/******************************************************************************
 *   Copyright (C) 2011-2015 Frank Osterfeld <frank.osterfeld@gmail.com>      *
 *                                                                            *
 * This program 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. For licensing and distribution        *
 * details, check the accompanying file 'COPYING'.                            *
 *****************************************************************************/
#include "keychain_p.h"
#include "gnomekeyring_p.h"

#include <QSettings>

#include <QScopedPointer>

using namespace QKeychain;

static QString typeKey( const QString& key )
{
    return QString::fromLatin1( "%1/type" ).arg( key );
}

static QString dataKey( const QString& key )
{
    return QString::fromLatin1( "%1/data" ).arg( key );
}

enum KeyringBackend {
    Backend_GnomeKeyring,
    Backend_Kwallet4,
    Backend_Kwallet5
};

enum DesktopEnvironment {
    DesktopEnv_Gnome,
    DesktopEnv_Kde4,
    DesktopEnv_Plasma5,
    DesktopEnv_Unity,
    DesktopEnv_Xfce,
    DesktopEnv_Other
};

// the following detection algorithm is derived from chromium,
// licensed under BSD, see base/nix/xdg_util.cc

static DesktopEnvironment getKdeVersion() {
    QString value = qgetenv("KDE_SESSION_VERSION");
    if ( value == "5" ) {
        return DesktopEnv_Plasma5;
    } else if (value == "4" ) {
        return DesktopEnv_Kde4;
    } else {
        // most likely KDE3
        return DesktopEnv_Other;
    }
}

static DesktopEnvironment detectDesktopEnvironment() {
    QByteArray xdgCurrentDesktop = qgetenv("XDG_CURRENT_DESKTOP");
    if ( xdgCurrentDesktop == "GNOME" ) {
        return DesktopEnv_Gnome;
    } else if ( xdgCurrentDesktop == "Unity" ) {
        return DesktopEnv_Unity;
    } else if ( xdgCurrentDesktop == "KDE" ) {
        return getKdeVersion();
    }

    QByteArray desktopSession = qgetenv("DESKTOP_SESSION");
    if ( desktopSession == "gnome" ) {
        return DesktopEnv_Gnome;
    } else if ( desktopSession == "kde" ) {
        return getKdeVersion();
    } else if ( desktopSession == "kde4" ) {
        return DesktopEnv_Kde4;
    } else if ( desktopSession.contains("xfce") || desktopSession == "xubuntu" ) {
        return DesktopEnv_Xfce;
    }

    if ( !qgetenv("GNOME_DESKTOP_SESSION_ID").isEmpty() ) {
        return DesktopEnv_Gnome;
    } else if ( !qgetenv("KDE_FULL_SESSION").isEmpty() ) {
        return getKdeVersion();
    }

    return DesktopEnv_Other;
}

static KeyringBackend detectKeyringBackend()
{
    switch (detectDesktopEnvironment()) {
    case DesktopEnv_Kde4:
        return Backend_Kwallet4;
        break;
    case DesktopEnv_Plasma5:
        return Backend_Kwallet5;
        break;
    // fall through
    case DesktopEnv_Gnome:
    case DesktopEnv_Unity:
    case DesktopEnv_Xfce:
    case DesktopEnv_Other:
    default:
        if ( GnomeKeyring::isAvailable() ) {
            return Backend_GnomeKeyring;
        } else {
            return Backend_Kwallet4;
        }
    }

}

static KeyringBackend getKeyringBackend()
{
    static KeyringBackend backend = detectKeyringBackend();
    return backend;
}

static void kwalletReadPasswordScheduledStartImpl(const char * service, const char * path, ReadPasswordJobPrivate * priv) {
    if ( QDBusConnection::sessionBus().isConnected() )
    {
        priv->iface = new org::kde::KWallet( QLatin1String(service), QLatin1String(path), QDBusConnection::sessionBus(), priv );
        const QDBusPendingReply<QString> reply = priv->iface->networkWallet();
        QDBusPendingCallWatcher* watcher = new QDBusPendingCallWatcher( reply, priv );
        priv->connect( watcher, SIGNAL(finished(QDBusPendingCallWatcher*)), priv, SLOT(kwalletWalletFound(QDBusPendingCallWatcher*)) );
    }
    else
    {
    // D-Bus is not reachable so none can tell us something about KWalletd
        QDBusError err( QDBusError::NoServer, ReadPasswordJobPrivate::tr("D-Bus is not running") );
        priv->fallbackOnError( err );
    }
}

void ReadPasswordJobPrivate::scheduledStart() {
    switch ( getKeyringBackend() ) {
    case Backend_GnomeKeyring:
        if ( !GnomeKeyring::find_network_password( key.toUtf8().constData(), q->service().toUtf8().constData(),
                                                   reinterpret_cast<GnomeKeyring::OperationGetStringCallback>( &ReadPasswordJobPrivate::gnomeKeyring_cb ),
                                                   this, 0 ) )
            q->emitFinishedWithError( OtherError, tr("Unknown error") );
        break;

    case Backend_Kwallet4:
        kwalletReadPasswordScheduledStartImpl("org.kde.kwalletd", "/modules/kwalletd", this);
        break;
    case Backend_Kwallet5:
        kwalletReadPasswordScheduledStartImpl("org.kde.kwalletd5", "/modules/kwalletd5", this);
        break;
    }
}

void ReadPasswordJobPrivate::kwalletWalletFound(QDBusPendingCallWatcher *watcher)
{
    watcher->deleteLater();
    const QDBusPendingReply<QString> reply = *watcher;
    const QDBusPendingReply<int> pendingReply = iface->open( reply.value(), 0, q->service() );
    QDBusPendingCallWatcher* pendingWatcher = new QDBusPendingCallWatcher( pendingReply, this );
    connect( pendingWatcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this, SLOT(kwalletOpenFinished(QDBusPendingCallWatcher*)) );
}

static QPair<Error, QString> mapGnomeKeyringError( int result )
{
    Q_ASSERT( result != GnomeKeyring::RESULT_OK );

    switch ( result ) {
    case GnomeKeyring::RESULT_DENIED:
        return qMakePair( AccessDenied, QObject::tr("Access to keychain denied") );
    case GnomeKeyring::RESULT_NO_KEYRING_DAEMON:
        return qMakePair( NoBackendAvailable, QObject::tr("No keyring daemon") );
    case GnomeKeyring::RESULT_ALREADY_UNLOCKED:
        return qMakePair( OtherError, QObject::tr("Already unlocked") );
    case GnomeKeyring::RESULT_NO_SUCH_KEYRING:
        return qMakePair( OtherError, QObject::tr("No such keyring") );
    case GnomeKeyring::RESULT_BAD_ARGUMENTS:
        return qMakePair( OtherError, QObject::tr("Bad arguments") );
    case GnomeKeyring::RESULT_IO_ERROR:
        return qMakePair( OtherError, QObject::tr("I/O error") );
    case GnomeKeyring::RESULT_CANCELLED:
        return qMakePair( OtherError, QObject::tr("Cancelled") );
    case GnomeKeyring::RESULT_KEYRING_ALREADY_EXISTS:
        return qMakePair( OtherError, QObject::tr("Keyring already exists") );
    case GnomeKeyring::RESULT_NO_MATCH:
        return qMakePair(  EntryNotFound, QObject::tr("No match") );
    default:
        break;
    }

    return qMakePair( OtherError, QObject::tr("Unknown error") );
}

void ReadPasswordJobPrivate::gnomeKeyring_cb( int result, const char* string, ReadPasswordJobPrivate* self )
{
    if ( result == GnomeKeyring::RESULT_OK ) {
        if ( self->dataType == ReadPasswordJobPrivate::Text )
            self->data = string;
        else
            self->data = QByteArray::fromBase64( string );
        self->q->emitFinished();
    } else {
        const QPair<Error, QString> errorResult = mapGnomeKeyringError( result );
        self->q->emitFinishedWithError( errorResult.first, errorResult.second );
    }
}

void ReadPasswordJobPrivate::fallbackOnError(const QDBusError& err )
{
    QScopedPointer<QSettings> local( !q->settings() ? new QSettings( q->service() ) : 0 );
    QSettings* actual = q->settings() ? q->settings() : local.data();

    if ( q->insecureFallback() && actual->contains( dataKey( key ) ) ) {

        const WritePasswordJobPrivate::Mode mode = WritePasswordJobPrivate::stringToMode( actual->value( typeKey( key ) ).toString() );
        if (mode == WritePasswordJobPrivate::Binary)
           dataType = Binary;
        else
            dataType = Text;
        data = actual->value( dataKey( key ) ).toByteArray();

        q->emitFinished();
    } else {
        if ( err.type() == QDBusError::ServiceUnknown ) //KWalletd not running
            q->emitFinishedWithError( NoBackendAvailable, tr("No keychain service available") );
        else
            q->emitFinishedWithError( OtherError, tr("Could not open wallet: %1; %2").arg( QDBusError::errorString( err.type() ), err.message() ) );
    }
}

void ReadPasswordJobPrivate::kwalletOpenFinished( QDBusPendingCallWatcher* watcher ) {
    watcher->deleteLater();
    const QDBusPendingReply<int> reply = *watcher;

    QScopedPointer<QSettings> local( !q->settings() ? new QSettings( q->service() ) : 0 );
    QSettings* actual = q->settings() ? q->settings() : local.data();

    if ( reply.isError() ) {
        fallbackOnError( reply.error() );
        return;
    }

    if ( actual->contains( dataKey( key ) ) ) {
        // We previously stored data in the insecure QSettings, but now have KWallet available.
        // Do the migration

        data = actual->value( dataKey( key ) ).toByteArray();
        const WritePasswordJobPrivate::Mode mode = WritePasswordJobPrivate::stringToMode( actual->value( typeKey( key ) ).toString() );
        actual->remove( key );

        q->emitFinished();


        WritePasswordJob* j = new WritePasswordJob( q->service(), 0 );
        j->setSettings( q->settings() );
        j->setKey( key );
        j->setAutoDelete( true );
        if ( mode == WritePasswordJobPrivate::Binary )
            j->setBinaryData( data );
        else if ( mode == WritePasswordJobPrivate::Text )
            j->setTextData( QString::fromUtf8( data ) );
        else
            Q_ASSERT( false );

        j->start();

        return;
    }

    walletHandle = reply.value();

    if ( walletHandle < 0 ) {
        q->emitFinishedWithError( AccessDenied, tr("Access to keychain denied") );
        return;
    }

    const QDBusPendingReply<int> nextReply = iface->entryType( walletHandle, q->service(), key, q->service() );
    QDBusPendingCallWatcher* nextWatcher = new QDBusPendingCallWatcher( nextReply, this );
    connect( nextWatcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this, SLOT(kwalletEntryTypeFinished(QDBusPendingCallWatcher*)) );
}

//Must be in sync with KWallet::EntryType (kwallet.h)
enum KWalletEntryType {
    Unknown=0,
    Password,
    Stream,
    Map
};

void ReadPasswordJobPrivate::kwalletEntryTypeFinished( QDBusPendingCallWatcher* watcher ) {
    watcher->deleteLater();
    if ( watcher->isError() ) {
        const QDBusError err = watcher->error();
        q->emitFinishedWithError( OtherError, tr("Could not determine data type: %1; %2").arg( QDBusError::errorString( err.type() ), err.message() ) );
        return;
    }

    const QDBusPendingReply<int> reply = *watcher;
    const int value = reply.value();

    switch ( value ) {
    case Unknown:
        q->emitFinishedWithError( EntryNotFound, tr("Entry not found") );
        return;
    case Password:
        dataType = Text;
        break;
    case Stream:
        dataType = Binary;
        break;
    case Map:
        q->emitFinishedWithError( EntryNotFound, tr("Unsupported entry type 'Map'") );
        return;
    default:
        q->emitFinishedWithError( OtherError, tr("Unknown kwallet entry type '%1'").arg( value ) );
        return;
    }

    const QDBusPendingCall nextReply = dataType == Text
        ? QDBusPendingCall( iface->readPassword( walletHandle, q->service(), key, q->service() ) )
        : QDBusPendingCall( iface->readEntry( walletHandle, q->service(), key, q->service() ) );
    QDBusPendingCallWatcher* nextWatcher = new QDBusPendingCallWatcher( nextReply, this );
    connect( nextWatcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this, SLOT(kwalletReadFinished(QDBusPendingCallWatcher*)) );
}

void ReadPasswordJobPrivate::kwalletReadFinished( QDBusPendingCallWatcher* watcher ) {
    watcher->deleteLater();
    if ( watcher->isError() ) {
        const QDBusError err = watcher->error();
        q->emitFinishedWithError( OtherError, tr("Could not read password: %1; %2").arg( QDBusError::errorString( err.type() ), err.message() ) );
        return;
    }

    if ( dataType == Binary ) {
        QDBusPendingReply<QByteArray> reply = *watcher;
        data = reply.value();
    } else {
        QDBusPendingReply<QString> reply = *watcher;
        data = reply.value().toUtf8();
    }
    q->emitFinished();
}

static void kwalletWritePasswordScheduledStart( const char * service, const char * path, WritePasswordJobPrivate * priv ) {
    if ( QDBusConnection::sessionBus().isConnected() )
    {
        priv->iface = new org::kde::KWallet( QLatin1String(service), QLatin1String(path), QDBusConnection::sessionBus(), priv );
        const QDBusPendingReply<QString> reply = priv->iface->networkWallet();
        QDBusPendingCallWatcher* watcher = new QDBusPendingCallWatcher( reply, priv );
        priv->connect( watcher, SIGNAL(finished(QDBusPendingCallWatcher*)), priv, SLOT(kwalletWalletFound(QDBusPendingCallWatcher*)) );
    }
    else
    {
        // D-Bus is not reachable so none can tell us something about KWalletd
        QDBusError err( QDBusError::NoServer, WritePasswordJobPrivate::tr("D-Bus is not running") );
        priv->fallbackOnError( err );
    }
}

void WritePasswordJobPrivate::scheduledStart() {
    switch ( getKeyringBackend() ) {
    case Backend_GnomeKeyring:
        if ( mode == WritePasswordJobPrivate::Delete ) {
            if ( !GnomeKeyring::delete_network_password( key.toUtf8().constData(), q->service().toUtf8().constData(),
                                                         reinterpret_cast<GnomeKeyring::OperationDoneCallback>( &WritePasswordJobPrivate::gnomeKeyring_cb ),
                                                         this, 0 ) )
                q->emitFinishedWithError( OtherError, tr("Unknown error") );
        } else {
            QByteArray password = mode == WritePasswordJobPrivate::Text ? textData.toUtf8() : binaryData.toBase64();
            QByteArray service = q->service().toUtf8();
            if ( !GnomeKeyring::store_network_password( GnomeKeyring::GNOME_KEYRING_DEFAULT, service.constData(),
                                                        key.toUtf8().constData(), service.constData(), password.constData(),
                                                        reinterpret_cast<GnomeKeyring::OperationDoneCallback>( &WritePasswordJobPrivate::gnomeKeyring_cb ),
                                                        this, 0 ) )
                q->emitFinishedWithError( OtherError, tr("Unknown error") );
        }
        break;

    case Backend_Kwallet4:
        kwalletWritePasswordScheduledStart("org.kde.kwalletd", "/modules/kwalletd", this);
        break;
    case Backend_Kwallet5:
        kwalletWritePasswordScheduledStart("org.kde.kwalletd5", "/modules/kwalletd5", this);
        break;
    }
}

QString WritePasswordJobPrivate::modeToString(Mode m)
{
    switch (m) {
    case Delete:
        return QLatin1String("Delete");
    case Text:
        return QLatin1String("Text");
    case Binary:
        return QLatin1String("Binary");
    }

    Q_ASSERT_X(false, Q_FUNC_INFO, "Unhandled Mode value");
    return QString();
}

WritePasswordJobPrivate::Mode WritePasswordJobPrivate::stringToMode(const QString& s)
{
    if (s == QLatin1String("Delete") || s == QLatin1String("0"))
        return Delete;
    if (s == QLatin1String("Text") || s == QLatin1String("1"))
        return Text;
    if (s == QLatin1String("Binary") || s == QLatin1String("2"))
        return Binary;

    qCritical("Unexpected mode string '%s'", qPrintable(s));

    return Text;
}

void WritePasswordJobPrivate::fallbackOnError(const QDBusError &err)
{
    QScopedPointer<QSettings> local( !q->settings() ? new QSettings( q->service() ) : 0 );
    QSettings* actual = q->settings() ? q->settings() : local.data();

    if ( !q->insecureFallback() ) {
        q->emitFinishedWithError( OtherError, tr("Could not open wallet: %1; %2").arg( QDBusError::errorString( err.type() ), err.message() ) );
        return;
    }

    if ( mode == Delete ) {
        actual->remove( key );
        actual->sync();

        q->emitFinished();
        return;
   }

    actual->setValue( QString::fromLatin1( "%1/type" ).arg( key ), mode );
    if ( mode == Text )
        actual->setValue( QString::fromLatin1( "%1/data" ).arg( key ), textData.toUtf8() );
    else if ( mode == Binary )
        actual->setValue( QString::fromLatin1( "%1/data" ).arg( key ), binaryData );
    actual->sync();

    q->emitFinished();
}

void WritePasswordJobPrivate::gnomeKeyring_cb( int result, WritePasswordJobPrivate* self )
{
    if ( result == GnomeKeyring::RESULT_OK ) {
        self->q->emitFinished();
    } else {
        const QPair<Error, QString> errorResult = mapGnomeKeyringError( result );
        self->q->emitFinishedWithError( errorResult.first, errorResult.second );
    }
}

void WritePasswordJobPrivate::kwalletWalletFound(QDBusPendingCallWatcher *watcher)
{
    watcher->deleteLater();
    const QDBusPendingReply<QString> reply = *watcher;
    const QDBusPendingReply<int> pendingReply = iface->open( reply.value(), 0, q->service() );
    QDBusPendingCallWatcher* pendingWatcher = new QDBusPendingCallWatcher( pendingReply, this );
    connect( pendingWatcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this, SLOT(kwalletOpenFinished(QDBusPendingCallWatcher*)) );
}

void WritePasswordJobPrivate::kwalletOpenFinished( QDBusPendingCallWatcher* watcher ) {
    watcher->deleteLater();
    QDBusPendingReply<int> reply = *watcher;

    QScopedPointer<QSettings> local( !q->settings() ? new QSettings( q->service() ) : 0 );
    QSettings* actual = q->settings() ? q->settings() : local.data();

    if ( reply.isError() ) {
        fallbackOnError( reply.error() );
        return;
    }

    if ( actual->contains( key ) )
    {
        // If we had previously written to QSettings, but we now have a kwallet available, migrate and delete old insecure data
        actual->remove( key );
        actual->sync();
    }

    const int handle = reply.value();

    if ( handle < 0 ) {
        q->emitFinishedWithError( AccessDenied, tr("Access to keychain denied") );
        return;
    }

    QDBusPendingReply<int> nextReply;

    if ( !textData.isEmpty() )
        nextReply = iface->writePassword( handle, q->service(), key, textData, q->service() );
    else if ( !binaryData.isEmpty() )
        nextReply = iface->writeEntry( handle, q->service(), key, binaryData, q->service() );
    else
        nextReply = iface->removeEntry( handle, q->service(), key, q->service() );

    QDBusPendingCallWatcher* nextWatcher = new QDBusPendingCallWatcher( nextReply, this );
    connect( nextWatcher, SIGNAL(finished(QDBusPendingCallWatcher*)), this, SLOT(kwalletWriteFinished(QDBusPendingCallWatcher*)) );
}

void WritePasswordJobPrivate::kwalletWriteFinished( QDBusPendingCallWatcher* watcher ) {
    watcher->deleteLater();
    QDBusPendingReply<int> reply = *watcher;
    if ( reply.isError() ) {
        const QDBusError err = reply.error();
        q->emitFinishedWithError( OtherError, tr("Could not open wallet: %1; %2").arg( QDBusError::errorString( err.type() ), err.message() ) );
        return;
    }

    q->emitFinished();
}