const R = require("ramda");
const { cpanel } = require("./lib/cpanel");
const { DOMAIN_DOMAIN, VALID_RECORD_TYPES } = require("./constants");
const { then, log, print, lazyTask, batchLazyTasks } = require("./helpers");

const BATCH_SIZE = 1;

const recordToRedirection = ({ name, address }) => ({
    domain: name === "@" ? DOMAIN_DOMAIN : `${name}.${DOMAIN_DOMAIN}`,
    redirect: address,
    type: "permanent",
    redirect_wildcard: 1,
    redirect_www: 1,
});
const recordToZone = ({ name, type, address, id, priority }) => ({
    line: id,
    name: name === "@" ? `${DOMAIN_DOMAIN}.` : name,
    type,
    address,
    ...(type === "MX" ? { priority } : {}),
    ...(type === "CNAME" ? { cname: address } : {}),
    ...(type === "TXT" ? { txtdata: address } : {}),
});

const cleanName = (name) =>
    [DOMAIN_DOMAIN, `${DOMAIN_DOMAIN}.`].includes(name)
        ? "@"
        : `${name}`
              .replace(new RegExp(`\\.${DOMAIN_DOMAIN}\\.?$`), "")
              .toLowerCase();

const zoneToRecord = ({
    name,
    type,
    cname,
    address,
    priority,
    preference,
    exchange,
    record,
    line: id,
}) => ({
    id,
    name: cleanName(name),
    type: `${type}`,
    address: `${exchange || cname || address || record}`
        .replace(/\.$/g, "")
        .toLowerCase(),
    priority: priority || preference,
});
const redirectionToRecord = ({ domain, destination }) => ({
    id: domain,
    name: cleanName(domain),
    type: "URL",
    address: `${destination}`.replace(/\/$/g, ""),
});

const recordToEmailMx = ({ name, address, priority }) => ({
    domain: `${name}.is-a.dev`,
    exchanger: address,
    priority,
});

const getHostKey = (host) =>
    `${host.name.toLowerCase()}##${host.type.toLowerCase()}##${host.address.toLowerCase()}`;

const isReserved = (domain) =>
    domain.name.startsWith("*") || !VALID_RECORD_TYPES.includes(domain.type);

const diffRecords = (oldRecords, newRecords) => {
    const isMatchingRecord = (a, b) => getHostKey(a) === getHostKey(b);

    const remove = R.differenceWith(isMatchingRecord, oldRecords, newRecords);
    const add = R.differenceWith(isMatchingRecord, newRecords, oldRecords);

    return { add, remove };
};

const executeBatch = (batches) =>
    batches.reduce((promise, batch, index) => {
        return promise.then(async () => {
            log(
                ">>> Running batch number:",
                index + 1,
                `(size: ${batch.length})`,
            );

            const values = await Promise.all(
                batch.map((fn) => fn().catch((e) => console.error(e))),
            );

            const results = values.map((data) =>
                R.pathOr({ result: data }, ["cpanelresult", "data", 0], data),
            );
            const failed = results.filter((x) => (x.result || {}).status != 1);

            log(`${values.length - failed.length}/${values.length}`);
            failed.length && log(JSON.stringify(failed, null, 2));

            return null;
        });
    }, Promise.resolve());

const getDomainService = ({ cpanel }) => {
    const fetchZoneRecords = R.compose(
        then(R.reject(isReserved)),
        then(R.map(zoneToRecord)),
        cpanel.zone.fetch,
    );
    const fetchRedirections = R.compose(
        then(R.map(redirectionToRecord)),
        cpanel.redirection.fetch,
    );

    const addZoneRecord = lazyTask(
        R.compose(
            R.ifElse(
                R.propEq("type", "MX"),
                R.compose(cpanel.email.add, recordToEmailMx),
                cpanel.zone.add,
            ),
            recordToZone,
            print(
                (r) => `Adding zone for ${r.name}: (${r.type} ${r.address})...`,
            ),
        ),
    );
    const removeZoneRecord = lazyTask(
        R.compose(
            R.ifElse(
                R.propEq("type", "MX"),
                R.compose(cpanel.email.remove, recordToEmailMx),
                R.compose(cpanel.zone.remove, R.pick(["line"])),
            ),
            recordToZone,
            print(
                (r) =>
                    `Deleting zone for ${r.name}: (${r.type} ${r.address})...`,
            ),
        ),
    );
    const addRedirection = lazyTask(
        R.compose(
            cpanel.redirection.add,
            recordToRedirection,
            print(({ name }) => `Adding redirection for ${name}`),
        ),
    );
    const removeRedirection = lazyTask(
        R.compose(
            cpanel.redirection.remove,
            R.pick(["domain"]),
            recordToRedirection,
            print(({ name }) => `Deleting redirection for ${name}`),
        ),
    );

    const getHosts = () =>
        Promise.all([fetchZoneRecords(), fetchRedirections()]).then(R.flatten);

    const addRecords = R.compose(
        batchLazyTasks(BATCH_SIZE),
        R.filter(Boolean),
        R.map(
            R.cond([
                [R.propEq("type", "URL"), addRedirection],
                [R.T, addZoneRecord],
            ]),
        ),
    );
    const removeRecords = R.compose(
        batchLazyTasks(BATCH_SIZE),
        R.map(
            R.cond([
                [R.propEq("type", "URL"), removeRedirection],
                [R.T, removeZoneRecord],
            ]),
        ),
        R.sort((a, b) => b.id - a.id),
    );

    const updateHosts = async (hosts) => {
        const remoteHostList = await getHosts();
        const { add, remove } = diffRecords(remoteHostList, hosts);
        console.log(`Adding ${add.length}; Removing ${remove.length}`);

        await executeBatch([...removeRecords(remove), ...addRecords(add)]);
        return { added: add.length, removed: remove.length };
    };

    return {
        getHosts,
        get: cpanel.zone.fetch,
        addZoneRecord,
        removeZoneRecord,
        updateHosts,
    };
};

const domainService = getDomainService({ cpanel });

module.exports = {
    getDomainService,
    domainService,
    diffRecords,
};