/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Data Visualization module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
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** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) any later version
** approved by the KDE Free Qt Foundation. The licenses are as published by
** the Free Software Foundation and appearing in the file LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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****************************************************************************/

#include "abstractitemmodelhandler_p.h"

QT_BEGIN_NAMESPACE_DATAVISUALIZATION

AbstractItemModelHandler::AbstractItemModelHandler(QObject *parent)
    : QObject(parent),
      resolvePending(0),
      m_fullReset(true)
{
    m_resolveTimer.setSingleShot(true);
    QObject::connect(&m_resolveTimer, &QTimer::timeout,
                     this, &AbstractItemModelHandler::handlePendingResolve);
}

AbstractItemModelHandler::~AbstractItemModelHandler()
{
}

void AbstractItemModelHandler::setItemModel(QAbstractItemModel *itemModel)
{
    if (itemModel != m_itemModel.data()) {
        if (!m_itemModel.isNull())
            QObject::disconnect(m_itemModel, 0, this, 0);

        m_itemModel = itemModel;

        if (!m_itemModel.isNull()) {
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::columnsInserted,
                             this, &AbstractItemModelHandler::handleColumnsInserted);
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::columnsMoved,
                             this, &AbstractItemModelHandler::handleColumnsMoved);
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::columnsRemoved,
                             this, &AbstractItemModelHandler::handleColumnsRemoved);
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::dataChanged,
                             this, &AbstractItemModelHandler::handleDataChanged);
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::layoutChanged,
                             this, &AbstractItemModelHandler::handleLayoutChanged);
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::modelReset,
                             this, &AbstractItemModelHandler::handleModelReset);
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::rowsInserted,
                             this, &AbstractItemModelHandler::handleRowsInserted);
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::rowsMoved,
                             this, &AbstractItemModelHandler::handleRowsMoved);
            QObject::connect(m_itemModel.data(), &QAbstractItemModel::rowsRemoved,
                             this, &AbstractItemModelHandler::handleRowsRemoved);
        }
        if (!m_resolveTimer.isActive())
            m_resolveTimer.start(0);

        emit itemModelChanged(itemModel);
    }
}

QAbstractItemModel *AbstractItemModelHandler::itemModel() const
{
    return m_itemModel.data();
}

void AbstractItemModelHandler::handleColumnsInserted(const QModelIndex &parent,
                                                     int start, int end)
{
    Q_UNUSED(parent)
    Q_UNUSED(start)
    Q_UNUSED(end)

    // Manipulating columns changes all rows in proxies that map rows/columns directly,
    // and its effects are not clearly defined in others -> always do full reset.
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleColumnsMoved(const QModelIndex &sourceParent,
                                                  int sourceStart,
                                                  int sourceEnd,
                                                  const QModelIndex &destinationParent,
                                                  int destinationColumn)
{
    Q_UNUSED(sourceParent)
    Q_UNUSED(sourceStart)
    Q_UNUSED(sourceEnd)
    Q_UNUSED(destinationParent)
    Q_UNUSED(destinationColumn)

    // Manipulating columns changes all rows in proxies that map rows/columns directly,
    // and its effects are not clearly defined in others -> always do full reset.
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleColumnsRemoved(const QModelIndex &parent,
                                                    int start, int end)
{
    Q_UNUSED(parent)
    Q_UNUSED(start)
    Q_UNUSED(end)

    // Manipulating columns changes all rows in proxies that map rows/columns directly,
    // and its effects are not clearly defined in others -> always do full reset.
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleDataChanged(const QModelIndex &topLeft,
                                                 const QModelIndex &bottomRight,
                                                 const QVector<int> &roles)
{
    Q_UNUSED(topLeft)
    Q_UNUSED(bottomRight)
    Q_UNUSED(roles)

    // Default handling for dataChanged is to do full reset, as it cannot be optimized
    // in a general case, where we do not know which row/column/index the item model item
    // actually ended up to in the proxy.
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleLayoutChanged(const QList<QPersistentModelIndex> &parents,
                                                   QAbstractItemModel::LayoutChangeHint hint)
{
    Q_UNUSED(parents)
    Q_UNUSED(hint)

    // Resolve entire model if layout changes
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleModelReset()
{
    // Data cleared, reset array
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleRowsInserted(const QModelIndex &parent, int start, int end)
{
    Q_UNUSED(parent)
    Q_UNUSED(start)
    Q_UNUSED(end)

    // Default handling for rowsInserted is to do full reset, as it cannot be optimized
    // in a general case, where we do not know which row/column/index the item model item
    // actually ended up to in the proxy.
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleRowsMoved(const QModelIndex &sourceParent,
                                               int sourceStart,
                                               int sourceEnd,
                                               const QModelIndex &destinationParent,
                                               int destinationRow)
{
    Q_UNUSED(sourceParent)
    Q_UNUSED(sourceStart)
    Q_UNUSED(sourceEnd)
    Q_UNUSED(destinationParent)
    Q_UNUSED(destinationRow)

    // Default handling for rowsMoved is to do full reset, as it cannot be optimized
    // in a general case, where we do not know which row/column/index the item model item
    // actually ended up to in the proxy.
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleRowsRemoved(const QModelIndex &parent, int start, int end)
{
    Q_UNUSED(parent)
    Q_UNUSED(start)
    Q_UNUSED(end)

    // Default handling for rowsRemoved is to do full reset, as it cannot be optimized
    // in a general case, where we do not know which row/column/index the item model item
    // actually ended up to in the proxy.
    if (!m_resolveTimer.isActive()) {
        m_fullReset = true;
        m_resolveTimer.start(0);
    }
}

void AbstractItemModelHandler::handleMappingChanged()
{
    if (!m_resolveTimer.isActive())
        m_resolveTimer.start(0);
}

void AbstractItemModelHandler::handlePendingResolve()
{
    resolveModel();
    m_fullReset = false;
}

QT_END_NAMESPACE_DATAVISUALIZATION