/*
  Copyright (C) 2010 Casey Link <unnamedrambler@gmail.com>
  Copyright (c) 2009-2010 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>

  This library is free software; you can redistribute it and/or modify it
  under the terms of the GNU Library General Public License as published by
  the Free Software Foundation; either version 2 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 Library General Public
  License for more details.

  You should have received a copy of the GNU Library General Public License
  along with this library; see the file COPYING.LIB.  If not, write to the
  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  02110-1301, USA.
*/

#include "visualfreebusywidget.h"
#include "freebusyganttproxymodel.h"
#include "CalendarSupport/FreeBusyItemModel"

#include <KGantt/KGanttGraphicsView>
#include <KGantt/KGanttView>
#include <KGantt/KGanttDateTimeGrid>
#include <KGantt/KGanttAbstractRowController>

#include <KComboBox>
#include "incidenceeditor_debug.h"
#include <KLocalizedString>

#include <QHeaderView>
#include <QLabel>
#include <QPointer>
#include <QPushButton>
#include <QScrollBar>
#include <QSplitter>
#include <QTreeView>
#include <QVBoxLayout>

using namespace IncidenceEditorNG;

namespace IncidenceEditorNG {
class RowController : public KGantt::AbstractRowController
{
private:
    static const int ROW_HEIGHT;
    QPointer<QAbstractItemModel> m_model;

public:
    RowController()
    {
        mRowHeight = 20;
    }

    void setModel(QAbstractItemModel *model)
    {
        m_model = model;
    }

    int headerHeight() const override
    {
        return 2 * mRowHeight + 10;
    }

    bool isRowVisible(const QModelIndex &) const override
    {
        return true;
    }

    bool isRowExpanded(const QModelIndex &) const override
    {
        return false;
    }

    KGantt::Span rowGeometry(const QModelIndex &idx) const override
    {
        return KGantt::Span(idx.row() * mRowHeight, mRowHeight);
    }

    int maximumItemHeight() const override
    {
        return mRowHeight / 2;
    }

    int totalHeight() const override
    {
        return m_model->rowCount() * mRowHeight;
    }

    QModelIndex indexAt(int height) const override
    {
        return m_model->index(height / mRowHeight, 0);
    }

    QModelIndex indexBelow(const QModelIndex &idx) const override
    {
        if (!idx.isValid()) {
            return QModelIndex();
        }
        return idx.model()->index(idx.row() + 1, idx.column(), idx.parent());
    }

    QModelIndex indexAbove(const QModelIndex &idx) const override
    {
        if (!idx.isValid()) {
            return QModelIndex();
        }
        return idx.model()->index(idx.row() - 1, idx.column(), idx.parent());
    }

    void setRowHeight(int height)
    {
        mRowHeight = height;
    }

private:
    int mRowHeight;
};

class GanttHeaderView : public QHeaderView
{
public:
    explicit GanttHeaderView(QWidget *parent = nullptr) : QHeaderView(Qt::Horizontal, parent)
    {
    }

    QSize sizeHint() const override
    {
        QSize s = QHeaderView::sizeHint();
        s.rheight() *= 2;
        return s;
    }
};
}

VisualFreeBusyWidget::VisualFreeBusyWidget(CalendarSupport::FreeBusyItemModel *model, int spacing,
                                           QWidget *parent)
    : QWidget(parent)
    , mGanttGrid(nullptr)
    , mScaleCombo(nullptr)
{
    QVBoxLayout *topLayout = new QVBoxLayout(this);
    topLayout->setSpacing(spacing);

    // The control panel for the gantt widget
    QBoxLayout *controlLayout = new QHBoxLayout();
    controlLayout->setSpacing(topLayout->spacing());
    topLayout->addItem(controlLayout);

    QLabel *label = new QLabel(i18nc("@label", "Scale: "), this);
    controlLayout->addWidget(label);

    mScaleCombo = new KComboBox(this);
    mScaleCombo->setToolTip(
        i18nc("@info:tooltip", "Set the Gantt chart zoom level"));
    mScaleCombo->setWhatsThis(
        xi18nc("@info:whatsthis",
               "Select the Gantt chart zoom level from one of the following:<nl/>"
               "'Hour' shows a range of several hours,<nl/>"
               "'Day' shows a range of a few days,<nl/>"
               "'Week' shows a range of a few months,<nl/>"
               "and 'Month' shows a range of a few years,<nl/>"
               "while 'Automatic' selects the range most "
               "appropriate for the current event or to-do."));
    mScaleCombo->addItem(i18nc("@item:inlistbox range in hours", "Hour"),
                         QVariant::fromValue<int>(KGantt::DateTimeGrid::ScaleHour));
    mScaleCombo->addItem(i18nc("@item:inlistbox range in days", "Day"),
                         QVariant::fromValue<int>(KGantt::DateTimeGrid::ScaleDay));
    mScaleCombo->addItem(i18nc("@item:inlistbox range in weeks", "Week"),
                         QVariant::fromValue<int>(KGantt::DateTimeGrid::ScaleWeek));
    mScaleCombo->addItem(i18nc("@item:inlistbox range in months", "Month"),
                         QVariant::fromValue<int>(KGantt::DateTimeGrid::ScaleMonth));
    mScaleCombo->addItem(i18nc("@item:inlistbox range is computed automatically", "Automatic"),
                         QVariant::fromValue<int>(KGantt::DateTimeGrid::ScaleAuto));
    mScaleCombo->setCurrentIndex(0);   // start with "hour"
    connect(mScaleCombo, QOverload< int>::of(&KComboBox::activated), this, &VisualFreeBusyWidget::slotScaleChanged);
    controlLayout->addWidget(mScaleCombo);

    QPushButton *button = new QPushButton(i18nc("@action:button", "Center on Start"), this);
    button->setToolTip(
        i18nc("@info:tooltip",
              "Center the Gantt chart on the event start date and time"));
    button->setWhatsThis(
        i18nc("@info:whatsthis",
              "Click this button to center the Gantt chart on the start "
              "time and day of this event."));
    connect(button, &QPushButton::clicked, this, &VisualFreeBusyWidget::slotCenterOnStart);
    controlLayout->addWidget(button);

    controlLayout->addStretch(1);

    button = new QPushButton(i18nc("@action:button", "Pick Date"), this);
    button->setToolTip(
        i18nc("@info:tooltip",
              "Move the event to a date and time when all "
              "attendees are available"));
    button->setWhatsThis(
        i18nc("@info:whatsthis",
              "Click this button to move the event to a date "
              "and time when all the attendees have time "
              "available in their Free/Busy lists."));
    button->setEnabled(false);
    connect(button, &QPushButton::clicked, this, &VisualFreeBusyWidget::slotPickDate);
    controlLayout->addWidget(button);

    controlLayout->addStretch(1);

    button = new QPushButton(i18nc("@action:button reload freebusy data", "Reload"), this);
    button->setToolTip(
        i18nc("@info:tooltip",
              "Reload Free/Busy data for all attendees"));
    button->setWhatsThis(
        i18nc("@info:whatsthis",
              "Pressing this button will cause the Free/Busy data for all "
              "attendees to be reloaded from their corresponding servers."));
    controlLayout->addWidget(button);
    connect(button, &QPushButton::clicked, this, &VisualFreeBusyWidget::manualReload);

    QSplitter *splitter = new QSplitter(Qt::Horizontal, this);
    connect(splitter, &QSplitter::splitterMoved, this, &VisualFreeBusyWidget::splitterMoved);
    mLeftView = new QTreeView(this);
    mLeftView->setModel(model);
    mLeftView->setHeader(new GanttHeaderView);
    mLeftView->header()->setStretchLastSection(true);
    mLeftView->setRootIsDecorated(false);
    mLeftView->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    mLeftView->setContextMenuPolicy(Qt::CustomContextMenu);
    mGanttGraphicsView = new KGantt::GraphicsView(this);
    mGanttGraphicsView->setObjectName(QStringLiteral("mGanttGraphicsView"));
    mGanttGraphicsView->setToolTip(
        i18nc("@info:tooltip",
              "Shows the Free/Busy status of all attendees"));
    mGanttGraphicsView->setWhatsThis(
        i18nc("@info:whatsthis",
              "Shows the Free/Busy status of all attendees. "
              "Double-clicking on an attendee's entry in the "
              "list will allow you to enter the location of "
              "their Free/Busy Information."));
    mModel = new FreeBusyGanttProxyModel(this);
    mModel->setSourceModel(model);

    mRowController = new RowController;
    mRowController->setRowHeight(fontMetrics().height());   //TODO: detect

    mRowController->setModel(mModel);
    mGanttGraphicsView->setRowController(mRowController);

    mGanttGrid = new KGantt::DateTimeGrid;
    mGanttGrid->setScale(KGantt::DateTimeGrid::ScaleHour);
    mGanttGrid->setDayWidth(800);
    mGanttGrid->setRowSeparators(true);
    mGanttGraphicsView->setGrid(mGanttGrid);
    mGanttGraphicsView->setModel(mModel);
    mGanttGraphicsView->viewport()->setFixedWidth(800 * 30);

    splitter->addWidget(mLeftView);
    splitter->addWidget(mGanttGraphicsView);

    topLayout->addWidget(splitter);
    topLayout->setStretchFactor(splitter, 100);

    // Initially, show 15 days back and forth
    // set start to even hours, i.e. to 12:AM 0 Min 0 Sec
    QDateTime horizonStart
        = QDateTime(QDateTime::currentDateTime().addDays(-15).date());
    mGanttGrid->setStartDateTime(horizonStart);

    connect(mLeftView, &QTreeView::customContextMenuRequested, this,
            &VisualFreeBusyWidget::showAttendeeStatusMenu);

}

VisualFreeBusyWidget::~VisualFreeBusyWidget()
{
}

void VisualFreeBusyWidget::showAttendeeStatusMenu()
{
}

void VisualFreeBusyWidget::slotCenterOnStart()
{
    KGantt::DateTimeGrid *grid = static_cast<KGantt::DateTimeGrid *>(mGanttGraphicsView->grid());
    int daysTo = grid->startDateTime().daysTo(mDtStart);
    mGanttGraphicsView->horizontalScrollBar()->setValue(daysTo * 800);
}

void VisualFreeBusyWidget::slotIntervalColorRectangleMoved(const QDateTime &start,
                                                           const QDateTime &end)
{
    mDtStart = start;
    mDtEnd = end;
    Q_EMIT dateTimesChanged(start, end);
}

/*!
  This slot is called when the user clicks the "Pick a date" button.
*/
void VisualFreeBusyWidget::slotPickDate()
{
}

void VisualFreeBusyWidget::slotScaleChanged(int newScale)
{
    const QVariant var = mScaleCombo->itemData(newScale);
    Q_ASSERT(var.isValid());

    int value = var.toInt();
    mGanttGrid->setScale((KGantt::DateTimeGrid::Scale)value);
}

void VisualFreeBusyWidget::slotUpdateIncidenceStartEnd(const QDateTime &dtFrom,
                                                       const QDateTime &dtTo)
{
    mDtStart = dtFrom;
    mDtEnd = dtTo;
    QDateTime horizonStart = QDateTime(dtFrom.addDays(-15).date());
    KGantt::DateTimeGrid *grid = static_cast<KGantt::DateTimeGrid *>(mGanttGraphicsView->grid());
    grid->setStartDateTime(horizonStart);
    slotCenterOnStart();
    mGanttGrid->setStartDateTime(horizonStart);
}

void VisualFreeBusyWidget::slotZoomToTime()
{
#if 0
    mGanttGraphicsView->zoomToFit();
#else
    qCDebug(INCIDENCEEDITOR_LOG) << "Disabled code, port to KDGantt2";
#endif
}

void VisualFreeBusyWidget::splitterMoved()
{
}
