'use strict';

exports = module.exports = {
    get,
    getPrimary,
    list,
    add,
    addDefault,
    del,

    setConfig,
    setLimits,
    setSchedule,
    setRetention,
    setPrimary,
    setEncryption,
    setName,

    removePrivateFields,

    startBackupTask,

    startCleanupTask,

    getSnapshotInfo,
    setSnapshotInfo,

    remount,
    getStatus,
    ensureMounted,

    storageApi,

    createPseudo,
};

const assert = require('node:assert'),
    backupFormats = require('./backupformats.js'),
    backups = require('./backups.js'),
    BoxError = require('./boxerror.js'),
    constants = require('./constants.js'),
    cron = require('./cron.js'),
    { CronTime } = require('cron'),
    crypto = require('node:crypto'),
    database = require('./database.js'),
    debug = require('debug')('box:backups'),
    eventlog = require('./eventlog.js'),
    hush = require('./hush.js'),
    locks = require('./locks.js'),
    path = require('node:path'),
    paths = require('./paths.js'),
    safe = require('safetydance'),
    tasks = require('./tasks.js');

// format: rsync or tgz
// provider: used to determine the api provider
// config: depends on the 'provider' field. 'provider' is not stored in config object. but it is injected when calling the api backends
//      s3 providers - accessKeyId, secretAccessKey, bucket, prefix etc . see s3.js
//      gcs - bucket, prefix, projectId, credentials . see gcs.js
//      ext4/xfs/disk (managed providers) - mountOptions (diskPath), prefix, noHardlinks. disk is legacy.
//      nfs/cifs/sshfs (managed providers) - mountOptions (host/username/password/seal/privateKey etc), prefix, noHardlinks
//      filesystem - backupDir, noHardlinks
//      mountpoint - mountPoint, prefix, noHardlinks
// encryption: 'encryptionPassword' and 'encryptedFilenames' is converted into an 'encryption' object using hush.js. Password is lost forever after conversion.
const BACKUP_TARGET_FIELDS = [ 'id', 'name', 'provider', 'configJson', 'limitsJson', 'retentionJson', 'schedule', 'encryptionJson', 'format', 'main', 'creationTime', 'ts', 'integrityKeyPairJson' ].join(',');

function storageApi(backupSite) {
    assert.strictEqual(typeof backupSite, 'object');

    switch (backupSite.provider) {
    case 'nfs': return require('./storage/filesystem.js');
    case 'cifs': return require('./storage/filesystem.js');
    case 'sshfs': return require('./storage/filesystem.js');
    case 'mountpoint': return require('./storage/filesystem.js');
    case 'disk': return require('./storage/filesystem.js');
    case 'ext4': return require('./storage/filesystem.js');
    case 's3': return require('./storage/s3.js');
    case 'gcs': return require('./storage/gcs.js');
    case 'filesystem': return require('./storage/filesystem.js');
    case 'minio': return require('./storage/s3.js');
    case 's3-v4-compat': return require('./storage/s3.js');
    case 'digitalocean-spaces': return require('./storage/s3.js');
    case 'exoscale-sos': return require('./storage/s3.js');
    case 'wasabi': return require('./storage/s3.js');
    case 'scaleway-objectstorage': return require('./storage/s3.js');
    case 'backblaze-b2': return require('./storage/s3.js');
    case 'cloudflare-r2': return require('./storage/s3.js');
    case 'linode-objectstorage': return require('./storage/s3.js');
    case 'ovh-objectstorage': return require('./storage/s3.js');
    case 'ionos-objectstorage': return require('./storage/s3.js');
    case 'idrive-e2': return require('./storage/s3.js');
    case 'vultr-objectstorage': return require('./storage/s3.js');
    case 'upcloud-objectstorage': return require('./storage/s3.js');
    case 'contabo-objectstorage': return require('./storage/s3.js');
    case 'hetzner-objectstorage': return require('./storage/s3.js');
    case 'noop': return require('./storage/noop.js');
    default: throw new BoxError(BoxError.BAD_FIELD, `Unknown provider: ${backupSite.provider}`);
    }
}

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

    result.config = result.configJson ? safe.JSON.parse(result.configJson) : {};
    delete result.configJson;

    result.limits = safe.JSON.parse(result.limitsJson) || {};
    delete result.limitsJson;

    result.retention = safe.JSON.parse(result.retentionJson) || {};
    delete result.retentionJson;

    result.encryption = result.encryptionJson ? safe.JSON.parse(result.encryptionJson) : null;
    delete result.encryptionJson;

    result.integrityKeyPair = result.integrityKeyPairJson ? safe.JSON.parse(result.integrityKeyPairJson) : null;
    delete result.integrityKeyPairJson;

    result.primary = !!result.main; // primary is a reserved keyword in mysql
    delete result.main;

    return result;
}

function removePrivateFields(site) {
    assert.strictEqual(typeof site, 'object');

    site.encrypted = site.encryption !== null;
    site.encryptedFilenames = site.encryption?.encryptedFilenames || false;
    site.encryptionPasswordHint = site.encryption?.encryptionPasswordHint || null;
    delete site.encryption;

    delete site.integrityKeyPair.privateKey;

    site.config = storageApi(site).removePrivateFields(site.config);
    return site;
}

function validateName(name) {
    assert.strictEqual(typeof name, 'string');

    if (name.length === 0) return new BoxError(BoxError.BAD_FIELD, 'name cannot be empty');
    if (name.length > 100) return new BoxError(BoxError.BAD_FIELD, 'name too long');
}

function validateSchedule(schedule) {
    assert.strictEqual(typeof schedule, 'string');

    if (schedule === constants.CRON_PATTERN_NEVER) return null;

    const job = safe.safeCall(function () { return new CronTime(schedule); });
    if (!job) return new BoxError(BoxError.BAD_FIELD, 'Invalid schedule pattern');

    return null;
}

function validateRetention(retention) {
    assert.strictEqual(typeof retention, 'object');

    if (!retention) return new BoxError(BoxError.BAD_FIELD, 'retention is required');
    if (!['keepWithinSecs','keepDaily','keepWeekly','keepMonthly','keepYearly'].find(k => !!retention[k])) return new BoxError(BoxError.BAD_FIELD, 'retention properties missing');
    if ('keepWithinSecs' in retention && typeof retention.keepWithinSecs !== 'number') return new BoxError(BoxError.BAD_FIELD, 'retention.keepWithinSecs must be a number');
    if ('keepDaily' in retention && typeof retention.keepDaily !== 'number') return new BoxError(BoxError.BAD_FIELD, 'retention.keepDaily must be a number');
    if ('keepWeekly' in retention && typeof retention.keepWeekly !== 'number') return new BoxError(BoxError.BAD_FIELD, 'retention.keepWeekly must be a number');
    if ('keepMonthly' in retention && typeof retention.keepMonthly !== 'number') return new BoxError(BoxError.BAD_FIELD, 'retention.keepMonthly must be a number');
    if ('keepYearly' in retention && typeof retention.keepYearly !== 'number') return new BoxError(BoxError.BAD_FIELD, 'retention.keepYearly must be a number');

    return null;
}

function validateEncryptionPassword(password) {
    assert.strictEqual(typeof password, 'string');

    if (password.length < 8) return new BoxError(BoxError.BAD_FIELD, 'password must be atleast 8 characters');
}

async function list(page, perPage) {
    assert(typeof page === 'number' && page > 0);
    assert(typeof perPage === 'number' && perPage > 0);

    const results = await database.query(`SELECT ${BACKUP_TARGET_FIELDS} FROM backupSites ORDER BY name DESC LIMIT ?,?`, [ (page-1)*perPage, perPage ]);

    results.forEach(function (result) { postProcess(result); });

    return results;
}

async function get(id) {
    const results = await database.query(`SELECT ${BACKUP_TARGET_FIELDS} FROM backupSites WHERE id=?`, [ id ]);
    if (results.length === 0) return null;
    return postProcess(results[0]);
}

async function getPrimary() {
    const results = await database.query(`SELECT ${BACKUP_TARGET_FIELDS} FROM backupSites WHERE main=?`, [ true ]);
    if (results.length === 0) return null;
    return postProcess(results[0]);
}

async function update(site, data) {
    assert.strictEqual(typeof site, 'object');
    assert(data && typeof data === 'object');

    const args = [];
    const fields = [];
    for (const k in data) {
        if (k === 'name' || k === 'schedule' || k === 'main') { // format, provider cannot be updated
            fields.push(k + ' = ?');
            args.push(data[k]);
        } else if (k === 'config' || k === 'limits' || k === 'retention') { // encryption cannot be updated
            fields.push(`${k}JSON = ?`);
            args.push(JSON.stringify(data[k]));
        }
    }
    args.push(site.id);

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

async function setSchedule(backupSite, schedule, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof schedule, 'string');
    assert.strictEqual(typeof auditSource, 'object');

    const error = await validateSchedule(schedule);
    if (error) throw error;

    await update(backupSite, { schedule });
    await cron.handleBackupScheduleChanged(Object.assign({}, backupSite, { schedule }));
    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_UPDATE, auditSource, { backupSite, schedule });
}

async function setLimits(backupSite, limits, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof limits, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    await update(backupSite, { limits });
    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_UPDATE, auditSource, { backupSite, limits });
}

async function setRetention(backupSite, retention, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof retention, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    const error = await validateRetention(retention);
    if (error) throw error;

    await update(backupSite, { retention });
    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_UPDATE, auditSource, { backupSite, retention });
}

async function setPrimary(backupSite, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    const queries = [
        { query: 'SELECT 1 FROM backupSites WHERE id=? FOR UPDATE', args: [ backupSite.id ] }, // ensure this exists!
        { query: 'UPDATE backupSites SET main=?', args: [ false ] },
        { query: 'UPDATE backupSites SET main=? WHERE id=?', args: [ true, backupSite.id ] }
    ];

    const [error, result] = await safe(database.transaction(queries));
    if (error) throw error;
    if (result[2].affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Target not found');

    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_UPDATE, auditSource, { backupSite, primary: true });
}

async function setEncryption(backupSite, data, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof data, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    let encryption = null;
    if (data.encryptionPassword) {
        const encryptionPasswordError = validateEncryptionPassword(data.encryptionPassword);
        if (encryptionPasswordError) throw encryptionPasswordError;
        encryption = hush.generateEncryptionKeysSync(data.encryptionPassword);
        encryption.encryptedFilenames = !!data.encryptedFilenames;
        encryption.encryptionPasswordHint = data.encryptionPasswordHint || '';
    }

    const queries = [
        { query: 'DELETE FROM backups WHERE siteId=?', args: [ backupSite.id ] },
        { query: 'UPDATE backupSites SET encryptionJson=? WHERE id=?', args: [ encryption ? JSON.stringify(encryption) : null, backupSite.id ] },
    ];

    const [error, result] = await safe(database.transaction(queries));
    if (error) throw error;
    if (result[1].affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Target not found');

    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_UPDATE, auditSource, { backupSite, encryption: !!encryption });
}

async function setName(backupSite, name, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof name, 'string');
    assert.strictEqual(typeof auditSource, 'object');

    const nameError = validateName(name);
    if (nameError) throw nameError;

    await update(backupSite, { name });
    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_UPDATE, auditSource, { backupSite, name });
}

async function del(backupSite, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    await safe(storageApi(backupSite).teardown(backupSite.config), { debug }); // ignore error

    if (backupSite.primary) throw new BoxError(BoxError.CONFLICT, 'Cannot delete the primary backup site');

    const queries = [
        { query: 'DELETE FROM archives WHERE backupId IN (SELECT id FROM backups WHERE siteId=?)', args: [ backupSite.id ] },
        { query: 'DELETE FROM backups WHERE siteId=?', args: [ backupSite.id ] },
        { query: 'DELETE FROM backupSites WHERE id=? AND main=?', args: [ backupSite.id, false ] }, // cannot delete primary
    ];

    const [error, result] = await safe(database.transaction(queries));
    if (error && error.code === 'ER_NO_REFERENCED_ROW_2') throw new BoxError(BoxError.NOT_FOUND, error);
    if (error) throw error;
    if (result[2].affectedRows !== 1) throw new BoxError(BoxError.NOT_FOUND, 'Target not found');
    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_REMOVE, auditSource, { backupSite: backupSite });

    backupSite.schedule = constants.CRON_PATTERN_NEVER;
    await cron.handleBackupScheduleChanged(backupSite);

    const infoDir = path.join(paths.BACKUP_INFO_DIR, backupSite.id);
    safe.fs.rmSync(infoDir, { recursive: true });
}

async function startBackupTask(site, auditSource) {
    assert.strictEqual(typeof site, 'object');

    const [error] = await safe(locks.acquire(`${locks.TYPE_FULL_BACKUP_TASK_PREFIX}${site.id}`));
    if (error) throw new BoxError(BoxError.BAD_STATE, `Another backup task is in progress: ${error.message}`);

    const memoryLimit = site.limits?.memoryLimit ? Math.max(site.limits.memoryLimit/1024/1024, 1024) : 1024;

    const taskId = await tasks.add(`${tasks.TASK_FULL_BACKUP_PREFIX}${site.id}`, [ site.id, { /* options */ } ]);

    await eventlog.add(eventlog.ACTION_BACKUP_START, auditSource, { taskId });

    // background
    tasks.startTask(taskId, { timeout: 24 * 60 * 60 * 1000 /* 24 hours */, nice: 15, memoryLimit, oomScoreAdjust: -999 })
        .then(async (backupId) => {
            const backup = await backups.get(backupId);
            await eventlog.add(eventlog.ACTION_BACKUP_FINISH, auditSource, { taskId, backupId, remotePath: backup.remotePath });
        })
        .catch(async (error) => {
            const timedOut = error.code === tasks.ETIMEOUT;
            await safe(eventlog.add(eventlog.ACTION_BACKUP_FINISH, auditSource, { taskId, errorMessage: error.message, timedOut }));
        })
        .finally(async () => {
            await locks.release(`${locks.TYPE_FULL_BACKUP_TASK_PREFIX}${site.id}`);
            await locks.releaseByTaskId(taskId);
        });

    return taskId;
}

async function removeCacheFiles(backupSite) {
    assert.strictEqual(typeof backupSite, 'object');

    const infoDir = path.join(paths.BACKUP_INFO_DIR, backupSite.id);
    const files = safe.fs.readdirSync(infoDir);
    if (!files) throw new BoxError(BoxError.FS_ERROR, `Unable to access ${infoDir}: ${safe.error.message}`);
    for (const f of files) {
        if (!f.endsWith('.sync.cache')) continue;
        safe.fs.unlinkSync(path.join(infoDir, f));
    }
}

// keeps track of contents of the snapshot directory. this provides a way to clean up backups of uninstalled apps
async function getSnapshotInfo(backupSite) {
    assert.strictEqual(typeof backupSite, 'object');

    const snapshotFilePath = path.join(paths.BACKUP_INFO_DIR, backupSite.id, constants.SNAPSHOT_INFO_FILENAME);
    const contents = safe.fs.readFileSync(snapshotFilePath, 'utf8');
    const info = safe.JSON.parse(contents);
    return info || {};
}

// keeps track of contents of the snapshot directory. this provides a way to clean up backups of uninstalled apps
async function setSnapshotInfo(backupSite, id, info) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof id, 'string'); // 'box', 'mail' or appId
    assert.strictEqual(typeof info, 'object');

    const infoDir = path.join(paths.BACKUP_INFO_DIR, backupSite.id);
    const snapshotFilePath = path.join(infoDir, constants.SNAPSHOT_INFO_FILENAME);
    const contents = safe.fs.readFileSync(snapshotFilePath, 'utf8');
    const data = safe.JSON.parse(contents) || {};
    if (info) data[id] = info; else delete data[id];
    if (!safe.fs.writeFileSync(snapshotFilePath, JSON.stringify(data, null, 4), 'utf8')) {
        throw new BoxError(BoxError.FS_ERROR, safe.error.message);
    }

    if (!info) { // unlink the cache files
        safe.fs.unlinkSync(path.join(infoDir, `${id}.sync.cache`));
        safe.fs.unlinkSync(path.join(infoDir, `${id}.sync.cache.new`));
    }
}

async function startCleanupTask(backupSite, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    const taskId = await tasks.add(`${tasks.TASK_CLEAN_BACKUPS_PREFIX}${backupSite.id}`, [ backupSite.id ]);

    // background
    tasks.startTask(taskId, {})
        .then(async (result) => { // { removedBoxBackupPaths, removedAppBackupPaths, removedMailBackupPaths, missingBackupPaths }
            await eventlog.add(eventlog.ACTION_BACKUP_CLEANUP_FINISH, auditSource, { taskId, errorMessage: null, ...result });
        })
        .catch(async (error) => {
            await eventlog.add(eventlog.ACTION_BACKUP_CLEANUP_FINISH, auditSource, { taskId, errorMessage: error.message });
        });

    return taskId;
}

async function remount(site) {
    assert.strictEqual(typeof site, 'object');

    await storageApi(site).setup(site.config);
}

async function getStatus(site) {
    assert.strictEqual(typeof site, 'object');

    return await storageApi(site).getStatus(site.config);
}

async function ensureMounted(site) {
    assert.strictEqual(typeof site, 'object');

    const status = await getStatus(site);
    if (status.state === 'active') return status;

    await remount();
    return await getStatus(site);
}

async function setConfig(backupSite, newConfig, auditSource) {
    assert.strictEqual(typeof backupSite, 'object');
    assert.strictEqual(typeof newConfig, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    if (constants.DEMO) throw new BoxError(BoxError.BAD_STATE, 'Not allowed in demo mode');

    const oldConfig = backupSite.config;

    storageApi(backupSite).injectPrivateFields(newConfig, oldConfig);

    debug('setConfig: validating new storage configuration');
    const sanitizedConfig = await storageApi(backupSite).verifyConfig({ id: backupSite.id, provider: backupSite.provider, config: newConfig });

    debug('setConfig: clearing backup cache');
    // FIXME: this cleans up the cache files in case the bucket or the prefix changes and the destination already has something there
    // however, this will also resync if just the credentials change
    await removeCacheFiles(backupSite);

    await update(backupSite, { config: sanitizedConfig });

    debug('setConfig: setting up new storage configuration');
    await storageApi(backupSite).setup(sanitizedConfig);

    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_UPDATE, auditSource, { backupSite, newConfig });
}

async function add(data, auditSource) {
    assert.strictEqual(typeof data, 'object');
    assert.strictEqual(typeof auditSource, 'object');

    if (constants.DEMO) throw new BoxError(BoxError.BAD_STATE, 'Not allowed in demo mode');

    const { provider, name, config, format, retention, schedule } = data; // required
    const limits = data.limits || null,
        encryptionPassword = data.encryptionPassword || null,
        encryptedFilenames = data.encryptedFilenames || false,
        encryptionPasswordHint = data.encryptionPasswordHint || null;

    const formatError = backupFormats.validateFormat(format);
    if (formatError) throw formatError;

    const nameError = validateName(name);
    if (nameError) throw nameError;

    let encryption = null;
    if (encryptionPassword) {
        const encryptionPasswordError = validateEncryptionPassword(encryptionPassword);
        if (encryptionPasswordError) throw encryptionPasswordError;
        encryption = hush.generateEncryptionKeysSync(encryptionPassword);
        encryption.encryptedFilenames = !!encryptedFilenames;
        encryption.encryptionPasswordHint = encryptionPasswordHint;
    }

    const integrityKeyPair = crypto.generateKeyPairSync('ed25519', {
        publicKeyEncoding: { type: 'spki', format: 'pem' },
        privateKeyEncoding: { type: 'pkcs8', format: 'pem' }
    });

    const id = `bc-${crypto.randomUUID()}`;
    if (!safe.fs.mkdirSync(`${paths.BACKUP_INFO_DIR}/${id}`)) throw new BoxError(BoxError.FS_ERROR, `Failed to create info dir: ${safe.error.message}`);

    debug('add: validating new storage configuration');
    const sanitizedConfig = await storageApi({ provider }).verifyConfig({id, provider, config });

    await database.query('INSERT INTO backupSites (id, name, provider, configJson, limitsJson, integrityKeyPairJson, retentionJson, schedule, encryptionJson, format, main) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)',
        [ id, name, provider, JSON.stringify(sanitizedConfig), JSON.stringify(limits), JSON.stringify(integrityKeyPair), JSON.stringify(retention), schedule, JSON.stringify(encryption), format, false ]);

    debug('add: setting up new storage configuration');
    await storageApi({ provider }).setup(sanitizedConfig);

    await eventlog.add(eventlog.ACTION_BACKUP_TARGET_ADD, auditSource, { id, name, provider, config, schedule, format });

    return id;
}

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

    debug('addDefault: adding default backup site');
    const defaultBackupSite = {
        name: 'Default',
        provider: 'filesystem',
        config: { backupDir: paths.DEFAULT_BACKUP_DIR },
        retention: { keepWithinSecs: 2 * 24 * 60 * 60 },
        schedule: '00 00 23 * * *',
        format: 'tgz'
    };
    defaultBackupSite.id = await add(defaultBackupSite, auditSource);
    await setPrimary(defaultBackupSite, auditSource);
}

// creates a backup site object that is not in the database
async function createPseudo(data) {
    assert.strictEqual(typeof data, 'object');

    const { id, provider, config, format } = data; // required
    const encryptionPassword = data.encryptionPassword ?? null,
        encryptedFilenames = !!data.encryptedFilenames;

    const formatError = backupFormats.validateFormat(format);
    if (formatError) throw formatError;

    let encryption = null;
    if (encryptionPassword) {
        const encryptionPasswordError = validateEncryptionPassword(encryptionPassword);
        if (encryptionPasswordError) throw encryptionPasswordError;
        encryption = hush.generateEncryptionKeysSync(encryptionPassword);
        encryption.encryptedFilenames = !!encryptedFilenames;
        encryption.encryptionPasswordHint = '';
    }

    debug('add: validating new storage configuration');
    const sanitizedConfig = await storageApi({ provider }).verifyConfig({id, provider, config });
    return { id, format, provider, config: sanitizedConfig, encryption };
}