'use strict';

exports = module.exports = {
    start,
    stop,
    revokeByUserId,
    getUserByAuthCode,
    consumeAuthCode,

    addClient,
    getClient,
    delClient,
    updateClient,
    listClients
};

const assert = require('assert'),
    apps = require('./apps.js'),
    AuditSource = require('./auditsource.js'),
    BoxError = require('./boxerror.js'),
    blobs = require('./blobs.js'),
    branding = require('./branding.js'),
    constants = require('./constants.js'),
    crypto = require('crypto'),
    dashboard = require('./dashboard.js'),
    database = require('./database.js'),
    debug = require('debug')('box:oidc'),
    dns = require('./dns.js'),
    ejs = require('ejs'),
    express = require('express'),
    eventlog = require('./eventlog.js'),
    fs = require('fs'),
    marked = require('marked'),
    middleware = require('./middleware'),
    path = require('path'),
    paths = require('./paths.js'),
    http = require('http'),
    HttpError = require('connect-lastmile').HttpError,
    jose = require('jose'),
    safe = require('safetydance'),
    settings = require('./settings.js'),
    tokens = require('./tokens.js'),
    translations = require('./translations.js'),
    url = require('url'),
    users = require('./users.js'),
    groups = require('./groups.js'),
    util = require('util');

const OIDC_CLIENTS_TABLE_NAME = 'oidcClients';
const OIDC_CLIENTS_FIELDS = [ 'id', 'secret', 'name', 'appId', 'loginRedirectUri', 'tokenSignatureAlgorithm' ];

const ROUTE_PREFIX = '/openid';
const DEFAULT_TOKEN_SIGNATURE_ALGORITHM='RS256';

let gHttpServer = null;

// -----------------------------
// Database model
// -----------------------------
function postProcess(result) {
    assert.strictEqual(typeof result, 'object');

    result.tokenSignatureAlgorithm = result.tokenSignatureAlgorithm || DEFAULT_TOKEN_SIGNATURE_ALGORITHM;

    return result;
}

async function addClient(id, data) {
    assert.strictEqual(typeof id, 'string');
    assert.strictEqual(typeof data.secret, 'string');
    assert.strictEqual(typeof data.loginRedirectUri, 'string');
    assert.strictEqual(typeof data.name, 'string');
    assert.strictEqual(typeof data.appId, 'string');
    assert(data.tokenSignatureAlgorithm === 'RS256' || data.tokenSignatureAlgorithm === 'EdDSA');

    const query = `INSERT INTO ${OIDC_CLIENTS_TABLE_NAME} (id, secret, name, appId, loginRedirectUri, tokenSignatureAlgorithm) VALUES (?, ?, ?, ?, ?, ?)`;
    const args = [ id, data.secret, data.name, data.appId, data.loginRedirectUri, data.tokenSignatureAlgorithm ];

    const [error] = await safe(database.query(query, args));
    if (error && error.code === 'ER_DUP_ENTRY') throw new BoxError(BoxError.ALREADY_EXISTS, 'client already exists');
    if (error) throw error;
}

async function getClient(id) {
    assert.strictEqual(typeof id, 'string');

    if (id === tokens.ID_WEBADMIN) {
        const { fqdn:dashboardFqdn } = await dashboard.getLocation();
        return {
            id: tokens.ID_WEBADMIN,
            secret: 'notused',
            application_type: 'web',
            response_types: ['code', 'code token'],
            grant_types: ['authorization_code', 'implicit'],
            loginRedirectUri: `https://${dashboardFqdn}/authcallback.html`
        };
    } else if (id === tokens.ID_DEVELOPMENT) {
        return {
            id: tokens.ID_DEVELOPMENT,
            secret: 'notused',
            application_type: 'native', // have to use native here to support plaintext http, this however makes it impossible to skip consent screen
            response_types: ['code', 'code token'],
            grant_types: ['authorization_code', 'implicit'],
            loginRedirectUri: 'http://localhost:4000/authcallback.html'
        };
    }

    const result = await database.query(`SELECT ${OIDC_CLIENTS_FIELDS} FROM ${OIDC_CLIENTS_TABLE_NAME} WHERE id = ?`, [ id ]);
    if (result.length === 0) return null;

    return postProcess(result[0]);
}

async function updateClient(id, data) {
    assert.strictEqual(typeof id, 'string');
    assert.strictEqual(typeof data.loginRedirectUri, 'string');
    assert.strictEqual(typeof data.name, 'string');
    assert.strictEqual(typeof data.appId, 'string');
    assert(data.tokenSignatureAlgorithm === 'RS256' || data.tokenSignatureAlgorithm === 'EdDSA');

    const result = await database.query(`UPDATE ${OIDC_CLIENTS_TABLE_NAME} SET name=?, appId=?, loginRedirectUri=?, tokenSignatureAlgorithm=? WHERE id = ?`, [ data.name, data.appId, data.loginRedirectUri, data.tokenSignatureAlgorithm, id]);
    if (result.affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'client not found');
}

async function delClient(id) {
    assert.strictEqual(typeof id, 'string');

    const result = await database.query(`DELETE FROM ${OIDC_CLIENTS_TABLE_NAME} WHERE id = ?`, [ id ]);
    if (result.affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'client not found');
}

async function listClients() {
    const results = await database.query(`SELECT * FROM ${OIDC_CLIENTS_TABLE_NAME} ORDER BY name ASC`, []);

    results.forEach(postProcess);

    return results;
}

// -----------------------------
// Basic in-memory json file backed based data store
// -----------------------------
const DATA_STORE = {};

function load(modelName) {
    assert.strictEqual(typeof modelName, 'string');

    if (DATA_STORE[modelName]) return;

    const filePath = path.join(paths.OIDC_STORE_DIR, `${modelName}.json`);
    debug(`load: model ${modelName} based on ${filePath}.`);

    let data = {};
    try {
        data = JSON.parse(fs.readFileSync(filePath), 'utf8');
    } catch (e) {
        if (e.code !== 'ENOENT') debug(`load: failed to read ${filePath}, use in-memory. %o`, e);
    }

    DATA_STORE[modelName] = data;
}

function save(modelName) {
    assert.strictEqual(typeof modelName, 'string');

    if (!DATA_STORE[modelName]) return;

    const filePath = path.join(paths.OIDC_STORE_DIR, `${modelName}.json`);

    try {
        fs.writeFileSync(filePath, JSON.stringify(DATA_STORE[modelName], null, 2), 'utf8');
    } catch (e) {
        debug(`save: model ${modelName} failed to write ${filePath}`, e);
    }
}

// -----------------------------
// Session, Grant and Token management
// -----------------------------
// This is based on the same storage as the below CloudronAdapter
async function revokeByUserId(userId) {
    assert.strictEqual(typeof userId, 'string');

    function revokeObjects(modelName) {
        load(modelName);

        for (const id in DATA_STORE[modelName]) {
            if (DATA_STORE[modelName][id].payload?.accountId === userId) delete DATA_STORE[modelName][id];
        }

        save(modelName);
    }

    revokeObjects('Session');
    revokeObjects('Grant');
    revokeObjects('AuthorizationCode');
    revokeObjects('AccessToken');
}

async function consumeAuthCode(authCode) {
    assert.strictEqual(typeof authCode, 'string');

    const authData = DATA_STORE['AuthorizationCode'][authCode];
    if (!authData || !authData.payload) return;

    DATA_STORE['AuthorizationCode'][authCode].consumed = true;

    save('AuthorizationCode');
}

async function getUserByAuthCode(authCode) {
    assert.strictEqual(typeof authCode, 'string');

    load('AuthorizationCode');
    const authData = DATA_STORE['AuthorizationCode'][authCode];

    if (!authData || !authData.payload || !authData.payload.accountId) return null;

    return await users.get(authData.payload.accountId);
}

// -----------------------------
// Generic oidc node module data store model
// -----------------------------
class CloudronAdapter {
    /**
     *
     * Creates an instance of MyAdapter for an oidc-provider model.
     *
     * @constructor
     * @param {string} name Name of the oidc-provider model. One of "Grant, "Session", "AccessToken",
     * "AuthorizationCode", "RefreshToken", "ClientCredentials", "Client", "InitialAccessToken",
     * "RegistrationAccessToken", "DeviceCode", "Interaction", "ReplayDetection",
     * "BackchannelAuthenticationRequest", or "PushedAuthorizationRequest"
     *
     */
    constructor(name) {
        this.name = name;

        debug(`Creating OpenID storage adapter for ${name}`);

        if (this.name === 'Client') {
            return;
        } else {
            load(name);
        }
    }

    /**
     *
     * Update or Create an instance of an oidc-provider model.
     *
     * @return {Promise} Promise fulfilled when the operation succeeded. Rejected with error when
     * encountered.
     * @param {string} id Identifier that oidc-provider will use to reference this model instance for
     * future operations.
     * @param {object} payload Object with all properties intended for storage.
     * @param {integer} expiresIn Number of seconds intended for this model to be stored.
     *
     */
    async upsert(id, payload, expiresIn) {
        debug(`[${this.name}] upsert: ${id}`);

        if (this.name === 'Client') {
            debug('upsert: this should not happen as it is stored in our db');
        } else if (this.name === 'AccessToken' && (payload.clientId === tokens.ID_WEBADMIN || payload.clientId === tokens.ID_DEVELOPMENT)) {
            const clientId = payload.clientId;
            const identifier = payload.accountId;
            const expires = Date.now() + constants.DEFAULT_TOKEN_EXPIRATION_MSECS;
            const accessToken = id;

            const [error] = await safe(tokens.add({ clientId, identifier, expires, accessToken }));
            if (error) {
                console.log('Error adding access token', error);
                throw error;
            }
        } else {
            DATA_STORE[this.name][id] = { id, expiresIn, payload, consumed: false };
            save(this.name);
        }
    }

    /**
     *
     * Return previously stored instance of an oidc-provider model.
     *
     * @return {Promise} Promise fulfilled with what was previously stored for the id (when found and
     * not dropped yet due to expiration) or falsy value when not found anymore. Rejected with error
     * when encountered.
     * @param {string} id Identifier of oidc-provider model
     *
     */
    async find(id) {
        debug(`[${this.name}] find: ${id}`);

        if (this.name === 'Client') {
            const [error, client] = await safe(getClient(id));
            if (error) {
                debug('find: error getting client', error);
                return null;
            }
            if (!client) return null;

            const tmp = {};
            tmp.application_type = client.application_type || 'native';  // default is web but we want more flexible redirectUris and this is only used in https://github.com/panva/node-oidc-provider/blob/03c9bc513860e68ee7be84f99bfc9dc930b224e8/lib/helpers/client_schema.js#L536
            tmp.client_id = id;
            tmp.client_secret = client.secret;
            tmp.id_token_signed_response_alg = client.tokenSignatureAlgorithm || 'RS256';

            if (client.response_types) tmp.response_types = client.response_types;
            if (client.grant_types) tmp.grant_types = client.grant_types;

            if (client.appId) {
                const [error, app] = await safe(apps.get(client.appId));
                if (error || !app) {
                    debug(`find: Unknown app for client with appId ${client.appId}`);
                    return null;
                }

                const domains = [ app.fqdn ].concat(app.aliasDomains.map(d => d.fqdn));

                // prefix login redirect uris with app.fqdn if it is just a path without a schema
                // native callbacks for apps have custom schema like app.immich:/
                tmp.redirect_uris = [];
                client.loginRedirectUri.split(',').map(s => s.trim()).forEach((s) => {
                    if (url.parse(s).protocol) tmp.redirect_uris.push(s);
                    else tmp.redirect_uris = tmp.redirect_uris.concat(domains.map(fqdn => `https://${fqdn}${s}`));
                });
            } else {
                tmp.redirect_uris = client.loginRedirectUri.split(',').map(s => s.trim());
            }

            return tmp;
        } else if (this.name === 'AccessToken') {
            const [error, result] = await safe(tokens.getByAccessToken(id));
            if (error || !result) {
                debug(`find: ${id} is not an API accessToken maybe oidc internal`);

                if (!DATA_STORE[this.name][id]) return null;
                return DATA_STORE[this.name][id].payload;
            }

            const tmp = {
                accountId: result.identifier,
                clientId: result.clientId
            };

            return tmp;
        } else {
            if (!DATA_STORE[this.name][id]) return null;

            return DATA_STORE[this.name][id].payload;
        }
    }

    /**
     *
     * Return previously stored instance of DeviceCode by the end-user entered user code. You only
     * need this method for the deviceFlow feature
     *
     * @return {Promise} Promise fulfilled with the stored device code object (when found and not
     * dropped yet due to expiration) or falsy value when not found anymore. Rejected with error
     * when encountered.
     * @param {string} userCode the user_code value associated with a DeviceCode instance
     *
     */
    async findByUserCode(userCode) {
        debug(`[${this.name}] FIXME findByUserCode userCode:${userCode}`);
    }

    /**
     *
     * Return previously stored instance of Session by its uid reference property.
     *
     * @return {Promise} Promise fulfilled with the stored session object (when found and not
     * dropped yet due to expiration) or falsy value when not found anymore. Rejected with error
     * when encountered.
     * @param {string} uid the uid value associated with a Session instance
     *
     */
    async findByUid(uid) {
        debug(`[${this.name}] findByUid: ${uid}`);

        if (this.name === 'Client' || this.name === 'AccessToken') {
            debug('findByUid: this should not happen as it is stored in our db');
        } else {
            for (const d in DATA_STORE[this.name]) {
                if (DATA_STORE[this.name][d].payload.uid === uid) return DATA_STORE[this.name][d].payload;
            }

            return false;
        }
    }

    /**
     *
     * Mark a stored oidc-provider model as consumed (not yet expired though!). Future finds for this
     * id should be fulfilled with an object containing additional property named "consumed" with a
     * truthy value (timestamp, date, boolean, etc).
     *
     * @return {Promise} Promise fulfilled when the operation succeeded. Rejected with error when
     * encountered.
     * @param {string} id Identifier of oidc-provider model
     *
     */
    async consume(id) {
        debug(`[${this.name}] consume: ${id}`);

        if (this.name === 'Client') {
            debug('consume: this should not happen as it is stored in our db');
        } else {
            if (DATA_STORE[this.name][id]) DATA_STORE[this.name][id].consumed = true;
            save(this.name);
        }
    }

    /**
     *
     * Destroy/Drop/Remove a stored oidc-provider model. Future finds for this id should be fulfilled
     * with falsy values.
     *
     * @return {Promise} Promise fulfilled when the operation succeeded. Rejected with error when
     * encountered.
     * @param {string} id Identifier of oidc-provider model
     *
     */
    async destroy(id) {
        debug(`[${this.name}] destroy: ${id}`);

        if (this.name === 'Client') {
            debug('destroy: this should not happen as it is stored in our db');
        } else {
            delete DATA_STORE[this.name][id];
            save(this.name);
        }
    }

    /**
     *
     * Destroy/Drop/Remove a stored oidc-provider model by its grantId property reference. Future
     * finds for all tokens having this grantId value should be fulfilled with falsy values.
     *
     * @return {Promise} Promise fulfilled when the operation succeeded. Rejected with error when
     * encountered.
     * @param {string} grantId the grantId value associated with a this model's instance
     *
     */
    async revokeByGrantId(grantId) {
        debug(`[${this.name}] revokeByGrantId: ${grantId}`);

        if (this.name === 'Client') {
            debug('revokeByGrantId: this should not happen as it is stored in our db');
        } else {
            for (const d in DATA_STORE[this.name]) {
                if (DATA_STORE[this.name][d].grantId === grantId) {
                    delete DATA_STORE[this.name][d];
                    return save(this.name);
                }
            }
        }
    }
}

// -----------------------------
// Route handler
// -----------------------------
function renderInteractionPage(provider) {
    assert.strictEqual(typeof provider, 'object');

    return async function (req, res) {
        const translationAssets = await translations.getTranslations();

        try {
            const { uid, prompt, params, session } = await provider.interactionDetails(req, res);

            const client = await getClient(params.client_id);

            let app = null;
            if (client.appId) app = await apps.get(client.appId);

            switch (prompt.name) {
            case 'login': {
                const options = {
                    SUBMIT_URL: `${ROUTE_PREFIX}/interaction/${uid}/login`,
                    ICON_URL: '/api/v1/cloudron/avatar',
                    NAME: client?.name || await branding.getCloudronName(),
                    FOOTER: marked.parse(await branding.renderFooter()),
                    NOTE: (client.id === tokens.ID_WEBADMIN && constants.DEMO) ? '<div style="text-align: center;">This is a demo. Username and password is "cloudron"</div>' : ''
                };

                if (app) {
                    options.NAME = app.label || app.fqdn;
                    options.ICON_URL = app.iconUrl;
                }

                // great ejs replacement!
                const template = fs.readFileSync(__dirname + '/../dashboard/login.html', 'utf-8');
                let html = translations.translate(template, translationAssets);
                Object.keys(options).forEach(key => {
                    html = html.replace(`##${key}##`, options[key], 'g');
                });

                return res.send(html);
            }
            case 'consent': {
                const options = {
                    hasAccess: false,
                    submitUrl: '',
                    iconUrl: '/api/v1/cloudron/avatar',
                    name: client?.name || '',
                    footer: marked.parse(await branding.renderFooter())
                };

                // check if user has access to the app if client refers to an app
                if (app) {
                    const user = await users.get(session.accountId);

                    options.name = app.label || app.fqdn;
                    options.iconUrl = app.iconUrl;
                    options.hasAccess = apps.canAccess(app, user);
                } else {
                    options.hasAccess = true;
                }

                options.submitUrl = `${ROUTE_PREFIX}/interaction/${uid}/${options.hasAccess ? 'confirm' : 'abort'}`;

                return res.render('interaction', options);
            }
            default:
                return undefined;
            }
        } catch (error) {
            debug('route interaction get error', error);
            return res.render('error', {
                errorMessage: error.error_description || 'Internal error',
                footer: marked.parse(await branding.renderFooter())
            });
        }
    };
}

function interactionLogin(provider) {
    assert.strictEqual(typeof provider, 'object');

    return async function(req, res, next) {
        const [detailsError, details] = await safe(provider.interactionDetails(req, res));
        if (detailsError) {
            if (detailsError.error_description === 'interaction session not found') return next(new HttpError(410, 'session timeout'));
            return next(new HttpError(400, detailsError));
        }

        const ip = req.headers['x-forwarded-for'] || req.connection.remoteAddress || null;
        const userAgent = req.headers['user-agent'] || '';
        const clientId = details.params.client_id;

        debug(`interactionLogin: for OpenID client ${clientId} from ${ip}`);

        // This is the auto login via token hack
        if (req.body.autoLoginToken) {
            if (typeof req.body.autoLoginToken !== 'string') return next(new HttpError(400, 'autoLoginToken must be string if provided'));

            const token = await tokens.getByAccessToken(req.body.autoLoginToken);
            if (!token) return next(new HttpError(401, 'No such token'));

            const user = await users.get(token.identifier);
            if (!user) return next(new HttpError(401,'User not found'));
            if (!user.active) return next(new HttpError(401,'User not active'));

            const result = {
                login: {
                    accountId: user.id,
                },
            };

            const [interactionFinishError, redirectTo] = await safe(provider.interactionResult(req, res, result));
            if (interactionFinishError) return next(new HttpError(500, interactionFinishError));

            const auditSource = AuditSource.fromOidcRequest(req);
            await eventlog.add(user.ghost ? eventlog.ACTION_USER_LOGIN_GHOST : eventlog.ACTION_USER_LOGIN, auditSource, { userId: user.id, user: users.removePrivateFields(user), appId: clientId });
            await safe(users.notifyLoginLocation(user, ip, userAgent, auditSource), { debug });

            // clear token as it is one-time use
            await tokens.delByAccessToken(req.body.autoLoginToken);

            return res.status(200).send({ redirectTo });
        }

        if (!req.body.username || typeof req.body.username !== 'string') return next(new HttpError(400, 'A username must be non-empty string'));
        if (!req.body.password || typeof req.body.password !== 'string') return next(new HttpError(400, 'A password must be non-empty string'));
        if ('totpToken' in req.body && typeof req.body.totpToken !== 'string') return next(new HttpError(400, 'totpToken must be a string' ));

        const { username, password, totpToken } = req.body;

        const verifyFunc = username.indexOf('@') === -1 ? users.verifyWithUsername : users.verifyWithEmail;

        const [verifyError, user] = await safe(verifyFunc(username, password, users.AP_WEBADMIN, { totpToken, skipTotpCheck: false }));
        if (verifyError && verifyError.reason === BoxError.INVALID_CREDENTIALS) return next(new HttpError(401, verifyError.message));
        if (verifyError && verifyError.reason === BoxError.NOT_FOUND) return next(new HttpError(401, 'Username and password does not match'));
        if (verifyError) return next(new HttpError(500, verifyError));
        if (!user) return next(new HttpError(401, 'Username and password does not match'));

        // TODO we may have to check what else the Account class provides, in which case we have to map those things
        const result = {
            login: {
                accountId: user.id,
            },
        };

        const [interactionFinishError, redirectTo] = await safe(provider.interactionResult(req, res, result));
        if (interactionFinishError) return next(new HttpError(500, interactionFinishError));

        res.status(200).send({ redirectTo });
    };
}

function interactionConfirm(provider) {
    assert.strictEqual(typeof provider, 'object');

    return async function (req, res, next) {
        async function raiseLoginEvent(user, clientId) {
            try {
                const ip = req.headers['x-forwarded-for'] || req.connection.remoteAddress || null;
                const userAgent = req.headers['user-agent'] || '';
                const auditSource = AuditSource.fromOidcRequest(req);

                await eventlog.add(user.ghost ? eventlog.ACTION_USER_LOGIN_GHOST : eventlog.ACTION_USER_LOGIN, auditSource, { userId: user.id, user: users.removePrivateFields(user), appId: clientId });
                await users.notifyLoginLocation(user, ip, userAgent, auditSource);
            } catch (e) {
                console.error('oidc: Failed to raise login event.', e);
            }
        }

        try {
            const interactionDetails = await provider.interactionDetails(req, res);
            const { grantId, uid, prompt: { name, details }, params, session: { accountId } } = interactionDetails;

            debug(`route interaction confirm post uid:${uid} prompt.name:${name} accountId:${accountId}`);

            assert.equal(name, 'consent');

            const client = await getClient(params.client_id);
            const user = await users.get(accountId);

            // Check if user has access to the app if client refers to an app
            // In most cases the user interaction already ends in the consent screen (see above)
            if (client.appId) {
                const app = await apps.get(client.appId);

                if (!apps.canAccess(app, user)) {
                    const result = {
                        error: 'access_denied',
                        error_description: 'User has no access to this app',
                    };

                    await raiseLoginEvent(user, client.appId);

                    return await provider.interactionFinished(req, res, result, { mergeWithLastSubmission: false });
                }
            }

            let grant;
            if (grantId) {
                // we'll be modifying existing grant in existing session
                grant = await provider.Grant.find(grantId);
            } else {
                // we're establishing a new grant
                grant = new provider.Grant({
                    accountId,
                    clientId: params.client_id,
                });
            }

            if (details.missingOIDCScope) {
                grant.addOIDCScope(details.missingOIDCScope.join(' '));
            }
            if (details.missingOIDCClaims) {
                grant.addOIDCClaims(details.missingOIDCClaims);
            }
            if (details.missingResourceScopes) {
                for (const [indicator, scopes] of Object.entries(details.missingResourceScopes)) {
                    grant.addResourceScope(indicator, scopes.join(' '));
                }
            }

            const savedGrantId = await grant.save();

            const consent = {};
            if (!interactionDetails.grantId) {
                // we don't have to pass grantId to consent, we're just modifying existing one
                consent.grantId = savedGrantId;
            }

            await raiseLoginEvent(user, params.client_id);

            const result = { consent };
            await provider.interactionFinished(req, res, result, { mergeWithLastSubmission: true });
        } catch (err) {
            next(err);
        }
    };
}

function interactionAbort(provider) {
    assert.strictEqual(typeof provider, 'object');

    return async function (req, res, next) {
        try {
            const result = {
                error: 'access_denied',
                error_description: 'End-User aborted interaction',
            };
            await provider.interactionFinished(req, res, result, { mergeWithLastSubmission: false });
        } catch (err) {
            next(err);
        }
    };
}

/**
   * @param use - can either be "id_token" or "userinfo", depending on
   *   where the specific claims are intended to be put in.
   * @param scope - the intended scope, while oidc-provider will mask
   *   claims depending on the scope automatically you might want to skip
   *   loading some claims from external resources etc. based on this detail
   *   or not return them in id tokens but only userinfo and so on.
   */
async function claims(userId/*, use, scope*/) {
    const [error, user] = await safe(users.get(userId));
    if (error) return { error: 'user not found' };

    const [groupsError, allGroups] = await safe(groups.listWithMembers());
    if (groupsError) return { error: groupsError.message };

    const displayName = user.displayName || user.username || ''; // displayName can be empty and username can be null
    const { firstName, lastName, middleName } = users.parseDisplayName(displayName);

    const { fqdn:dashboardFqdn } = await dashboard.getLocation();

    // https://openid.net/specs/openid-connect-core-1_0.html#StandardClaims
    const claims = {
        sub: user.username, // it is essential to always return a sub claim
        email: user.email,
        email_verified: true,
        family_name: lastName,
        middle_name: middleName,
        given_name: firstName,
        locale: 'en-US',
        name: user.displayName,
        picture: `https://${dashboardFqdn}/api/v1/profile/avatar/${user.id}.png`, // some apps get surprised if we respond with a svg
        preferred_username: user.username,
        groups: allGroups.filter(function (g) { return g.userIds.indexOf(user.id) !== -1; }).map(function (g) { return `${g.name}`; })
    };

    return claims;
}

async function findAccount(ctx, id) {
    return {
        accountId: id,
        async claims(use, scope) { return await claims(id, use, scope); },
    };
}

async function renderError(ctx, out, error) {
    const data = {
        errorMessage: error.error_description || error.error_detail || 'Unknown error',
        footer: marked.parse(await branding.renderFooter())
    };

    debug('renderError: %o', error);

    ctx.type = 'html';
    ctx.body = ejs.render(fs.readFileSync(path.join(__dirname, 'oidc_templates/error.ejs'), 'utf8'), data, {});
}

async function start() {
    assert(gHttpServer === null, 'OIDC aerver already started');

    const app = express();

    gHttpServer = http.createServer(app);

    const Provider = (await import('oidc-provider')).default;

    // TODO we may want to rotate those in the future
    const jwksKeys = [];

    let keyEdDsa = await blobs.getString(blobs.OIDC_KEY_EDDSA);
    if (!keyEdDsa) {
        debug('Generating new OIDC EdDSA key');
        const { privateKey } = await jose.generateKeyPair('EdDSA');
        keyEdDsa = await jose.exportJWK(privateKey);
        await blobs.setString(blobs.OIDC_KEY_EDDSA, JSON.stringify(keyEdDsa));
        jwksKeys.push(keyEdDsa);
    } else {
        debug('Using existing OIDC EdDSA key');
        jwksKeys.push(JSON.parse(keyEdDsa));
    }

    let keyRs256 = await blobs.getString(blobs.OIDC_KEY_RS256);
    if (!keyRs256) {
        debug('Generating new OIDC RS256 key');
        const { privateKey } = await jose.generateKeyPair('RS256');
        keyRs256 = await jose.exportJWK(privateKey);
        await blobs.setString(blobs.OIDC_KEY_RS256, JSON.stringify(keyRs256));
        jwksKeys.push(keyRs256);
    } else {
        debug('Using existing OIDC RS256 key');
        jwksKeys.push(JSON.parse(keyRs256));
    }

    let cookieSecret = await settings.get(settings.OIDC_COOKIE_SECRET_KEY);
    if (!cookieSecret) {
        debug('Generating new cookie secret');
        cookieSecret = crypto.randomBytes(256).toString('base64');
        await settings.set(settings.OIDC_COOKIE_SECRET_KEY, cookieSecret);
    }

    const configuration = {
        findAccount,
        renderError,
        adapter: CloudronAdapter,
        interactions: {
            url: async function(ctx, interaction) {
                return `${ROUTE_PREFIX}/interaction/${interaction.uid}`;
            }
        },
        jwks: {
            jwksKeys
        },
        claims: {
            email: ['email', 'email_verified'],
            profile: [ 'family_name', 'given_name', 'locale', 'name', 'preferred_username', 'picture' ],
            groups: [ 'groups' ]
        },
        features: {
            rpInitiatedLogout: { enabled: false },
            devInteractions: { enabled: false }
        },
        clientDefaults: {
            response_types: ['code', 'id_token'],
            grant_types: ['authorization_code', 'implicit', 'refresh_token']
        },
        responseTypes: [
            'code',
            'id_token', 'id_token token',
            'code id_token', 'code token', 'code id_token token',
            'none',
        ],
        // if a client only has one redirect uri specified, the client does not have to provide it in the request
        allowOmittingSingleRegisteredRedirectUri: true,
        clients: [],
        cookies: {
            keys: [ cookieSecret ]
        },
        pkce: {
            required: function pkceRequired(/*ctx, client*/) {
                return false;
            }
        },
        clientBasedCORS(ctx, origin, client) {
            // allow CORS for clients where at least the origin matches where we redirect back to
            if (client.redirectUris.find((u) => u.indexOf(origin) === 0)) return true;

            return false;
        },
        conformIdTokenClaims: false,
        // https://github.com/panva/node-oidc-provider/blob/main/recipes/skip_consent.md
        loadExistingGrant: async function (ctx) {
            const grantId = ctx.oidc.result?.consent?.grantId
              || ctx.oidc.session.grantIdFor(ctx.oidc.client.clientId);

            if (grantId) {
                return await ctx.oidc.provider.Grant.find(grantId);
            } else if (ctx.oidc.client.clientId === tokens.ID_WEBADMIN || ctx.oidc.client.clientId === tokens.ID_DEVELOPMENT) {
                const grant = new ctx.oidc.provider.Grant({
                    clientId: ctx.oidc.client.clientId,
                    accountId: ctx.oidc.session.accountId,
                });

                grant.addOIDCScope('openid email profile groups');
                // grant.addOIDCClaims(['first_name']);
                await grant.save();

                return grant;
            }
        },
        // https://github.com/panva/node-oidc-provider/blob/main/docs/README.md#issuerefreshtoken
        async issueRefreshToken(ctx, client, code) {
            if (!client.grantTypeAllowed('refresh_token') && !client.grantTypeAllowed('authorization_code')) {
                return false;
            }
            return code.scopes.has('offline_access') || (client.applicationType === 'native' && client.clientAuthMethod === 'client_secret_basic');
        },
        ttl: {
            // in seconds, can also be a function returning the seconds https://github.com/panva/node-oidc-provider/blob/b1c1a9318036c2d3793cc9e668f99937c5c36bc6/docs/README.md#ttl
            AccessToken: 3600, // 1 hour
            IdToken: 3600, // 1 hour
            Grant: 1209600, // 14 days
            Session: 1209600, // 14 days
            Interaction: 3600, // 1 hour
            RefreshToken: 1209600 // 14 days
        }
    };

    const { subdomain, domain } = await dashboard.getLocation();
    const fqdn = dns.fqdn(subdomain, domain);
    debug(`start: create provider for ${fqdn} at ${ROUTE_PREFIX}`);
    const provider = new Provider(`https://${fqdn}${ROUTE_PREFIX}`, configuration);

    app.enable('trust proxy');
    provider.proxy = true;

    app.set('views', path.join(__dirname, 'oidc_templates'));
    app.set('view engine', 'ejs');

    const json = express.json({ strict: true, limit: '2mb' });
    function setNoCache(req, res, next) {
        res.set('cache-control', 'no-store');
        next();
    }

    app.get (`${ROUTE_PREFIX}/interaction/:uid`,          setNoCache,       renderInteractionPage(provider));
    app.post(`${ROUTE_PREFIX}/interaction/:uid/login`,    setNoCache, json, interactionLogin(provider));
    app.post(`${ROUTE_PREFIX}/interaction/:uid/confirm`,  setNoCache, json, interactionConfirm(provider));
    app.get (`${ROUTE_PREFIX}/interaction/:uid/abort`,    setNoCache,       interactionAbort(provider));

    app.use(ROUTE_PREFIX, provider.callback());
    app.use(middleware.lastMile());

    await util.promisify(gHttpServer.listen.bind(gHttpServer))(constants.OIDC_PORT, '127.0.0.1');
}

async function stop() {
    if (!gHttpServer) return;

    await util.promisify(gHttpServer.close.bind(gHttpServer))();
    gHttpServer = null;
}