD = path.join(__dirname, 'scripts/restartservice.sh');

function nginxLocation(s) {
    if (!s.startsWith('!')) return s;

    const re = s.replace(/[\^$\\.*+?()[\]{}|]/g, '\\$&'); // https://github.com/es-shims/regexp.escape/blob/master/implementation.js
    return `~ ^(?!(${re.slice(1)}))`; // negative regex assertion - https://stackoverflow.com/questions/16302897/nginx-location-not-equal-to-regex
}

async function getAcmeApiOptions(domainObject) {
    assert.strictEqual(typeof domainObject, 'object');

    const apiOptions = { prod: false, performHttpAuthorization: false, wildcard: false, email: '' };
    apiOptions.prod = domainObject.tlsConfig.provider.match(/.*-prod/) !== null; // matches 'le-prod' or 'letsencrypt-prod'
    apiOptions.performHttpAuthorization = domainObject.provider.match(/noop|manual|wildcard/) !== null;
    apiOptions.wildcard = !!domainObject.tlsConfig.wildcard;

    // registering user with an email requires A or MX record (https://github.com/letsencrypt/boulder/issues/1197)
    // we cannot use admin@fqdn because the user might not have set it up.
    // we simply update the account with the latest email we have each time when getting letsencrypt certs
    // https://github.com/ietf-wg-acme/acme/issues/30
    const [error, owner] = await safe(users.getOwner());
    apiOptions.email = (error || !owner) ? 'webmaster@cloudron.io' : owner.email; // can error if not activated yet

    return apiOptions;
}

function getExpiryDate(certFilePath) {
    assert.strictEqual(typeof certFilePath, 'string');

    if (!fs.existsSync(certFilePath)) return null; // not found

    const result = safe.child_process.spawnSync('/usr/bin/openssl', [ 'x509', '-enddate', '-noout', '-in', certFilePath ]);
    if (!result) return null; // some error

    const notAfter = result.stdout.toString('utf8').trim().split('=')[1];
    const notAfterDate = new Date(notAfter);

    const daysLeft = (notAfterDate - new Date())/(24 * 60 * 60 * 1000);
    debug(`expiryDate: ${certFilePath} notAfter=${notAfter} daysLeft=${daysLeft}`);

    return notAfterDate;
}

async function isOcspEnabled(certFilePath) {
    // on some servers, OCSP does not work. see #796
    const config = await settings.getReverseProxyConfig();
    if (!config.ocsp) return false;

    // We used to check for the must-staple in the cert using openssl x509 -text -noout -in ${certFilePath} | grep -q status_request
    // however, we cannot set the must-staple because first request to nginx fails because of it's OCSP caching behavior
    const result = safe.child_process.execSync(`openssl x509 -in ${certFilePath} -noout -ocsp_uri`, { encoding: 'utf8' });
    return result && result.length > 0; // no error and has uri
}

// checks if the certificate matches the options provided by user (like wildcard, le-staging etc)
function providerMatchesSync(domainObject, certFilePath, apiOptions) {
    assert.strictEqual(typeof domainObject, 'object');
    assert.strictEqual(typeof certFilePath, 'string');
    assert.strictEqual(typeof apiOptions, 'object');

    if (!fs.existsSync(certFilePath)) return false; // not found

    const subjectAndIssuer = safe.child_process.execSync(`/usr/bin/openssl x509 -noout -subject -issuer -in "${certFilePath}"`, { encoding: 'utf8' });
    if (!subjectAndIssuer) return false; // something bad happenned

    const subject = subjectAndIssuer.match(/^subject=(.*)$/m)[1];
    const domain = subject.substr(subject.indexOf('=') + 1).trim(); // subject can be /CN=, CN=, CN = and other forms
    const issuer = subjectAndIssuer.match(/^issuer=(.*)$/m)[1];
    const isWildcardCert = domain.includes('*');
    const isLetsEncryptProd = issuer.includes('Let\'s Encrypt') && !issuer.includes('STAGING');

    const issuerMismatch = (apiOptions.prod && !isLetsEncryptProd) || (!apiOptions.prod && isLetsEncryptProd);
    // bare domain is not part of wildcard SAN
    const wildcardMismatch = (domain !== domainObject.domain) && (apiOptions.wildcard && !isWildcardCert) || (!apiOptions.wildcard && isWildcardCert);

    const mismatch = issuerMismatch || wildcardMismatch;

    debug(`providerMatchesSync: ${certFilePath} subject=${subject} domain=${domain} issuer=${issuer} `
        + `wildcard=${isWildcardCert}/${apiOptions.wildcard} prod=${isLetsEncryptProd}/${apiOptions.prod} `
        + `issuerMismatch=${issuerMismatch} wildcardMismatch=${wildcardMismatch} match=${!mismatch}`);

    return !mismatch;
}

// note: https://tools.ietf.org/html/rfc4346#section-7.4.2 (certificate_list) requires that the
// servers certificate appears first (and not the intermediate cert)
function validateCertificate(subdomain, domainObject, certificate) {
    assert.strictEqual(typeof subdomain, 'string');
    assert.strictEqual(typeof domainObject, 'object');
    assert(certificate && typeof certificate, 'object');

    const { cert, key } = certificate;

    // check for empty cert and key strings
    if (!cert && key) return new BoxError(BoxError.BAD_FIELD, 'missing cert');
    if (cert && !key) return new BoxError(BoxError.BAD_FIELD, 'missing key');

    // -checkhost checks for SAN or CN exclusively. SAN takes precedence and if present, ignores the CN.
    const fqdn = dns.fqdn(subdomain, domainObject);

    let result = safe.child_process.execSync(`openssl x509 -noout -checkhost "${fqdn}"`, { encoding: 'utf8', input: cert });
    if (result === null) return new BoxError(BoxError.BAD_FIELD, 'Unable to get certificate subject:' + safe.error.message);

    if (result.indexOf('does match certificate') === -1) return new BoxError(BoxError.BAD_FIELD, `Certificate is not valid for this domain. Expecting ${fqdn}`);

    // check if public key in the cert and private key matches. pkey below works for RSA and ECDSA keys
    const pubKeyFromCert = safe.child_process.execSync('openssl x509 -noout -pubkey', { encoding: 'utf8', input: cert });
    if (pubKeyFromCert === null) return new BoxError(BoxError.BAD_FIELD, `Unable to get public key from certificate: ${safe.error.message}`);

    const pubKeyFromKey = safe.child_process.execSync('openssl pkey -pubout', { encoding: 'utf8', input: key });
    if (pubKeyFromKey === null) return new BoxError(BoxError.BAD_FIELD, `Unable to get public key from private key: ${safe.error.message}`);

    if (pubKeyFromCert !== pubKeyFromKey) return new BoxError(BoxError.BAD_FIELD, 'Public key does not match the certificate.');

    // check expiration
    result = safe.child_process.execSync('openssl x509 -checkend 0', { encoding: 'utf8', input: cert });
    if (!result) return new BoxError(BoxError.BAD_FIELD, 'Certificate has expired.');

    return null;
}

async function reload() {
    if (constants.TEST) return;

    const [error] = await safe(shell.promises.sudo('reload', [ RESTART_SERVICE_CMD, 'nginx' ], {}));
    if (error) throw new BoxError(BoxError.NGINX_ERROR, `Error reloading nginx: ${error.message}`);
}

// this is used in migration - 20211006200150-domains-ensure-fallbackCertificate.js
async function generateFallbackCertificate(domain) {
    assert.strictEqual(typeof domain, 'string');

    const certFilePath = path.join(os.tmpdir(), `${domain}-${crypto.randomBytes(4).readUInt32LE(0)}.cert`);
    const keyFilePath = path.join(os.tmpdir(), `${domain}-${crypto.randomBytes(4).readUInt32LE(0)}.key`);

    const opensslConf = safe.fs.readFileSync('/etc/ssl/openssl.cnf', 'utf8');
    // SAN must contain all the domains since CN check is based on implementation if SAN is found. -checkhost also checks only SAN if present!
    let opensslConfWithSan;
    const cn = domain;

    debug(`generateFallbackCertificate: domain=${domain} cn=${cn}`);

    opensslConfWithSan = `${opensslConf}\n[SAN]\nsubjectAltName=DNS:${domain},DNS:*.${cn}\n`;
    const configFile = path.join(os.tmpdir(), 'openssl-' + crypto.randomBytes(4).readUInt32LE(0) + '.conf');
    safe.fs.writeFileSync(configFile, opensslConfWithSan, 'utf8');
    // the days field is chosen to be less than 825 days per apple requirement (https://support.apple.com/en-us/HT210176)
    const certCommand = util.format(`openssl req -x509 -newkey rsa:2048 -keyout ${keyFilePath} -out ${certFilePath} -days 800 -subj /CN=*.${cn} -extensions SAN -config ${configFile} -nodes`);
    if (!safe.child_process.execSync(certCommand)) throw new BoxError(BoxError.OPENSSL_ERROR, safe.error.message);
    safe.fs.unlinkSync(configFile);

    const cert = safe.fs.readFileSync(certFilePath, 'utf8');
    if (!cert) throw new BoxError(BoxError.FS_ERROR, safe.error.message);
    safe.fs.unlinkSync(certFilePath);

    const key = safe.fs.readFileSync(keyFilePath, 'utf8');
    if (!key) throw new BoxError(BoxError.FS_ERROR, safe.error.message);
    safe.fs.unlinkSync(keyFilePath);

    return { cert, key };
}

async function setFallbackCertificate(domain, certificate) {
    assert.strictEqual(typeof domain, 'string');
    assert(certificate && typeof certificate === 'object');

    debug(`setFallbackCertificate: setting certs for domain ${domain}`);
    if (!safe.fs.writeFileSync(path.join(paths.NGINX_CERT_DIR, `${domain}.host.cert`), certificate.cert)) throw new BoxError(BoxError.FS_ERROR, safe.error.message);
    if (!safe.fs.writeFileSync(path.join(paths.NGINX_CERT_DIR, `${domain}.host.key`), certificate.key)) throw new BoxError(BoxError.FS_ERROR, safe.error.message);

    // TODO: maybe the cert is being used by the mail container
    await reload();
}

async function restoreFallbackCertificates() {
    const result = await domains.list();

    for (const domain of result) {
        if (!safe.fs.writeFileSync(path.join(paths.NGINX_CERT_DIR, `${domain.domain}.host.cert`), domain.fallbackCertificate.cert)) throw new BoxError(BoxError.FS_ERROR, safe.error.message);
        if (!safe.fs.writeFileSync(path.join(paths.NGINX_CERT_DIR, `${domain.domain}.host.key`), domain.fallbackCertificate.key)) throw new BoxError(BoxError.FS_ERROR, safe.error.message);
    }
}

function getFallbackCertificatePathSync(domain) {
    assert.strictEqual(typeof domain, 'string');

    const certFilePath = path.join(paths.NGINX_CERT_DIR, `${domain}.host.cert`);
    const keyFilePath = path.join(paths.NGINX_CERT_DIR, `${domain}.host.key`);

    return { certFilePath, keyFilePath };
}

function getUserCertificatePathSync(fqdn) {
    assert.strictEqual(typeof fqdn, 'string');

    const certFilePath = path.join(paths.NGINX_CERT_DIR, `${fqdn}.user.cert`);
    const keyFilePath = path.join(paths.NGINX_CERT_DIR, `${fqdn}.user.key`);

    return { certFilePath, keyFilePath };
}

function getAcmeCertificateName(fqdn, domainObject) {
    assert.strictEqual(typeof fqdn, 'string'); // this can contain wildcard domain (for alias domains)
    assert.strictEqual(typeof domainObject, 'object');

    if (fqdn !== domainObject.domain && domainObject.tlsConfig.wildcard) { // bare domain is not part of wildcard SAN
        return dns.makeWildcard(fqdn).replace('*.', '_.');
    } else {
        return fqdn;
    }
}

function getAcmeCertificatePathSync(fqdn, domainObject) {
    assert.strictEqual(typeof fqdn, 'string'); // this can contain wildcard domain (for alias domains)
    assert.strictEqual(typeof domainObject, 'object');

    const certName = getAcmeCertificateName(fqdn, domainObject);
    const certFilePath = path.join(paths.NGINX_CERT_DIR, `${certName}.cert`);
    const keyFilePath = path.join(paths.NGINX_CERT_DIR, `${certName}.key`);
    const csrFilePath = path.join(paths.NGINX_CERT_DIR, `${certName}.csr`);

    return { certFilePath, keyFilePath, csrFilePath };
}

async function getCertificatePath(fqdn, domain) {
    assert.strictEqual(typeof fqdn, 'string');
    assert.strictEqual(typeof domain, 'string');

    const domainObject = await domains.get(domain);

    const subdomain = fqdn.substr(0, fqdn.length - domainObject.domain.length - 1);
    const userCertificate = await apps.getCertificate(subdomain, domainObject.domain);
    if (userCertificate) return getUserCertificatePathSync(fqdn);

    if (domainObject.tlsConfig.provider === 'fallback') return getFallbackCertificatePathSync(domain);

    const acmeCertificate = await getAcmeCertificate(fqdn, domainObject);
    if (acmeCertificate) return getAcmeCertificatePathSync(fqdn, domainObject);

    // only use fallback certs if acme cert was never got. expired acme certs will continue to be used
    return getFallbackCertificatePathSync(domain);
}

async function writeUserCertificate(fqdn, domainObject) {
    assert.strictEqual(typeof fqdn, 'string'); // this can contain wildcard domain (for alias domains)
    assert.strictEqual(typeof domainObject, 'object');

    const subdomain = fqdn.substr(0, fqdn.length - domainObject.domain.length - 1);
    const userCertificate = await apps.getCertificate(subdomain, domainObject.domain);
    if (!userCertificate) return false;

    const { certFilePath, keyFilePath } = getUserCertificatePathSync(fqdn);

    if (!safe.fs.writeFileSync(certFilePath, userCertificate.cert)) throw new BoxError(BoxError.FS_ERROR, `Failed to write certificate: ${safe.error.message}`);
    if (!safe.fs.writeFileSync(keyFilePath, userCertificate.key)) throw new BoxError(BoxError.FS_ERROR, `Failed to write key: ${safe.error.message}`);

    return true;
}

async function getAcmeCertificate(fqdn, domainObject) {
    assert.strictEqual(typeof fqdn, 'string'); // this can contain wildcard domain (for alias domains)
    assert.strictEqual(typeof domainObject, 'object');

    const certName = getAcmeCertificateName(fqdn, domainObject);

    const privateKey = await blobs.get(`${blobs.CERT_PREFIX}-${certName}.key`);
    const cert = await blobs.get(`${blobs.CERT_PREFIX}-${certName}.cert`);

    if (!privateKey || !cert) return  null;

    return { privateKey, cert };
}

async function writeAcmeCertificate(fqdn, domainObject) {
    assert.strictEqual(typeof fqdn, 'string'); // this can contain wildcard domain (for alias domains)
    assert.strictEqual(typeof domainObject, 'object');

    const certName = getAcmeCertificateName(fqdn, domainObject);
    const privateKey = await blobs.get(`${blobs.CERT_PREFIX}-${certName}.key`);
    const cert = await blobs.get(`${blobs.CERT_PREFIX}-${certName}.cert`);
    const csr = await blobs.get(`${blobs.CERT_PREFIX}-${certName}.csr`);

    if (!privateKey || !cert) return false;

    const { keyFilePath, certFilePath, csrFilePath } = getAcmeCertificatePathSync(fqdn, domainObject);
    if (!safe.fs.writeFileSync(keyFilePath, privateKey)) throw new BoxError(BoxError.FS_ERROR, `Failed to write private key: ${safe.error.message}`);
    if (!safe.fs.writeFileSync(certFilePath, cert)) throw new BoxError(BoxError.FS_ERROR, `Failed to write certificate: ${safe.error.message}`);
    if (csr) safe.fs.writeFileSync(csrFilePath, csr);

    return true;
}

async function updateCertBlobs(fqdn, domainObject) {
    assert.strictEqual(typeof fqdn, 'string'); // this can contain wildcard domain (for alias domains)
    assert.strictEqual(typeof domainObject, 'object');

    const { certFilePath, keyFilePath, csrFilePath } = getAcmeCertificatePathSync(fqdn, domainObject);

    const privateKey = safe.fs.readFileSync(keyFilePath);
    if (!privateKey) throw new BoxError(BoxError.FS_ERROR, `Failed to read private key: ${safe.error.message}`);

    const cert = safe.fs.readFileSync(certFilePath);
    if (!cert) throw new BoxError(BoxError.FS_ERROR, `Failed to read cert: ${safe.error.message}`);

    const csr = safe.fs.readFileSync(csrFilePath);
    if (!csr) throw new BoxError(BoxError.FS_ERROR, `Failed to read csr: ${safe.error.message}`);

    const certName = getAcmeCertificateName(fqdn, domainObject);
    await blobs.set(`${blobs.CERT_PREFIX}-${certName}.key`, privateKey);
    await blobs.set(`${blobs.CERT_PREFIX}-${certName}.cert`, cert);
    await blobs.set(`${blobs.CERT_PREFIX}-${certName}.csr`, csr);
}

async function needsRenewal(fqdn, domainObject) {
    const apiOptions = await getAcmeApiOptions(domainObject);
    const { certFilePath } = getAcmeCertificatePathSync(fqdn, domainObject);

    const notAfter = getExpiryDate(certFilePath);
    const isExpiring = (notAfter - new Date()) <= (30 * 24 * 60 * 60 * 1000); // expiring in a month
    if (!isExpiring && providerMatchesSync(domainObject, certFilePath, apiOptions)) return false;
    debug(`needsRenewal: ${certFilePath} cert requires renewal`);
    return true;
}

async function renewCert(fqdn, domainObject) {
    const apiOptions = await getAcmeApiOptions(domainObject);
    const acmePaths = getAcmeCertificatePathSync(fqdn, domainObject);

    const [error] = await safe(acme2.getCertificate(fqdn, domainObject.domain, acmePaths, apiOptions));
    if (error) { // write the fallback cert to keep the nginx configs consistent
        fs.writeFileSync(acmePaths.certFilePath, domainObject.certificate.cert);
        fs.writeFileSync(acmePaths.keyFilePath, domainObject.certificate.key);
    } else {
        await safe(updateCertBlobs(fqdn, domainObject));
    }

    if (settings.mailFqdn() === fqdn) {
        debug('renewCert: restarting mail container');
        const [restartError] = await safe(mail.handleCertChanged());
        if (restartError) debug(`renewCert: error restarting mail container on cert change: ${restartError.message}`);
    }

    if (settings.dashboardFqdn() === fqdn) {
        debug('renewCert: restarting directory server');
        const [restartError] = await safe(directoryServer.handleCertChanged());
        if (restartError) debug(`renewCert: error restarting directory server on cert change: ${restartError.message}`);
    }
}

// ensures the cert of fqdn is available on disk. returns the path to the cert
async function ensureCertificate(fqdn, domainObject, options, auditSource) {
    assert.strictEqual(typeof fqdn, 'string');
    assert.strictEqual(typeof domainObject, 'object');
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    if (await writeUserCertificate(fqdn, domainObject)) {
        debug(`ensureCertificate: ${fqdn} will use user certs`);
        return;
    }

    if (domainObject.tlsConfig.provider === 'fallback') {
        debug(`ensureCertificate: ${fqdn} will use fallback certs`);
        return;
    }

    let renewal = false;

    if (await writeAcmeCertificate(fqdn, domainObject)) {
        if (!await needsRenewal(fqdn, domainObject)) return;
        renewal = true;
        debug(`ensureCertificate: ${fqdn} cert requires renewal`);
    } else {
        debug(`ensureCertificate: ${fqdn} cert does not exist`);
    }

    if (options.skipRenewal) return;

    const [renewError] = await safe(renewCert(fqdn, domainObject));
    debug(`ensureCertificate: error: ${renewError ? renewError.message : 'null'}`);

    await safe(eventlog.add(renewal ? eventlog.ACTION_CERTIFICATE_RENEWAL : eventlog.ACTION_CERTIFICATE_NEW, auditSource, { domain: fqdn, errorMessage: renewError?.message || '' }));
}

async function writeDashboardNginxConfig(fqdn, certificatePath) {
    assert.strictEqual(typeof fqdn, 'string');
    assert.strictEqual(typeof certificatePath, 'object');

    const data = {
        sourceDir: path.resolve(__dirname, '..'),
        vhost: fqdn,
        hasIPv6: sysinfo.hasIPv6(),
        endpoint: 'dashboard',
        certFilePath: certificatePath.certFilePath,
        keyFilePath: certificatePath.keyFilePath,
        robotsTxtQuoted: JSON.stringify('User-agent: *\nDisallow: /\n'),
        proxyAuth: { enabled: false, id: null, location: nginxLocation('/') },
        ocsp: await isOcspEnabled(certificatePath.certFilePath)
    };
    const nginxConf = ejs.render(NGINX_APPCONFIG_EJS, data);
    const nginxConfigFilename = path.join(paths.NGINX_APPCONFIG_DIR, `${fqdn}.conf`);

    if (!safe.fs.writeFileSync(nginxConfigFilename, nginxConf)) throw new BoxError(BoxError.FS_ERROR, safe.error);

    await reload();
}

async function writeDashboardConfig(domainObject) {
    assert.strictEqual(typeof domainObject, 'object');

    debug(`writeDashboardConfig: writing admin config for ${domainObject.domain}`);

    const dashboardFqdn = dns.fqdn(constants.DASHBOARD_SUBDOMAIN, domainObject);
    const certificatePath = await getCertificatePath(dashboardFqdn, domainObject.domain);

    await writeDashboardNginxConfig(dashboardFqdn, certificatePath);
}

function getNginxConfigFilename(app, fqdn, type) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof fqdn, 'string');
    assert.strictEqual(typeof type, 'string');

    let nginxConfigFilenameSuffix = '';

    if (type === apps.LOCATION_TYPE_ALIAS) {
        nginxConfigFilenameSuffix = `-alias-${fqdn.replace('*', '_')}`;
    } else if (type === apps.LOCATION_TYPE_SECONDARY) {
        nginxConfigFilenameSuffix = `-secondary-${fqdn}`;
    } else if (type === apps.LOCATION_TYPE_REDIRECT) {
        nginxConfigFilenameSuffix = `-redirect-${fqdn}`;
    }

    return path.join(paths.NGINX_APPCONFIG_DIR, `${app.id}${nginxConfigFilenameSuffix}.conf`);
}

async function writeAppNginxConfig(app, fqdn, type, certificatePath) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof fqdn, 'string');
    assert.strictEqual(typeof type, 'string');
    assert.strictEqual(typeof certificatePath, 'object');

    const data = {
        sourceDir: path.resolve(__dirname, '..'),
        vhost: fqdn,
        hasIPv6: sysinfo.hasIPv6(),
        ip: null,
        port: null,
        endpoint: null,
        redirectTo: null,
        certFilePath: certificatePath.certFilePath,
        keyFilePath: certificatePath.keyFilePath,
        robotsTxtQuoted: null,
        cspQuoted: null,
        hideHeaders: [],
        proxyAuth: { enabled: false },
        upstreamUri: '', // only for endpoint === external
        ocsp: await isOcspEnabled(certificatePath.certFilePath)
    };

    if (type === apps.LOCATION_TYPE_PRIMARY || type === apps.LOCATION_TYPE_ALIAS || type === apps.LOCATION_TYPE_SECONDARY) {
        data.endpoint = 'app';

        if (app.manifest.id === constants.PROXY_APP_APPSTORE_ID) {
            data.endpoint = 'external';

            // prevent generating invalid nginx configs
            if (!app.upstreamUri) throw new BoxError(BoxError.BAD_FIELD, 'upstreamUri cannot be empty');

            data.upstreamUri = app.upstreamUri;
        }

        // maybe these should become per domain at some point
        const reverseProxyConfig = app.reverseProxyConfig || {}; // some of our code uses fake app objects
        if (reverseProxyConfig.robotsTxt) data.robotsTxtQuoted = JSON.stringify(app.reverseProxyConfig.robotsTxt);
        if (reverseProxyConfig.csp) {
            data.cspQuoted = `"${app.reverseProxyConfig.csp}"`;
            data.hideHeaders = [ 'Content-Security-Policy' ];
            if (reverseProxyConfig.csp.includes('frame-ancestors ')) data.hideHeaders.push('X-Frame-Options');
        }
        if (type === apps.LOCATION_TYPE_PRIMARY || type == apps.LOCATION_TYPE_ALIAS) {
            data.proxyAuth = {
                enabled: app.sso && app.manifest.addons && app.manifest.addons.proxyAuth,
                id: app.id,
                location: nginxLocation(safe.query(app.manifest, 'addons.proxyAuth.path') || '/')
            };
            data.ip = app.containerIp;
            data.port = app.manifest.httpPort;
        } else if (type === apps.LOCATION_TYPE_SECONDARY) {
            data.ip = app.containerIp;
            const secondaryDomain = app.secondaryDomains.find(sd => sd.fqdn === fqdn);
            data.port = app.manifest.httpPorts[secondaryDomain.environmentVariable].containerPort;
        }
    } else if (type === apps.LOCATION_TYPE_REDIRECT) {
        data.proxyAuth = { enabled: false, id: app.id, location: nginxLocation('/') };
        data.endpoint = 'redirect';
        data.redirectTo = app.fqdn;
    }

    const nginxConf = ejs.render(NGINX_APPCONFIG_EJS, data);
    const filename = getNginxConfigFilename(app, fqdn, type);
    debug(`writeAppNginxConfig: writing config for "${fqdn}" to ${filename} with options ${JSON.stringify(data)}`);
    if (!safe.fs.writeFileSync(filename, nginxConf)) {
        debug(`Error creating nginx config for "${app.fqdn}" : ${safe.error.message}`);
        throw new BoxError(BoxError.FS_ERROR, safe.error);
    }

    await reload();
}

async function writeAppConfigs(app) {
    assert.strictEqual(typeof app, 'object');

    const locations = appLocationsSync(app);

    for (const location of locations) {
        const certificatePath = await getCertificatePath(location.fqdn, location.domain);
        await writeAppNginxConfig(app, location.fqdn, location.type, certificatePath);
    }
}

async function setUserCertificate(app, fqdn, certificate) {
    const { certFilePath, keyFilePath } = getUserCertificatePathSync(fqdn);

    if (certificate !== null) {
        if (!safe.fs.writeFileSync(certFilePath, certificate.cert)) throw safe.error;
        if (!safe.fs.writeFileSync(keyFilePath, certificate.key)) throw safe.error;
    } else { // remove existing cert/key
        if (!safe.fs.unlinkSync(certFilePath)) debug(`Error removing cert: ${safe.error.message}`);
        if (!safe.fs.unlinkSync(keyFilePath)) debug(`Error removing key: ${safe.error.message}`);
    }

    await writeAppConfigs(app);
}

function appLocationsSync(app) {
    assert.strictEqual(typeof app, 'object');

    const locations = [{ domain: app.domain, fqdn: app.fqdn, certificate: app.certificate, type: apps.LOCATION_TYPE_PRIMARY }]
        .concat(app.secondaryDomains.map(sd => { return { domain: sd.domain, certificate: sd.certificate, fqdn: sd.fqdn, type: apps.LOCATION_TYPE_SECONDARY }; }))
        .concat(app.redirectDomains.map(rd => { return { domain: rd.domain, certificate: rd.certificate, fqdn: rd.fqdn, type: apps.LOCATION_TYPE_REDIRECT }; }))
        .concat(app.aliasDomains.map(ad => { return { domain: ad.domain, certificate: ad.certificate, fqdn: ad.fqdn, type: apps.LOCATION_TYPE_ALIAS }; }));

    return locations;
}

async function configureApp(app, auditSource) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    const locations = await appLocationsSync(app);
    const domainObjectMap = await domains.getDomainObjectMap();

    for (const location of locations) {
        await ensureCertificate(location.fqdn, domainObjectMap[location.domain], {}, auditSource);
    }

    await writeAppConfigs(app);
}

async function unconfigureApp(app) {
    assert.strictEqual(typeof app, 'object');

    const configFilenames = safe.fs.readdirSync(paths.NGINX_APPCONFIG_DIR);
    if (!configFilenames) throw new BoxError(BoxError.FS_ERROR, `Error loading nginx config files: ${safe.error.message}`);

    for (const filename of configFilenames) {
        if (!filename.startsWith(app.id)) continue;

        safe.fs.unlinkSync(path.join(paths.NGINX_APPCONFIG_DIR, filename));
    }

    await reload();
}

async function renewCerts(options, auditSource, progressCallback) {
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof auditSource, 'object');
    assert.strictEqual(typeof progressCallback, 'function');

    const domainObjects = await domains.list();
    let domainObjectMap = {};
    for (const d of domainObjects) { domainObjectMap[d.domain] = d; }

    const allApps = await apps.list();
    let locations = [];
    // important: mail domain goes first because restart is only done on renewal. when using wildcard, renewal will skip if it appears later
    if (settings.dashboardDomain() !== settings.mailDomain()) locations.push({ domain: settings.mailDomain(), fqdn: settings.mailFqdn(), certificate: null });
    locations.push({ domain: settings.dashboardDomain(), fqdn: settings.dashboardFqdn(), certificate: null });

    for (const app of allApps) {
        if (app.runState === apps.RSTATE_STOPPED) continue; // do not renew certs of stopped apps
        locations = locations.concat(appLocationsSync(app));
    }

    let percent = 1, renewedCertificateNames = [];
    for (const location of locations) {
        percent += Math.round(100/locations.length);
        progressCallback({ percent, message: `Ensuring certs of ${location.fqdn}` });

        const domainObject = domainObjectMap[location.domain];
        if (location.certificate?.key && location.certificate?.cert) continue; // user cert
        if (domainObject.tlsConfig.provider === 'fallback') {
            progressCallback({ message: `${location.fqdn} is using fallback certs` });
            continue;
        }

        if (await needsRenewal(location.fqdn, domainObject)) {
            await renewCert(location.fqdn, domainObject);
            renewedCertificateNames.push(getAcmeCertificateName(location.fqdn, domainObject));
        } else {
            progressCallback({ message: `Cert of ${location.fqdn} does not require renewal` });
        }
    }

    if (renewedCertificateNames.length === 0) return;

    progressCallback({ message: `Reloading nginx after renewing ${JSON.stringify(renewedCertificateNames)}` });

    await reload();

    for (const app of allApps) {
        if (!app.manifest.addons?.tls) continue;
        const addonCertificateName = getAcmeCertificateName(app.fqdn, domainObjectMap[app.domain]);
        if (renewedCertificateNames.includes(addonCertificateName)) await apps.restart(app, auditSource);
    }
}

async function cleanupCerts(auditSource, progressCallback) {
    assert.strictEqual(typeof auditSource, 'object');
    assert.strictEqual(typeof progressCallback, 'function');

    progressCallback({ message: 'Checking expired certs for removal' });

    let locations = [];
    if (settings.dashboardDomain() !== settings.mailDomain()) locations.push({ domain: settings.mailDomain(), fqdn: settings.mailFqdn(), certificate: null });
    locations.push({ domain: settings.dashboardDomain(), fqdn: settings.dashboardFqdn(), certificate: null });

    for (const app of await apps.list()) {
        if (app.runState === apps.RSTATE_STOPPED) continue; // not in use
        locations = locations.concat(appLocationsSync(app));
    }

    const certsInUse = [ 'default.cert' ];
    for (const location of locations) {
        const certificatePath = await getCertificatePath(location.fqdn, location.domain);
        certsInUse.push(path.basename(certificatePath.certFilePath));
    }

    const filenames = await fs.promises.readdir(paths.NGINX_CERT_DIR);
    const certFilenames = filenames.filter(f => f.endsWith('.cert') && !f.endsWith('.user.cert') && !f.endsWith('host.cert') && !certsInUse.includes(f));
    const now = new Date();

    debug(`cleanupCerts: considering ${JSON.stringify(certFilenames)} for cleanup`);

    const fqdns = [];

    for (const certFilename of certFilenames) {
        const certFilePath = path.join(paths.NGINX_CERT_DIR, certFilename);
        const notAfter = getExpiryDate(certFilePath);
        if (!notAfter) continue; // some error

        if (now - notAfter >= (60 * 60 * 24 * 30 * 6 * 1000)) { // expired 6 months ago
            const fqdn = certFilename.replace(/\.cert$/, '');
            progressCallback({ message: `deleting certs of ${fqdn}` });

            // it is safe to delete the certs of stopped apps because their nginx configs are removed
            safe.fs.unlinkSync(certFilePath);
            safe.fs.unlinkSync(path.join(paths.NGINX_CERT_DIR, `${fqdn}.key`));
            safe.fs.unlinkSync(path.join(paths.NGINX_CERT_DIR, `${fqdn}.csr`));

            await blobs.del(`${blobs.CERT_PREFIX}-${fqdn}.key`);
            await blobs.del(`${blobs.CERT_PREFIX}-${fqdn}.cert`);
            await blobs.del(`${blobs.CERT_PREFIX}-${fqdn}.csr`);

            fqdns.push(fqdn);
        }
    }

    if (fqdns.length) await safe(eventlog.add(eventlog.ACTION_CERTIFICATE_CLEANUP, auditSource, { domains: fqdns }));

    debug('cleanupCerts: done');
}

async function checkCerts(options, auditSource, progressCallback) {
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof auditSource, 'object');
    assert.strictEqual(typeof progressCallback, 'function');

    await renewCerts(options, auditSource, progressCallback);
    await cleanupCerts(auditSource, progressCallback);
}

function removeAppConfigs() {
    const dashboardConfigFilename = `${settings.dashboardFqdn()}.conf`;

    debug('removeAppConfigs: reomving nginx configs of apps');

    // remove all configs which are not the default or current dashboard
    for (const appConfigFile of fs.readdirSync(paths.NGINX_APPCONFIG_DIR)) {
        if (appConfigFile !== constants.NGINX_DEFAULT_CONFIG_FILE_NAME && appConfigFile !== dashboardConfigFilename) {
            fs.unlinkSync(path.join(paths.NGINX_APPCONFIG_DIR, appConfigFile));
        }
    }
}

async function writeDefaultConfig(options) {
    assert.strictEqual(typeof options, 'object');

    const certFilePath = path.join(paths.NGINX_CERT_DIR,  'default.cert');
    const keyFilePath = path.join(paths.NGINX_CERT_DIR, 'default.key');

    if (!fs.existsSync(certFilePath) || !fs.existsSync(keyFilePath)) {
        debug('writeDefaultConfig: create new cert');

        const cn = 'cloudron-' + (new Date()).toISOString(); // randomize date a bit to keep firefox happy
        // the days field is chosen to be less than 825 days per apple requirement (https://support.apple.com/en-us/HT210176)
        if (!safe.child_process.execSync(`openssl req -x509 -newkey rsa:2048 -keyout ${keyFilePath} -out ${certFilePath} -days 800 -subj /CN=${cn} -nodes`)) {
            debug(`writeDefaultConfig: could not generate certificate: ${safe.error.message}`);
            throw new BoxError(BoxError.OPENSSL_ERROR, safe.error);
        }
    }

    const data = {
        sourceDir: path.resolve(__dirname, '..'),
        vhost: '',
        hasIPv6: sysinfo.hasIPv6(),
        endpoint: options.activated ? 'ip' : 'setup',
        certFilePath,
        keyFilePath,
        robotsTxtQuoted: JSON.stringify('User-agent: *\nDisallow: /\n'),
        proxyAuth: { enabled: false, id: null, location: nginxLocation('/') },
        ocsp: false // self-signed cert
    };
    const nginxConf = ejs.render(NGINX_APPCONFIG_EJS, data);
    const nginxConfigFilename = path.join(paths.NGINX_APPCONFIG_DIR, constants.NGINX_DEFAULT_CONFIG_FILE_NAME);

    debug(`writeDefaultConfig: writing configs for endpoint "${data.endpoint}"`);

    if (!safe.fs.writeFileSync(nginxConfigFilename, nginxConf)) throw new BoxError(BoxError.FS_ERROR, safe.error);

    await reload();
}