/*
 * Copyright (C) 2006,2007  Justin Karneges <justin@affinix.com>
 *
 * 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) any later version.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301  USA
 *
 */

#include "qca_support.h"

#include "qca_safeobj.h"
#include "qpipe.h"

#include <QMutex>
#include <QPointer>
#include <QTextCodec>

#ifdef Q_OS_WIN
#include <windows.h>
#else
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>
#endif

#include <cstdio>
#include <cstdlib>

#define CONSOLEPROMPT_INPUT_MAX 56

Q_DECLARE_METATYPE(QCA::SecureArray)

namespace QCA {

//----------------------------------------------------------------------------
// ConsoleWorker
//----------------------------------------------------------------------------
class ConsoleWorker : public QObject
{
    Q_OBJECT
private:
    QPipeEnd   in, out;
    bool       started;
    QByteArray in_left, out_left;

public:
    ConsoleWorker(QObject *parent = nullptr)
        : QObject(parent)
        , in(this)
        , out(this)
    {
        started = false;
    }

    ~ConsoleWorker() override
    {
        stop();
    }

    void start(Q_PIPE_ID in_id, Q_PIPE_ID out_id)
    {
        Q_ASSERT(!started);

        if (in_id != INVALID_Q_PIPE_ID) {
            in.take(in_id, QPipeDevice::Read);
            connect(&in, &QPipeEnd::readyRead, this, &ConsoleWorker::in_readyRead);
            connect(&in, &QPipeEnd::closed, this, &ConsoleWorker::in_closed);
            connect(&in, &QPipeEnd::error, this, &ConsoleWorker::in_error);
            in.enable();
        }

        if (out_id != INVALID_Q_PIPE_ID) {
            out.take(out_id, QPipeDevice::Write);
            connect(&out, &QPipeEnd::bytesWritten, this, &ConsoleWorker::out_bytesWritten);
            connect(&out, &QPipeEnd::closed, this, &ConsoleWorker::out_closed);
            out.enable();
        }

        started = true;
    }

    void stop()
    {
        if (!started)
            return;

        if (in.isValid())
            in.finalizeAndRelease();
        if (out.isValid())
            out.release();

        in_left  = in.read();
        out_left = out.takeBytesToWrite();

        started = false;
    }

    Q_INVOKABLE bool isValid() const
    {
        return in.isValid();
    }

    Q_INVOKABLE int bytesAvailable() const
    {
        return in.bytesAvailable();
    }

    Q_INVOKABLE int bytesToWrite() const
    {
        return in.bytesToWrite();
    }

public Q_SLOTS:

    void setSecurityEnabled(bool enabled)
    {
        if (in.isValid())
            in.setSecurityEnabled(enabled);
        if (out.isValid())
            out.setSecurityEnabled(enabled);
    }

    QByteArray read(int bytes = -1)
    {
        return in.read(bytes);
    }

    void write(const QByteArray &a)
    {
        out.write(a);
    }

    QCA::SecureArray readSecure(int bytes = -1)
    {
        return in.readSecure(bytes);
    }

    void writeSecure(const QCA::SecureArray &a)
    {
        out.writeSecure(a);
    }

    void closeOutput()
    {
        out.close();
    }

public:
    QByteArray takeBytesToRead()
    {
        QByteArray a = in_left;
        in_left.clear();
        return a;
    }

    QByteArray takeBytesToWrite()
    {
        QByteArray a = out_left;
        out_left.clear();
        return a;
    }

Q_SIGNALS:
    void readyRead();
    void bytesWritten(int bytes);
    void inputClosed();
    void outputClosed();

private Q_SLOTS:
    void in_readyRead()
    {
        emit readyRead();
    }

    void out_bytesWritten(int bytes)
    {
        emit bytesWritten(bytes);
    }

    void in_closed()
    {
        emit inputClosed();
    }

    void in_error(QCA::QPipeEnd::Error)
    {
        emit inputClosed();
    }

    void out_closed()
    {
        emit outputClosed();
    }
};

//----------------------------------------------------------------------------
// ConsoleThread
//----------------------------------------------------------------------------
class ConsoleThread : public SyncThread
{
    Q_OBJECT
public:
    ConsoleWorker *worker;
    Q_PIPE_ID      _in_id, _out_id;
    QByteArray     in_left, out_left;
    QMutex         call_mutex;

    ConsoleThread(QObject *parent = nullptr)
        : SyncThread(parent)
    {
        qRegisterMetaType<SecureArray>("QCA::SecureArray");
    }

    ~ConsoleThread() override
    {
        stop();
    }

    void start(Q_PIPE_ID in_id, Q_PIPE_ID out_id)
    {
        _in_id  = in_id;
        _out_id = out_id;
        SyncThread::start();
    }

    void stop()
    {
        SyncThread::stop();
    }

    QVariant mycall(QObject *obj, const char *method, const QVariantList &args = QVariantList())
    {
        QVariant ret;
        bool     ok;

        call_mutex.lock();
        ret = call(obj, method, args, &ok);
        call_mutex.unlock();

        Q_ASSERT(ok);
        if (!ok) {
            fprintf(stderr, "QCA: ConsoleWorker call [%s] failed.\n", method);
            abort();
            return QVariant();
        }
        return ret;
    }

    bool isValid()
    {
        return mycall(worker, "isValid").toBool();
    }

    void setSecurityEnabled(bool enabled)
    {
        mycall(worker, "setSecurityEnabled", QVariantList() << enabled);
    }

    QByteArray read(int bytes = -1)
    {
        return mycall(worker, "read", QVariantList() << bytes).toByteArray();
    }

    void write(const QByteArray &a)
    {
        mycall(worker, "write", QVariantList() << a);
    }

    SecureArray readSecure(int bytes = -1)
    {
        return mycall(worker, "readSecure", QVariantList() << bytes).value<SecureArray>();
    }

    void writeSecure(const SecureArray &a)
    {
        mycall(worker, "writeSecure", QVariantList() << QVariant::fromValue<SecureArray>(a));
    }

    void closeOutput()
    {
        mycall(worker, "closeOutput");
    }

    int bytesAvailable()
    {
        return mycall(worker, "bytesAvailable").toInt();
    }

    int bytesToWrite()
    {
        return mycall(worker, "bytesToWrite").toInt();
    }

    QByteArray takeBytesToRead()
    {
        QByteArray a = in_left;
        in_left.clear();
        return a;
    }

    QByteArray takeBytesToWrite()
    {
        QByteArray a = out_left;
        out_left.clear();
        return a;
    }

Q_SIGNALS:
    void readyRead();
    void bytesWritten(int);
    void inputClosed();
    void outputClosed();

protected:
    void atStart() override
    {
        worker = new ConsoleWorker;

        // use direct connections here, so that the emits come from
        //   the other thread.  we can also connect to our own
        //   signals to avoid having to make slots just to emit.
        connect(worker, &ConsoleWorker::readyRead, this, &ConsoleThread::readyRead, Qt::DirectConnection);
        connect(worker, &ConsoleWorker::bytesWritten, this, &ConsoleThread::bytesWritten, Qt::DirectConnection);
        connect(worker, &ConsoleWorker::inputClosed, this, &ConsoleThread::inputClosed, Qt::DirectConnection);
        connect(worker, &ConsoleWorker::outputClosed, this, &ConsoleThread::outputClosed, Qt::DirectConnection);

        worker->start(_in_id, _out_id);
    }

    void atEnd() override
    {
        in_left  = worker->takeBytesToRead();
        out_left = worker->takeBytesToWrite();
        delete worker;
    }
};

//----------------------------------------------------------------------------
// Console
//----------------------------------------------------------------------------
class ConsolePrivate : public QObject
{
    Q_OBJECT
public:
    Console *q;

    bool                  started;
    Console::Type         type;
    Console::ChannelMode  cmode;
    Console::TerminalMode mode;
    ConsoleThread        *thread;
    ConsoleReference     *ref;
    Q_PIPE_ID             in_id;

#ifdef Q_OS_WIN
    DWORD old_mode;
#else
    struct termios old_term_attr;
#endif

    ConsolePrivate(Console *_q)
        : QObject(_q)
        , q(_q)
    {
        started = false;
        mode    = Console::Default;
        thread  = new ConsoleThread(this);
        ref     = nullptr;
    }

    ~ConsolePrivate() override
    {
        delete thread;
        setInteractive(Console::Default);
    }

    void setInteractive(Console::TerminalMode m)
    {
        // no change
        if (m == mode)
            return;

        if (m == Console::Interactive) {
#ifdef Q_OS_WIN
            GetConsoleMode(in_id, &old_mode);
            SetConsoleMode(in_id, old_mode & (~ENABLE_LINE_INPUT & ~ENABLE_ECHO_INPUT));
#else
            int            fd = in_id;
            struct termios attr;
            tcgetattr(fd, &attr);
            old_term_attr = attr;

            attr.c_lflag &= ~(ECHO);   // turn off the echo flag
            attr.c_lflag &= ~(ICANON); // no wait for a newline
            attr.c_cc[VMIN]  = 1;      // read at least 1 char
            attr.c_cc[VTIME] = 0;      // set wait time to zero

            // set the new attributes
            tcsetattr(fd, TCSAFLUSH, &attr);
#endif
        } else {
#ifdef Q_OS_WIN
            SetConsoleMode(in_id, old_mode);
#else
            int fd = in_id;
            tcsetattr(fd, TCSANOW, &old_term_attr);
#endif
        }

        mode = m;
    }
};

static Console *g_tty_console = nullptr, *g_stdio_console = nullptr;

Console::Console(Type type, ChannelMode cmode, TerminalMode tmode, QObject *parent)
    : QObject(parent)
{
    if (type == Tty) {
        Q_ASSERT(g_tty_console == nullptr);
        g_tty_console = this;
    } else {
        Q_ASSERT(g_stdio_console == nullptr);
        g_stdio_console = this;
    }

    d        = new ConsolePrivate(this);
    d->type  = type;
    d->cmode = cmode;

    Q_PIPE_ID in  = INVALID_Q_PIPE_ID;
    Q_PIPE_ID out = INVALID_Q_PIPE_ID;

#ifdef Q_OS_WIN
    if (type == Tty) {
        in = CreateFileA(
            "CONIN$", GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
    } else {
        in = GetStdHandle(STD_INPUT_HANDLE);
    }
#else
    if (type == Tty) {
        in = open("/dev/tty", O_RDONLY);
    } else {
        in = 0; // stdin
    }
#endif
    if (cmode == ReadWrite) {
#ifdef Q_OS_WIN
        if (type == Tty) {
            out = CreateFileA("CONOUT$",
                              GENERIC_READ | GENERIC_WRITE,
                              FILE_SHARE_READ | FILE_SHARE_WRITE,
                              NULL,
                              OPEN_EXISTING,
                              0,
                              NULL);
        } else {
            out = GetStdHandle(STD_OUTPUT_HANDLE);
        }
#else
        if (type == Tty) {
            out = open("/dev/tty", O_WRONLY);
        } else {
            out = 1; // stdout
        }
#endif
    }

    d->in_id = in;
    d->setInteractive(tmode);
    d->thread->start(in, out);
}

Console::~Console()
{
    release();
    Console::Type type = d->type;
    delete d;
    if (type == Tty)
        g_tty_console = nullptr;
    else
        g_stdio_console = nullptr;
}

Console::Type Console::type() const
{
    return d->type;
}

Console::ChannelMode Console::channelMode() const
{
    return d->cmode;
}

Console::TerminalMode Console::terminalMode() const
{
    return d->mode;
}

bool Console::isStdinRedirected()
{
#ifdef Q_OS_WIN
    HANDLE h = GetStdHandle(STD_INPUT_HANDLE);
    DWORD  mode;
    if (GetConsoleMode(h, &mode))
        return false;
    return true;
#else
    return (isatty(0) ? false : true); // 0 == stdin
#endif
}

bool Console::isStdoutRedirected()
{
#ifdef Q_OS_WIN
    HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
    DWORD  mode;
    if (GetConsoleMode(h, &mode))
        return false;
    return true;
#else
    return (isatty(1) ? false : true); // 1 == stdout
#endif
}

Console *Console::ttyInstance()
{
    return g_tty_console;
}

Console *Console::stdioInstance()
{
    return g_stdio_console;
}

void Console::release()
{
    d->thread->stop();
}

QByteArray Console::bytesLeftToRead()
{
    return d->thread->takeBytesToRead();
}

QByteArray Console::bytesLeftToWrite()
{
    return d->thread->takeBytesToWrite();
}

//----------------------------------------------------------------------------
// ConsoleReference
//----------------------------------------------------------------------------
class ConsoleReferencePrivate : public QObject
{
    Q_OBJECT
public:
    ConsoleReference *q;

    Console                       *console;
    ConsoleThread                 *thread;
    ConsoleReference::SecurityMode smode;
    SafeTimer                      lateTrigger;
    bool                           late_read, late_close;

    ConsoleReferencePrivate(ConsoleReference *_q)
        : QObject(_q)
        , q(_q)
        , lateTrigger(this)
    {
        console = nullptr;
        thread  = nullptr;
        connect(&lateTrigger, &SafeTimer::timeout, this, &ConsoleReferencePrivate::doLate);
        lateTrigger.setSingleShot(true);
    }

private Q_SLOTS:
    void doLate()
    {
        QPointer<QObject> self = this;
        if (late_read)
            emit q->readyRead();
        if (!self)
            return;
        if (late_close)
            emit q->inputClosed();
    }
};

ConsoleReference::ConsoleReference(QObject *parent)
    : QObject(parent)
{
    d = new ConsoleReferencePrivate(this);
}

ConsoleReference::~ConsoleReference()
{
    stop();
    delete d;
}

bool ConsoleReference::start(Console *console, SecurityMode mode)
{
    // make sure this reference isn't using a console already
    Q_ASSERT(!d->console);

    // one console reference at a time
    Q_ASSERT(console->d->ref == nullptr);

    // let's take it
    d->console         = console;
    d->thread          = d->console->d->thread;
    d->console->d->ref = this;

    const bool valid = d->thread->isValid();
    const int  avail = d->thread->bytesAvailable();

    // pipe already closed and no data?  consider this an error
    if (!valid && avail == 0) {
        d->console->d->ref = nullptr;
        d->thread          = nullptr;
        d->console         = nullptr;
        return false;
    }

    // enable security?  it will last for this active session only
    d->smode = mode;
    if (mode == SecurityEnabled)
        d->thread->setSecurityEnabled(true);

    connect(d->thread, &ConsoleThread::readyRead, this, &ConsoleReference::readyRead);
    connect(d->thread, &ConsoleThread::bytesWritten, this, &ConsoleReference::bytesWritten);
    connect(d->thread, &ConsoleThread::inputClosed, this, &ConsoleReference::inputClosed);
    connect(d->thread, &ConsoleThread::outputClosed, this, &ConsoleReference::outputClosed);

    d->late_read  = false;
    d->late_close = false;

    if (avail > 0)
        d->late_read = true;

    if (!valid)
        d->late_close = true;

    if (d->late_read || d->late_close)
        d->lateTrigger.start();

    return true;
}

void ConsoleReference::stop()
{
    if (!d->console)
        return;

    d->lateTrigger.stop();

    disconnect(d->thread, nullptr, this, nullptr);

    // automatically disable security when we go inactive
    d->thread->setSecurityEnabled(false);

    d->console->d->ref = nullptr;
    d->thread          = nullptr;
    d->console         = nullptr;
}

Console *ConsoleReference::console() const
{
    return d->console;
}

ConsoleReference::SecurityMode ConsoleReference::securityMode() const
{
    return d->smode;
}

QByteArray ConsoleReference::read(int bytes)
{
    return d->thread->read(bytes);
}

void ConsoleReference::write(const QByteArray &a)
{
    d->thread->write(a);
}

SecureArray ConsoleReference::readSecure(int bytes)
{
    return d->thread->readSecure(bytes);
}

void ConsoleReference::writeSecure(const SecureArray &a)
{
    d->thread->writeSecure(a);
}

void ConsoleReference::closeOutput()
{
    d->thread->closeOutput();
}

int ConsoleReference::bytesAvailable() const
{
    return d->thread->bytesAvailable();
}

int ConsoleReference::bytesToWrite() const
{
    return d->thread->bytesToWrite();
}

//----------------------------------------------------------------------------
// ConsolePrompt
//----------------------------------------------------------------------------
class ConsolePrompt::Private : public QObject
{
    Q_OBJECT
public:
    ConsolePrompt *q;

    Synchronizer                sync;
    Console                    *con;
    bool                        own_con;
    ConsoleReference            console;
    QString                     promptStr;
    SecureArray                 result;
    bool                        waiting;
    int                         at;
    bool                        done;
    bool                        charMode;
    QTextCodec                 *codec;
    QTextCodec::ConverterState *encstate, *decstate;

    Private(ConsolePrompt *_q)
        : QObject(_q)
        , q(_q)
        , sync(_q)
        , console(this)
    {
        connect(&console, &ConsoleReference::readyRead, this, &Private::con_readyRead);
        connect(&console, &ConsoleReference::inputClosed, this, &Private::con_inputClosed);

        con     = nullptr;
        own_con = false;
        waiting = false;

#ifdef Q_OS_WIN
        codec = QTextCodec::codecForMib(106); // UTF-8
#else
        codec = QTextCodec::codecForLocale();
#endif
        encstate = nullptr;
        decstate = nullptr;
    }

    ~Private() override
    {
        reset();
    }

    void reset()
    {
        delete encstate;
        encstate = nullptr;
        delete decstate;
        decstate = nullptr;

        console.stop();
        if (own_con) {
            delete con;
            con     = nullptr;
            own_con = false;
        }
    }

    bool start(bool _charMode)
    {
        own_con = false;
        con     = Console::ttyInstance();
        if (!con) {
            con     = new Console(Console::Tty, Console::ReadWrite, Console::Interactive);
            own_con = true;
        }

        result.clear();
        at       = 0;
        done     = false;
        charMode = _charMode;

        encstate = new QTextCodec::ConverterState(QTextCodec::IgnoreHeader);
        decstate = new QTextCodec::ConverterState(QTextCodec::IgnoreHeader);

        if (!console.start(con, ConsoleReference::SecurityEnabled)) {
            reset();
            fprintf(stderr, "Console input not available or closed\n");
            return false;
        }

        if (!charMode)
            writeString(promptStr + QStringLiteral(": "));

        return true;
    }

    void writeString(const QString &str)
    {
        console.writeSecure(codec->fromUnicode(str.unicode(), str.length(), encstate));
    }

    // process each char.  internally store the result as utf16, which
    //   is easier to edit (e.g. backspace)
    bool processChar(QChar c)
    {
        if (charMode) {
            appendChar(c);
            done = true;
            return false;
        }

        if (c == QLatin1Char('\r') || c == QLatin1Char('\n')) {
            writeString(QStringLiteral("\n"));
            done = true;
            return false;
        }

        if (c == QLatin1Char('\b') || c.unicode() == 0x7f) {
            if (at > 0) {
                --at;
                writeString(QStringLiteral("\b \b"));
                result.resize(at * sizeof(ushort));
            }
            return true;
        } else if (c.unicode() < 0x20)
            return true;

        if (at >= CONSOLEPROMPT_INPUT_MAX)
            return true;

        appendChar(c);

        writeString(QStringLiteral("*"));
        return true;
    }

    void appendChar(QChar c)
    {
        if ((at + 1) * (int)sizeof(ushort) > result.size())
            result.resize((at + 1) * sizeof(ushort));
        ushort *p = reinterpret_cast<ushort *>(result.data());
        p[at++]   = c.unicode();
    }

    void convertToUtf8()
    {
        // convert result from utf16 to utf8, securely
        QTextCodec                *codec = QTextCodec::codecForMib(106);
        QTextCodec::ConverterState cstate(QTextCodec::IgnoreHeader);
        SecureArray                out;
        const ushort              *ustr = reinterpret_cast<ushort *>(result.data());
        const int                  len  = result.size() / sizeof(ushort);
        for (int n = 0; n < len; ++n) {
            QChar c(ustr[n]);
            out += codec->fromUnicode(&c, 1, &cstate);
        }
        result = out;
    }

private Q_SLOTS:
    void con_readyRead()
    {
        while (console.bytesAvailable() > 0) {
            SecureArray buf = console.readSecure(1);
            if (buf.isEmpty())
                break;

            // convert to unicode and process
            const QString str  = codec->toUnicode(buf.data(), 1, decstate);
            bool          quit = false;
            for (const QChar &c : str) {
                if (!processChar(c)) {
                    quit = true;
                    break;
                }
            }
            if (quit)
                break;
        }

        if (done) {
            convertToUtf8();

            reset();
            if (waiting)
                sync.conditionMet();
            else
                emit q->finished();
        }
    }

    void con_inputClosed()
    {
        fprintf(stderr, "Console input closed\n");
        if (!done) {
            done = true;
            result.clear();

            reset();
            if (waiting)
                sync.conditionMet();
            else
                emit q->finished();
        }
    }
};

ConsolePrompt::ConsolePrompt(QObject *parent)
    : QObject(parent)
{
    d = new Private(this);
}

ConsolePrompt::~ConsolePrompt()
{
    delete d;
}

void ConsolePrompt::getHidden(const QString &promptStr)
{
    d->reset();

    d->promptStr = promptStr;
    if (!d->start(false)) {
        QMetaObject::invokeMethod(this, "finished", Qt::QueuedConnection);
        return;
    }
}

void ConsolePrompt::getChar()
{
    d->reset();

    if (!d->start(true)) {
        QMetaObject::invokeMethod(this, "finished", Qt::QueuedConnection);
        return;
    }
}

void ConsolePrompt::waitForFinished()
{
    // reparent the Console under us (for Synchronizer)
    QObject *orig_parent = d->con->parent();
    d->con->setParent(this);

    // block while prompting
    d->waiting = true;
    d->sync.waitForCondition();
    d->waiting = false;

    // restore parent (if con still exists)
    if (d->con)
        d->con->setParent(orig_parent);
}

SecureArray ConsolePrompt::result() const
{
    return d->result;
}

QChar ConsolePrompt::resultChar() const
{
    const QString str = QString::fromUtf8(d->result.toByteArray());

    // this will never happen if getChar completes
    if (str.isEmpty())
        return QChar();

    return str[0];
}

}

#include "console.moc"