#!/usr/bin/env node

'use strict';

exports = module.exports = {
    run: run,

    // exported for testing
    _reserveHttpPort: reserveHttpPort,
    _configureReverseProxy: configureReverseProxy,
    _unconfigureReverseProxy: unconfigureReverseProxy,
    _createAppDir: createAppDir,
    _deleteAppDir: deleteAppDir,
    _verifyManifest: verifyManifest,
    _registerSubdomains: registerSubdomains,
    _unregisterSubdomains: unregisterSubdomains,
    _waitForDnsPropagation: waitForDnsPropagation
};

require('supererror')({ splatchError: true });

var addons = require('./addons.js'),
    appdb = require('./appdb.js'),
    apps = require('./apps.js'),
    assert = require('assert'),
    async = require('async'),
    auditSource = require('./auditsource.js'),
    backups = require('./backups.js'),
    BoxError = require('./boxerror.js'),
    collectd = require('./collectd.js'),
    constants = require('./constants.js'),
    debug = require('debug')('box:apptask'),
    df = require('@sindresorhus/df'),
    docker = require('./docker.js'),
    domains = require('./domains.js'),
    ejs = require('ejs'),
    eventlog = require('./eventlog.js'),
    fs = require('fs'),
    manifestFormat = require('cloudron-manifestformat'),
    net = require('net'),
    os = require('os'),
    path = require('path'),
    paths = require('./paths.js'),
    reverseProxy = require('./reverseproxy.js'),
    rimraf = require('rimraf'),
    safe = require('safetydance'),
    settings = require('./settings.js'),
    sftp = require('./sftp.js'),
    shell = require('./shell.js'),
    superagent = require('superagent'),
    sysinfo = require('./sysinfo.js'),
    util = require('util'),
    _ = require('underscore');

const COLLECTD_CONFIG_EJS = fs.readFileSync(__dirname + '/collectd/app.ejs', { encoding: 'utf8' }),
    MV_VOLUME_CMD = path.join(__dirname, 'scripts/mvvolume.sh'),
    LOGROTATE_CONFIG_EJS = fs.readFileSync(__dirname + '/logrotate.ejs', { encoding: 'utf8' }),
    CONFIGURE_LOGROTATE_CMD = path.join(__dirname, 'scripts/configurelogrotate.sh');

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

    debug(app.fqdn + ' ' + util.format.apply(util, Array.prototype.slice.call(arguments, 1)));
}

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

    // track a few variables which helps 'repair' restart the task (see also scheduleTask in apps.js)
    error.details.taskId = app.taskId;
    error.details.installationState = app.installationState;
    return error.toPlainObject();
}

// updates the app object and the database
function updateApp(app, values, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof values, 'object');
    assert.strictEqual(typeof callback, 'function');

    debugApp(app, 'updating app with values: %j', values);

    appdb.update(app.id, values, function (error) {
        if (error) return callback(error);

        for (var value in values) {
            app[value] = values[value];
        }

        callback(null);
    });
}

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

    let server = net.createServer();
    server.listen(0, function () {
        let port = server.address().port;

        updateApp(app, { httpPort: port }, function (error) {
            server.close(function (/* closeError */) {
                if (error) return callback(new BoxError(BoxError.NETWORK_ERROR, `Failed to allocate http port ${port}: ${error.message}`));

                callback(null);
            });
        });
    });
}

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

    reverseProxy.configureApp(app, { userId: null, username: 'apptask' }, function (error) {
        if (error) return callback(error);

        callback(null);
    });
}

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

    reverseProxy.unconfigureApp(app, function (error) {
        if (error) return callback(error);

        callback(null);
    });
}

function createContainer(app, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof callback, 'function');
    assert(!app.containerId); // otherwise, it will trigger volumeFrom

    debugApp(app, 'creating container');

    docker.createContainer(app, function (error, container) {
        if (error) return callback(error);

        updateApp(app, { containerId: container.id }, function (error) {
            if (error) return callback(error);

            // re-generate configs that rely on container id
            async.series([
                addLogrotateConfig.bind(null, app),
                addCollectdProfile.bind(null, app)
            ], callback);
        });
    });
}

function deleteContainers(app, options, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof callback, 'function');

    debugApp(app, 'deleting app containers (app, scheduler)');

    async.series([
        // remove configs that rely on container id
        removeCollectdProfile.bind(null, app),
        removeLogrotateConfig.bind(null, app),
        docker.stopContainers.bind(null, app.id),
        docker.deleteContainers.bind(null, app.id, options),
        updateApp.bind(null, app, { containerId: null })
    ], callback);
}

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

    const appDir = path.join(paths.APPS_DATA_DIR, app.id);
    fs.mkdir(appDir, { recursive: true }, function (error) {
        if (error) return callback(new BoxError(BoxError.FS_ERROR, `Error creating directory: ${error.message}`, { appDir }));

        callback(null);
    });
}

function deleteAppDir(app, options, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof callback, 'function');

    const appDataDir = path.join(paths.APPS_DATA_DIR, app.id);

    // resolve any symlinked data dir
    const stat = safe.fs.lstatSync(appDataDir);
    if (!stat) return callback(null);

    const resolvedAppDataDir = stat.isSymbolicLink() ? safe.fs.readlinkSync(appDataDir) : appDataDir;

    if (safe.fs.existsSync(resolvedAppDataDir)) {
        const entries = safe.fs.readdirSync(resolvedAppDataDir);
        if (!entries) return callback(new BoxError(BoxError.FS_ERROR, `Error listing ${resolvedAppDataDir}: ${safe.error.message}`));

        // remove only files. directories inside app dir are currently volumes managed by the addons
        // we cannot delete those dirs anyway because of perms
        entries.forEach(function (entry) {
            let stat = safe.fs.statSync(path.join(resolvedAppDataDir, entry));
            if (stat && !stat.isDirectory()) safe.fs.unlinkSync(path.join(resolvedAppDataDir, entry));
        });
    }

    // if this fails, it's probably because the localstorage/redis addons have not cleaned up properly
    if (options.removeDirectory) {
        if (stat.isSymbolicLink()) {
            if (!safe.fs.unlinkSync(appDataDir)) {
                if (safe.error.code !== 'ENOENT') return callback(new BoxError(BoxError.FS_ERROR, `Error unlinking dir ${appDataDir} : ${safe.error.message}`));
            }
        } else {
            if (!safe.fs.rmdirSync(appDataDir)) {
                if (safe.error.code !== 'ENOENT') return callback(new BoxError(BoxError.FS_ERROR, `Error removing dir ${appDataDir} : ${safe.error.message}`));
            }
        }
    }

    callback(null);
}

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

    var collectdConf = ejs.render(COLLECTD_CONFIG_EJS, { appId: app.id, containerId: app.containerId, appDataDir: apps.getDataDir(app, app.dataDir) });
    collectd.addProfile(app.id, collectdConf, callback);
}

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

    collectd.removeProfile(app.id, callback);
}

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

    docker.inspect(app.containerId, function (error, result) {
        if (error) return callback(error);

        var runVolume = result.Mounts.find(function (mount) { return mount.Destination === '/run'; });
        if (!runVolume) return callback(new BoxError(BoxError.DOCKER_ERROR, 'App does not have /run mounted'));

        // logrotate configs can have arbitrary commands, so the config files must be owned by root
        var logrotateConf = ejs.render(LOGROTATE_CONFIG_EJS, { volumePath: runVolume.Source, appId: app.id });
        var tmpFilePath = path.join(os.tmpdir(), app.id + '.logrotate');
        fs.writeFile(tmpFilePath, logrotateConf, function (error) {
            if (error) return callback(new BoxError(BoxError.FS_ERROR, `Error writing logrotate config: ${error.message}`));

            shell.sudo('addLogrotateConfig', [ CONFIGURE_LOGROTATE_CMD, 'add', app.id, tmpFilePath ], {}, function (error) {
                if (error) return callback(new BoxError(BoxError.LOGROTATE_ERROR, `Error adding logrotate config: ${error.message}`));

                callback(null);
            });
        });
    });
}

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

    shell.sudo('removeLogrotateConfig', [ CONFIGURE_LOGROTATE_CMD, 'remove', app.id ], {}, function (error) {
        if (error) return callback(new BoxError(BoxError.LOGROTATE_ERROR, `Error removing logrotate config: ${error.message}`));

        callback(null);
    });
}

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

    // note that redis container logs are cleaned up by the addon
    rimraf(path.join(paths.LOG_DIR, app.id), function (error) {
        if (error) debugApp(app, 'cannot cleanup logs: %s', error);

        callback(null);
    });
}

function verifyManifest(manifest, callback) {
    assert.strictEqual(typeof manifest, 'object');
    assert.strictEqual(typeof callback, 'function');

    var error = manifestFormat.parse(manifest);
    if (error) return callback(new BoxError(BoxError.BAD_FIELD, `Manifest error: ${error.message}`, { field: 'manifest' }));

    error = apps.checkManifestConstraints(manifest);
    if (error) return callback(new BoxError(BoxError.CONFLICT, `Manifest constraint check failed: ${error.message}`, { field: 'manifest' }));

    callback(null);
}

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

    // nothing to download if we dont have an appStoreId
    if (!app.appStoreId) return callback(null);

    debugApp(app, 'Downloading icon of %s@%s', app.appStoreId, app.manifest.version);

    var iconUrl = settings.apiServerOrigin() + '/api/v1/apps/' + app.appStoreId + '/versions/' + app.manifest.version + '/icon';

    async.retry({ times: 10, interval: 5000 }, function (retryCallback) {
        superagent
            .get(iconUrl)
            .buffer(true)
            .timeout(30 * 1000)
            .end(function (error, res) {
                if (error && !error.response) return retryCallback(new BoxError(BoxError.NETWORK_ERROR, `Network error downloading icon : ${error.message}`));
                if (res.statusCode !== 200) return retryCallback(null); // ignore error. this can also happen for apps installed with cloudron-cli

                const iconPath = path.join(paths.APP_ICONS_DIR, app.id + '.png');
                if (!safe.fs.writeFileSync(iconPath, res.body)) return retryCallback(new BoxError(BoxError.FS_ERROR, `Error saving icon to ${iconPath}: ${safe.error.message}`));

                retryCallback(null);
            });
    }, callback);
}

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

    if (!safe.fs.unlinkSync(path.join(paths.APP_ICONS_DIR, app.id + '.png'))) {
        if (safe.error.code !== 'ENOENT') debugApp(app, 'cannot remove icon : %s', safe.error);
    }

    if (!safe.fs.unlinkSync(path.join(paths.APP_ICONS_DIR, app.id + '.user.png'))) {
        if (safe.error.code !== 'ENOENT') debugApp(app, 'cannot remove user icon : %s', safe.error);
    }

    callback(null);
}

function registerSubdomains(app, overwrite, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof overwrite, 'boolean');
    assert.strictEqual(typeof callback, 'function');

    sysinfo.getServerIp(function (error, ip) {
        if (error) return callback(error);

        const allDomains = [ { subdomain: app.location, domain: app.domain }].concat(app.alternateDomains);

        debug(`registerSubdomain: Will register ${JSON.stringify(allDomains)}`);

        async.eachSeries(allDomains, function (domain, iteratorDone) {
            async.retry({ times: 200, interval: 5000 }, function (retryCallback) {
                debugApp(app, 'Registering subdomain: %s%s', domain.subdomain ? (domain.subdomain + '.') : '', domain.domain);

                // get the current record before updating it
                domains.getDnsRecords(domain.subdomain, domain.domain, 'A', function (error, values) {
                    if (error && error.reason === BoxError.EXTERNAL_ERROR) return retryCallback(new BoxError(BoxError.EXTERNAL_ERROR, error.message, { domain })); // try again
                    if (error && error.reason === BoxError.ACCESS_DENIED) return retryCallback(null, new BoxError(BoxError.ACCESS_DENIED, error.message, { domain }));
                    if (error && error.reason === BoxError.NOT_FOUND) return retryCallback(null, new BoxError(BoxError.NOT_FOUND, error.message, { domain }));
                    if (error) return retryCallback(null, new BoxError(BoxError.EXTERNAL_ERROR, error.message, domain)); // give up for other errors

                    if (values.length !== 0 && values[0] === ip) return retryCallback(null); // up-to-date

                    // refuse to update any existing DNS record for custom domains that we did not create
                    if (values.length !== 0 && !overwrite) return retryCallback(null, new BoxError(BoxError.ALREADY_EXISTS, 'DNS Record already exists', { domain }));

                    domains.upsertDnsRecords(domain.subdomain, domain.domain, 'A', [ ip ], function (error) {
                        if (error && (error.reason === BoxError.BUSY || error.reason === BoxError.EXTERNAL_ERROR)) {
                            debug('registerSubdomains: Upsert error. Will retry.', error.message);
                            return retryCallback(new BoxError(BoxError.EXTERNAL_ERROR, error.message, { domain })); // try again
                        }

                        retryCallback(null, error ? new BoxError(BoxError.EXTERNAL_ERROR, error.message, domain) : null);
                    });
                });
            }, function (error, result) {
                if (error || result) return iteratorDone(error || result);

                iteratorDone(null);
            });
        }, callback);
    });
}

function unregisterSubdomains(app, allDomains, callback) {
    assert.strictEqual(typeof app, 'object');
    assert(Array.isArray(allDomains));
    assert.strictEqual(typeof callback, 'function');

    sysinfo.getServerIp(function (error, ip) {
        if (error) return callback(error);

        async.eachSeries(allDomains, function (domain, iteratorDone) {
            async.retry({ times: 30, interval: 5000 }, function (retryCallback) {
                debugApp(app, 'Unregistering subdomain: %s%s', domain.subdomain ? (domain.subdomain + '.') : '', domain.domain);

                domains.removeDnsRecords(domain.subdomain, domain.domain, 'A', [ ip ], function (error) {
                    if (error && error.reason === BoxError.NOT_FOUND) return retryCallback(null, null);
                    if (error && (error.reason === BoxError.SBUSY || error.reason === BoxError.EXTERNAL_ERROR)) {
                        debug('registerSubdomains: Remove error. Will retry.', error.message);
                        return retryCallback(new BoxError(BoxError.EXTERNAL_ERROR, error.message, { domain })); // try again
                    }

                    retryCallback(null, error ? new BoxError(BoxError.EXTERNAL_ERROR, error.message, { domain }) : null);
                });
            }, function (error, result) {
                if (error || result) return iteratorDone(error || result);

                iteratorDone();
            });
        }, callback);
    });
}

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

    if (!constants.CLOUDRON) {
        debugApp(app, 'Skipping dns propagation check for development');
        return callback(null);
    }

    sysinfo.getServerIp(function (error, ip) {
        if (error) return callback(new BoxError(BoxError.NETWORK_ERROR, `Error getting public IP: ${error.message}`));

        domains.waitForDnsRecord(app.location, app.domain, 'A', ip, { times: 240 }, function (error) {
            if (error) return callback(new BoxError(BoxError.DNS_ERROR, `DNS Record is not synced yet: ${error.message}`, { ip: ip, subdomain: app.location, domain: app.domain }));

            // now wait for alternateDomains, if any
            async.eachSeries(app.alternateDomains, function (domain, iteratorCallback) {
                domains.waitForDnsRecord(domain.subdomain, domain.domain, 'A', ip, { times: 240 }, function (error) {
                    if (error) return callback(new BoxError(BoxError.DNS_ERROR, `DNS Record is not synced yet: ${error.message}`, { ip: ip, subdomain: domain.subdomain, domain: domain.domain }));

                    iteratorCallback();
                });
            }, callback);
        });
    });
}

function moveDataDir(app, targetDir, callback) {
    assert.strictEqual(typeof app, 'object');
    assert(targetDir === null || typeof targetDir === 'string');
    assert.strictEqual(typeof callback, 'function');

    let resolvedSourceDir = apps.getDataDir(app, app.dataDir);
    let resolvedTargetDir = apps.getDataDir(app, targetDir);

    debug(`moveDataDir: migrating data from ${resolvedSourceDir} to ${resolvedTargetDir}`);

    if (resolvedSourceDir === resolvedTargetDir) return callback();

    shell.sudo('moveDataDir', [ MV_VOLUME_CMD, resolvedSourceDir, resolvedTargetDir ], {}, function (error) {
        if (error) return callback(new BoxError(BoxError.EXTERNAL_ERROR, `Error migrating data directory: ${error.message}`));

        callback(null);
    });
}

function downloadImage(manifest, callback) {
    assert.strictEqual(typeof manifest, 'object');
    assert.strictEqual(typeof callback, 'function');

    docker.info(function (error, info) {
        if (error) return callback(error);

        const dfAsync = util.callbackify(df.file);
        dfAsync(info.DockerRootDir, function (error, diskUsage) {
            if (error) return callback(new BoxError(BoxError.FS_ERROR, `Error getting file system info: ${error.message}`));
            if (diskUsage.available < (1024*1024*1024)) return callback(new BoxError(BoxError.DOCKER_ERROR, 'Not enough disk space to pull docker image', { diskUsage: diskUsage, dockerRootDir: info.DockerRootDir }));

            docker.downloadImage(manifest, function (error) {
                if (error) return callback(error);

                callback(null);
            });
        });
    });
}

function startApp(app, callback){
    if (app.runState === apps.RSTATE_STOPPED) return callback();

    docker.startContainer(app.id, callback);
}

function install(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    const restoreConfig = args.restoreConfig; // has to be set when restoring
    const overwriteDns = args.overwriteDns;
    const oldManifest = args.oldManifest;

    async.series([
        // this protects against the theoretical possibility of an app being marked for install/restore from
        // a previous version of box code
        verifyManifest.bind(null, app.manifest),

        // teardown for re-installs
        progressCallback.bind(null, { percent: 10, message: 'Cleaning up old install' }),
        unconfigureReverseProxy.bind(null, app),
        deleteContainers.bind(null, app, { managedOnly: true }),
        function teardownAddons(next) {
            // when restoring, app does not require these addons anymore. remove carefully to preserve the db passwords
            let addonsToRemove;
            if (oldManifest) {
                addonsToRemove = _.omit(oldManifest.addons, Object.keys(app.manifest.addons));
            } else {
                addonsToRemove = app.manifest.addons;
            }

            addons.teardownAddons(app, addonsToRemove, next);
        },

        function deleteAppDirIfNeeded(done) {
            if (restoreConfig && !restoreConfig.backupId) return done(); // in-place import should not delete data dir

            deleteAppDir(app, { removeDirectory: false }, done); // do not remove any symlinked appdata dir
        },

        function deleteImageIfChanged(done) {
            if (!oldManifest || oldManifest.dockerImage === app.manifest.dockerImage) return done();

            docker.deleteImage(oldManifest, done);
        },

        reserveHttpPort.bind(null, app),

        progressCallback.bind(null, { percent: 20, message: 'Downloading icon' }),
        downloadIcon.bind(null, app),

        progressCallback.bind(null, { percent: 30, message: 'Registering subdomains' }),
        registerSubdomains.bind(null, app, overwriteDns),

        progressCallback.bind(null, { percent: 40, message: 'Downloading image' }),
        downloadImage.bind(null, app.manifest),

        progressCallback.bind(null, { percent: 50, message: 'Creating app data directory' }),
        createAppDir.bind(null, app),

        function restoreFromBackup(next) {
            if (!restoreConfig) {
                async.series([
                    progressCallback.bind(null, { percent: 60, message: 'Setting up addons' }),
                    addons.setupAddons.bind(null, app, app.manifest.addons),
                ], next);
            } else if (!restoreConfig.backupId) { // in-place import
                async.series([
                    progressCallback.bind(null, { percent: 60, message: 'Importing addons in-place' }),
                    addons.setupAddons.bind(null, app, app.manifest.addons),
                    addons.clearAddons.bind(null, app, _.omit(app.manifest.addons, 'localstorage')),
                    addons.restoreAddons.bind(null, app, app.manifest.addons),
                ], next);
            } else {
                async.series([
                    progressCallback.bind(null, { percent: 65, message: 'Download backup and restoring addons' }),
                    addons.setupAddons.bind(null, app, app.manifest.addons),
                    addons.clearAddons.bind(null, app, app.manifest.addons),
                    backups.downloadApp.bind(null, app, restoreConfig, (progress) => {
                        progressCallback({ percent: 65, message: progress.message });
                    }),
                    addons.restoreAddons.bind(null, app, app.manifest.addons)
                ], next);
            }
        },

        progressCallback.bind(null, { percent: 70, message: 'Creating container' }),
        createContainer.bind(null, app),

        startApp.bind(null, app),

        progressCallback.bind(null, { percent: 85, message: 'Waiting for DNS propagation' }),
        exports._waitForDnsPropagation.bind(null, app),

        progressCallback.bind(null, { percent: 95, message: 'Configuring reverse proxy' }),
        configureReverseProxy.bind(null, app),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error installing app: %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }
        callback(null);
    });
}

function backup(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    async.series([
        progressCallback.bind(null, { percent: 10, message: 'Backing up' }),
        backups.backupApp.bind(null, app, { /* options */ }, (progress) => {
            progressCallback({ percent: 30, message: progress.message });
        }),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error backing up app: %s', error);
            // return to installed state intentionally. the error is stashed only in the task and not the app (the UI shows error state otherwise)
            return updateApp(app, { installationState: apps.ISTATE_INSTALLED, error: null }, callback.bind(null, makeTaskError(error, app)));
        }
        callback(null);
    });
}

function create(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    async.series([
        progressCallback.bind(null, { percent: 10, message: 'Cleaning up old install' }),
        deleteContainers.bind(null, app, { managedOnly: true }),

        // FIXME: re-setup addons only because sendmail addon to re-inject env vars on mailboxName change
        progressCallback.bind(null, { percent: 30, message: 'Setting up addons' }),
        addons.setupAddons.bind(null, app, app.manifest.addons),

        progressCallback.bind(null, { percent: 60, message: 'Creating container' }),
        createContainer.bind(null, app),

        startApp.bind(null, app),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error creating : %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }
        callback(null);
    });
}

function changeLocation(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    const oldConfig = args.oldConfig;
    const locationChanged = oldConfig.fqdn !== app.fqdn;
    const overwriteDns = args.overwriteDns;

    async.series([
        progressCallback.bind(null, { percent: 10, message: 'Cleaning up old install' }),
        unconfigureReverseProxy.bind(null, app),
        deleteContainers.bind(null, app, { managedOnly: true }),
        function (next) {
            let obsoleteDomains = oldConfig.alternateDomains.filter(function (o) {
                return !app.alternateDomains.some(function (n) { return n.subdomain === o.subdomain && n.domain === o.domain; });
            });

            if (locationChanged) obsoleteDomains.push({ subdomain: oldConfig.location, domain: oldConfig.domain });

            if (obsoleteDomains.length === 0) return next();

            unregisterSubdomains(app, obsoleteDomains, next);
        },

        progressCallback.bind(null, { percent: 30, message: 'Registering subdomains' }),
        registerSubdomains.bind(null, app, overwriteDns),

        // re-setup addons since they rely on the app's fqdn (e.g oauth)
        progressCallback.bind(null, { percent: 50, message: 'Setting up addons' }),
        addons.setupAddons.bind(null, app, app.manifest.addons),

        progressCallback.bind(null, { percent: 60, message: 'Creating container' }),
        createContainer.bind(null, app),

        startApp.bind(null, app),

        progressCallback.bind(null, { percent: 80, message: 'Waiting for DNS propagation' }),
        exports._waitForDnsPropagation.bind(null, app),

        progressCallback.bind(null, { percent: 90, message: 'Configuring reverse proxy' }),
        configureReverseProxy.bind(null, app),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error changing location : %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }
        callback(null);
    });
}

function migrateDataDir(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    let newDataDir = args.newDataDir;
    assert(newDataDir === null || typeof newDataDir === 'string');

    async.series([
        progressCallback.bind(null, { percent: 10, message: 'Cleaning up old install' }),
        deleteContainers.bind(null, app, { managedOnly: true }),

        progressCallback.bind(null, { percent: 45, message: 'Ensuring app data directory' }),
        createAppDir.bind(null, app),

        // re-setup addons since this creates the localStorage volume
        progressCallback.bind(null, { percent: 50, message: 'Setting up addons' }),
        addons.setupAddons.bind(null, _.extend({}, app, { dataDir: newDataDir }), app.manifest.addons),

        progressCallback.bind(null, { percent: 60, message: 'Moving data dir' }),
        moveDataDir.bind(null, app, newDataDir),

        progressCallback.bind(null, { percent: 90, message: 'Creating container' }),
        createContainer.bind(null, app),

        startApp.bind(null, app),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null, dataDir: newDataDir })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error migrating data dir : %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }

        // We do this after the app has the new data commited to the database
        sftp.rebuild({}, function (error) {
            if (error) console.error('Failed to rebuild sftp addon:', error);
            callback();
        });
    });
}

// configure is called for an infra update and repair to re-create container, reverseproxy config. it's all "local"
function configure(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    async.series([
        progressCallback.bind(null, { percent: 10, message: 'Cleaning up old install' }),
        unconfigureReverseProxy.bind(null, app),
        deleteContainers.bind(null, app, { managedOnly: true }),
        reserveHttpPort.bind(null, app),

        progressCallback.bind(null, { percent: 20, message: 'Downloading icon' }),
        downloadIcon.bind(null, app),

        progressCallback.bind(null, { percent: 40, message: 'Downloading image' }),
        downloadImage.bind(null, app.manifest),

        progressCallback.bind(null, { percent: 45, message: 'Ensuring app data directory' }),
        createAppDir.bind(null, app),

        // re-setup addons since they rely on the app's fqdn (e.g oauth)
        progressCallback.bind(null, { percent: 50, message: 'Setting up addons' }),
        addons.setupAddons.bind(null, app, app.manifest.addons),

        progressCallback.bind(null, { percent: 60, message: 'Creating container' }),
        createContainer.bind(null, app),

        startApp.bind(null, app),

        progressCallback.bind(null, { percent: 90, message: 'Configuring reverse proxy' }),
        configureReverseProxy.bind(null, app),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error reconfiguring : %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }
        callback(null);
    });
}

// nginx configuration is skipped because app.httpPort is expected to be available
function update(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    const updateConfig = args.updateConfig;
    debugApp(app, `Updating to ${updateConfig.manifest.version}`);

    // app does not want these addons anymore
    // FIXME: this does not handle option changes (like multipleDatabases)
    var unusedAddons = _.omit(app.manifest.addons, Object.keys(updateConfig.manifest.addons));

    async.series([
        // this protects against the theoretical possibility of an app being marked for update from
        // a previous version of box code
        progressCallback.bind(null, { percent: 5, message: 'Verify manifest' }),
        verifyManifest.bind(null, updateConfig.manifest),

        function (next) {
            if (updateConfig.skipBackup) return next(null);

            async.series([
                progressCallback.bind(null, { percent: 15, message: 'Backing up app' }),
                // preserve update backups for 3 weeks
                backups.backupApp.bind(null, app, { preserveSecs: 3*7*24*60*60 }, (progress) => {
                    progressCallback({ percent: 15, message: `Backup - ${progress.message}` });
                })
            ], function (error) {
                if (error) error.backupError = true;
                next(error);
            });
        },

        // download new image before app is stopped. this is so we can reduce downtime
        // and also not remove the 'common' layers when the old image is deleted
        progressCallback.bind(null, { percent: 25, message: 'Downloading image' }),
        downloadImage.bind(null, updateConfig.manifest),

        // note: we cleanup first and then backup. this is done so that the app is not running should backup fail
        // we cannot easily 'recover' from backup failures because we have to revert manfest and portBindings
        progressCallback.bind(null, { percent: 35, message: 'Cleaning up old install' }),
        deleteContainers.bind(null, app, { managedOnly: true }),
        function deleteImageIfChanged(done) {
            if (app.manifest.dockerImage === updateConfig.manifest.dockerImage) return done();

            docker.deleteImage(app.manifest, done);
        },

        // only delete unused addons after backup
        addons.teardownAddons.bind(null, app, unusedAddons),

        // free unused ports
        function (next) {
            const currentPorts = app.portBindings || {};
            const newTcpPorts = updateConfig.manifest.tcpPorts || {};
            const newUdpPorts = updateConfig.manifest.udpPorts || {};

            async.each(Object.keys(currentPorts), function (portName, callback) {
                if (newTcpPorts[portName] || newUdpPorts[portName]) return callback(null); // port still in use

                appdb.delPortBinding(currentPorts[portName], apps.PORT_TYPE_TCP, function (error) {
                    if (error && error.reason === BoxError.NOT_FOUND) console.error('Portbinding does not exist in database.');
                    else if (error) return next(error);

                    // also delete from app object for further processing (the db is updated in the next step)
                    delete app.portBindings[portName];

                    callback(null);
                });
            }, next);
        },

        updateApp.bind(null, app, _.pick(updateConfig, 'manifest', 'appStoreId', 'memoryLimit')), // switch over to the new config

        progressCallback.bind(null, { percent: 45, message: 'Downloading icon' }),
        downloadIcon.bind(null, app),

        progressCallback.bind(null, { percent: 70, message: 'Updating addons' }),
        addons.setupAddons.bind(null, app, updateConfig.manifest.addons),

        progressCallback.bind(null, { percent: 80, message: 'Creating container' }),
        createContainer.bind(null, app),

        startApp.bind(null, app),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null, updateTime: new Date() })
    ], function seriesDone(error) {
        if (error && error.backupError) {
            debugApp(app, 'update aborted because backup failed', error);
            updateApp(app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null }, callback.bind(null, error));
        } else if (error) {
            debugApp(app, 'Error updating app: %s', error);
            updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        } else {
            eventlog.add(eventlog.ACTION_APP_UPDATE_FINISH, auditSource.APP_TASK, { app: app, success: true }, () => callback()); // ignore error
        }
    });
}

function start(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    async.series([
        progressCallback.bind(null, { percent: 10, message: 'Starting app services' }),
        addons.startAppServices.bind(null, app),

        progressCallback.bind(null, { percent: 35, message: 'Starting container' }),
        docker.startContainer.bind(null, app.id),

        // stopped apps do not renew certs. currently, we don't do DNS to not overwrite existing user settings
        progressCallback.bind(null, { percent: 60, message: 'Configuring reverse proxy' }),
        configureReverseProxy.bind(null, app),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error starting app: %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }
        callback(null);
    });
}

function stop(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    async.series([
        progressCallback.bind(null, { percent: 20, message: 'Stopping container' }),
        docker.stopContainers.bind(null, app.id),

        progressCallback.bind(null, { percent: 50, message: 'Stopping app services' }),
        addons.stopAppServices.bind(null, app),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error starting app: %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }
        callback(null);
    });
}

function restart(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    async.series([
        progressCallback.bind(null, { percent: 20, message: 'Restarting container' }),
        docker.restartContainer.bind(null, app.id),

        progressCallback.bind(null, { percent: 100, message: 'Done' }),
        updateApp.bind(null, app, { installationState: apps.ISTATE_INSTALLED, error: null, health: null })
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error starting app: %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }
        callback(null);
    });
}

function uninstall(app, args, progressCallback, callback) {
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    async.series([
        progressCallback.bind(null, { percent: 20, message: 'Deleting container' }),
        unconfigureReverseProxy.bind(null, app),
        deleteContainers.bind(null, app, {}),

        progressCallback.bind(null, { percent: 30, message: 'Teardown addons' }),
        addons.teardownAddons.bind(null, app, app.manifest.addons),

        progressCallback.bind(null, { percent: 40, message: 'Remove sftp addon binding' }),
        function (callback) {
            if (!app.dataDir) return callback();
            sftp.rebuild({ ignoredDataDirs: [ app.dataDir ] }, callback);
        },

        progressCallback.bind(null, { percent: 50, message: 'Deleting app data directory' }),
        deleteAppDir.bind(null, app, { removeDirectory: true }),

        progressCallback.bind(null, { percent: 60, message: 'Deleting image' }),
        docker.deleteImage.bind(null, app.manifest),

        progressCallback.bind(null, { percent: 70, message: 'Unregistering domains' }),
        unregisterSubdomains.bind(null, app, [ { subdomain: app.location, domain: app.domain } ].concat(app.alternateDomains)),

        progressCallback.bind(null, { percent: 80, message: 'Cleanup icon' }),
        removeIcon.bind(null, app),

        progressCallback.bind(null, { percent: 90, message: 'Cleanup logs' }),
        cleanupLogs.bind(null, app),

        progressCallback.bind(null, { percent: 95, message: 'Remove app from database' }),
        appdb.del.bind(null, app.id)
    ], function seriesDone(error) {
        if (error) {
            debugApp(app, 'error uninstalling app: %s', error);
            return updateApp(app, { installationState: apps.ISTATE_ERROR, error: makeTaskError(error, app) }, callback.bind(null, error));
        }
        callback(null);
    });
}

function run(appId, args, progressCallback, callback) {
    assert.strictEqual(typeof appId, 'string');
    assert.strictEqual(typeof args, 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    // determine what to do
    apps.get(appId, function (error, app) {
        if (error) return callback(error);

        debugApp(app, 'startTask installationState: %s runState: %s', app.installationState, app.runState);

        switch (app.installationState) {
        case apps.ISTATE_PENDING_INSTALL:
        case apps.ISTATE_PENDING_CLONE:
        case apps.ISTATE_PENDING_RESTORE:
            return install(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_CONFIGURE:
            return configure(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_RECREATE_CONTAINER:
        case apps.ISTATE_PENDING_RESIZE:
        case apps.ISTATE_PENDING_DEBUG:
            return create(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_LOCATION_CHANGE:
            return changeLocation(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_DATA_DIR_MIGRATION:
            return migrateDataDir(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_UNINSTALL:
            return uninstall(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_UPDATE:
            return update(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_BACKUP:
            return backup(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_START:
            return start(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_STOP:
            return stop(app, args, progressCallback, callback);
        case apps.ISTATE_PENDING_RESTART:
            return restart(app, args, progressCallback, callback);
        default:
            debugApp(app, 'apptask launched with invalid command');
            return callback(new BoxError(BoxError.INTERNAL_ERROR, 'Unknown install command in apptask:' + app.installationState));
        }
    });
}