'use strict';

exports = module.exports = {
    getServerIp: getServerIp,

    hasIPv6: hasIPv6
};

var assert = require('assert'),
    ec2 = require('./sysinfo/ec2.js'),
    fs = require('fs'),
    generic = require('./sysinfo/generic.js'),
    scaleway = require('./sysinfo/scaleway.js'),
    settings = require('./settings.js');

function getApi(config, callback) {
    assert.strictEqual(typeof config, 'object');
    assert.strictEqual(typeof callback, 'function');

    const provider = config.provider || 'generic';

    switch (provider) {
    case 'ec2': return callback(null, ec2);
    case 'lightsail': return callback(null, ec2);
    case 'ami': return callback(null, ec2);
    case 'scaleway': return callback(null, scaleway);
    default: return callback(null, generic);
    }
}

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

    settings.getSysinfoConfig(function (error, config) {
        if (error) return callback(error);

        getApi(config, function (error, api) {
            if (error) return callback(error);

            api.getServerIp(config, callback);
        });
    });
}

function hasIPv6() {
    const IPV6_PROC_FILE = '/proc/net/if_inet6';
    // on contabo, /proc/net/if_inet6 is an empty file. so just exists is not enough
    return fs.existsSync(IPV6_PROC_FILE) && fs.readFileSync(IPV6_PROC_FILE, 'utf8').trim().length !== 0;
}