/*
 *  Copyright 2013-2016  Andreas Cord-Landwehr <cordlandwehr@kde.org>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) version 3, or any
 *  later version accepted by the membership of KDE e.V. (or its
 *  successor approved by the membership of KDE e.V.), which shall
 *  act as a proxy defined in Section 6 of version 3 of the license.
 *
 *  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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "learninggoalmodel.h"
#include "profilemanager.h"
#include "learner.h"

#include <QAbstractItemModel>
#include <QAbstractListModel>
#include <QSignalMapper>

#include <KLocalizedString>
#include "liblearner_debug.h"

using namespace LearnerProfile;

// private class LearningGoalModelPrivate
class LearningGoalModelPrivate {
public:
    LearningGoalModelPrivate()
        : m_profileManager(nullptr)
        , m_learner(nullptr)
        , m_signalMapper(new QSignalMapper())
    {
    }

    ~LearningGoalModelPrivate()
    {
        delete m_signalMapper;
    }

    void updateGoals();
    void updateMappings();

    ProfileManager *m_profileManager;
    Learner *m_learner;
    QList<LearningGoal*> m_goals;
    QSignalMapper *m_signalMapper;
};

void LearningGoalModelPrivate::updateGoals()
{
    m_goals.clear();
    // if learner is set, only set its goals
    if (m_learner) {
        foreach (LearningGoal *goal, m_learner->goals()) {
            m_goals.append(goal);
        }
        return;
    }
    // else set all registered goals from profile manager
    if (m_profileManager) {
        foreach (LearningGoal *goal, m_profileManager->goals()) {
            m_goals.append(goal);
        }
    }
}

void LearningGoalModelPrivate::updateMappings()
{
    if (!m_profileManager) {
        return;
    }
    int goals = m_goals.count();
    for (int i = 0; i < goals; ++i) {
        m_signalMapper->setMapping(m_goals.at(i), i);
    }
}

// class LearningGoalModel
LearningGoalModel::LearningGoalModel(QObject *parent)
    : QAbstractListModel(parent)
    , d(new LearningGoalModelPrivate)
{
    connect(d->m_signalMapper, static_cast<void (QSignalMapper::*)(int)>(&QSignalMapper::mapped),
            this, &LearningGoalModel::emitLearningGoalChanged);
}

LearningGoalModel::~LearningGoalModel()
{

}

QHash< int, QByteArray > LearningGoalModel::roleNames() const
{
    QHash<int, QByteArray> roles;
    roles[TitleRole] = "title";
    roles[IdRole] = "id";
    roles[DataRole] = "dataRole";

    return roles;
}

void LearningGoalModel::setProfileManager(ProfileManager *profileManager)
{
    if (d->m_profileManager == profileManager) {
        return;
    }

    beginResetModel();

    if (d->m_profileManager) {
        d->m_profileManager->disconnect(this);
    }

    d->m_profileManager = profileManager;
    d->updateGoals();
    d->updateMappings();
    endResetModel();

    emit profileManagerChanged();
}

ProfileManager * LearningGoalModel::profileManager() const
{
    return d->m_profileManager;
}

Learner * LearningGoalModel::learner() const
{
    return d->m_learner;
}

void LearningGoalModel::setLearner(Learner *learner)
{
    if (!learner) {
        return;
    }
    emit beginResetModel();
    if (d->m_learner) {
        learner->disconnect(this);
    }
    d->m_learner = learner;
    d->updateGoals();
    d->updateMappings();
    connect(learner, &Learner::goalAboutToBeAdded,
            this, &LearningGoalModel::onLearningGoalAboutToBeAdded);
    connect(learner, &Learner::goalAdded,
            this, &LearningGoalModel::onLearningGoalAdded);
    connect(learner, &Learner::goalAboutToBeRemoved, this,
            &LearningGoalModel::onLearningGoalAboutToBeRemoved);
    emit learnerChanged();
    emit endResetModel();
}

QVariant LearningGoalModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid()) {
        return QVariant();
    }

    if (index.row() >= d->m_goals.count()) {
        return QVariant();
    }

    LearningGoal * const goal = d->m_goals.at(index.row());

    switch(role)
    {
    case Qt::DisplayRole:
        return !goal->name().isEmpty()?
                QVariant(goal->name()): QVariant(i18nc("@item:inlistbox:", "unknown"));
    case Qt::ToolTipRole:
        return QVariant(goal->name());
    case TitleRole:
        return goal->name();
    case IdRole:
        return goal->identifier();
    case DataRole:
        return QVariant::fromValue<QObject*>(goal);
    default:
        return QVariant();
    }
}

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

void LearningGoalModel::onLearningGoalAboutToBeAdded(LearningGoal *goal, int index)
{
    Q_UNUSED(index)
    beginInsertRows(QModelIndex(), d->m_goals.count(), d->m_goals.count());
    d->m_goals.append(goal);
    d->updateMappings();
}

void LearningGoalModel::onLearningGoalAdded()
{
    endInsertRows();
}

void LearningGoalModel::onLearningGoalAboutToBeRemoved(int index)
{
    if (!d->m_learner) {
        return;
    }

    if (index < 0 || d->m_goals.count() <= index) {
        qCWarning(LIBLEARNER_LOG) << "Cannot remove learning goal from model, not registered";
        return;
    }
    beginRemoveRows(QModelIndex(), index, index);
    d->m_goals.removeAt(index);
    d->updateMappings();
    endRemoveRows();
}

void LearningGoalModel::emitLearningGoalChanged(int row)
{
    emit learningGoalChanged(row);
    emit dataChanged(index(row, 0), index(row, 0));
}

QVariant LearningGoalModel::headerData(int section, Qt::Orientation orientation, int role) const
{
    if (role != Qt::DisplayRole) {
        return QVariant();
    }
    if (orientation == Qt::Vertical) {
        return QVariant(section + 1);
    }
    return QVariant(i18nc("@title:column", "Learning Goal"));
}

QVariant LearningGoalModel::learningGoal(int row) const
{
    return data(index(row, 0), LearningGoalModel::DataRole);
}
