'use strict';

exports = module.exports = {
    updateToLatest,
    update
};

var apps = require('./apps.js'),
    assert = require('assert'),
    async = require('async'),
    BoxError = require('./boxerror.js'),
    child_process = require('child_process'),
    backups = require('./backups.js'),
    constants = require('./constants.js'),
    crypto = require('crypto'),
    debug = require('debug')('box:updater'),
    df = require('@sindresorhus/df'),
    eventlog = require('./eventlog.js'),
    fs = require('fs'),
    locker = require('./locker.js'),
    os = require('os'),
    path = require('path'),
    paths = require('./paths.js'),
    safe = require('safetydance'),
    semver = require('semver'),
    settings = require('./settings.js'),
    shell = require('./shell.js'),
    tasks = require('./tasks.js'),
    updateChecker = require('./updatechecker.js');

const RELEASES_PUBLIC_KEY = path.join(__dirname, 'releases.gpg');
const UPDATE_CMD = path.join(__dirname, 'scripts/update.sh');

function downloadUrl(url, file, callback) {
    assert.strictEqual(typeof file, 'string');
    assert.strictEqual(typeof callback, 'function');

    // do not assert since it comes from the appstore
    if (typeof url !== 'string')  return callback(new BoxError(BoxError.EXTERNAL_ERROR, `url cannot be download to ${file} as it is not a string`));

    let retryCount = 0;

    safe.fs.unlinkSync(file);

    async.retry({ times: 10, interval: 5000 }, function (retryCallback) {
        debug(`Downloading ${url} to ${file}. Try ${++retryCount}`);

        const args = `-s --fail ${url} -o ${file}`;

        debug(`downloadUrl: curl ${args}`);

        shell.spawn('downloadUrl', '/usr/bin/curl', args.split(' '), {}, function (error) {
            if (error) return retryCallback(new BoxError(BoxError.NETWORK_ERROR, `Failed to download ${url}: ${error.message}`));

            debug(`downloadUrl: downloadUrl ${url} to ${file}`);

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

function gpgVerify(file, sig, callback) {
    const cmd = `/usr/bin/gpg --status-fd 1 --no-default-keyring --keyring ${RELEASES_PUBLIC_KEY} --verify ${sig} ${file}`;

    debug(`gpgVerify: ${cmd}`);

    child_process.exec(cmd, { encoding: 'utf8' }, function (error, stdout, stderr) {
        if (error) {
            debug(`gpgVerify: command failed. error: ${error}\n stdout: ${stdout}\n stderr: ${stderr}`);
            return callback(new BoxError(BoxError.NOT_SIGNED, `The signature in ${path.basename(sig)} could not be verified (command failed)`));
        }

        if (stdout.indexOf('[GNUPG:] VALIDSIG 0EADB19CDDA23CD0FE71E3470A372F8703C493CC') !== -1) return callback();

        debug(`gpgVerify: verification of ${sig} failed: ${stdout}\n${stderr}`);

        return callback(new BoxError(BoxError.NOT_SIGNED, `The signature in ${path.basename(sig)} could not be verified (bad sig)`));
    });
}

function extractTarball(tarball, dir, callback) {
    const args = `-zxf ${tarball} -C ${dir}`;

    debug(`extractTarball: tar ${args}`);

    shell.spawn('extractTarball', '/bin/tar', args.split(' '), {}, function (error) {
        if (error) return callback(new BoxError(BoxError.FS_ERROR, `Failed to extract release package: ${error.message}`));

        safe.fs.unlinkSync(tarball);

        debug(`extractTarball: extracted ${tarball} to ${dir}`);

        callback();
    });
}

function verifyUpdateInfo(versionsFile, updateInfo, callback) {
    assert.strictEqual(typeof versionsFile, 'string');
    assert.strictEqual(typeof updateInfo, 'object');
    assert.strictEqual(typeof callback, 'function');

    const releases = safe.JSON.parse(safe.fs.readFileSync(versionsFile, 'utf8')) || {};
    if (!releases[constants.VERSION]) return callback(new BoxError(BoxError.EXTERNAL_ERROR, `No version info for ${constants.VERSION}`));
    if (!releases[constants.VERSION].next) return callback(new BoxError(BoxError.EXTERNAL_ERROR, `No next version info for ${constants.VERSION}`));
    const nextVersion = releases[constants.VERSION].next;
    if (typeof releases[nextVersion] !== 'object' || !releases[nextVersion]) return callback(new BoxError(BoxError.EXTERNAL_ERROR, 'No next version info'));
    if (releases[nextVersion].sourceTarballUrl !== updateInfo.sourceTarballUrl) return callback(new BoxError(BoxError.EXTERNAL_ERROR, 'Version info mismatch'));

    callback();
}

function downloadAndVerifyRelease(updateInfo, callback) {
    assert.strictEqual(typeof updateInfo, 'object');
    assert.strictEqual(typeof callback, 'function');

    let newBoxSource = path.join(os.tmpdir(), 'box-' + crypto.randomBytes(4).readUInt32LE(0));

    async.series([
        downloadUrl.bind(null, updateInfo.boxVersionsUrl, `${paths.UPDATE_DIR}/versions.json`),
        downloadUrl.bind(null, updateInfo.boxVersionsSigUrl, `${paths.UPDATE_DIR}/versions.json.sig`),
        gpgVerify.bind(null, `${paths.UPDATE_DIR}/versions.json`, `${paths.UPDATE_DIR}/versions.json.sig`),
        verifyUpdateInfo.bind(null, `${paths.UPDATE_DIR}/versions.json`, updateInfo),
        downloadUrl.bind(null, updateInfo.sourceTarballUrl, `${paths.UPDATE_DIR}/box.tar.gz`),
        downloadUrl.bind(null, updateInfo.sourceTarballSigUrl, `${paths.UPDATE_DIR}/box.tar.gz.sig`),
        gpgVerify.bind(null, `${paths.UPDATE_DIR}/box.tar.gz`, `${paths.UPDATE_DIR}/box.tar.gz.sig`),
        fs.mkdir.bind(null, newBoxSource, { recursive: true }),
        extractTarball.bind(null, `${paths.UPDATE_DIR}/box.tar.gz`, newBoxSource)
    ], function (error) {
        if (error) return callback(error);

        callback(null, { file: newBoxSource });
    });
}

function checkFreeDiskSpace(neededSpace, callback) {
    assert.strictEqual(typeof neededSpace, 'number');
    assert.strictEqual(typeof callback, 'function');

    // can probably be a bit more aggressive here since a new update can bring in new docker images
    df.file('/').then(function (diskUsage) {
        if (diskUsage.available < neededSpace) return callback(new BoxError(BoxError.FS_ERROR, 'Not enough disk space'));

        callback(null);
    }).catch(function (error) {
        callback(new BoxError(BoxError.FS_ERROR, error));
    });
}

function update(boxUpdateInfo, options, progressCallback, callback) {
    assert(boxUpdateInfo && typeof boxUpdateInfo === 'object');
    assert(options && typeof options === 'object');
    assert.strictEqual(typeof progressCallback, 'function');
    assert.strictEqual(typeof callback, 'function');

    progressCallback({ percent: 1, message: 'Checking disk space' });

    checkFreeDiskSpace(1024*1024*1024, function (error) {
        if (error) return callback(error);

        progressCallback({ percent: 5, message: 'Downloading and verifying release' });

        downloadAndVerifyRelease(boxUpdateInfo, function (error, packageInfo) {
            if (error) return callback(error);

            function maybeBackup(next) {
                if (options.skipBackup) return next();

                progressCallback({ percent: 10, message: 'Backing up' });

                backups.backupBoxAndApps({ preserveSecs: 3*7*24*60*60 }, (progress) => progressCallback({ percent: 10+progress.percent*70/100, message: progress.message }), next);
            }

            maybeBackup(function (error) {
                if (error) return callback(error);

                debug('updating box %s', boxUpdateInfo.sourceTarballUrl);

                progressCallback({ percent: 70, message: 'Installing update' });

                // run installer.sh from new box code as a separate service
                shell.sudo('update', [ UPDATE_CMD, packageInfo.file ], {}, function (error) {
                    if (error) return callback(error);

                    // Do not add any code here. The installer script will stop the box code any instant
                });
            });
        });
    });
}

function canUpdate(boxUpdateInfo, callback) {
    assert.strictEqual(typeof boxUpdateInfo, 'object');
    assert.strictEqual(typeof callback, 'function');

    apps.getAll(function (error, result) {
        if (error) return callback(error);

        for (let app of result) {
            const maxBoxVersion = app.manifest.maxBoxVersion;
            if (semver.valid(maxBoxVersion) && semver.gt(boxUpdateInfo.version, maxBoxVersion)) {
                return callback(new BoxError(BoxError.BAD_STATE, `Cannot update to v${boxUpdateInfo.version} because ${app.fqdn} has a maxBoxVersion of ${maxBoxVersion}`));
            }
        }

        callback();
    });
}

function updateToLatest(options, auditSource, callback) {
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof auditSource, 'object');
    assert.strictEqual(typeof callback, 'function');

    var boxUpdateInfo = updateChecker.getUpdateInfo().box;
    if (!boxUpdateInfo) return callback(new BoxError(BoxError.NOT_FOUND, 'No update available'));
    if (!boxUpdateInfo.sourceTarballUrl) return callback(new BoxError(BoxError.BAD_STATE, 'No automatic update available'));

    canUpdate(boxUpdateInfo, function (error) {
        if (error) return callback(error);

        error = locker.lock(locker.OP_BOX_UPDATE);
        if (error) return callback(new BoxError(BoxError.BAD_STATE, `Cannot update now: ${error.message}`));

        settings.getBackupConfig(function (error, backupConfig) {
            if (error) return callback(error);

            const memoryLimit = 'memoryLimit' in backupConfig ? Math.max(backupConfig.memoryLimit/1024/1024, 400) : 400;

            tasks.add(tasks.TASK_UPDATE, [ boxUpdateInfo, options ], function (error, taskId) {
                if (error) return callback(error);

                eventlog.add(eventlog.ACTION_UPDATE, auditSource, { taskId, boxUpdateInfo });

                tasks.startTask(taskId, { timeout: 20 * 60 * 60 * 1000 /* 20 hours */, nice: 15, memoryLimit }, (error) => {
                    locker.unlock(locker.OP_BOX_UPDATE);

                    debug('Update failed with error', error);

                    const timedOut = error.code === tasks.ETIMEOUT;
                    eventlog.add(eventlog.ACTION_UPDATE_FINISH, auditSource, { taskId, errorMessage: error.message, timedOut });
                });

                callback(null, taskId);
            });
        });
    });
}