kamail.cpp

/*
 *  kamail.cpp  -  email functions
 *  Program:  kalarm
 *  Copyright © 2002-2011 by David Jarvie <djarvie@kde.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "kalarm.h"   //krazy:exclude=includes (kalarm.h must be first)
#include "kamail.h"

#include "functions.h"
#include "kalarmapp.h"
#include "mainwindow.h"
#include "messagebox.h"
#include "preferences.h"

#include <kalarmcal/identities.h>
#include <KIdentityManagement/kidentitymanagement/identitymanager.h>
#include <KIdentityManagement/kidentitymanagement/identity.h>
#include <MailTransport/mailtransport/transportmanager.h>
#include <MailTransport/mailtransport/transport.h>
#include <MailTransport/mailtransport/messagequeuejob.h>
#include <KCalCore/Person>
#include <kmime/kmime_header_parsing.h>
#include <kmime/kmime_headers.h>
#include <kmime/kmime_message.h>

#include <KEmailAddress>
#include <K4AboutData>
#include <KLocale>
#include <KUrl>
#include <KLocalizedString>
#include <kfileitem.h>
#include <kio/netaccess.h>
#include <kemailsettings.h>
#include <kcodecs.h>
#include <kcharsets.h>

#include <QFile>
#include <QHostInfo>
#include <QList>
#include <QByteArray>
#include <QTextCodec>
#include <QStandardPaths>
#include <QtDBus/QtDBus>
#include "kalarm_debug.h"

#include <pwd.h>

#include "kmailinterface.h"

static const QLatin1String KMAIL_DBUS_SERVICE("org.kde.kmail");
//static const QLatin1String KMAIL_DBUS_PATH("/KMail");

namespace HeaderParsing
{
bool parseAddress( const char* & scursor, const char * const send,
                   KMime::Types::Address & result, bool isCRLF=false );
}

static void initHeaders(KMime::Message&, KAMail::JobData&);
static KMime::Types::Mailbox::List parseAddresses(const QString& text, QString& invalidItem);
static QString     extractEmailAndNormalize(const QString& emailAddress);
static QStringList extractEmailsAndNormalize(const QString& emailAddresses);
static QByteArray autoDetectCharset(const QString& text);
static const QTextCodec* codecForName(const QByteArray& str);

QString KAMail::i18n_NeedFromEmailAddress()
{ return i18nc("@info", "A 'From' email address must be configured in order to execute email alarms."); }

QString KAMail::i18n_sent_mail()
{ return i18nc("@info KMail folder name: this should be translated the same as in kmail", "sent-mail"); }

KAMail*                              KAMail::mInstance = Q_NULLPTR;   // used only to enable signals/slots to work
QQueue<MailTransport::MessageQueueJob*> KAMail::mJobs;
QQueue<KAMail::JobData>                 KAMail::mJobData;

KAMail* KAMail::instance()
{
    if (!mInstance)
        mInstance = new KAMail();
    return mInstance;
}

/******************************************************************************
* Send the email message specified in an event.
* Reply = 1 if the message was sent - 'errmsgs' may contain copy error messages.
*       = 0 if the message is queued for sending.
*       = -1 if the message was not sent - 'errmsgs' contains the error messages.
*/
int KAMail::send(JobData& jobdata, QStringList& errmsgs)
{
    QString err;
    KIdentityManagement::Identity identity;
    if (!jobdata.event.emailFromId())
        jobdata.from = Preferences::emailAddress();
    else
    {
        identity = Identities::identityManager()->identityForUoid(jobdata.event.emailFromId());
        if (identity.isNull())
        {
            qCCritical(KALARM_LOG) << "Identity" << jobdata.event.emailFromId() << "not found";
            errmsgs = errors(xi18nc("@info", "Invalid 'From' email address.<nl/>Email identity <resource>%1</resource> not found", jobdata.event.emailFromId()));
            return -1;
        }
        if (identity.primaryEmailAddress().isEmpty())
        {
            qCCritical(KALARM_LOG) << "Identity" << identity.identityName() << "uoid" << identity.uoid() << ": no email address";
            errmsgs = errors(xi18nc("@info", "Invalid 'From' email address.<nl/>Email identity <resource>%1</resource> has no email address", identity.identityName()));
            return -1;
        }
        jobdata.from = identity.fullEmailAddr();
    }
    if (jobdata.from.isEmpty())
    {
        switch (Preferences::emailFrom())
        {
            case Preferences::MAIL_FROM_KMAIL:
                errmsgs = errors(xi18nc("@info", "<para>No 'From' email address is configured (no default email identity found)</para>"
                                                "<para>Please set it in <application>KMail</application> or in the <application>KAlarm</application> Configuration dialog.</para>"));
                break;
            case Preferences::MAIL_FROM_SYS_SETTINGS:
                errmsgs = errors(xi18nc("@info", "<para>No 'From' email address is configured.</para>"
                                                "<para>Please set it in the KDE System Settings or in the <application>KAlarm</application> Configuration dialog.</para>"));
                break;
            case Preferences::MAIL_FROM_ADDR:
            default:
                errmsgs = errors(xi18nc("@info", "<para>No 'From' email address is configured.</para>"
                                                "<para>Please set it in the <application>KAlarm</application> Configuration dialog.</para>"));
                break;
        }
        return -1;
    }
    jobdata.bcc  = (jobdata.event.emailBcc() ? Preferences::emailBccAddress() : QString());
    qCDebug(KALARM_LOG) << "To:" << jobdata.event.emailAddresses(QStringLiteral(","))
                  << endl << "Subject:" << jobdata.event.emailSubject();

    MailTransport::TransportManager* manager = MailTransport::TransportManager::self();
    MailTransport::Transport* transport = Q_NULLPTR;
#warning Remove sendmail support!
#if 0
    if (Preferences::emailClient() == Preferences::sendmail)
    {
        qCDebug(KALARM_LOG) << "Sending via sendmail";
        const QList<MailTransport::Transport*> transports = manager->transports();
        for (int i = 0, count = transports.count();  i < count;  ++i)
        {
            if (transports[i]->type() == MailTransport::Transport::EnumType::Sendmail)
            {
                // Use the first sendmail transport found
                transport = transports[i];
                break;
            }
        }
        if (!transport)
        {
            QStringList paths;
            paths << QStringLiteral("/sbin") << QStringLiteral("/usr/sbin") << QStringLiteral("/usr/lib");
            QString command = QStandardPaths::findExecutable(QStringLiteral("sendmail"), paths);
            transport = manager->createTransport();
            transport->setName(QStringLiteral("sendmail"));
            transport->setType(MailTransport::Transport::EnumType::Sendmail);
            transport->setHost(command);
            transport->setRequiresAuthentication(false);
            transport->setStorePassword(false);
            manager->addTransport(transport);
            transport->save();
            qCDebug(KALARM_LOG) << "Creating sendmail transport, id=" << transport->id();
        }
    }
    else
#endif
    {
        qCDebug(KALARM_LOG) << "Sending via KDE";
        const int transportId = identity.transport().isEmpty() ? -1 : identity.transport().toInt();
        transport = manager->transportById(transportId, true);
        if (!transport)
        {
            qCCritical(KALARM_LOG) << "No mail transport found for identity" << identity.identityName() << "uoid" << identity.uoid();
            errmsgs = errors(xi18nc("@info", "No mail transport configured for email identity <resource>%1</resource>", identity.identityName()));
            return -1;
        }
    }
    qCDebug(KALARM_LOG) << "Using transport" << transport->name() << ", id=" << transport->id();

    KMime::Message::Ptr message = KMime::Message::Ptr(new KMime::Message);
    initHeaders(*message, jobdata);
    err = appendBodyAttachments(*message, jobdata);
    if (!err.isNull())
    {
        qCCritical(KALARM_LOG) << "Error compiling message:" << err;
        errmsgs = errors(err);
        return -1;
    }

    MailTransport::MessageQueueJob* mailjob = new MailTransport::MessageQueueJob(kapp);
    mailjob->setMessage(message);
    mailjob->transportAttribute().setTransportId(transport->id());
    // MessageQueueJob email addresses must be pure, i.e. without display name. Note
    // that display names are included in the actual headers set up by initHeaders().
    mailjob->addressAttribute().setFrom(extractEmailAndNormalize(jobdata.from));
    mailjob->addressAttribute().setTo(extractEmailsAndNormalize(jobdata.event.emailAddresses(QStringLiteral(","))));
    if (!jobdata.bcc.isEmpty())
        mailjob->addressAttribute().setBcc(extractEmailsAndNormalize(jobdata.bcc));
    MailTransport::SentBehaviourAttribute::SentBehaviour sentAction =
                         (Preferences::emailClient() == Preferences::kmail || Preferences::emailCopyToKMail())
                         ? MailTransport::SentBehaviourAttribute::MoveToDefaultSentCollection : MailTransport::SentBehaviourAttribute::Delete;
    mailjob->sentBehaviourAttribute().setSentBehaviour(sentAction);
    mJobs.enqueue(mailjob);
    mJobData.enqueue(jobdata);
    if (mJobs.count() == 1)
    {
        // There are no jobs already active or queued, so send now
        connect(mailjob, SIGNAL(result(KJob*)), instance(), SLOT(slotEmailSent(KJob*)));
        mailjob->start();
    }
    return 0;
}

/******************************************************************************
* Called when sending an email is complete.
*/
void KAMail::slotEmailSent(KJob* job)
{
    bool copyerr = false;
    QStringList errmsgs;
    if (job->error())
    {
        qCCritical(KALARM_LOG) << "Failed:" << job->errorString();
        errmsgs = errors(job->errorString(), SEND_ERROR);
    }
    JobData jobdata;
    if (mJobs.isEmpty()  ||  mJobData.isEmpty()  ||  job != mJobs.head())
    {
        // The queue has been corrupted, so we can't locate the job's data
        qCCritical(KALARM_LOG) << "Wrong job at head of queue: wiping queue";
        mJobs.clear();
        mJobData.clear();
        if (!errmsgs.isEmpty())
            theApp()->emailSent(jobdata, errmsgs);
        errmsgs.clear();
        errmsgs += i18nc("@info", "Emails may not have been sent");
        errmsgs += i18nc("@info", "Program error");
        theApp()->emailSent(jobdata, errmsgs);
        return;
    }
    mJobs.dequeue();
    jobdata = mJobData.dequeue();
    if (jobdata.allowNotify)
        notifyQueued(jobdata.event);
    theApp()->emailSent(jobdata, errmsgs, copyerr);
    if (!mJobs.isEmpty())
    {
        // Send the next queued email
        connect(mJobs.head(), SIGNAL(result(KJob*)), instance(), SLOT(slotEmailSent(KJob*)));
        mJobs.head()->start();
    }
}

/******************************************************************************
* Create the headers part of the email.
*/
void initHeaders(KMime::Message& message, KAMail::JobData& data)
{
    KMime::Headers::Date* date = new KMime::Headers::Date;
//QT5 port it
    date->setDateTime(QDateTime::currentDateTime(/*Preferences::timeZone()*/));
    message.setHeader(date);

    KMime::Headers::From* from = new KMime::Headers::From;
    from->fromUnicodeString(data.from, autoDetectCharset(data.from));
    message.setHeader(from);

    KMime::Headers::To* to = new KMime::Headers::To;
    KCalCore::Person::List toList = data.event.emailAddressees();
    for (int i = 0, count = toList.count();  i < count;  ++i)
        to->addAddress(toList[i]->email().toLatin1(), toList[i]->name());
    message.setHeader(to);

    if (!data.bcc.isEmpty())
    {
        KMime::Headers::Bcc* bcc = new KMime::Headers::Bcc;
        bcc->fromUnicodeString(data.bcc, autoDetectCharset(data.bcc));
        message.setHeader(bcc);
    }

    KMime::Headers::Subject* subject = new KMime::Headers::Subject;
    QString str = data.event.emailSubject();
    subject->fromUnicodeString(str, autoDetectCharset(str));
    message.setHeader(subject);

    KMime::Headers::UserAgent* agent = new KMime::Headers::UserAgent;
    agent->fromUnicodeString(KComponentData::mainComponent().aboutData()->programName() + QLatin1String("/" KALARM_VERSION), "us-ascii");
    message.setHeader(agent);

    KMime::Headers::MessageID* id = new KMime::Headers::MessageID;
    id->generate(data.from.mid(data.from.indexOf(QLatin1Char('@')) + 1).toLatin1());
    message.setHeader(id);
}

/******************************************************************************
* Append the body and attachments to the email text.
* Reply = reason for error
*       = empty string if successful.
*/
QString KAMail::appendBodyAttachments(KMime::Message& message, JobData& data)
{
    QStringList attachments = data.event.emailAttachments();
    if (!attachments.count())
    {
        // There are no attachments, so simply append the message body
        message.contentType()->setMimeType("text/plain");
        message.contentType()->setCharset("utf-8");
        message.fromUnicodeString(data.event.message());
        auto encodings = KMime::encodingsForData(message.body());
        encodings.removeAll(KMime::Headers::CE8Bit);  // not handled by KMime
        message.contentTransferEncoding()->setEncoding(encodings[0]);
        message.assemble();
    }
    else
    {
        // There are attachments, so the message must be in MIME format
        message.contentType()->setMimeType("multipart/mixed");
        message.contentType()->setBoundary(KMime::multiPartBoundary());

        if (!data.event.message().isEmpty())
        {
            // There is a message body
            KMime::Content* content = new KMime::Content();
            content->contentType()->setMimeType("text/plain");
            content->contentType()->setCharset("utf-8");
            content->fromUnicodeString(data.event.message());
            auto encodings = KMime::encodingsForData(content->body());
            encodings.removeAll(KMime::Headers::CE8Bit);  // not handled by KMime
            content->contentTransferEncoding()->setEncoding(encodings[0]);
            content->assemble();
            message.addContent(content);
        }

        // Append each attachment in turn
        for (QStringList::Iterator at = attachments.begin();  at != attachments.end();  ++at)
        {
            QString attachment = QString::fromLatin1((*at).toLocal8Bit());
            KUrl url(attachment);
            QString attachError = xi18nc("@info", "Error attaching file: <filename>%1</filename>", attachment);
            url.cleanPath();
            KIO::UDSEntry uds;
            if (!KIO::NetAccess::stat(url, uds, MainWindow::mainMainWindow()))
            {
                qCCritical(KALARM_LOG) << "Not found:" << attachment;
                return xi18nc("@info", "Attachment not found: <filename>%1</filename>", attachment);
            }
            KFileItem fi(uds, url);
            if (fi.isDir()  ||  !fi.isReadable())
            {
                qCCritical(KALARM_LOG) << "Not file/not readable:" << attachment;
                return attachError;
            }

            // Read the file contents
            QString tmpFile;
            if (!KIO::NetAccess::download(url, tmpFile, MainWindow::mainMainWindow()))
            {
                qCCritical(KALARM_LOG) << "Load failure:" << attachment;
                return attachError;
            }
            QFile file(tmpFile);
            if (!file.open(QIODevice::ReadOnly))
            {
                qCDebug(KALARM_LOG) << "tmp load error:" << attachment;
                return attachError;
            }
            qint64 size = file.size();
            QByteArray contents = file.readAll();
            file.close();
            bool atterror = false;
            if (contents.size() < size)
            {
                qCDebug(KALARM_LOG) << "Read error:" << attachment;
                atterror = true;
            }

            QByteArray coded = KCodecs::base64Encode(contents, true);
            KMime::Content* content = new KMime::Content();
            content->setBody(coded + "\n\n");

            // Set the content type
            QMimeDatabase mimeDb;
            QString typeName = mimeDb.mimeTypeForUrl(url).name();
            KMime::Headers::ContentType* ctype = new KMime::Headers::ContentType;
            ctype->fromUnicodeString(typeName, autoDetectCharset(typeName));
            ctype->setName(attachment, "local");
            content->setHeader(ctype);

            // Set the encoding
            KMime::Headers::ContentTransferEncoding* cte = new KMime::Headers::ContentTransferEncoding;
            cte->setEncoding(KMime::Headers::CEbase64);
            cte->setDecoded(false);
            content->setHeader(cte);
            content->assemble();
            message.addContent(content);
            if (atterror)
                return attachError;
        }
        message.assemble();
    }
    return QString();
}

/******************************************************************************
* If any of the destination email addresses are non-local, display a
* notification message saying that an email has been queued for sending.
*/
void KAMail::notifyQueued(const KAEvent& event)
{
    KMime::Types::Address addr;
    const QString localhost = QStringLiteral("localhost");
    const QString hostname  = QHostInfo::localHostName();
    KCalCore::Person::List addresses = event.emailAddressees();
    for (int i = 0, end = addresses.count();  i < end;  ++i)
    {
        QByteArray email = addresses[i]->email().toLocal8Bit();
        const char* em = email;
        if (!email.isEmpty()
        &&  HeaderParsing::parseAddress(em, em + email.length(), addr))
        {
            QString domain = addr.mailboxList.at(0).addrSpec().domain;
            if (!domain.isEmpty()  &&  domain != localhost  &&  domain != hostname)
            {
                KAMessageBox::information(MainWindow::mainMainWindow(), i18nc("@info", "An email has been queued to be sent"), QString(), Preferences::EMAIL_QUEUED_NOTIFY);
                return;
            }
        }
    }
}

/******************************************************************************
* Fetch the user's email address configured in the KDE System Settings.
*/
QString KAMail::controlCentreAddress()
{
    KEMailSettings e;
    return e.getSetting(KEMailSettings::EmailAddress);
}

/******************************************************************************
* Parse a list of email addresses, optionally containing display names,
* entered by the user.
* Reply = the invalid item if error, else empty string.
*/
QString KAMail::convertAddresses(const QString& items, KCalCore::Person::List& list)
{
    list.clear();
    QString invalidItem;
    const KMime::Types::Mailbox::List mailboxes = parseAddresses(items, invalidItem);
    if (!invalidItem.isEmpty())
        return invalidItem;
    for (int i = 0, count = mailboxes.count();  i < count;  ++i)
    {
        KCalCore::Person::Ptr person(new KCalCore::Person(mailboxes[i].name(), mailboxes[i].addrSpec().asString()));
        list += person;
    }
    return QString();
}

/******************************************************************************
* Check the validity of an email address.
* Because internal email addresses don't have to abide by the usual internet
* email address rules, only some basic checks are made.
* Reply = 1 if alright, 0 if empty, -1 if error.
*/
int KAMail::checkAddress(QString& address)
{
    address = address.trimmed();
    // Check that there are no list separator characters present
    if (address.indexOf(QLatin1Char(',')) >= 0  ||  address.indexOf(QLatin1Char(';')) >= 0)
        return -1;
    int n = address.length();
    if (!n)
        return 0;
    int start = 0;
    int end   = n - 1;
    if (address[end] == QLatin1Char('>'))
    {
        // The email address is in <...>
        if ((start = address.indexOf(QLatin1Char('<'))) < 0)
            return -1;
        ++start;
        --end;
    }
    int i = address.indexOf(QLatin1Char('@'), start);
    if (i >= 0)
    {
        if (i == start  ||  i == end)          // check @ isn't the first or last character
//        ||  address.indexOf(QLatin1Char('@'), i + 1) >= 0)    // check for multiple @ characters
            return -1;
    }
/*    else
    {
        // Allow the @ character to be missing if it's a local user
        if (!getpwnam(address.mid(start, end - start + 1).toLocal8Bit()))
            return false;
    }
    for (int i = start;  i <= end;  ++i)
    {
        char ch = address[i].toLatin1();
        if (ch == '.'  ||  ch == '@'  ||  ch == '-'  ||  ch == '_'
        ||  (ch >= 'A' && ch <= 'Z')  ||  (ch >= 'a' && ch <= 'z')
        ||  (ch >= '0' && ch <= '9'))
            continue;
        return false;
    }*/
    return 1;
}

/******************************************************************************
* Convert a comma or semicolon delimited list of attachments into a
* QStringList. The items are checked for validity.
* Reply = the invalid item if error, else empty string.
*/
QString KAMail::convertAttachments(const QString& items, QStringList& list)
{
    KUrl url;
    list.clear();
    int length = items.length();
    for (int next = 0;  next < length;  )
    {
        // Find the first delimiter character (, or ;)
        int i = items.indexOf(QLatin1Char(','), next);
        if (i < 0)
            i = items.length();
        int sc = items.indexOf(QLatin1Char(';'), next);
        if (sc < 0)
            sc = items.length();
        if (sc < i)
            i = sc;
        QString item = items.mid(next, i - next).trimmed();
        switch (checkAttachment(item))
        {
            case 1:   list += item;  break;
            case 0:   break;          // empty attachment name
            case -1:
            default:  return item;    // error
        }
        next = i + 1;
    }
    return QString();
}

/******************************************************************************
* Check for the existence of the attachment file.
* If non-null, '*url' receives the KUrl of the attachment.
* Reply = 1 if attachment exists
*       = 0 if null name
*       = -1 if doesn't exist.
*/
int KAMail::checkAttachment(QString& attachment, KUrl* url)
{
    attachment = attachment.trimmed();
    if (attachment.isEmpty())
    {
        if (url)
            *url = KUrl();
        return 0;
    }
    // Check that the file exists
    KUrl u(attachment);
    u.cleanPath();
    if (url)
        *url = u;
    return checkAttachment(u) ? 1 : -1;
}

/******************************************************************************
* Check for the existence of the attachment file.
*/
bool KAMail::checkAttachment(const KUrl& url)
{
    KIO::UDSEntry uds;
    if (!KIO::NetAccess::stat(url, uds, MainWindow::mainMainWindow()))
        return false;       // doesn't exist
    KFileItem fi(uds, url);
    if (fi.isDir()  ||  !fi.isReadable())
        return false;
    return true;
}

/******************************************************************************
* Set the appropriate error messages for a given error string.
*/
QStringList KAMail::errors(const QString& err, ErrType prefix)
{
    QString error1;
    switch (prefix)
    {
        case SEND_FAIL:  error1 = i18nc("@info", "Failed to send email");  break;
        case SEND_ERROR:  error1 = i18nc("@info", "Error sending email");  break;
    }
    if (err.isEmpty())
        return QStringList(error1);
    QStringList errs(QString::fromLatin1("%1:").arg(error1));
    errs += err;
    return errs;
}

/******************************************************************************
* Get the body of an email from KMail, given its serial number.
*/
QString KAMail::getMailBody(quint32 serialNumber)
{
    QList<QVariant> args;
    args << serialNumber << (int)0;
#ifdef __GNUC__
#warning Set correct DBus interface/object for kmail
#endif
    QDBusInterface iface(KMAIL_DBUS_SERVICE, QString(), QStringLiteral("KMailIface"));
    QDBusReply<QString> reply = iface.callWithArgumentList(QDBus::Block, QStringLiteral("getDecodedBodyPart"), args);
    if (!reply.isValid())
    {
        qCCritical(KALARM_LOG) << "D-Bus call failed:" << reply.error().message();
        return QString();
    }
    return reply.value();
}

/******************************************************************************
* Extract the pure addresses from given email addresses.
*/
QString extractEmailAndNormalize(const QString& emailAddress)
{
    return KEmailAddress::extractEmailAddress(KEmailAddress::normalizeAddressesAndEncodeIdn(emailAddress));
}

QStringList extractEmailsAndNormalize(const QString& emailAddresses)
{
    const QStringList splitEmails(KEmailAddress::splitAddressList(emailAddresses));
    QStringList normalizedEmail;
    Q_FOREACH(const QString& email, splitEmails)
    {
        normalizedEmail << KEmailAddress::extractEmailAddress(KEmailAddress::normalizeAddressesAndEncodeIdn(email));
    }
    return normalizedEmail;
}

//-----------------------------------------------------------------------------
// Based on KMail KMMsgBase::autoDetectCharset().
QByteArray autoDetectCharset(const QString& text)
{
    static QList<QByteArray> charsets;
    if (charsets.isEmpty())
        charsets << "us-ascii" << "iso-8859-1" << "locale" << "utf-8";

    for (int i = 0, count = charsets.count();  i < count;  ++i)
    {
        QByteArray encoding = charsets[i];
        if (encoding == "locale")
        {
            encoding = QTextCodec::codecForName(KLocale::global()->encoding())->name();
            encoding = encoding.toLower();
        }
        if (text.isEmpty())
            return encoding;
        if (encoding == "us-ascii")
        {
            if (KMime::isUsAscii(text))
                return encoding;
        }
        else
        {
            const QTextCodec *codec = codecForName(encoding);
            if (!codec)
                qCDebug(KALARM_LOG) <<"Auto-Charset: Something is wrong and I cannot get a codec. [" << encoding <<"]";
            else
            {
                 if (codec->canEncode(text))
                     return encoding;
            }
        }
    }
    return QByteArray();
}

//-----------------------------------------------------------------------------
// Based on KMail KMMsgBase::codecForName().
const QTextCodec* codecForName(const QByteArray& str)
{
    if (str.isEmpty())
        return Q_NULLPTR;
    QByteArray codec = str.toLower();
    return KCharsets::charsets()->codecForName(QLatin1String(codec));
}

/******************************************************************************
* Parse a string containing multiple addresses, separated by comma or semicolon,
* while retaining Unicode name parts.
* Note that this only needs to parse strings input into KAlarm, so it only
* needs to accept the common syntax for email addresses, not obsolete syntax.
*/
KMime::Types::Mailbox::List parseAddresses(const QString& text, QString& invalidItem)
{
    KMime::Types::Mailbox::List list;
    int state     = 0;
    int start     = 0;  // start of this item
    int endName   = 0;  // character after end of name
    int startAddr = 0;  // start of address
    int endAddr   = 0;  // character after end of address
    char lastch = '\0';
    bool ended    = false;   // found the end of the item
    for (int i = 0, count = text.length();  i <= count;  ++i)
    {
        if (i == count)
            ended = true;
        else
        {
            char ch = text[i].toLatin1();
            switch (state)
            {
                case 0:   // looking for start of item
                    if (ch == ' ' || ch == '\t')
                        continue;
                    start = i;
                    state = (ch == '"') ? 10 : 1;
                    break;
                case 1:   // looking for start of address, or end of item
                    switch (ch)
                    {
                        case '<':
                            startAddr = i + 1;
                            state = 2;
                            break;
                        case ',':
                        case ';':
                            ended = true;
                            break;
                        case ' ':
                            break;
                        default:
                            endName = i + 1;
                            break;
                    }
                    break;
                case 2:   // looking for '>' at end of address
                    if (ch == '>')
                    {
                        endAddr = i;
                        state = 3;
                    }
                    break;
                case 3:   // looking for item separator
                    if (ch == ','  ||  ch == ';')
                        ended = true;
                    else if (ch != ' ')
                    {
                        invalidItem = text.mid(start);
                        return KMime::Types::Mailbox::List();
                    }
                    break;
                case 10:   // looking for closing quote
                    if (ch == '"'  &&  lastch != '\\')
                    {
                        ++start;   // remove opening quote from name
                        endName = i;
                        state = 11;
                    }
                    lastch = ch;
                    break;
                case 11:   // looking for '<'
                    if (ch == '<')
                    {
                        startAddr = i + 1;
                        state = 2;
                    }
                    break;
            }
        }
        if (ended)
        {
            // Found the end of the item - add it to the list
            if (!startAddr)
            {
                startAddr = start;
                endAddr   = endName;
                endName   = 0;
            }
            QString addr = text.mid(startAddr, endAddr - startAddr);
            KMime::Types::Mailbox mbox;
            mbox.fromUnicodeString(addr);
            if (mbox.address().isEmpty())
            {
                invalidItem = text.mid(start, endAddr - start);
                return KMime::Types::Mailbox::List();
            }
            if (endName)
            {
                int len = endName - start;
                QString name = text.mid(start, endName - start);
                if (name[0] == QLatin1Char('"')  &&  name[len - 1] == QLatin1Char('"'))
                    name = name.mid(1, len - 2);
                mbox.setName(name);
            }
            list.append(mbox);

            endName = startAddr = endAddr = 0;
            start = i + 1;
            state = 0;
            ended = false;
        }
    }
    return list;
}

/*=============================================================================
=  HeaderParsing :  modified and additional functions.
=  The following functions are modified from, or additional to, those in
=  libkmime kmime_header_parsing.cpp.
=============================================================================*/

namespace HeaderParsing
{

using namespace KMime;
using namespace KMime::Types;
using namespace KMime::HeaderParsing;

/******************************************************************************
* New function.
* Allow a local user name to be specified as an email address.
*/
bool parseUserName( const char* & scursor, const char * const send,
                    QString & result, bool isCRLF ) {

  QString maybeLocalPart;
  QString tmp;

  if ( scursor != send ) {
    // first, eat any whitespace
    eatCFWS( scursor, send, isCRLF );

    char ch = *scursor++;
    switch ( ch ) {
    case '.': // dot
    case '@':
    case '"': // quoted-string
      return false;

    default: // atom
      scursor--; // re-set scursor to point to ch again
      tmp.clear();
      if ( parseAtom( scursor, send, result, false /* no 8bit */ ) ) {
        if (getpwnam(result.toLocal8Bit()))
          return true;
      }
      return false; // parseAtom can only fail if the first char is non-atext.
    }
  }
  return false;
}

/******************************************************************************
* Modified function.
* Allow a local user name to be specified as an email address, and reinstate
* the original scursor on error return.
*/
bool parseAddress( const char* & scursor, const char * const send,
                   Address & result, bool isCRLF ) {
  // address       := mailbox / group

  eatCFWS( scursor, send, isCRLF );
  if ( scursor == send )
    return false;

  // first try if it's a single mailbox:
  Mailbox maybeMailbox;
  const char * oldscursor = scursor;
  if ( parseMailbox( scursor, send, maybeMailbox, isCRLF ) ) {
    // yes, it is:
    result.displayName.clear();
    result.mailboxList.append( maybeMailbox );
    return true;
  }
  scursor = oldscursor;

  // KAlarm: Allow a local user name to be specified
  // no, it's not a single mailbox. Try if it's a local user name:
  QString maybeUserName;
  if ( parseUserName( scursor, send, maybeUserName, isCRLF ) ) {
    // yes, it is:
    maybeMailbox.setName( QString() );
    AddrSpec addrSpec;
    addrSpec.localPart = maybeUserName;
    addrSpec.domain.clear();
    maybeMailbox.setAddress( addrSpec );
    result.displayName.clear();
    result.mailboxList.append( maybeMailbox );
    return true;
  }
  scursor = oldscursor;

  Address maybeAddress;

  // no, it's not a single mailbox. Try if it's a group:
  if ( !parseGroup( scursor, send, maybeAddress, isCRLF ) )
  {
    scursor = oldscursor;   // KAlarm: reinstate original scursor on error return
    return false;
  }

  result = maybeAddress;
  return true;
}

} // namespace HeaderParsing

// vim: et sw=4: