'use strict';

exports = module.exports = {
    getDisks,
    checkDiskSpace,
    getMemory,
    getMemoryAllocation
};

const apps = require('./apps.js'),
    assert = require('assert'),
    async = require('async'),
    BoxError = require('./boxerror.js'),
    debug = require('debug')('box:disks'),
    df = require('@sindresorhus/df'),
    docker = require('./docker.js'),
    notifications = require('./notifications.js'),
    os = require('os'),
    paths = require('./paths.js'),
    safe = require('safetydance'),
    settings = require('./settings.js'),
    volumes = require('./volumes.js');

const dfAsync = async.asyncify(df), dfFileAsync = async.asyncify(df.file);

async function getVolumeDisks(appsDataDisk) {
    assert.strictEqual(typeof appsDataDisk, 'string');

    let volumeDisks = {};
    const allVolumes = await volumes.list();

    for (const volume of allVolumes) {
        const [error, result] = await safe(df(volume.hostPath));
        volumeDisks[volume.id] = error ? appsDataDisk : result.filesystem; // ignore any errors
    }

    return volumeDisks;
}

async function getAppDisks(appsDataDisk) {
    assert.strictEqual(typeof appsDataDisk, 'string');

    let appDisks = {};

    return new Promise((resolve, reject) => {
        apps.getAll(async function (error, allApps) {
            if (error) return reject(error);

            for (const app of allApps) {
                if (!app.dataDir) {
                    appDisks[app.id] = appsDataDisk;
                } else {
                    const [error, result] = await safe(df.file(app.dataDir));
                    appDisks[app.id] = error ? appsDataDisk : result.filesystem; // ignore any errors
                }
            }

            resolve(appDisks);
        });
    });
}

function getBackupDisk(callback) {
    assert.strictEqual(typeof callback, 'function');

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

        if (backupConfig.provider !== 'filesystem') return callback(null, null);

        dfFileAsync(backupConfig.backupFolder, function (error, result) {
            if (error) return callback(error);

            callback(null, result.filesystem);
        });
    });
}

function getDisks(callback) {
    assert.strictEqual(typeof callback, 'function');

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

        async.series([
            dfAsync,
            dfFileAsync.bind(null, paths.BOX_DATA_DIR),
            dfFileAsync.bind(null, paths.PLATFORM_DATA_DIR),
            dfFileAsync.bind(null, paths.APPS_DATA_DIR),
            dfFileAsync.bind(null, info.DockerRootDir),
            getBackupDisk,
        ], async function (error, values) {
            if (error) return callback(new BoxError(BoxError.FS_ERROR, error));

            // filter by ext4 and then sort to make sure root disk is first
            const ext4Disks = values[0].filter((r) => r.type === 'ext4').sort((a, b) => a.mountpoint.localeCompare(b.mountpoint));

            const disks = {
                disks: ext4Disks, // root disk is first. { filesystem, type, size, used, avialable, capacity, mountpoint }
                boxDataDisk: values[1].filesystem,
                mailDataDisk: values[1].filesystem,
                platformDataDisk: values[2].filesystem,
                appsDataDisk: values[3].filesystem,
                dockerDataDisk: values[4].filesystem,
                backupsDisk: values[5],
                apps: {}, // filled below
                volumes: {} // filled below
            };

            [error, disks.apps] = await safe(getAppDisks(disks.appsDataDisk));
            if (error) return callback(error);

            [error, disks.volumes] = await safe(getVolumeDisks(disks.appsDataDisk));
            if (error) return callback(error);

            callback(null, disks);
        });
    });
}

function checkDiskSpace(callback) {
    assert.strictEqual(typeof callback, 'function');

    debug('checkDiskSpace: checking disk space');

    getDisks(async function (error, disks) {
        if (error) {
            debug('checkDiskSpace: error getting disks %s', error.message);
            return callback();
        }

        let markdownMessage = '';

        disks.disks.forEach(function (entry) {
            // ignore other filesystems but where box, app and platform data is
            if (entry.filesystem !== disks.boxDataDisk
                && entry.filesystem !== disks.platformDataDisk
                && entry.filesystem !== disks.appsDataDisk
                && entry.filesystem !== disks.backupsDisk
                && entry.filesystem !== disks.dockerDataDisk) return false;

            if (entry.available <= (1.25 * 1024 * 1024 * 1024)) { // 1.5G
                markdownMessage += `* ${entry.filesystem} is at ${entry.capacity*100}% capacity.\n`;
            }
        });

        debug(`checkDiskSpace: disk space checked. out of space: ${markdownMessage || 'no'}`);

        if (markdownMessage) markdownMessage = `One or more file systems are running out of space. Please increase the disk size at the earliest.\n\n${markdownMessage}`;

        await notifications.alert(notifications.ALERT_DISK_SPACE, 'Server is running out of disk space', markdownMessage);

        callback();
    });
}

function getSwapSize() {
    const stdout = safe.child_process.execSync('swapon --noheadings --raw --bytes --show=SIZE', { encoding: 'utf8' });
    const swap = !stdout ? 0 : stdout.trim().split('\n').map(x => parseInt(x, 10) || 0).reduce((acc, cur) => acc + cur);

    return swap;
}

function getMemory(callback) {
    assert.strictEqual(typeof callback, 'function');

    callback(null, {
        memory: os.totalmem(),
        swap: getSwapSize()
    });
}

function getMemoryAllocation(limit) {
    let ratio = parseFloat(safe.fs.readFileSync(paths.SWAP_RATIO_FILE, 'utf8'), 10);

    if (!ratio) {
        const pc = os.totalmem() / (os.totalmem() + getSwapSize());
        ratio = Math.round(pc * 10) / 10; // a simple ratio
    }

    return Math.round(Math.round(limit * ratio) / 1048576) * 1048576; // nearest MB
}