'use strict';

exports = module.exports = {
    getSystem,
    getContainers,

    sendToGraphite
};

const apps = require('./apps.js'),
    assert = require('assert'),
    BoxError = require('./boxerror.js'),
    constants = require('./constants.js'),
    debug = require('debug')('box:metrics'),
    docker = require('./docker.js'),
    execSync = require('child_process').execSync,
    net = require('net'),
    os = require('os'),
    safe = require('safetydance'),
    services = require('./services.js'),
    superagent = require('./superagent.js');

    function parseSiSize(size) {
    const units = {
        "B": 1,
        "KB": Math.pow(10, 3),
        "MB": Math.pow(10, 6),
        "GB": Math.pow(10, 9),
        "TB": Math.pow(10, 12)
    };

    const match = size.toUpperCase().match(/^(\d+(\.\d+)?)\s*(\D+)$/);
    if (!match) {
        throw new Error("Invalid size format");
    }

    const number = parseFloat(match[1]);
    const unit = match[3];

    return Math.floor(number * units[unit]);
}

function parseBinarySize(size) {
    const units = {
        "B": 1,
        "KIB": Math.pow(2, 10),
        "MIB": Math.pow(2, 20),
        "GIB": Math.pow(2, 30),
        "TIB": Math.pow(2, 40)
    };

    const match = size.toUpperCase().match(/^(\d+(\.\d+)?)\s*(\D+)$/);
    if (!match) {
        throw new Error("Invalid size format");
    }

    const number = parseFloat(match[1]);
    const unit = match[3];

    return Math.floor(number * units[unit]);
}

async function getDockerMetrics() {
    const lines = execSync('docker stats --format  "{{ json . }}" --no-stream --no-trunc', { encoding: 'utf8' }).trim().split('\n');

    const metrics = [];

    for (const line of lines) {
        const stat = JSON.parse(line);
        const name = stat.Name; // appid or addon name

        const networkData = stat.NetIO.split('/');
        const networkRead = parseSiSize(networkData[0].trim());
        const networkWrite = parseSiSize(networkData[1].trim());

        const blockData = stat.BlockIO.split('/');
        const blockRead = parseSiSize(blockData[0].trim());
        const blockWrite = parseSiSize(blockData[1].trim());

        const memUsageData = stat.MemUsage.split('/');
        const memUsed = parseBinarySize(memUsageData[0].trim());
        const memMax = parseBinarySize(memUsageData[1].trim());

        const cpuPercData = stat.CPUPerc.trim().replace('%', '');
        const cpuPerc = parseFloat(cpuPercData);

        metrics.push(
            { path: `cloudron.container-${name}.network-read`, value: networkRead },
            { path: `cloudron.container-${name}.network-write`, value: networkWrite },
            { path: `cloudron.container-${name}.blockio-read`, value: blockRead },
            { path: `cloudron.container-${name}.blockio-write`, value: blockWrite },
            { path: `cloudron.container-${name}.mem-used`, value: memUsed },
            { path: `cloudron.container-${name}.mem-max`, value: memMax },
            { path: `cloudron.container-${name}.cpu-perc`, value: cpuPerc },
        );
    }

    return metrics;
}

async function getMemoryMetrics() {
    // we can also read /proc/meminfo but complicated to match the 'used' output of free
    const output = execSync('free --bytes --wide', { encoding: 'utf8' }).trim(); // --line is not in older ubuntu
    const memoryRe = /Mem:\s+(?<total>\d+)\s+(?<used>\d+)\s+(?<free>\d+)\s+(?<shared>\d+)\s+(?<buffers>\d+)\s+(?<cache>\d+)\s+(?<available>\d+)/;

    const memory = output.match(memoryRe);
    if (!memory) throw new BoxError(BoxError.EXTERNAL_ERROR, 'Could not find memory used');

    return [
        { path: `cloudron.system.memory-used`, value: memory.groups.used  },
    ];
}

async function getCpuMetrics() {
    const cpus = os.cpus();
    const userMillis = cpus.map(c => c.times.user).reduce((p, c) => p+c);
    const sysMillis = cpus.map(c => c.times.sys).reduce((p, c) => p+c);

    // this value is time spent since system start
    return [
        { path: `cloudron.system.cpu-user`, value: userMillis  },
        { path: `cloudron.system.cpu-sys`, value: sysMillis  },
    ];
}

async function sendToGraphite() {
    debug('sendStatsToGraphite: collecting stats');
    const dockerMetrics = await getDockerMetrics();
    const memoryMetrics = await getMemoryMetrics();
    const cpuMetrics = await getCpuMetrics();

    return new Promise((resolve) => {
        const client = new net.Socket();
        client.connect(constants.GRAPHITE_PORT, '127.0.0.1', () => {
            debug('connected to graphite');

            const now = Math.floor(Date.now() / 1000);

            for (const metric of [...dockerMetrics, ...memoryMetrics, ...cpuMetrics]) {
                client.write(`${metric.path} ${metric.value} ${now}\n`);
            }
            client.end();
        });

        client.on('error', (error) => {
            debug(error);
            resolve();
        });

        client.on('end', () => {
            debug('sent to graphite');
            resolve();
        });
    });
}

// for testing locally: curl 'http://${graphite-ip}:8000/graphite-web/render?format=json&from=-1min&target=absolute(collectd.localhost.du-docker.capacity-usage)'
// the datapoint is (value, timestamp) https://graphite.readthedocs.io/en/latest/
async function getGraphiteUrl() {
    const [error, result] = await safe(docker.inspect('graphite'));
    if (error && error.reason === BoxError.NOT_FOUND) return { status: exports.SERVICE_STATUS_STOPPED };
    if (error) throw error;

    const ip = safe.query(result, 'NetworkSettings.Networks.cloudron.IPAddress', null);
    if (!ip) throw new BoxError(BoxError.INACTIVE, 'Error getting IP of graphite service');

    return `http://${ip}:8000/graphite-web/render`;
}

async function getContainers(name, options) {
    assert.strictEqual(typeof name, 'string');
    assert.strictEqual(typeof options, 'object');

    const { fromSecs, intervalSecs, noNullPoints } = options;

    const graphiteUrl = await getGraphiteUrl();

    const targets = [
        `summarize(cloudron.container-${name}.cpu-perc, "${intervalSecs}s", "avg")`,
        `summarize(cloudron.container-${name}.mem-used, "${intervalSecs}s", "avg")`,
        `summarize(cloudron.container-${name}.blockio-read, "${intervalSecs}s", "sum")`,
        `summarize(cloudron.container-${name}.blockio-write, "${intervalSecs}s", "sum")`,
        `summarize(cloudron.container-${name}.network-read, "${intervalSecs}s", "sum")`,
        `summarize(cloudron.container-${name}.network-write, "${intervalSecs}s", "sum")`,
        `summarize(cloudron.container-${name}.blockio-read, "${intervalSecs}s", "max")`,
        `summarize(cloudron.container-${name}.blockio-write, "${intervalSecs}s", "max")`,
        `summarize(cloudron.container-${name}.network-read, "${intervalSecs}s", "max")`,
        `summarize(cloudron.container-${name}.network-write, "${intervalSecs}s", "max")`,
    ];

    const results = [];

    for (const target of targets) {
        const query = {
            target: target,
            format: 'json',
            from: `-${fromSecs}s`,
            until: 'now',
            noNullPoints: !!noNullPoints
        };

        const [error, response] = await safe(superagent.get(graphiteUrl).query(query).timeout(30 * 1000).ok(() => true));
        if (error) throw new BoxError(BoxError.NETWORK_ERROR, error);
        if (response.status !== 200) throw new BoxError(BoxError.EXTERNAL_ERROR, `Unknown error with ${target}: ${response.status} ${response.text}`);

        results.push(response.body[0] && response.body[0].datapoints ? response.body[0].datapoints : []);
    }

    // results are datapoints[[value, ts], [value, ts], ...];
    return {
        cpu: results[0],
        memory: results[1],
        blockRead: results[2],
        blockWrite: results[3],
        networkRead: results[4],
        networkWrite: results[5],
        blockReadTotal: results[6][0] && results[6][0][0] ? results[6][0][0] : 0,
        blockWriteTotal: results[7][0] && results[7][0][0] ? results[7][0][0] : 0,
        networkReadTotal: results[8][0] && results[8][0][0] ? results[8][0][0] : 0,
        networkWriteTotal: results[9][0] && results[9][0][0] ? results[9][0][0] : 0,
        cpuCount: os.cpus().length
    };
}

async function getSystemStats(options) {
    assert.strictEqual(typeof options, 'object');

    const { fromSecs, intervalSecs, noNullPoints } = options;

    const graphiteUrl = await getGraphiteUrl();

    // example: curl 'http://172.18.30.5:8000/graphite-web/render?target=cloudron.system.cpu-user&target=cloudron.system.cpu-sys&format=json&from=-1min&until=now&noNullPoints=false' | python3 -m json.tool
    const targets = [
        // perSecond is nonNegativeDerivative over time . this value is the cpu usage in msecs .
        // (cpu usage msecs) / (cpus * 1000) is the percent but over all cpus. times 100 is the percent.
        // but the y-scale is cpus times 100. so, we only need to scale by 0.1
        `scale(perSecond(sumSeries(cloudron.system.cpu-user,cloudron.system.cpu-sys)),0.1)`,
        `summarize(cloudron.system.memory-used, "${intervalSecs}s", "avg")`
    ];

    const results = [];

    for (const target of targets) {
        const query = {
            target: target,
            format: 'json',
            from: `-${fromSecs}s`,
            until: 'now',
            noNullPoints: !!noNullPoints
        };

        const [error, response] = await safe(superagent.get(graphiteUrl).query(query).timeout(30 * 1000).ok(() => true));
        if (error) throw new BoxError(BoxError.NETWORK_ERROR, error);
        if (response.status !== 200) throw new BoxError(BoxError.EXTERNAL_ERROR, `Unknown error with ${target}: ${response.status} ${response.text}`);

        results.push(response.body[0] && response.body[0].datapoints ? response.body[0].datapoints : []);
    }

    return {
        cpu: results[0],
        memory: results[1]
    };
}

async function getSystem(options) {
    assert.strictEqual(typeof options, 'object');

    const systemStats = await getSystemStats(options);

    const appStats = {};
    for (const app of await apps.list()) {
        appStats[app.id] = await getContainers(app.id, options);
    }

    const serviceStats = {};
    for (const serviceId of await services.listServices()) {
        serviceStats[serviceId] = await getContainers(serviceId, options);
    }

    return {
        cpu: systemStats.cpu,
        memory: systemStats.memory,
        apps: appStats,
        services: serviceStats,
        cpuCount: os.cpus().length
    };
}