/*************************************************************************
 * Copyright (C) 2014 by Hugo Pereira Da Costa <hugo.pereira@free.fr>    *
 *                                                                       *
 * 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 "adwaitasplitterproxy.h"

#include "adwaita.h"

#include <QCoreApplication>
#include <QDebug>
#include <QPainter>

namespace Adwaita
{

//____________________________________________________________________
void SplitterFactory::setEnabled(bool value)
{
    if (_enabled != value) {
        // store
        _enabled = value;

        // assign to existing splitters
        for (WidgetMap::iterator iter = _widgets.begin(); iter != _widgets.end(); ++iter) {
            if (iter.value()) iter.value().data()->setEnabled(value);
        }
    }
}

//____________________________________________________________________
bool SplitterFactory::registerWidget(QWidget *widget)
{
    // check widget type
    if (qobject_cast<QMainWindow *>(widget)) {
        WidgetMap::iterator iter(_widgets.find(widget));
        if (iter == _widgets.end() || !iter.value()) {
            widget->installEventFilter(&_addEventFilter);
            SplitterProxy *proxy(new SplitterProxy(widget, _enabled));
            widget->removeEventFilter(&_addEventFilter);

            widget->installEventFilter(proxy);
            _widgets.insert(widget, proxy);
        } else {
            widget->removeEventFilter(iter.value().data());
            widget->installEventFilter(iter.value().data());
        }

        return true;
    } else if (qobject_cast<QSplitterHandle *>(widget)) {
        QWidget *window(widget->window());
        WidgetMap::iterator iter(_widgets.find(window));
        if (iter == _widgets.end() || !iter.value()) {
            window->installEventFilter(&_addEventFilter);
            SplitterProxy *proxy(new SplitterProxy(window, _enabled));
            window->removeEventFilter(&_addEventFilter);

            widget->installEventFilter(proxy);
            _widgets.insert(window, proxy);
        } else {
            widget->removeEventFilter(iter.value().data());
            widget->installEventFilter(iter.value().data());
        }

        return true;
    } else {
        return false;
    }
}

//____________________________________________________________________
void SplitterFactory::unregisterWidget(QWidget *widget)
{
    WidgetMap::iterator iter(_widgets.find(widget));
    if (iter != _widgets.end()) {
        if (iter.value()) iter.value().data()->deleteLater();
        _widgets.erase(iter);
    }
}

//____________________________________________________________________
SplitterProxy::SplitterProxy(QWidget *parent, bool enabled):
    QWidget(parent),
    _enabled(enabled),
    _timerId(0)
{
    setAttribute(Qt::WA_TranslucentBackground, true);
    setAttribute(Qt::WA_OpaquePaintEvent, false);
    hide();
}

//____________________________________________________________________
SplitterProxy::~SplitterProxy(void)
{}

//____________________________________________________________________
void SplitterProxy::setEnabled(bool value)
{
    // make sure status has changed
    if (_enabled != value) {
        _enabled = value;
        if (_enabled) clearSplitter();
    }
}

//____________________________________________________________________
bool SplitterProxy::eventFilter(QObject *object, QEvent *event)
{
    // do nothing if disabled
    if (!_enabled) {
        return false;
    }

    // do nothing in case of mouse grab
    if (mouseGrabber()) {
        return false;
    }

    switch (event->type()) {
    case QEvent::HoverEnter:
        if (!isVisible()) {
            // cast to splitter handle
            if (QSplitterHandle *handle = qobject_cast<QSplitterHandle *>(object)) {
                setSplitter(handle);
            }
        }

        return false;
    case QEvent::HoverMove:
    case QEvent::HoverLeave:
        return isVisible() && object == _splitter.data();
    case QEvent::MouseMove:
    case QEvent::Timer:
    case QEvent::Move:
        return false;
    case QEvent::CursorChange:
        if (QWidget *window = qobject_cast<QMainWindow *>(object)) {
            if (window->cursor().shape() == Qt::SplitHCursor || window->cursor().shape() == Qt::SplitVCursor) {
                setSplitter(window);
            }
        }
        return false;
    case QEvent::WindowDeactivate:
    case QEvent::MouseButtonRelease:
        clearSplitter();
        return false;
    default:
        return false;
    }
}

//____________________________________________________________________
bool SplitterProxy::event(QEvent *event)
{
    switch (event->type()) {
#if 0
    case QEvent::Paint: {
        QPainter painter(this);
        painter.setClipRegion(static_cast<QPaintEvent *>(event)->region());
        painter.setRenderHints(QPainter::Antialiasing);
        painter.setPen(Qt::red);
        painter.drawRect(QRectF(rect()).adjusted(0.5, 0.5, -0.5, -0.5));
        return true;
    }
#endif
    case QEvent::MouseMove:
    case QEvent::MouseButtonPress:
    case QEvent::MouseButtonRelease: {
        // check splitter
        if (!_splitter) {
            return false;
        }
        event->accept();

        // grab on mouse press
        if (event->type() == QEvent::MouseButtonPress) {
            grabMouse();
            resize(1, 1);
        }

        // cast to mouse event
        QMouseEvent *mouseEvent(static_cast<QMouseEvent *>(event));

        // get relevant position to post mouse drag event to application
        if (event->type() == QEvent::MouseButtonPress) {
            // use hook, to make sure splitter is properly dragged
            QMouseEvent copy(
                mouseEvent->type(),
                _hook,
                _splitter.data()->mapToGlobal(_hook),
                mouseEvent->button(),
                mouseEvent->buttons(), mouseEvent->modifiers());

            QCoreApplication::sendEvent(_splitter.data(), &copy);
        } else {
            // map event position to current splitter and post.
            QMouseEvent copy(
                mouseEvent->type(),
                _splitter.data()->mapFromGlobal(mouseEvent->globalPos()),
                mouseEvent->globalPos(),
                mouseEvent->button(),
                mouseEvent->buttons(), mouseEvent->modifiers());

            QCoreApplication::sendEvent(_splitter.data(), &copy);
        }

        // release grab on mouse-Release
        if (event->type() == QEvent::MouseButtonRelease && mouseGrabber() == this) {
            releaseMouse();
        }

        return true;
    }
    case QEvent::Timer:
        if (static_cast<QTimerEvent *>(event)->timerId() != _timerId) {
            return QWidget::event(event);
        }
    /*
    Fall through is intended.
    We somehow lost a QEvent::Leave before timeout. We fix it from here
    */

    case QEvent::HoverLeave:
    case QEvent::Leave: {
        if (mouseGrabber() == this) {
            return true;
        }
        // reset splitter
        if (isVisible() && !rect().contains(mapFromGlobal(QCursor::pos()))) {
            clearSplitter();
        }
        return true;
    }
    default:
        return QWidget::event(event);

    }
}

//____________________________________________________________________
void SplitterProxy::setSplitter(QWidget *widget)
{
    // check if changed
    if (_splitter.data() == widget) {
        return;
    }

    // get cursor position
    QPoint position(QCursor::pos());

    // store splitter and hook
    _splitter = widget;
    _hook = _splitter.data()->mapFromGlobal(position);

    // adjust rect
    QRect rect(0, 0, 2 * Adwaita::Config::SplitterProxyWidth, 2 * Adwaita::Config::SplitterProxyWidth);
    rect.moveCenter(parentWidget()->mapFromGlobal(position));
    setGeometry(rect);
    setCursor(_splitter.data()->cursor().shape());

    // show
    raise();
    show();

    // timer used to automatically hide proxy in case leave events are lost
    if (!_timerId) {
        _timerId = startTimer(150);
    }
}

//____________________________________________________________________
void SplitterProxy::clearSplitter(void)
{
    // check if changed
    if (!_splitter) {
        return;
    }

    // release mouse
    if (mouseGrabber() == this) {
        releaseMouse();
    }

    // hide
    parentWidget()->setUpdatesEnabled(false);
    hide();
    parentWidget()->setUpdatesEnabled(true);

    // send hover event
    if (_splitter) {
        QHoverEvent hoverEvent(
            qobject_cast<QSplitterHandle *>(_splitter.data()) ? QEvent::HoverLeave : QEvent::HoverMove,
            _splitter.data()->mapFromGlobal(QCursor::pos()), _hook);
        QCoreApplication::sendEvent(_splitter.data(), &hoverEvent);
        _splitter.clear();
    }

    // kill timer if any
    if (_timerId) {
        killTimer(_timerId);
        _timerId = 0;
    }
}

} // namespace Adwaita
