/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Designer of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL-EXCEPT$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "widgetselection.h"
#include "formwindow.h"
#include "formwindowmanager.h"

// sdk
#include <QtDesigner/abstractformeditor.h>
#include <QtDesigner/qextensionmanager.h>

// shared
#include <qdesigner_command_p.h>
#include <qdesigner_propertycommand_p.h>
#include <layout_p.h>
#include <layoutinfo_p.h>
#include <formwindowbase_p.h>
#include <grid_p.h>

#include <QtWidgets/qmenu.h>
#include <QtWidgets/qwidget.h>
#include <QtGui/qevent.h>
#include <QtWidgets/qstylepainter.h>
#include <QtWidgets/qgridlayout.h>
#include <QtWidgets/qformlayout.h>
#include <QtWidgets/qstyleoption.h>
#include <QtWidgets/qapplication.h>

#include <QtCore/qvariant.h>
#include <QtCore/qdebug.h>

#include <algorithm>

QT_BEGIN_NAMESPACE

namespace qdesigner_internal {
enum { debugWidgetSelection = 0 };

// Return the layout the widget is in
template <class Layout>
static inline Layout *managedLayoutOf(const QDesignerFormEditorInterface *core,
                                      QWidget *w,
                                      const Layout * /* vs6dummy */ = nullptr)
{
    if (QWidget *p = w->parentWidget())
        if (QLayout *l = LayoutInfo::managedLayout(core, p))
            return qobject_cast<Layout*>(l);
    return nullptr;
}

// ----------- WidgetHandle
WidgetHandle::WidgetHandle(FormWindow *parent, WidgetHandle::Type t, WidgetSelection *s) :
    InvisibleWidget(parent->formContainer()),
    m_widget(nullptr),
    m_type(t),
    m_formWindow( parent),
    m_sel(s),
    m_active(true)
{
    setMouseTracking(false);
    setAutoFillBackground(true);

    setBackgroundRole(m_active ? QPalette::Text : QPalette::Dark);
    setFixedSize(6, 6);

    updateCursor();
}

void WidgetHandle::updateCursor()
{
#if QT_CONFIG(cursor)
    if (!m_active) {
        setCursor(Qt::ArrowCursor);
        return;
    }

    switch (m_type) {
    case LeftTop:
        setCursor(Qt::SizeFDiagCursor);
        break;
    case Top:
        setCursor(Qt::SizeVerCursor);
        break;
    case RightTop:
        setCursor(Qt::SizeBDiagCursor);
        break;
    case Right:
        setCursor(Qt::SizeHorCursor);
        break;
    case RightBottom:
        setCursor(Qt::SizeFDiagCursor);
        break;
    case Bottom:
        setCursor(Qt::SizeVerCursor);
        break;
    case LeftBottom:
        setCursor(Qt::SizeBDiagCursor);
        break;
    case Left:
        setCursor(Qt::SizeHorCursor);
        break;
    default:
        Q_ASSERT(0);
    }
#endif
}

QDesignerFormEditorInterface *WidgetHandle::core() const
{
    if (m_formWindow)
        return m_formWindow->core();

    return nullptr;
}

void WidgetHandle::setActive(bool a)
{
    m_active = a;
    setBackgroundRole(m_active ? QPalette::Text : QPalette::Dark);
    updateCursor();
}

void WidgetHandle::setWidget(QWidget *w)
{
    m_widget = w;
}

void WidgetHandle::paintEvent(QPaintEvent *)
{
    QDesignerFormWindowManagerInterface *m = m_formWindow->core()->formWindowManager();

    QStylePainter p(this);
    if (m_formWindow->currentWidget() == m_widget) {
        p.setPen(m->activeFormWindow() == m_formWindow ? Qt::blue : Qt::red);
        p.drawRect(0, 0, width() - 1, height() - 1);
    }
}

void WidgetHandle::mousePressEvent(QMouseEvent *e)
{
    e->accept();

    if (!m_formWindow->hasFeature(FormWindow::EditFeature))
        return;

    if (!(m_widget && e->button() == Qt::LeftButton))
        return;

    if (!(m_active))
        return;

    QWidget *container = m_widget->parentWidget();

    m_origPressPos = container->mapFromGlobal(e->globalPosition().toPoint());
    m_geom = m_origGeom = m_widget->geometry();

    switch (WidgetSelection::widgetState(m_formWindow->core(), m_widget)) {
    case WidgetSelection::UnlaidOut:
    case WidgetSelection::LaidOut:
        m_formWindow->setHandleOperation(FormWindow::ResizeHandleOperation);
        break;
    case WidgetSelection::ManagedGridLayout:
    case WidgetSelection::ManagedFormLayout:
        m_formWindow->setHandleOperation(FormWindow::ChangeLayoutSpanHandleOperation);
        break;
    }
}

void WidgetHandle::mouseMoveEvent(QMouseEvent *e)
{
    if (!(m_widget && m_active && e->buttons() & Qt::LeftButton))
        return;

    e->accept();

    QWidget *container = m_widget->parentWidget();

    const QPoint rp = container->mapFromGlobal(e->globalPosition().toPoint());
    const QPoint d = rp - m_origPressPos;

    const QRect pr = container->rect();

    qdesigner_internal::Grid grid;
    if (const qdesigner_internal::FormWindowBase *fwb = qobject_cast<const qdesigner_internal::FormWindowBase*>(m_formWindow))
        grid = fwb->designerGrid();

    switch (m_type) {

    case LeftTop: {
        if (rp.x() > pr.width() - 2 * width() || rp.y() > pr.height() - 2 * height())
            return;

        int w = m_origGeom.width() - d.x();
        m_geom.setWidth(w);
        w = grid.widgetHandleAdjustX(w);

        int h = m_origGeom.height() - d.y();
        m_geom.setHeight(h);
        h = grid.widgetHandleAdjustY(h);

        const int dx = m_widget->width() - w;
        const int dy = m_widget->height() - h;

        trySetGeometry(m_widget, m_widget->x() + dx, m_widget->y() + dy, w, h);
    } break;

    case Top: {
        if (rp.y() > pr.height() - 2 * height())
            return;

        int h = m_origGeom.height() - d.y();
        m_geom.setHeight(h);
        h = grid.widgetHandleAdjustY(h);

        const int dy = m_widget->height() - h;
        trySetGeometry(m_widget, m_widget->x(), m_widget->y() + dy, m_widget->width(), h);
    } break;

    case RightTop: {
        if (rp.x() < 2 * width() || rp.y() > pr.height() - 2 * height())
            return;

        int h = m_origGeom.height() - d.y();
        m_geom.setHeight(h);
        h = grid.widgetHandleAdjustY(h);

        const int dy = m_widget->height() - h;

        int w = m_origGeom.width() + d.x();
        m_geom.setWidth(w);
        w = grid.widgetHandleAdjustX(w);

        trySetGeometry(m_widget, m_widget->x(), m_widget->y() + dy, w, h);
    } break;

    case Right: {
        if (rp.x() < 2 * width())
            return;

        int w = m_origGeom.width() + d.x();
        m_geom.setWidth(w);
        w = grid.widgetHandleAdjustX(w);

        tryResize(m_widget, w, m_widget->height());
    } break;

    case RightBottom: {
        if (rp.x() < 2 * width() || rp.y() < 2 * height())
            return;

        int w = m_origGeom.width() + d.x();
        m_geom.setWidth(w);
        w = grid.widgetHandleAdjustX(w);

        int h = m_origGeom.height() + d.y();
        m_geom.setHeight(h);
        h = grid.widgetHandleAdjustY(h);

        tryResize(m_widget, w, h);
    } break;

    case Bottom: {
        if (rp.y() < 2 * height())
            return;

        int h = m_origGeom.height() + d.y();
        m_geom.setHeight(h);
        h = grid.widgetHandleAdjustY(h);

        tryResize(m_widget, m_widget->width(), h);
    } break;

    case LeftBottom: {
        if (rp.x() > pr.width() - 2 * width() || rp.y() < 2 * height())
            return;

        int w = m_origGeom.width() - d.x();
        m_geom.setWidth(w);
        w = grid.widgetHandleAdjustX(w);

        int h = m_origGeom.height() + d.y();
        m_geom.setHeight(h);
        h = grid.widgetHandleAdjustY(h);

        int dx = m_widget->width() - w;

        trySetGeometry(m_widget, m_widget->x() + dx, m_widget->y(), w, h);
    } break;

    case Left: {
        if (rp.x() > pr.width() - 2 * width())
            return;

        int w = m_origGeom.width() - d.x();
        m_geom.setWidth(w);
        w = grid.widgetHandleAdjustX(w);

        const int dx = m_widget->width() - w;

        trySetGeometry(m_widget, m_widget->x() + dx, m_widget->y(), w, m_widget->height());
    } break;

    default: break;

    } // end switch

    m_sel->updateGeometry();

    if (LayoutInfo::layoutType(m_formWindow->core(), m_widget) != LayoutInfo::NoLayout)
        m_formWindow->updateChildSelections(m_widget);
}

void WidgetHandle::mouseReleaseEvent(QMouseEvent *e)
{
    m_formWindow->setHandleOperation(FormWindow::NoHandleOperation);

    if (e->button() != Qt::LeftButton || !m_active)
        return;

    e->accept();

    if (!m_formWindow->hasFeature(FormWindow::EditFeature))
        return;

    switch (WidgetSelection::widgetState(m_formWindow->core(), m_widget)) {
    case WidgetSelection::UnlaidOut:
       if (m_geom != m_widget->geometry()) {
           SetPropertyCommand *cmd = new SetPropertyCommand(m_formWindow);
           cmd->init(m_widget, QStringLiteral("geometry"), m_widget->geometry());
           cmd->setOldValue(m_origGeom);
           m_formWindow->commandHistory()->push(cmd);
           m_formWindow->emitSelectionChanged();
       }
       break;
    case WidgetSelection::LaidOut:
       break;
    case WidgetSelection::ManagedGridLayout:
       changeGridLayoutItemSpan();
       break;
    case WidgetSelection::ManagedFormLayout:
        changeFormLayoutItemSpan();
        break;
    }
}

// Match the left/right widget handle mouse movements to form layout span-changing operations
static inline int formLayoutLeftHandleOperation(int dx, unsigned possibleOperations)
{
    if (dx < 0) {
        if (possibleOperations & ChangeFormLayoutItemRoleCommand::FieldToSpanning)
            return ChangeFormLayoutItemRoleCommand::FieldToSpanning;
        return 0;
    }
    if (possibleOperations & ChangeFormLayoutItemRoleCommand::SpanningToField)
        return ChangeFormLayoutItemRoleCommand::SpanningToField;
    return 0;
}

static inline int formLayoutRightHandleOperation(int dx, unsigned possibleOperations)
{
    if (dx < 0) {
        if (possibleOperations & ChangeFormLayoutItemRoleCommand::SpanningToLabel)
            return ChangeFormLayoutItemRoleCommand::SpanningToLabel;
        return 0;
    }
    if (possibleOperations & ChangeFormLayoutItemRoleCommand::LabelToSpanning)
        return ChangeFormLayoutItemRoleCommand::LabelToSpanning;
    return 0;
}

// Change form layout item horizontal span
void WidgetHandle::changeFormLayoutItemSpan()
{
    QUndoCommand *cmd = nullptr;
    // Figure out command according to the movement
    const int dx = m_widget->geometry().center().x() - m_origGeom.center().x();
    if (qAbs(dx) >= QApplication::startDragDistance()) {
        int operation = 0;
        if (const unsigned possibleOperations = ChangeFormLayoutItemRoleCommand::possibleOperations(m_formWindow->core(), m_widget)) {
            switch (m_type) {
            case WidgetHandle::Left:
                operation = formLayoutLeftHandleOperation(dx, possibleOperations);
                break;
            case WidgetHandle::Right:
                operation = formLayoutRightHandleOperation(dx, possibleOperations);
                break;
            default:
                break;
            }
            if (operation) {
                ChangeFormLayoutItemRoleCommand *fcmd = new ChangeFormLayoutItemRoleCommand(m_formWindow);
                fcmd->init(m_widget, static_cast<ChangeFormLayoutItemRoleCommand::Operation>(operation));
                cmd = fcmd;
            }
        }
    }
    if (cmd) {
        m_formWindow->commandHistory()->push(cmd);
    } else {
        // Cancelled/Invalid. Restore the size of the widget.
        if (QFormLayout *form = managedLayoutOf<QFormLayout>(m_formWindow->core(), m_widget)) {
            form->invalidate();
            form->activate();
            m_formWindow->clearSelection(false);
            m_formWindow->selectWidget(m_widget);
        }
    }
}

void WidgetHandle::changeGridLayoutItemSpan()
{
    QDesignerLayoutDecorationExtension *deco = qt_extension<QDesignerLayoutDecorationExtension*>(core()->extensionManager(), m_widget->parentWidget());
    if (!deco)
       return;
    QGridLayout *grid = managedLayoutOf<QGridLayout>(m_formWindow->core(), m_widget);
    if (!grid)
       return;

    const int index = deco->indexOf(m_widget);
    const QRect info = deco->itemInfo(index);
    const int top = deco->findItemAt(info.top() - 1, info.left());
    const int left = deco->findItemAt(info.top(), info.left() - 1);
    const int bottom = deco->findItemAt(info.bottom() + 1, info.left());
    const int right = deco->findItemAt(info.top(), info.right() + 1);

    const QPoint pt = m_origGeom.center() - m_widget->geometry().center();

    ChangeLayoutItemGeometry *cmd = nullptr;

    switch (m_type) {
    default:
       break;

    case WidgetHandle::Top: {
       if (pt.y() < 0 && info.height() > 1) {
           cmd = new ChangeLayoutItemGeometry(m_formWindow);
           cmd->init(m_widget, info.y() + 1, info.x(), info.height() - 1, info.width());
       } else if (pt.y() > 0 && top != -1 && grid->itemAt(top)->spacerItem()) {
           cmd = new ChangeLayoutItemGeometry(m_formWindow);
           cmd->init(m_widget, info.y() - 1, info.x(), info.height() + 1, info.width());
       }
    }
       break;

    case WidgetHandle::Left: {
       if (pt.x() < 0 && info.width() > 1) {
           cmd = new ChangeLayoutItemGeometry(m_formWindow);
           cmd->init(m_widget, info.y(), info.x() + 1, info.height(), info.width() - 1);
       } else if (pt.x() > 0 && left != -1 && grid->itemAt(left)->spacerItem()) {
           cmd = new ChangeLayoutItemGeometry(m_formWindow);
           cmd->init(m_widget, info.y(), info.x() - 1, info.height(), info.width() + 1);
       }
    }
       break;

    case WidgetHandle::Right: {
       if (pt.x() > 0 && info.width() > 1) {
           cmd = new ChangeLayoutItemGeometry(m_formWindow);
           cmd->init(m_widget, info.y(), info.x(), info.height(), info.width() - 1);
       } else if (pt.x() < 0 && right != -1 && grid->itemAt(right)->spacerItem()) {
           cmd = new ChangeLayoutItemGeometry(m_formWindow);
           cmd->init(m_widget, info.y(), info.x(), info.height(), info.width() + 1);
       }
    }
       break;

    case WidgetHandle::Bottom: {
       if (pt.y() > 0 && info.height() > 1) {
           cmd = new ChangeLayoutItemGeometry(m_formWindow);
           cmd->init(m_widget, info.y(), info.x(), info.height() - 1, info.width());
       } else if (pt.y() < 0 && bottom != -1 && grid->itemAt(bottom)->spacerItem()) {
           cmd = new ChangeLayoutItemGeometry(m_formWindow);
           cmd->init(m_widget, info.y(), info.x(), info.height() + 1, info.width());
       }
    }
       break;
    }

    if (cmd != nullptr) {
       m_formWindow->commandHistory()->push(cmd);
    } else {
       grid->invalidate();
       grid->activate();
       m_formWindow->clearSelection(false);
       m_formWindow->selectWidget(m_widget);
    }
}

void WidgetHandle::trySetGeometry(QWidget *w, int x, int y, int width, int height)
{
    if (!m_formWindow->hasFeature(FormWindow::EditFeature))
        return;

    int minw = w->minimumSize().width();
    minw = qMax(minw, 2 * m_formWindow->grid().x());

    int minh = w->minimumSize().height();
    minh = qMax(minh, 2 * m_formWindow->grid().y());

    if (qMax(minw, width) > w->maximumWidth() ||
         qMax(minh, height) > w->maximumHeight())
        return;

    if (width < minw && x != w->x())
        x -= minw - width;

    if (height < minh && y != w->y())
        y -= minh - height;

    w->setGeometry(x, y, qMax(minw, width), qMax(minh, height));
}

void WidgetHandle::tryResize(QWidget *w, int width, int height)
{
    int minw = w->minimumSize().width();
    minw = qMax(minw, 16);

    int minh = w->minimumSize().height();
    minh = qMax(minh, 16);

    w->resize(qMax(minw, width), qMax(minh, height));
}

// ------------------ WidgetSelection

WidgetSelection::WidgetState WidgetSelection::widgetState(const QDesignerFormEditorInterface *core, QWidget *w)
{
    bool isManaged;
    const LayoutInfo::Type  lt =  LayoutInfo::laidoutWidgetType(core, w, &isManaged);
    if (lt == LayoutInfo::NoLayout)
       return UnlaidOut;
    if (!isManaged)
        return LaidOut;
    switch (lt) {
    case LayoutInfo::Grid:
        return ManagedGridLayout;
    case  LayoutInfo::Form:
        return ManagedFormLayout;
    default:
        break;
    }
    return LaidOut;
}

WidgetSelection::WidgetSelection(FormWindow *parent)   :
    m_widget(nullptr),
    m_formWindow(parent)
{
    for (int i = WidgetHandle::LeftTop; i < WidgetHandle::TypeCount; ++i)
        m_handles[i] = new WidgetHandle(m_formWindow, static_cast<WidgetHandle::Type>(i), this);
    hide();
}

void WidgetSelection::setWidget(QWidget *w)
{
    if (m_widget != nullptr)
        m_widget->removeEventFilter(this);

    if (w == nullptr) {
        hide();
        m_widget = nullptr;
        return;
    }

    m_widget = w;

    m_widget->installEventFilter(this);

    updateActive();

    updateGeometry();
    show();
}

void WidgetSelection::updateActive()
{
    const WidgetState ws = widgetState(m_formWindow->core(), m_widget);
    bool active[WidgetHandle::TypeCount];
    std::fill(active, active + WidgetHandle::TypeCount, false);
    // Determine active handles
    switch (ws) {
    case UnlaidOut:
        std::fill(active, active + WidgetHandle::TypeCount, true);
        break;
    case ManagedGridLayout: // Grid: Allow changing span
        active[WidgetHandle::Left] = active[WidgetHandle::Top] = active[WidgetHandle::Right] = active[WidgetHandle::Bottom] = true;
        break;
    case ManagedFormLayout:  // Form: Allow changing column span
        if (const unsigned operation = ChangeFormLayoutItemRoleCommand::possibleOperations(m_formWindow->core(), m_widget)) {
            active[WidgetHandle::Left]  = operation & (ChangeFormLayoutItemRoleCommand::SpanningToField|ChangeFormLayoutItemRoleCommand::FieldToSpanning);
            active[WidgetHandle::Right] = operation & (ChangeFormLayoutItemRoleCommand::SpanningToLabel|ChangeFormLayoutItemRoleCommand::LabelToSpanning);
        }
        break;
    default:
        break;
    }

    for (int i = WidgetHandle::LeftTop; i < WidgetHandle::TypeCount; ++i)
        if (WidgetHandle *h = m_handles[i]) {
            h->setWidget(m_widget);
            h->setActive(active[i]);
        }
}

bool WidgetSelection::isUsed() const
{
    return m_widget != nullptr;
}

void WidgetSelection::updateGeometry()
{
    if (!m_widget || !m_widget->parentWidget())
        return;

    QPoint p = m_widget->parentWidget()->mapToGlobal(m_widget->pos());
    p = m_formWindow->formContainer()->mapFromGlobal(p);
    const QRect r(p, m_widget->size());

    const int w = 6;
    const int h = 6;

    for (int i = WidgetHandle::LeftTop; i < WidgetHandle::TypeCount; ++i) {
        WidgetHandle *hndl = m_handles[ i ];
        if (!hndl)
            continue;
        switch (i) {
        case WidgetHandle::LeftTop:
            hndl->move(r.x() - w / 2, r.y() - h / 2);
            break;
        case WidgetHandle::Top:
            hndl->move(r.x() + r.width() / 2 - w / 2, r.y() - h / 2);
            break;
        case WidgetHandle::RightTop:
            hndl->move(r.x() + r.width() - w / 2, r.y() - h / 2);
            break;
        case WidgetHandle::Right:
            hndl->move(r.x() + r.width() - w / 2, r.y() + r.height() / 2 - h / 2);
            break;
        case WidgetHandle::RightBottom:
            hndl->move(r.x() + r.width() - w / 2, r.y() + r.height() - h / 2);
            break;
        case WidgetHandle::Bottom:
            hndl->move(r.x() + r.width() / 2 - w / 2, r.y() + r.height() - h / 2);
            break;
        case WidgetHandle::LeftBottom:
            hndl->move(r.x() - w / 2, r.y() + r.height() - h / 2);
            break;
        case WidgetHandle::Left:
            hndl->move(r.x() - w / 2, r.y() + r.height() / 2 - h / 2);
            break;
        default:
            break;
        }
    }
}

void WidgetSelection::hide()
{
    for (WidgetHandle *h : m_handles) {
        if (h)
            h->hide();
    }
}

void WidgetSelection::show()
{
    for (WidgetHandle *h : m_handles) {
        if (h) {
            h->show();
            h->raise();
        }
    }
}

void WidgetSelection::update()
{
    for (WidgetHandle *h : m_handles) {
        if (h)
            h->update();
    }
}

QWidget *WidgetSelection::widget() const
{
    return m_widget;
}

QDesignerFormEditorInterface *WidgetSelection::core() const
{
    if (m_formWindow)
        return m_formWindow->core();

    return nullptr;
}

bool WidgetSelection::eventFilter(QObject *object, QEvent *event)
{
    if (object != widget())
        return false;

    switch (event->type()) {
        default: break;

        case QEvent::Move:
        case QEvent::Resize:
            updateGeometry();
            break;
        case QEvent::ZOrderChange:
            show();
            break;
    } // end switch

    return false;
}

}

QT_END_NAMESPACE
