// This is the signal/slot helper code for SIP.
//
// Copyright (c) 2016 Riverbank Computing Limited <info@riverbankcomputing.com>
// 
// This file is part of PyQt4.
// 
// This file may be used under the terms of the GNU General Public License
// version 3.0 as published by the Free Software Foundation and appearing in
// the file LICENSE included in the packaging of this file.  Please review the
// following information to ensure the GNU General Public License version 3.0
// requirements will be met: http://www.gnu.org/copyleft/gpl.html.
// 
// If you do not wish to use this file under the terms of the GPL version 3.0
// then you may purchase a commercial license.  For more information contact
// info@riverbankcomputing.com.
// 
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.


#include <string.h>

#include <Python.h>

#include <QByteArray>
#include <QMetaObject>
#include <QMutex>
#include <QObject>

#include "qpycore_chimera.h"
#include "qpycore_pyqtboundsignal.h"
#include "qpycore_pyqtproxy.h"
#include "qpycore_pyqtpyobject.h"
#include "qpycore_sip.h"
#include "qpycore_sip_helpers.h"


// Forward declarations.
static PyQtShortcircuitSignalProxy *find_shortcircuit_signal(QObject *qtx,
        const char **sig);
static PyQtProxy *find_signal(QObject *qtx, const QByteArray &sig);
static void emit_shortcircuit_signal(QObject *tx, const char *sig,
        PyObject *sigargs);
static bool is_shortcircuit_signal(const char *sig);


// Find an existing Python short-circuited signal proxy.  Returns a pointer to
// the instance or 0 there wasn't one.
static PyQtShortcircuitSignalProxy *find_shortcircuit_signal(QObject *qtx,
        const char **sig)
{
    PyQtShortcircuitSignalProxy *proxy = PyQtShortcircuitSignalProxy::find(qtx, *sig);

    if (proxy)
        *sig = SIGNAL(pysignal(const PyQt_PyObject &));

    return proxy;
}


// Find an existing Python signal proxy.  Returns a pointer to the instance or
// 0 there wasn't one.
static PyQtProxy *find_signal(QObject *qtx, const QByteArray &sig)
{
    PyQtProxy::ProxyHash::const_iterator it(PyQtProxy::proxy_signals.find(qtx));

    while (it != PyQtProxy::proxy_signals.end() && it.key() == qtx)
    {
        PyQtProxy *proxy = it.value();

        if (proxy->signature == sig)
            return proxy;

        ++it;
    }

    return 0;
}


// Find an existing signal emitter for the given object and signature.  Returns
// a pointer to the emitter or 0 if there wasn't one, and updates the signature
// if necessary.
QObject *qpycore_find_signal(QObject *qtx, const char **sigp)
{
    // See if it a short-circuit signal.
    if (is_shortcircuit_signal(*sigp))
        return find_shortcircuit_signal(qtx, sigp);

    // See if the object can be used itself.
    QByteArray norm_sig = QMetaObject::normalizedSignature(&(*sigp)[1]);

    if (qtx->metaObject()->indexOfSignal(norm_sig.constData()) >= 0)
        return qtx;

    // Look for an existing proxy.
    return find_signal(qtx, norm_sig);
}



#if SIP_VERSION < 0x050000
// Find an existing signal emitter for the given object and signature.  Returns
// a pointer to the emitter or 0 if there wasn't one, and updates the signature
// if necessary.
extern "C" void *sipQtFindUniversalSignal(void *tx, const char **sig)
{
    return qpycore_find_signal(reinterpret_cast<QObject *>(tx), sig);
}
#endif


// Factory function to create a signal emitter for the given object and
// signature.  Returns a pointer to the emitter and updates the signature if
// necessary.
QObject *qpycore_create_universal_signal(QObject *qtx, const char **sigp)
{
    QObject *proxy;
    const char *sig = *sigp;

    // See if it a short-circuit signal.
    if (is_shortcircuit_signal(sig))
    {
        Py_BEGIN_ALLOW_THREADS
        proxy = new PyQtShortcircuitSignalProxy(qtx);
        proxy->setObjectName(sig);
        Py_END_ALLOW_THREADS

        *sigp = SIGNAL(pysignal(const PyQt_PyObject &));
    }
    else
    {
        Py_BEGIN_ALLOW_THREADS
        proxy = new PyQtProxy(qtx, &sig[1]);
        Py_END_ALLOW_THREADS
    }

    return proxy;
}


#if SIP_VERSION < 0x050000
// Factory function to create a signal emitter for the given object and
// signature.  Returns a pointer to the emitter or 0 if there was an error, and
// updates the signature if necessary.
extern "C" void *sipQtCreateUniversalSignal(void *tx, const char **sigp)
{
    return qpycore_create_universal_signal(reinterpret_cast<QObject *>(tx),
            sigp);
}
#endif


// Factory function to create a universal slot instance.  Returns a pointer to
// the instance or 0 if there was an error.  Note that we may also return a
// Qt signal (from a bound signal).
QObject *qpycore_create_universal_slot(sipWrapper *tx, const char *sig,
        PyObject *rxObj, const char *slot, const char **member, int flags)
{
    // Get the receiver C++ QObject if there is one.
    PyObject *qrxObj;

    if (slot)
    {
        qrxObj = rxObj;
    }
    else if (Py_TYPE(rxObj) == &qpycore_pyqtBoundSignal_Type)
    {
        qpycore_pyqtBoundSignal *bs = (qpycore_pyqtBoundSignal *)rxObj;

        *member = bs->unbound_signal->signature->signature.constData();

        return bs->bound_qobject;
    }
    else if (PyMethod_Check(rxObj))
    {
        qrxObj = PyMethod_GET_SELF(rxObj);
    }
    else
    {
        qrxObj = 0;
    }

    QObject *qrx = 0;

    if (qrxObj)
    {
        int iserr = 0;
        void *rx = sipForceConvertToType(qrxObj, sipType_QObject, 0,
                SIP_NOT_NONE|SIP_NO_CONVERTORS, 0, &iserr);

        if (iserr)
            PyErr_Clear();
        else
            qrx = reinterpret_cast<QObject *>(rx);
    }

    PyQtProxy *res;

    Py_BEGIN_ALLOW_THREADS

    res = new PyQtProxy(tx, sig, rxObj, slot, member, flags);

    if (res->metaObject())
    {
        // If the receiver is a QObject then move the proxy to the same thread.
        if (qrx)
            res->moveToThread(qrx->thread());
    }
    else
    {
        delete res;
        res = 0;
    }

    Py_END_ALLOW_THREADS

    return res;
}


#if SIP_VERSION < 0x050000
// Factory function to create a universal slot instance.  Returns a pointer to
// the instance or 0 if there was an error.  Note that we may also return a
// Qt signal (from a bound signal).
extern "C" void *sipQtCreateUniversalSlot(sipWrapper *tx, const char *sig,
        PyObject *rxObj, const char *slot, const char **member, int flags)
{
    return qpycore_create_universal_slot(tx, sig, rxObj, slot, member, flags);
}
#endif


#if SIP_VERSION < 0x050000
// Dispose of a receiver that might be a universal slot.
extern "C" void sipQtDestroyUniversalSlot(void *rx)
{
    Py_BEGIN_ALLOW_THREADS
    PyQtProxy::mutex->lock();

    PyQtProxy::ProxyHash::const_iterator it(PyQtProxy::proxy_slots.begin());

    while (it != PyQtProxy::proxy_slots.end())
    {
        PyQtProxy *up = it.value();

        if (up == reinterpret_cast<QObject *>(rx))
        {
            // If we are disconnecting within the slot that is connected then
            // disable() will make sure the proxy isn't deleted until the slot
            // returns.
            up->disable();
            break;
        }

        ++it;
    }

    PyQtProxy::mutex->unlock();
    Py_END_ALLOW_THREADS
}
#endif


#if SIP_VERSION < 0x050000
// Search for the universal slot connected to a particular Qt signal.
extern "C" void *sipQtFindSlot(void *tx, const char *sig, PyObject *rxObj,
        const char *slot, const char **member)
{
    return PyQtProxy::findSlotProxy(tx, sig, rxObj, slot, member);
}
#endif


#if SIP_VERSION < 0x050000
// Connect a Qt signal to a Qt slot.
extern "C" int sipQtConnect(void *tx, const char *sig, void *rx, const char *slot, int type)
{
    // Unlike Qt3, Qt4 does not check that the signal and slot arguments are
    // compatible in a release build.  I think this is a bug, so we do the
    // missing check here.
#if defined(QT_NO_DEBUG)
    if (!QMetaObject::checkConnectArgs(sig, slot))
        return 0;
#endif

    int res;

    Py_BEGIN_ALLOW_THREADS
    res = (bool)QObject::connect(reinterpret_cast<QObject *>(tx), sig,
                           reinterpret_cast<QObject *>(rx), slot,
                           (Qt::ConnectionType)type);
    Py_END_ALLOW_THREADS

    return res;
}
#endif


#if SIP_VERSION < 0x050000
// Disconnect a Qt signal from a Qt slot.
extern "C" int sipQtDisconnect(void *tx, const char *sig, void *rx, const char *slot)
{
    int res;

    Py_BEGIN_ALLOW_THREADS
    res = QObject::disconnect(reinterpret_cast<QObject *>(tx), sig,
                              reinterpret_cast<QObject *>(rx), slot);
    Py_END_ALLOW_THREADS

    return res;
}
#endif


#if SIP_VERSION < 0x050000
// See if two signal or slot names are the same.
extern "C" int sipQtSameSignalSlotName(const char *s1, const char *s2)
{
    // Signal and slot names are always normalised so a simple string
    // comparison will do.
    return (qstrcmp(s1, s2) == 0);
}
#endif


#if SIP_VERSION < 0x050000
// Return the next slot for a particular transmitter.  This will be called with
// the GIL locked.
extern "C" sipSlot *sipQtFindSipslot(void *tx, void **context)
{
    PyQtProxy::ProxyHash::const_iterator it;
    PyQtProxy::ProxyHash::const_iterator *itp = *reinterpret_cast<PyQtProxy::ProxyHash::const_iterator **>(context);

    // Use the existing context if there is one, otherwise initialise a new
    // one.
    if (itp)
        it = *itp;
    else
    {
        it = PyQtProxy::proxy_slots.find(tx);
        itp = new PyQtProxy::ProxyHash::const_iterator(it);
        *context = itp;
    }

    if (it != PyQtProxy::proxy_slots.end() && it.key() == tx)
    {
        PyQtProxy *up = it++.value();

        // Save the current context.
        *itp = it;

        return &up->real_slot.sip_slot;
    }

    // Discard the context as it is no longer needed.
    delete itp;
    *context = 0;

    return 0;
}
#endif


// Emit the given signal from the given object.  Note that we do not apply the
// hacks when building against Qt5 that workaround the problems with signals
// with optional arguments.  New style signals must be used instead.
sipErrorState qpycore_qobject_emit(QObject *qtx, PyObject *sigObj,
        PyObject *sigargs)
{
    // Finish converting the arguments.
    const char *sig = pyqt4_get_signal(sigObj);
    if (!sig)
        return sipBadCallableArg(0, sigObj);

    // We need to explicitly check for anything that uses a proxy, so we might
    // as well check for everything.
    if (qtx->signalsBlocked())
        return sipErrorNone;

    // See if it is a short-circuit signal.
    if (is_shortcircuit_signal(sig))
    {
        emit_shortcircuit_signal(qtx, sig, sigargs);
        return sipErrorNone;
    }

    QByteArray norm_sig = QMetaObject::normalizedSignature(&sig[1]);
    int signal_index = qtx->metaObject()->indexOfSignal(norm_sig.constData());

    // If the signal doesn't exist then see if there is a proxy for it.
    if (signal_index < 0)
    {
        PyQtProxy *proxy = find_signal(qtx, norm_sig);

        // Unfortunately we can't distinguish between a Qt name with a typo and
        // an unconnected Python signal - so we just ignore the emit.
        if (!proxy)
            return sipErrorNone;

        // Use the proxy instead.
        qtx = proxy;
        signal_index = proxy->metaObject()->indexOfSignal(norm_sig.constData());
    }

    // Parse the signature.
    const Chimera::Signature *parsed_signature = Chimera::parse(norm_sig,
            "a signal argument");

    if (!parsed_signature)
        return sipErrorFail;

    bool ok = qpycore_emit(qtx, signal_index, parsed_signature,
            parsed_signature->py_signature.constData(), sigargs);
    delete parsed_signature;

    return (ok ? sipErrorNone : sipErrorFail);
}


// Emit a signal based on a parsed signature.
bool qpycore_emit(QObject *qtx, int signal_index,
        const Chimera::Signature *parsed_signature, const char *docstring,
        PyObject *sigargs)
{
    const QList<const Chimera *> &args = parsed_signature->parsed_arguments;

    if (args.size() != PyTuple_GET_SIZE(sigargs))
    {
        PyErr_Format(PyExc_TypeError,
                "%s signal has %d argument(s) but %d provided", docstring,
                args.size(), (int)PyTuple_GET_SIZE(sigargs));

        return false;
    }

    // Convert the arguments.
    QList<Chimera::Storage *> values;
    void **argv = new void *[1 + args.size()];

    argv[0] = 0;

    QList<const Chimera *>::const_iterator it = args.constBegin();

    for (int a = 0; it != args.constEnd(); ++a)
    {
        PyObject *arg_obj = PyTuple_GET_ITEM(sigargs, a);
        Chimera::Storage *val = (*it)->fromPyObjectToStorage(arg_obj);

        if (!val)
        {
            // Mimic SIP's exception text.
            PyErr_Format(PyExc_TypeError,
                    "%s.emit(): argument %d has unexpected type '%s'",
                    docstring, a + 1, Py_TYPE(arg_obj)->tp_name);

            delete[] argv;
            qDeleteAll(values.constBegin(), values.constEnd());

            return false;
        }

        argv[1 + a] = val->address();
        values << val;

        ++it;
    }

    Py_BEGIN_ALLOW_THREADS
#if QT_VERSION >= 0x050000
    QMetaObject::activate(qtx, signal_index, argv);
#else
    QMetaObject::activate(qtx, signal_index, signal_index, argv);
#endif
    Py_END_ALLOW_THREADS

    delete[] argv;
    qDeleteAll(values.constBegin(), values.constEnd());

    return true;
}


// Emit a shortcircuit signal.
static void emit_shortcircuit_signal(QObject *tx, const char *sig,
        PyObject *sigargs)
{
    // Find the proxy emitter.  Unfortunately we can't distinguish between a Qt
    // name with a typo and an unconnected Python signal - so we just ignore
    // the emit.
    PyQtShortcircuitSignalProxy *proxy = PyQtShortcircuitSignalProxy::find(tx, sig);

    if (proxy)
    {
        PyQt_PyObject wrapped_args(sigargs);

        Py_BEGIN_ALLOW_THREADS
        proxy->emit_signal(wrapped_args);
        Py_END_ALLOW_THREADS
    }
}


// Return true if the signature is of a short-circuit signal.
static bool is_shortcircuit_signal(const char *sig)
{
    return !strchr(sig, '(');
}