'use strict';

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

const apps = require('./apps.js'),
    assert = require('assert'),
    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');

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 = {};

    const allApps = await apps.list();
    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
        }
    }

    return appDisks;
}

async function getBackupsFilesystem() {
    const backupConfig = await settings.getBackupConfig();

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

    const result = await df.file(backupConfig.backupFolder);
    return result.filesystem;
}

async function getDisks() {
    const info = await docker.info();

    let [error, allDisks] = await safe(df());
    if (error) throw new BoxError(BoxError.FS_ERROR, error);

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

    const diskInfos = [];
    for (const p of [ paths.BOX_DATA_DIR, paths.PLATFORM_DATA_DIR, paths.APPS_DATA_DIR, info.DockerRootDir ]) {
        const [dfError, diskInfo] = await safe(df.file(p));
        if (dfError) throw new BoxError(BoxError.FS_ERROR, dfError);
        diskInfos.push(diskInfo);
    }

    const backupsFilesystem = await getBackupsFilesystem();

    const result = {
        disks: ext4Disks, // root disk is first. { filesystem, type, size, used, avialable, capacity, mountpoint }
        boxDataDisk: diskInfos[0].filesystem,
        mailDataDisk: diskInfos[0].filesystem,
        platformDataDisk: diskInfos[1].filesystem,
        appsDataDisk: diskInfos[2].filesystem,
        dockerDataDisk: diskInfos[3].filesystem,
        backupsDisk: backupsFilesystem,
        apps: {}, // filled below
        volumes: {} // filled below
    };

    result.apps = await getAppDisks(result.appsDataDisk);
    result.volumes = await getVolumeDisks(result.appsDataDisk);

    return result;
}

async function checkDiskSpace() {
    debug('checkDiskSpace: checking disk space');

    const disks = await getDisks();

    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);
}

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;
}

async function getMemory() {
    return {
        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
}