/*
    Copyright 2019  Nicolas Fella <nicolas.fella@gmx.de>
    Copyright 2020  Carson Black <uhhadd@gmail.com>
    Copyright 2020  David Redondo <kde@david-redondo.de>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) version 3, or any
    later version accepted by the membership of KDE e.V. (or its
    successor approved by the membership of KDE e.V.), which shall
    act as a proxy defined in Section 6 of version 3 of the license.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "user.h"
#include "kcmusers_debug.h"
#include "user_interface.h"
#include <KLocalizedString>
#include <KWallet>
#include <QImage>
#include <QtConcurrent>
#include <sys/types.h>
#include <unistd.h>

User::User(QObject *parent)
    : QObject(parent)
{
}

int User::uid() const
{
    return mUid;
}

void User::setUid(int value)
{
    if (mUid == value) {
        return;
    }
    mUid = value;
    Q_EMIT uidChanged();
}

QString User::name() const
{
    return mName;
}

void User::setName(const QString &value)
{
    if (mName == value) {
        return;
    }
    mName = value;
    Q_EMIT nameChanged();
}

QString User::realName() const
{
    return mRealName;
}

void User::setRealName(const QString &value)
{
    if (mRealName == value) {
        return;
    }
    mRealName = value;
    Q_EMIT realNameChanged();
}

QString User::email() const
{
    return mEmail;
}

void User::setEmail(const QString &value)
{
    if (mEmail == value) {
        return;
    }
    mEmail = value;
    Q_EMIT emailChanged();
}

QUrl User::face() const
{
    return mFace;
}

bool User::faceValid() const
{
    return mFaceValid;
}

void User::setFace(const QUrl &value)
{
    if (mFace == value) {
        return;
    }
    mFace = value;
    mFaceValid = QFile::exists(value.path());
    Q_EMIT faceValidChanged();
    Q_EMIT faceChanged();
}

bool User::administrator() const
{
    return mAdministrator;
}
void User::setAdministrator(bool value)
{
    if (mAdministrator == value) {
        return;
    }
    mAdministrator = value;
    Q_EMIT administratorChanged();
}

void User::setPath(const QDBusObjectPath &path)
{
    if (!m_dbusIface.isNull())
        delete m_dbusIface;
    m_dbusIface = new OrgFreedesktopAccountsUserInterface(QStringLiteral("org.freedesktop.Accounts"), path.path(), QDBusConnection::systemBus(), this);

    if (m_dbusIface->systemAccount()) {
        return;
    }

    mPath = path;

    connect(m_dbusIface, &OrgFreedesktopAccountsUserInterface::Changed, [=]() {
        loadData();
    });

    loadData();
}

void User::loadData()
{
    bool userDataChanged = false;
    if (mUid != m_dbusIface->uid()) {
        mUid = m_dbusIface->uid();
        userDataChanged = true;
        Q_EMIT uidChanged();
    }
    if (mName != m_dbusIface->userName()) {
        mName = m_dbusIface->userName();
        userDataChanged = true;
        Q_EMIT nameChanged();
    }
    if (mFace != QUrl(m_dbusIface->iconFile())) {
        mFace = QUrl(m_dbusIface->iconFile());
        mFaceValid = QFileInfo::exists(mFace.toString());
        userDataChanged = true;
        Q_EMIT faceChanged();
        Q_EMIT faceValidChanged();
    }
    if (mRealName != m_dbusIface->realName()) {
        mRealName = m_dbusIface->realName();
        userDataChanged = true;
        Q_EMIT realNameChanged();
    }
    if (mEmail != m_dbusIface->email()) {
        mEmail = m_dbusIface->email();
        userDataChanged = true;
        Q_EMIT emailChanged();
    }
    const auto administrator = (m_dbusIface->accountType() == 1);
    if (mAdministrator != administrator) {
        mAdministrator = administrator;
        userDataChanged = true;
        Q_EMIT administratorChanged();
    }
    const auto loggedIn = (mUid == getuid());
    if (mLoggedIn != loggedIn) {
        mLoggedIn = loggedIn;
        userDataChanged = true;
    }
    if (userDataChanged) {
        Q_EMIT dataChanged();
    }
}

static char saltCharacter()
{
    static constexpr const quint32 letterCount = 64;
    static const char saltCharacters[] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "abcdefghijklmnopqrstuvwxyz"
        "./0123456789"; // and trailing NUL
    static_assert(sizeof(saltCharacters) == (letterCount + 1), // 64 letters and trailing NUL
                  "Salt-chars array is not exactly 64 letters long");

    const quint32 index = QRandomGenerator::system()->bounded(0u, letterCount);

    return saltCharacters[index];
}

static QString saltPassword(const QString &plain)
{
    QString salt;

    salt.append("$6$");

    for (auto i = 0; i < 16; i++) {
        salt.append(saltCharacter());
    }

    salt.append("$");

    auto stdStrPlain = plain.toStdString();
    auto cStrPlain = stdStrPlain.c_str();
    auto stdStrSalt = salt.toStdString();
    auto cStrSalt = stdStrSalt.c_str();

    auto salted = crypt(cStrPlain, cStrSalt);

    return QString::fromUtf8(salted);
}

void User::setPassword(const QString &password)
{
    // Blocking because we need to wait for the password to be changed before we
    // can ask the user about also possibly changing their KWallet password
    auto invocation = m_dbusIface->SetPassword(saltPassword(password), QString());
    invocation.waitForFinished();
    if (!invocation.isError()) {
        Q_EMIT passwordSuccessfullyChanged();
    }
}

QDBusObjectPath User::path() const
{
    return mPath;
}

void User::apply()
{
    auto job = new UserApplyJob(m_dbusIface, mName, mEmail, mRealName, mFace.toString().replace("file://", ""), mAdministrator ? 1 : 0);
    connect(job, &UserApplyJob::result, this, [this, job] {
        switch (static_cast<UserApplyJob::Error>(job->error())) {
        case UserApplyJob::Error::PermissionDenied:
            loadData(); // Reload the old data to avoid half transactions
            Q_EMIT applyError(i18n("Could not get permission to save user %1", mName));
            break;
        case UserApplyJob::Error::Failed:
        case UserApplyJob::Error::Unknown:
            loadData(); // Reload the old data to avoid half transactions
            Q_EMIT applyError(i18n("There was an error while saving changes"));
            break;
        case UserApplyJob::Error::NoError:; // Do nothing
        }
    });
    job->start();
}

bool User::usesDefaultWallet()
{
    const QStringList wallets = KWallet::Wallet::walletList();
    return wallets.contains(QStringLiteral("kdewallet"));
}
void User::changeWalletPassword()
{
    KWallet::Wallet::changePassword(QStringLiteral("kdewallet"), 1);
}

bool User::loggedIn() const
{
    return mLoggedIn;
}

UserApplyJob::UserApplyJob(QPointer<OrgFreedesktopAccountsUserInterface> dbusIface, QString name, QString email, QString realname, QString icon, int type)
    : KJob()
    , m_name(name)
    , m_email(email)
    , m_realname(realname)
    , m_icon(icon)
    , m_type(type)
    , m_dbusIface(dbusIface)
{
}

void UserApplyJob::start()
{
    // With our UI the user expects the as a single transaction, but the accountsservice API does not provide that
    // When one of the writes fails, e.g. because the user cancelled the authentication dialog then none of the values should be applied
    // Not all calls trigger an authentication dialog, e.g. SetRealName for the current user does not but SetAccountType does
    // Therefore make a blocking call to SetAccountType first to trigger the auth dialog. If the user declines don't attempt to write anything else
    // This avoids settings any data when the user thinks they aborted the transaction, see https://bugs.kde.org/show_bug.cgi?id=425036
    // Subsequent calls do not trigger the auth dialog again
    auto setAccount = m_dbusIface->SetAccountType(m_type);
    setAccount.waitForFinished();
    if (setAccount.isError()) {
        setError(setAccount.error());
        qCWarning(KCMUSERS) << setAccount.error().name() << setAccount.error().message();
        emitResult();
        return;
    }

    const std::multimap<QString, QDBusPendingReply<> (OrgFreedesktopAccountsUserInterface::*)(const QString &)> set = {
        {m_name, &OrgFreedesktopAccountsUserInterface::SetUserName},
        {m_email, &OrgFreedesktopAccountsUserInterface::SetEmail},
        {m_realname, &OrgFreedesktopAccountsUserInterface::SetRealName},
    };
    for (auto const &x : set) {
        auto resp = (m_dbusIface->*(x.second))(x.first);
        resp.waitForFinished();
        if (resp.isError()) {
            setError(resp.error());
            qCWarning(KCMUSERS) << resp.error().name() << resp.error().message();
            emitResult();
            return;
        }
    }

    // Icon is special, since we want to resize it.
    {
        QImage icon(m_icon);
        // 256dp square is plenty big for an avatar and will definitely be smaller than 1MB
        QImage scaled = icon.scaled(QSize(256, 256), Qt::KeepAspectRatio, Qt::SmoothTransformation);

        QTemporaryFile file;
        if (!file.open()) {
            setErrorText(i18n("Failed to resize image: opening temp file failed"));
            qCWarning(KCMUSERS) << i18n("Failed to resize image: opening temp file failed");
            KJob::setError(static_cast<int>(Error::UserFacing));
            emitResult();
            return;
        }

        if (!scaled.save(&file, "png")) {
            setErrorText(i18n("Failed to resize image: writing to temp file failed"));
            qCWarning(KCMUSERS) << i18n("Failed to resize image: writing to temp file failed");
            KJob::setError(static_cast<int>(Error::UserFacing));
            emitResult();
            return;
        }

        file.close();

        auto resp = m_dbusIface->SetIconFile(file.fileName());

        resp.waitForFinished();
        if (resp.isError()) {
            setError(resp.error());
            qCWarning(KCMUSERS) << resp.error().name() << resp.error().message();
            emitResult();
            return;
        }
    }

    emitResult();
}

void UserApplyJob::setError(const QDBusError &error)
{
    setErrorText(error.message());
    if (error.name() == QLatin1String("org.freedesktop.Accounts.Error.Failed")) {
        KJob::setError(static_cast<int>(Error::Failed));
    } else if (error.name() == QLatin1String("org.freedesktop.Accounts.Error.PermissionDenied")) {
        KJob::setError(static_cast<int>(Error::PermissionDenied));
    } else {
        KJob::setError(static_cast<int>(Error::Unknown));
    }
}