'use strict';

exports = module.exports = {
    get,
    update,
    list,
    del,

    onEvent,

    ALERT_BACKUP_CONFIG: 'backupConfig',
    ALERT_DISK_SPACE: 'diskSpace',
    ALERT_MAIL_STATUS: 'mailStatus',
    ALERT_REBOOT: 'reboot',
    ALERT_BOX_UPDATE: 'boxUpdate',
    ALERT_UPDATE_UBUNTU: 'ubuntuUpdate',

    alert,

    // exported for testing
    _add: add
};

const assert = require('assert'),
    auditSource = require('./auditsource.js'),
    BoxError = require('./boxerror.js'),
    changelog = require('./changelog.js'),
    database = require('./database.js'),
    eventlog = require('./eventlog.js'),
    mailer = require('./mailer.js'),
    settings = require('./settings.js'),
    users = require('./users.js'),
    util = require('util');

const NOTIFICATION_FIELDS = [ 'id', 'eventId', 'title', 'message', 'creationTime', 'acknowledged' ];

function postProcess(result) {
    assert.strictEqual(typeof result, 'object');
    result.id = String(result.id);

    // convert to boolean
    result.acknowledged = !!result.acknowledged;
    return result;
}

async function add(eventId, title, message) {
    assert(typeof eventId === 'string' || eventId === null);
    assert.strictEqual(typeof title, 'string');
    assert.strictEqual(typeof message, 'string');

    const query = 'INSERT INTO notifications (eventId, title, message, acknowledged) VALUES (?, ?, ?, ?)';
    const args = [ eventId, title, message, false ];

    const result = await database.query(query, args);
    return String(result.insertId);
}

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

    const result = await database.query('SELECT ' + NOTIFICATION_FIELDS + ' FROM notifications WHERE id = ?', [ id ]);
    if (result.length === 0) return null;

    return postProcess(result[0]);
}

async function getByTitle(title) {
    assert.strictEqual(typeof title, 'string');

    const results = await database.query('SELECT ' + NOTIFICATION_FIELDS + ' from notifications WHERE title = ? ORDER BY creationTime LIMIT 1', [ title ]);
    if (results.length === 0) return null;

    return postProcess(results[0]);
}

async function update(notification, data) {
    assert.strictEqual(typeof notification, 'object');
    assert.strictEqual(typeof data, 'object');

    let args = [ ];
    let fields = [ ];
    for (let k in data) {
        fields.push(k + ' = ?');
        args.push(data[k]);
    }
    args.push(notification.id);

    const result = await database.query('UPDATE notifications SET ' + fields.join(', ') + ' WHERE id = ?', args);
    if (result.affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Notification not found');
}

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

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

async function list(filters, page, perPage) {
    assert.strictEqual(typeof filters, 'object');
    assert.strictEqual(typeof page, 'number');
    assert.strictEqual(typeof perPage, 'number');

    let args = [];

    let where = [];
    if ('acknowledged' in filters) {
        where.push('acknowledged=?');
        args.push(filters.acknowledged);
    }

    let query = `SELECT ${NOTIFICATION_FIELDS} FROM notifications`;
    if (where.length) query += ' WHERE ' + where.join(' AND ');
    query += ' ORDER BY creationTime DESC LIMIT ?,?';

    args.push((page-1)*perPage);
    args.push(perPage);

    const results = await database.query(query, args);
    results.forEach(postProcess);
    return results;
}

async function oomEvent(eventId, app, addon, containerId /*, event*/) {
    assert.strictEqual(typeof eventId, 'string');
    assert.strictEqual(typeof app, 'object');
    assert.strictEqual(typeof addon, 'object');
    assert.strictEqual(typeof containerId, 'string');

    assert(app || addon);

    let title, message;
    if (app) {
        title = `The application at ${app.fqdn} ran out of memory.`;
        message = `The application has been restarted automatically. If you see this notification often, consider increasing the [memory limit](${settings.dashboardOrigin()}/#/app/${app.id}/resources)`;
    } else if (addon) {
        title = `The ${addon.name} service ran out of memory`;
        message = `The service has been restarted automatically. If you see this notification often, consider increasing the [memory limit](${settings.dashboardOrigin()}/#/services)`;
    }

    await add(eventId, title, message);
}

async function appUpdated(eventId, app) {
    assert.strictEqual(typeof eventId, 'string');
    assert.strictEqual(typeof app, 'object');

    if (!app.appStoreId) return; // skip notification of dev apps

    const tmp = app.manifest.description.match(/<upstream>(.*)<\/upstream>/i);
    const upstreamVersion = (tmp && tmp[1]) ? tmp[1] : '';
    const title = upstreamVersion ? `${app.manifest.title} at ${app.fqdn} updated to ${upstreamVersion} (package version ${app.manifest.version})`
        : `${app.manifest.title} at ${app.fqdn} updated to package version ${app.manifest.version}`;

    await add(eventId, title, `The application installed at https://${app.fqdn} was updated.\n\nChangelog:\n${app.manifest.changelog}\n`);
}

async function boxUpdated(eventId, oldVersion, newVersion) {
    assert.strictEqual(typeof eventId, 'string');
    assert.strictEqual(typeof oldVersion, 'string');
    assert.strictEqual(typeof newVersion, 'string');

    const changes = changelog.getChanges(newVersion);
    const changelogMarkdown = changes.map((m) => `* ${m}\n`).join('');

    await add(eventId, `Cloudron updated to v${newVersion}`, `Cloudron was updated from v${oldVersion} to v${newVersion}.\n\nChangelog:\n${changelogMarkdown}\n`);
}

async function boxUpdateError(eventId, errorMessage) {
    assert.strictEqual(typeof eventId, 'string');
    assert.strictEqual(typeof errorMessage, 'string');

    await add(eventId, 'Cloudron update failed', `Failed to update Cloudron: ${errorMessage}.`);
}

async function certificateRenewalError(eventId, vhost, errorMessage) {
    assert.strictEqual(typeof eventId, 'string');
    assert.strictEqual(typeof vhost, 'string');
    assert.strictEqual(typeof errorMessage, 'string');

    const getAdmins = util.callbackify(users.getAdmins);

    const admins = await getAdmins();

    for (const admin of admins) {
        mailer.certificateRenewalError(admin.email, vhost, errorMessage);
    }

    await add(eventId, `Certificate renewal of ${vhost} failed`, `Failed to renew certs of ${vhost}: ${errorMessage}. Renewal will be retried in 12 hours`);
}

async function backupFailed(eventId, taskId, errorMessage) {
    assert.strictEqual(typeof eventId, 'string');
    assert.strictEqual(typeof taskId, 'string');
    assert.strictEqual(typeof errorMessage, 'string');

    const getSuperAdmins = util.callbackify(users.getSuperAdmins);

    const superAdmins = await getSuperAdmins();

    for (const superAdmin of superAdmins) {
        mailer.backupFailed(superAdmin.email, errorMessage, `${settings.dashboardOrigin()}/logs.html?taskId=${taskId}`);
    }

    await add(eventId, 'Backup failed', `Backup failed: ${errorMessage}. Logs are available [here](/logs.html?taskId=${taskId}).`);
}

async function alert(id, title, message) {
    assert.strictEqual(typeof id, 'string');
    assert.strictEqual(typeof title, 'string');
    assert.strictEqual(typeof message, 'string');

    const acknowledged = !message;

    const result = await getByTitle(title);
    if (!result && acknowledged) return; // do not add acked alerts

    if (!result) {
        await add(null /* eventId */, title, message);
    } else {
        await update(result, {
            eventId: null,
            title,
            message,
            acknowledged,
            creationTime: new Date()
        });
    }
}

async function onEvent(id, action, source, data) {
    assert.strictEqual(typeof id, 'string');
    assert.strictEqual(typeof action, 'string');
    assert.strictEqual(typeof source, 'object');
    assert.strictEqual(typeof data, 'object');

    // external ldap syncer does not generate notifications - FIXME username might be an issue here
    if (source.username === auditSource.EXTERNAL_LDAP_TASK.username) return;

    switch (action) {
    case eventlog.ACTION_APP_OOM:
        return await oomEvent(id, data.app, data.addon, data.containerId, data.event);

    case eventlog.ACTION_APP_UPDATE_FINISH:
        return await appUpdated(id, data.app);

    case eventlog.ACTION_CERTIFICATE_RENEWAL:
    case eventlog.ACTION_CERTIFICATE_NEW:
        if (!data.errorMessage) return;
        if (!data.notAfter || (data.notAfter - new Date() >= (60 * 60 * 24 * 10 * 1000))) return; // more than 10 days left to expire
        return await certificateRenewalError(id, data.domain, data.errorMessage);

    case eventlog.ACTION_BACKUP_FINISH:
        if (!data.errorMessage) return;
        if (source.username !== auditSource.CRON.username && !data.timedOut) return; // manual stop by user

        return await backupFailed(id, data.taskId, data.errorMessage); // only notify for automated backups or timedout

    case eventlog.ACTION_UPDATE_FINISH:
        if (!data.errorMessage) return await boxUpdated(id, data.oldVersion, data.newVersion);
        if (data.timedOut) return await boxUpdateError(id, data.errorMessage);
        return;

    default:
        return;
    }
}