#include "credentials.h"
#include <qt5keychain/keychain.h>
#include <QXmppPromise.h>
#include <QXmppConfiguration.h>
#include <iostream>

static const QString service = "xxcc", sep = ";";

QXmppTask<Credentials::PairListResult> Credentials::load(
    Credentials::PairList &pairs,
    QStringList::const_iterator &it,
    QStringList::const_iterator end)
{
    if (it == end)
        return QXmpp::Private::makeReadyTask<PairListResult>(
            PairListResult(pairs));

    QXmppPromise<PairListResult> promise;

    load(*it).then(this,
    [=] (LoadResult &&result) mutable
    {
        if (std::holds_alternative<QString>(result))
        {
            pairs << Pair(*it, std::get<QString>(result));

            load(pairs, ++it, end).then(this,
            [=] (PairListResult &&result) mutable
            {
                promise.finish(result);
            });
        }
        else if (std::holds_alternative<Error>(result))
            promise.finish(Error{std::get<Error>(result)});
    });

    return promise.task();
}

QXmppTask<Credentials::PairListResult> Credentials::load()
{
    QXmppPromise<PairListResult> promise;

    storedUsers().then(this,
    [=] (Users &&result) mutable
    {
        if (std::holds_alternative<QStringList>(result))
        {
            PairList pairs;
            auto list = new QStringList(std::get<QStringList>(result));
            auto begin = list->cbegin();
            const auto end = list->cend();

            load(pairs, begin, end).then(this,
            [=] (PairListResult &&result) mutable
            {
                delete list;
                promise.finish(result);
            });
        }
        else if (std::holds_alternative<Error>(result))
            promise.finish(Error{std::get<Error>(result)});
    });

    return promise.task();
}

QXmppTask<Credentials::StoreResult> Credentials::store(Client *c)
{
    QXmppPromise<StoreResult> promise;
    const QXmppConfiguration &cfg = c->configuration();
    const QString user = cfg.jidBare();

    store(user, cfg.password()).then(this,
    [=] (StoreResult &&result) mutable
    {
        store(user).then(this,
        [=] (StoreResult &&result) mutable
        {
            promise.finish(result);
        });
    });

    return promise.task();
}

QXmppTask<Credentials::StoreResult> Credentials::store(const QString &user)
{
    QXmppPromise<StoreResult> promise;

    storedUsersList().then(this,
    [=] (LoadResult &&result) mutable
    {
        if (std::holds_alternative<QString>(result))
        {
            auto &list = std::get<QString>(result);

            if (!list.isEmpty())
                list += sep;

            list += user;
            store("users", list).then(this,
            [=] (StoreResult &&result) mutable
            {
                promise.finish(result);
            });
        }
        else if (std::holds_alternative<Error>(result))
        {
            store("users", user).then(this,
            [=] (StoreResult &&result) mutable
            {
                promise.finish(result);
            });
        }
    });

    return promise.task();
}

QXmppTask<Credentials::LoadResult> Credentials::storedUsersList()
{
    QXmppPromise<LoadResult> promise;

    load("users").then(this,
    [=] (LoadResult &&result) mutable
    {
        promise.finish(result);
    });

    return promise.task();

}

QXmppTask<Credentials::LoadResult> Credentials::load(const QString &key)
{
    QXmppPromise<LoadResult> promise;
    auto job = new QKeychain::ReadPasswordJob(service);

    job->setKey(key);
    job->connect(job, &QKeychain::Job::finished, this,
    [=] (QKeychain::Job *const job) mutable
    {
        auto readjob = dynamic_cast<QKeychain::ReadPasswordJob *>(job);

        if (readjob->error())
        {
            const auto error = "Failed to load " + key + ": "
                + readjob->errorString();

            std::cerr << qPrintable(error) << std::endl;
            promise.finish(Error{error});
        }
        else
        {
            auto users = readjob->textData();

            promise.finish(QString(users));
        }
    });

    job->start();
    return promise.task();
}

QXmppTask<Credentials::StoreResult> Credentials::store(const QString &key,
    const QString &value)
{
    QXmppPromise<StoreResult> promise;
    auto job = new QKeychain::WritePasswordJob(service);

    job->setKey(key);
    job->setTextData(value);
    job->connect(job, &QKeychain::Job::finished, this,
    [=] (QKeychain::Job *const job) mutable
    {
        if (job->error())
        {
            StoreResult sr;

            const auto error = "Failed to store " + key + ": "
                + job->errorString();

            std::cerr << qPrintable(error) << std::endl;
            sr = Error{error};
            promise.finish(StoreResult(sr));
        }
        else
            promise.finish(Success{});
    });

    job->start();
    return promise.task();
}

QXmppTask<Credentials::Users> Credentials::storedUsers()
{
    QXmppPromise<Users> promise;

    storedUsersList().then(this,
    [=] (LoadResult &&result) mutable
    {
        if (std::holds_alternative<QString>(result))
        {
            const auto &value = std::get<QString>(result);

            promise.finish(QStringList(value.split(sep)));
        }
        else if (std::holds_alternative<Error>(result))
        {
            const auto &error = std::get<Error>(result);

            promise.finish(Error{error.description});
        }
    });

    return promise.task();
}