/****************************************************************************
 **
 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
 ** Contact: Qt Software Information (qt-info@nokia.com)
 **
 ** This file is part of the WebClient project on Trolltech Labs.
 **
 ** This file may be used under the terms of the GNU General Public
 ** License version 2.0 or 3.0 as published by the Free Software Foundation
 ** and appearing in the file LICENSE.GPL included in the packaging of
 ** this file.  Please review the following information to ensure GNU
 ** General Public Licensing requirements will be met:
 ** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
 ** http://www.gnu.org/copyleft/gpl.html.
 **
 ** If you are unsure which license is appropriate for your use, please
 ** contact the sales department at qt-sales@nokia.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 <QtGui>
#include "widgeteventhandler.h"
#include "webclient.h"

bool takeEvents = true;

class QLineEditAccess : public QLineEdit
{
public:
    void emitTextEdited(const QString &text) { QLineEdit::textChanged(text); QLineEdit::textEdited(text); }
};

class QTextEditAccess : public QTextEdit
{
public:
    void emitTextEdited(const QString &) { QTextEdit::textChanged(); }
};

void setTextOnWidget(QWidget *widget, const QString &text)
{
    if (QLineEdit * lineEdit = qobject_cast<QLineEdit *>(widget)) {
        lineEdit->setText(text);
        reinterpret_cast<QLineEditAccess *>(lineEdit)->emitTextEdited(text);
    } else if (QTextEdit * textEdit = qobject_cast<QTextEdit *>(widget)) {
        textEdit->setText(text);
        reinterpret_cast<QTextEditAccess *>(textEdit)->emitTextEdited(text);
    }
}

QWidget * findEventTarget(QWidget *root, QPoint pos)
{
    QWidget *current = root;
    QWidget *next = current->childAt(pos);

    while (next) {
        current = next;
        next = current->childAt(pos);
    }
    return current;
}


WidgetEventHandler::WidgetEventHandler(QObject *parent, Server *server)
: QObject(parent), graphicsWidget(false), grabbing(false), server(server)
{
    focusWidget = 0;
}

void WidgetEventHandler::setRootWidget(QWidget *root)
{
    DEBUG << "set root widget" << root;
    rootWidget = root;
    recursivelyInstallEventHandler(root);
}

bool WidgetEventHandler::shouldProcessChildWidgets(QWidget *widget)
{
    if (qobject_cast<QTextEdit *>(widget))
        return false;
    return true;
}

void WidgetEventHandler::recursivelyInstallEventHandler(QWidget *widget)
{
    if (server->shouldSkipUpdate(widget->metaObject()->className())) {
        //qDebug() << "skip plain widget" << widget;
    } else {
        widget->installEventFilter(this);
    }

    //qDebug << "event filter on" << widget->metaObject()->className() << widget->objectName() << int(widget);

    if (QLineEdit *lineEdit = qobject_cast<QLineEdit *>(widget)) {
        connect(lineEdit, SIGNAL(textChanged(const QString &)), this, SLOT(textChange()));
    } else if (QTextEdit *textEdit = qobject_cast<QTextEdit *>(widget)) {
        connect(textEdit, SIGNAL(textChanged()), this, SLOT(textChange()));
    } else if (QAbstractScrollArea *scrollArea = qobject_cast<QAbstractScrollArea *>(widget)) {
        recursivelyInstallEventHandler(scrollArea->viewport());
    }

    if (shouldProcessChildWidgets(widget) == false)
        return;

    foreach (QObject *child, widget->children()) {
        if (QWidget *childWidget = qobject_cast<QWidget *>(child))
            recursivelyInstallEventHandler(childWidget);
    }
}

void WidgetEventHandler::setSession(Session *session)
{
    events.setSession(session);
}

Session *WidgetEventHandler::session()
{
    return events.m_session;
}

void WidgetEventHandler::addPendingUpdate(QWidget* widget, const QRect &rect)
{
    if (pendingUpdates.isEmpty())
        QTimer::singleShot(0, this, SLOT(updatePendingWidgets()));

    pendingUpdates.insert(widget, rect);
}

bool WidgetEventHandler::eventFilter(QObject *object, QEvent *event)
{
    QWidget *widget = qobject_cast<QWidget *>(object);
    extern QWidget *sharedRoot;
    if (widget == sharedRoot)
        return true;
    if (event->type() == QEvent::Paint) {
        if (server->shouldSkipUpdate(widget->metaObject()->className())) {
           // qDebug() << "skip plain widget" << widget;
            return true;
        }

        if (QLabel *label = qobject_cast<QLabel *>(widget)) {
            events.addEvent(idForWidget(widget), EventEntry::TextUpdate);
            return true;
        } else if (QTextEdit *textEdit = qobject_cast<QTextEdit *>(widget)) {
            events.addEvent(idForWidget(widget), EventEntry::TextUpdate);
            return true;
        } else if (QPushButton *textEdit = qobject_cast<QPushButton *>(widget)) {
            events.addEvent(idForWidget(widget), EventEntry::TextUpdate);
            return true;
        }
        else if (!grabbing) {
            DEBUG << " add paint update" << object;
            addPendingUpdate(widget, static_cast<QPaintEvent*>(event)->rect());
        }
    }

    if (event->type() == QEvent::Show) {
        DEBUG << "show" << object;
        // Add immediate show update if we have an image to serve.
        if (events.images.contains(idForWidget(widget))) {
            addShowEvent(widget);
        }

        // Add pending paint update
        addPendingUpdate(widget, widget->rect());

        recursivelyAddShow(widget);
    }

    if (event->type() == QEvent::Hide) {
        DEBUG << "hide" << object;
        events.addEvent(idForWidget(widget), EventEntry::Hide);
        recursivelyAddHide(widget);
    }

    if (event->type() == QEvent::Move) {
        QRect geometry = globalGeometry(widget);
        DEBUG << "move geometry" << object->metaObject()->className() << geometry;
        if (disableUpdates.contains(sender()) == false)
            events.addGeometryEvent(idForWidget(widget), geometry);
    }

    if (event->type() == QEvent::Resize) {
        QRect geometry = globalGeometry(widget);
        DEBUG << "resize geometry" << geometry;

        events.addGeometryEvent(idForWidget(widget), geometry);
    }

    if (event->type() == QEvent::ParentChange) {
        DEBUG << "parentChange" << "parent"<< widget->parentWidget() << "child" << widget;
        events.addParentChangeEvent(idForWidget(widget));
    }

    return false;
}

void WidgetEventHandler::updatePendingWidgets()
{
    const QHash<QWidget *, QRect>::const_iterator end = pendingUpdates.end();
    QHash<QWidget *, QRect>::const_iterator it = pendingUpdates.begin();
    while(it != end) {
        widgetPaint(it.key(), it.value());
        ++it;
    }
    pendingUpdates.clear();
}

void WidgetEventHandler::handleRequest(HttpRequest *request, HttpResponse *response)
{
    const QByteArray path = request->path();
    bool handled = false;
    DEBUG << "request" << path;
    if (path.startsWith("/mousepress") || path.startsWith("/mouserelease") || path.startsWith("/mousedoubleclick")) {
//        DEBUG << "handle mouse press";
        handleMousePress(path);
        handled = true;
    } else if (path.startsWith("/keypress") || path.startsWith("/keyrelease")) {
        DEBUG << "handle key press";
        handleKeyPress(path);
        handled = true;
    } else if (path.startsWith("/json")) {
        handled = handleJsonMessage(path);
    }
    if (!handled) {
        if (path.startsWith("/content")) {
            events.reset(); // refresh everything
            recursivelyAddUpdate(rootWidget);
        }
        events.handleRequest(request, response);
    }
}

// Keep track of the current live widgets, to avoid dereferencing
// stale widget pointers when clients sends updated for a certain
// widget id. This also protects against malicious clients that
// sends fake ids.
quintptr WidgetEventHandler::idForWidget(QWidget *widget)
{
    quintptr id = reinterpret_cast<quintptr>(widget);
    if (liveWidgets.contains(id) == false) {
        liveWidgets.insert(id);
        connect(widget, SIGNAL(destroyed()), SLOT(widgetDeleted()));
    }
    return id;
}

QWidget *WidgetEventHandler::widgetForId(quintptr id)
{
    if (liveWidgets.contains(id))
        return reinterpret_cast<QWidget *>(id);
    return 0;
}

void WidgetEventHandler::widgetDeleted()
{
    liveWidgets.remove(reinterpret_cast<quintptr>(sender()));
}

bool WidgetEventHandler::handleJsonMessage(const QByteArray &message)
{
    QByteArray jsonText = QUrl::fromPercentEncoding(message.mid(5)).toUtf8(); // remove "/json", decode.
    DEBUG << "json request" << jsonText;
    json_object* request = json_tokener_parse(jsonText.data());
    json_object* type = json_object_object_get(request, "type");

    QByteArray typeText = json_object_get_string(type);
    DEBUG << typeText;

    if (typeText == "textupdate") {
        handleTextUpdate(request);
        json_object_put(request); //free
        return true;
    } else if (typeText == "positionupdate") {
        handlePositionUpdate(request);
        json_object_put(request); //free
        return true;
    }
    json_object_put(request); //free
    return false;
}


void WidgetEventHandler::handleMousePress(const QByteArray &message)
{
    QList<QByteArray> tokens = message.split('-');
    QPoint p(tokens.at(1).toInt(), tokens.at(2).toInt()); // ### assumes well-formed string

    QWidget *target = findEventTarget(rootWidget, p);

    QPoint local = target->mapFrom(rootWidget, p);

    if (message.startsWith("/mousepress")) {
        QMouseEvent press(QEvent::MouseButtonPress, local ,  Qt::LeftButton, Qt::LeftButton, Qt::NoModifier);
        QApplication::sendEvent(target, &press);
    } else if (message.startsWith("/mouserelease")) {
        QMouseEvent release(QEvent::MouseButtonRelease, local ,  Qt::LeftButton, Qt::LeftButton, Qt::NoModifier);
        QApplication::sendEvent(target, &release);
        focusWidget = target;
    } else if (message.startsWith("/mousedoubleclick")) {
        QMouseEvent press(QEvent::MouseButtonDblClick, local ,  Qt::LeftButton, Qt::LeftButton, Qt::NoModifier);
        QApplication::sendEvent(target, &press);
    }
}

void WidgetEventHandler::handleKeyPress(const QByteArray &message)
{
    if (!focusWidget)
        return;

    QList<QByteArray> tokens = message.split('-');
    int code = tokens.at(1).toInt(); // ###
    QChar c(code);

    if (code == 8) {
//                DEBUG << "backspace";
        QKeyEvent press(QEvent::KeyPress, Qt::Key_Backspace, Qt::NoModifier, QString());
        QKeyEvent release(QEvent::KeyRelease, Qt::Key_Backspace, Qt::NoModifier, QString());
        QApplication::sendEvent(focusWidget, &press);
        QApplication::sendEvent(focusWidget, &release);
    } else {
        QKeyEvent press(QEvent::KeyPress, code, Qt::NoModifier, c);
        QKeyEvent release(QEvent::KeyRelease, code, Qt::NoModifier, c);
        QApplication::sendEvent(focusWidget, &press);
        QApplication::sendEvent(focusWidget, &release);
    }
//    DEBUG << "got key press" << c;

    qApp->processEvents();
}

void WidgetEventHandler::handleTextUpdate(json_object* request)
{
    json_object* idObject = json_object_object_get(request, "id");
    const int id = json_object_get_int(idObject);
    json_object* tmp = json_object_object_get(request, "text");
    QByteArray text = json_object_get_string(tmp);

    QWidget *widget = widgetForId(id);
    if (!widget)
        return;

    disableUpdates.insert(widget);
    if (text == "enter!")  { // FIXME! :)
        QKeyEvent keyEvent(QEvent::KeyPress, Qt::Key_Return, Qt::NoModifier);
        qApp->sendEvent(widget, &keyEvent);
    } else {
        setTextOnWidget(widget, text);
    }
    disableUpdates.remove(widget);
}

void WidgetEventHandler::handlePositionUpdate(json_object *request)
{
    const int id = json_object_get_int(json_object_object_get(request, "id"));
    const int x = json_object_get_int(json_object_object_get(request, "x"));
    const int y = json_object_get_int(json_object_object_get(request, "y"));

    QWidget *widget = widgetForId(id);
    if (!widget)
        return;

    disableUpdates.insert(widget);
    widget->move(x, y);
    disableUpdates.remove(widget);
    //            DEBUG() << "position update" << id << x << y;
}

void WidgetEventHandler::widgetPaint(QWidget *widget, const QRect &updateRect)
{
    if (server->shouldSkipUpdate(widget->metaObject()->className())) {
            return ;
    }

    // Skip the painting step for static widgets that already has been painted,
    // but send the update event to the client.
    if (server->testHint(widget, WebClient::StaticWidget)) {
        if (events.staticCompressedImages.contains(idForWidget(widget))) {
            events.addStaticUpdateEvent(idForWidget(widget));
            return;
        }
    }

    DEBUG << "paint" << widget << widget->rect() << "update" << updateRect;

    QImage image(widget->size(), QImage::Format_ARGB32_Premultiplied);
    DEBUG << "widget->size" << widget->size();
    image.fill(QColor(0,0,0,0).rgba()); // fill with transparent pixels

    grabbing = true; // prevent recusion
    //DEBUG << "render";
    // grab widget only, no background or children
    widget->render(&image, QPoint(0,0), QRegion(QRect(QPoint(0,0), widget->size())), QWidget::RenderFlags(0));
    //DEBUG << "render done";
    grabbing = false;

    quintptr id = idForWidget(widget);

    // The visual representation of a static widget does not change. Store the images
    // for static widgets in png compressed form. Also store the hash of the
    // image, and send this as the identity and eTag to the client. This way
    // the client can cache the image, even across sessions when the widget
    // pointer (id) changes value.
    if (server->testHint(widget, WebClient::StaticWidget)){
        if (events.staticCompressedImages.contains(id) == false) {
            QByteArray compressedImage = EventQueue::pngCompress(image);
            uint hash = qHash(compressedImage);
            events.addStaticUpdateEvent(id, hash, compressedImage);
        }
    } else {
//    DEBUG << "update" << widget << (int)widget;
        events.addUpdateEvent(idForWidget(widget), image, updateRect);
    }
//    DEBUG << "geometry" << widget << (int)widget << globalGeometry(widget);
    events.addGeometryEvent(idForWidget(widget), globalGeometry(widget));
}

QRect WidgetEventHandler::globalGeometry(QWidget *widget)
{
//    QRect gemetry = widget->rect();
    QRect geometry;
    if (widget->isWindow())
        geometry = QRect(QPoint(0,0), widget->size());
    else
        geometry = QRect(widget->mapToParent(QPoint(0,0)), widget->size());
//    DEBUG << "geometry for" << widget << geometry;
    return geometry;
}


void WidgetEventHandler::recursivelyAddHide(QWidget *widget)
{
    events.addEvent((int)widget, EventEntry::Hide);

    if (shouldProcessChildWidgets(widget) == false)
        return;

    foreach (QObject *child, widget->children()) {
        if (QWidget *childWidget = qobject_cast<QWidget *>(child))
            recursivelyAddHide(childWidget);
    }
}

void WidgetEventHandler::recursivelyAddShow(QWidget *root)
{
    if (shouldProcessChildWidgets(root) == false)
        return;

    foreach (QObject *child, root->children()) {
        if (QWidget *childWidget = qobject_cast<QWidget *>(child)) {
            if (childWidget->isVisible() == false)
                continue;
            if (events.images.contains((int)childWidget)) {
                addShowEvent(childWidget);
            }
            // Add pending paint update
            addPendingUpdate(childWidget, childWidget->rect());
        }
    }
}

void WidgetEventHandler::recursivelyAddUpdate(QWidget *widget)
{
    if (widget->isVisible() == false)
        return;

    addShowEvent(widget);
    events.addGeometryEvent((int)widget, globalGeometry(widget));
    events.addParentChangeEvent((int) widget);

    if (QLineEdit *lineEdit = qobject_cast<QLineEdit *>(widget)) {
        events.addEvent((int)widget, EventEntry::TextUpdate);
    }
    else if (QTextEdit *textEdit = qobject_cast<QTextEdit *>(widget)) {
        events.addEvent((int)widget, EventEntry::TextUpdate);
    }
    else if (QPushButton *pusb = qobject_cast<QPushButton *>(widget)) {
        events.addEvent((int)widget, EventEntry::TextUpdate);
    }
    else if (QLabel *label = qobject_cast<QLabel *>(widget)) {
        events.addEvent((int)widget, EventEntry::TextUpdate);
    }

    // Add pending paint update
    addPendingUpdate(widget, widget->rect());

    if (shouldProcessChildWidgets(widget) == false)
        return;

    foreach (QObject *child, widget->children()) {
        if (QWidget *childWidget = qobject_cast<QWidget *>(child))
            recursivelyAddUpdate(childWidget);
    }
}

void WidgetEventHandler::addShowEvent(QWidget *widget)
{
    DEBUG << "add show event" << widget;
    events.addEvent((int)widget, EventEntry::Show);
}

void WidgetEventHandler::textChange()
{
    if (disableUpdates.contains(sender()) == false)
        events.addEvent((int)sender(), EventEntry::TextUpdate);
}