'use strict';

exports = module.exports = {
    testIPv4Config,
    testIPv6Config,

    getBlocklist,
    setBlocklist,

    getDynamicDns,
    setDynamicDns,

    getIPv4Config,
    setIPv4Config,

    getIPv6Config,
    setIPv6Config,

    getIPv4,
    hasIPv6,
    getIPv6
};

const assert = require('assert'),
    BoxError = require('./boxerror.js'),
    constants = require('./constants.js'),
    cron = require('./cron.js'),
    fs = require('fs'),
    ipaddr = require('ipaddr.js'),
    path = require('path'),
    paths = require('./paths.js'),
    safe = require('safetydance'),
    settings = require('./settings.js'),
    shell = require('./shell.js'),
    validator = require('validator');

const SET_BLOCKLIST_CMD = path.join(__dirname, 'scripts/setblocklist.sh');

function api(provider) {
    assert.strictEqual(typeof provider, 'string');

    switch (provider) {
    case 'noop': return require('./network/noop.js');
    case 'fixed': return require('./network/fixed.js');
    case 'network-interface': return require('./network/network-interface.js');
    default: return require('./network/generic.js');
    }
}

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;
}

async function testIPv4Config(config) {
    assert.strictEqual(typeof config, 'object');

    return await api(config.provider).testIPv4Config(config);
}

async function testIPv6Config(config) {
    assert.strictEqual(typeof config, 'object');

    return await api(config.provider).testIPv6Config(config);
}

async function getBlocklist() {
    const value = await settings.getBlob(settings.FIREWALL_BLOCKLIST_KEY);
    return value ? value.toString('utf8') : '';
}

async function setBlocklist(blocklist, auditSource) {
    assert.strictEqual(typeof blocklist, 'string');
    assert.strictEqual(typeof auditSource, 'object');

    const parsedIp = ipaddr.process(auditSource.ip);

    for (const line of blocklist.split('\n')) {
        if (!line || line.startsWith('#')) continue;
        const rangeOrIP = line.trim();
        // this checks for IPv4 and IPv6
        if (!validator.isIP(rangeOrIP) && !validator.isIPRange(rangeOrIP)) throw new BoxError(BoxError.BAD_FIELD, `${rangeOrIP} is not a valid IP or range`);

        if (rangeOrIP.indexOf('/') === -1) {
            if (auditSource.ip === rangeOrIP) throw new BoxError(BoxError.BAD_FIELD, `${rangeOrIP} includes client IP. Cannot block yourself`);
        } else {
            const parsedRange = ipaddr.parseCIDR(rangeOrIP); // returns [addr, range]
            if (parsedRange[0].kind() === parsedIp.kind() && parsedIp.match(parsedRange)) throw new BoxError(BoxError.BAD_FIELD, `${rangeOrIP} includes client IP. Cannot block yourself`);
        }
    }

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

    // store in blob since the value field is TEXT and has 16kb size limit
    await settings.setBlob(settings.FIREWALL_BLOCKLIST_KEY, Buffer.from(blocklist));

    // this is done only because it's easier for the shell script and the firewall service to get the value
    if (!safe.fs.writeFileSync(paths.FIREWALL_BLOCKLIST_FILE, blocklist + '\n', 'utf8')) throw new BoxError(BoxError.FS_ERROR, safe.error.message);

    const [error] = await safe(shell.promises.sudo('setBlocklist', [ SET_BLOCKLIST_CMD ], {}));
    if (error) throw new BoxError(BoxError.IPTABLES_ERROR, `Error setting blocklist: ${error.message}`);
}

async function getDynamicDns() {
    const enabled = await settings.get(settings.DYNAMIC_DNS_KEY);
    return enabled ? !!enabled : false; // db holds string values only
}

async function setDynamicDns(enabled) {
    assert.strictEqual(typeof enabled, 'boolean');

    await settings.set(settings.DYNAMIC_DNS_KEY, enabled ? 'enabled' : ''); // db holds string values only
    await cron.handleDynamicDnsChanged(enabled);
}

async function getIPv4Config() {
    const value = await settings.getJson(settings.IPV4_CONFIG_KEY);
    return value || { provider: 'generic' };
}

async function setIPv4Config(ipv4Config) {
    assert.strictEqual(typeof ipv4Config, 'object');

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

    const error = await testIPv4Config(ipv4Config);
    if (error) throw error;

    await settings.setJson(settings.IPV4_CONFIG_KEY, ipv4Config);
}

async function getIPv6Config() {
    const value = await settings.getJson(settings.IPV6_CONFIG_KEY);
    return value || { provider: 'noop' };
}

async function setIPv6Config(ipv6Config) {
    assert.strictEqual(typeof ipv6Config, 'object');

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

    const error = await testIPv6Config(ipv6Config);
    if (error) throw error;

    await settings.setJson(settings.IPV6_CONFIG_KEY, ipv6Config);
}

async function getIPv4() {
    const config = await getIPv4Config();

    return await api(config.provider).getIPv4(config);
}

// returns RFC 5952 formatted address (https://datatracker.ietf.org/doc/html/rfc5952)
async function getIPv6() {
    const config = await getIPv6Config();
    const result = await api(config.provider).getIPv6(config);
    if (!result) return null;
    return ipaddr.parse(result).toRFC5952String();
}