/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the Qt Quick Calendar module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL3$
** 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 http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPLv3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or later 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 the GNU General Public License version 2.0 requirements will be
** met: http://www.gnu.org/licenses/gpl-2.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qquickcalendarmodel_p.h"

#include <QtCore/private/qabstractitemmodel_p.h>

QT_BEGIN_NAMESPACE

class QQuickCalendarModelPrivate : public QAbstractItemModelPrivate
{
    Q_DECLARE_PUBLIC(QQuickCalendarModel)

public:
    QQuickCalendarModelPrivate() : complete(false),
        from(1,1,1), to(275759, 9, 25), count(0)
    {
    }

    static int getCount(const QDate& from, const QDate &to);

    void populate(const QDate &from, const QDate &to, bool force = false);

    bool complete;
    QDate from;
    QDate to;
    int count;
};

int QQuickCalendarModelPrivate::getCount(const QDate& from, const QDate &to)
{
    QDate f(from.year(), from.month(), 1);
    QDate t(to.year(), to.month(), to.daysInMonth());
    QDate r = QDate(1, 1, 1).addDays(f.daysTo(t));
    int years = r.year() - 1;
    int months = r.month() - 1;
    return 12 * years + months + (r.day() / t.day());
}

void QQuickCalendarModelPrivate::populate(const QDate &f, const QDate &t, bool force)
{
    Q_Q(QQuickCalendarModel);
    if (!force && f == from && t == to)
        return;

    int c = getCount(from, to);
    if (c != count) {
        q->beginResetModel();
        count = c;
        q->endResetModel();
        emit q->countChanged();
    } else {
        emit q->dataChanged(q->index(0, 0), q->index(c - 1, 0));
    }
}

QQuickCalendarModel::QQuickCalendarModel(QObject *parent) :
    QAbstractListModel(*(new QQuickCalendarModelPrivate), parent)
{
}

QDate QQuickCalendarModel::from() const
{
    Q_D(const QQuickCalendarModel);
    return d->from;
}

void QQuickCalendarModel::setFrom(const QDate &from)
{
    Q_D(QQuickCalendarModel);
    if (d->from != from) {
        if (d->complete)
            d->populate(from, d->to);
        d->from = from;
        emit fromChanged();
    }
}

QDate QQuickCalendarModel::to() const
{
    Q_D(const QQuickCalendarModel);
    return d->to;
}

void QQuickCalendarModel::setTo(const QDate &to)
{
    Q_D(QQuickCalendarModel);
    if (d->to != to) {
        if (d->complete)
            d->populate(d->from, to);
        d->to = to;
        emit fromChanged();
    }
}

int QQuickCalendarModel::monthAt(int index) const
{
    Q_D(const QQuickCalendarModel);
    return d->from.addMonths(index).month();
}

int QQuickCalendarModel::yearAt(int index) const
{
    Q_D(const QQuickCalendarModel);
    return d->from.addMonths(index).year();
}

int QQuickCalendarModel::indexOf(const QDate &date) const
{
    return indexOf(date.year(), date.month());
}

int QQuickCalendarModel::indexOf(int year, int month) const
{
    Q_D(const QQuickCalendarModel);
    return d->getCount(d->from, QDate(year, month, 1)) - 1;
}

QVariant QQuickCalendarModel::data(const QModelIndex &index, int role) const
{
    Q_D(const QQuickCalendarModel);
    if (index.isValid() && index.row() < d->count) {
        switch (role) {
        case MonthRole:
            return monthAt(index.row());
        case YearRole:
            return yearAt(index.row());
        default:
            break;
        }
    }
    return QVariant();
}

int QQuickCalendarModel::rowCount(const QModelIndex &parent) const
{
    Q_D(const QQuickCalendarModel);
    if (!parent.isValid())
        return d->count;
    return 0;
}

QHash<int, QByteArray> QQuickCalendarModel::roleNames() const
{
    QHash<int, QByteArray> roles;
    roles[MonthRole] = QByteArrayLiteral("month");
    roles[YearRole] = QByteArrayLiteral("year");
    return roles;
}

void QQuickCalendarModel::classBegin()
{
}

void QQuickCalendarModel::componentComplete()
{
    Q_D(QQuickCalendarModel);
    d->complete = true;
    d->populate(d->from, d->to, true);
}

QT_END_NAMESPACE