/*********
*
* In the name of the Father, and of the Son, and of the Holy Spirit.
*
* This file is part of BibleTime's source code, http://www.bibletime.info/.
*
* Copyright 1999-2009 by the BibleTime developers.
* The BibleTime source code is licensed under the GNU General Public License
* version 2.0.
*
**********/

#include "backend/bookshelfmodel/btbookshelftreemodel.h"

#include <QSet>
#include "backend/bookshelfmodel/categoryitem.h"
#include "backend/bookshelfmodel/distributionitem.h"
#include "backend/bookshelfmodel/languageitem.h"
#include "backend/bookshelfmodel/moduleitem.h"


using namespace BookshelfModel;

BtBookshelfTreeModel::BtBookshelfTreeModel(QObject *parent)
        : QAbstractItemModel(parent), m_sourceModel(0), m_rootItem(new RootItem),
        m_defaultChecked(MODULE_HIDDEN), m_checkable(false) {
    m_groupingOrder.push_back(GROUP_CATEGORY);
    m_groupingOrder.push_back(GROUP_LANGUAGE);
}

BtBookshelfTreeModel::BtBookshelfTreeModel(const Grouping &g, QObject *parent)
        : QAbstractItemModel(parent), m_sourceModel(0), m_rootItem(new RootItem),
        m_groupingOrder(g), m_defaultChecked(MODULE_HIDDEN), m_checkable(false)
{
    // Intentionally empty
}

BtBookshelfTreeModel::~BtBookshelfTreeModel() {
    delete m_rootItem;
}

int BtBookshelfTreeModel::rowCount(const QModelIndex &parent) const {
    return getItem(parent)->children().size();
}

int BtBookshelfTreeModel::columnCount(const QModelIndex &parent) const {
    return 1;
}

bool BtBookshelfTreeModel::hasChildren(const QModelIndex &parent) const {
    return !getItem(parent)->children().isEmpty();
}

QModelIndex BtBookshelfTreeModel::index(int row, int column,
                                        const QModelIndex &parent) const {
    if (!hasIndex(row, column, parent)) return QModelIndex();

    Item *parentItem(getItem(parent));
    Item *childItem(parentItem->childAt(row));
    if (childItem != 0) {
        return createIndex(row, column, childItem);
    }
    else {
        return QModelIndex();
    }
}

QModelIndex BtBookshelfTreeModel::parent(const QModelIndex &index) const {
    if (!index.isValid()) return QModelIndex();

    Item *childItem(static_cast<Item*>(index.internalPointer()));
    Q_ASSERT(childItem != 0);
    Item *parentItem(childItem->parent());
    Q_ASSERT(parentItem != 0);

    if (parentItem == m_rootItem) {
        return QModelIndex();
    }
    return createIndex(parentItem->childIndex(), 0, parentItem);
}

QVariant BtBookshelfTreeModel::data(const QModelIndex &index, int role) const {
    if (!index.isValid() || index.column() != 0) {
        return QVariant();
    }

    Item *i(static_cast<Item*>(index.internalPointer()));
    Q_ASSERT(i != 0);
    switch (role) {
        case Qt::DisplayRole:
            if (i->type() == Item::ITEM_MODULE) {
                return parentData(static_cast<ModuleItem *>(i), role);
            } else {
                return i->name();
            }
        case Qt::CheckStateRole:
            if (!m_checkable) break;
        case BtBookshelfTreeModel::CheckStateRole:
            return i->checkState();
        case Qt::DecorationRole:
            if (i->type() == Item::ITEM_MODULE) {
                return parentData(static_cast<ModuleItem *>(i), role);
            } else {
                return i->icon();
            }
        case BtBookshelfModel::ModulePointerRole:
            if (i->type() == Item::ITEM_MODULE) {
                ModuleItem *mi(static_cast<ModuleItem *>(i));
                return qVariantFromValue((void*) mi->moduleInfo());
            }
            return 0;
        case BtBookshelfModel::ModuleHiddenRole:
            return i->isHidden();
        default:
            if (i->type() == Item::ITEM_MODULE) {
                return parentData(static_cast<ModuleItem *>(i), role);
            }
            break;
    }
    return QVariant();
}

bool BtBookshelfTreeModel::setData(const QModelIndex &itemIndex,
                                   const QVariant &value,
                                   int role) {
    typedef QPair<Item *, QModelIndex> IP;

    Qt::CheckState newState;
    if (role == BtBookshelfModel::ModuleHiddenRole) {
        newState = value.toBool() ? Qt::Checked : Qt::Unchecked;
    } else if (role == Qt::CheckStateRole) {
        bool ok;
        newState = (Qt::CheckState) value.toInt(&ok);
        if (!ok || newState == Qt::PartiallyChecked) return false;
    } else {
        return false;
    }

    Item *item(static_cast<Item*>(itemIndex.internalPointer()));
    Q_ASSERT(item != 0);
    if (item->checkState() == newState) return false;

    // Recursively (un)check all children:
    QList<IP> q;
    IP p(item, itemIndex);
    for (;;) {
        if (item->checkState() != newState) {
            item->setCheckState(newState);
            emit dataChanged(p.second, p.second);
            if (item->type() == Item::ITEM_MODULE) {
                ModuleItem *mi(static_cast<ModuleItem*>(item));
                emit moduleChecked(mi->moduleInfo(), newState == Qt::Checked);
            } else {
                const QList<Item*> &children(item->children());
                for (int i(0); i < children.size(); i++) {
                    q.append(IP(children.at(i), index(i, 0, p.second)));
                }
            }
        }
        if (q.empty()) break;
        p = q.takeFirst();
        item = p.first;
    }

    // Recursively change parent check states.
    resetParentCheckStates(itemIndex.parent());

    return true;
}

Qt::ItemFlags BtBookshelfTreeModel::flags(const QModelIndex &index) const {
    if (!index.isValid()) return 0;

    Qt::ItemFlags f(Qt::ItemIsEnabled | Qt::ItemIsSelectable);

    if (m_checkable) {
        f |= Qt::ItemIsUserCheckable;

        Item *i(static_cast<Item*>(index.internalPointer()));
        Q_ASSERT(i != 0);

        if (i->type() != Item::ITEM_MODULE) {
            f |= Qt::ItemIsTristate;
        }
    }

    return f;
}

QVariant BtBookshelfTreeModel::headerData(int section,
        Qt::Orientation orientation,
        int role) const {
    if (orientation == Qt::Horizontal) {
        return m_sourceModel->headerData(section, orientation, role);
    }
    return QVariant();
}

void BtBookshelfTreeModel::setSourceModel(QAbstractItemModel *sourceModel) {
    if (m_sourceModel == sourceModel) return;

    if (m_sourceModel != 0) {
        disconnect(this, SLOT(moduleInserted(QModelIndex, int, int)));
        disconnect(this, SLOT(moduleRemoved(QModelIndex, int, int)));
        disconnect(this, SLOT(moduleDataChanged(QModelIndex, QModelIndex)));
        beginRemoveRows(QModelIndex(), 0, m_rootItem->children().size() - 1);
        delete m_rootItem;
        m_modules.clear();
        m_sourceIndexMap.clear();
        m_rootItem = new RootItem;
        endRemoveRows();
    }

    m_sourceModel = sourceModel;

    if (sourceModel != 0) {
        connect(sourceModel, SIGNAL(rowsAboutToBeRemoved(QModelIndex, int, int)),
                this,        SLOT(moduleRemoved(QModelIndex, int, int)));
        connect(sourceModel, SIGNAL(rowsInserted(QModelIndex, int, int)),
                this,        SLOT(moduleInserted(QModelIndex, int, int)));
        connect(sourceModel, SIGNAL(dataChanged(QModelIndex, QModelIndex)),
                this,        SLOT(moduleDataChanged(QModelIndex, QModelIndex)));

        for (int i(0); i < sourceModel->rowCount(); i++) {
            typedef BtBookshelfModel::ModuleRole MRole;
            static const MRole HR(BtBookshelfModel::ModuleHiddenRole);
            static const MRole PR(BtBookshelfModel::ModulePointerRole);
            QModelIndex moduleIndex(sourceModel->index(i, 0));
            CSwordModuleInfo *module(
                static_cast<CSwordModuleInfo *>(
                    sourceModel->data(moduleIndex, PR).value<void*>()
                )
            );
            Q_ASSERT(module != 0);
            bool checked;
            if (m_defaultChecked == MODULE_HIDDEN) {
                checked = !sourceModel->data(moduleIndex, HR).toBool();
            } else {
                checked = (m_defaultChecked == CHECKED);
            }
            m_sourceIndexMap[module] = moduleIndex;
            addModule(module, checked);
        }
    }
}

void BtBookshelfTreeModel::setGroupingOrder(const Grouping &groupingOrder) {
    if (m_groupingOrder == groupingOrder) return;
    m_groupingOrder = groupingOrder;

    if (m_sourceModel != 0) {
        QSet<CSwordModuleInfo*> checked(checkedModules().toSet());
        beginRemoveRows(QModelIndex(), 0, m_rootItem->children().size() - 1);
        delete m_rootItem;
        m_modules.clear();
        m_rootItem = new RootItem;
        endRemoveRows();

        BtBookshelfModel *m(dynamic_cast<BtBookshelfModel*>(m_sourceModel));
        if (m != 0) {
            Q_FOREACH(CSwordModuleInfo *module, m->modules()) {
                addModule(module, checked.contains(module));
            }
        }
        else {
            for (int i(0); i < m_sourceModel->rowCount(); i++) {
                CSwordModuleInfo *module(
                    static_cast<CSwordModuleInfo *>(
                        m_sourceModel->data(
                            m_sourceModel->index(i, 0),
                            BtBookshelfModel::ModulePointerRole
                        ).value<void*>()
                    )
                );
                Q_ASSERT(module != 0);
                addModule(module, checked.contains(module));
            }
        }
    }
}

void BtBookshelfTreeModel::setCheckable(bool checkable) {
    if (m_checkable == checkable) return;
    m_checkable = checkable;
    if (m_sourceModel != 0) {
        QModelIndexList queue;
        queue.append(QModelIndex());
        do {
            QModelIndex parent(queue.takeFirst());
            int numChildren(rowCount(parent));
            emit dataChanged(index(0, 0, parent),
                             index(numChildren - 1, 0, parent));
            for (int i(0); i < numChildren; i++) {
                QModelIndex childIndex(index(i, 0, parent));
                if (rowCount(childIndex) > 0) {
                    queue.append(childIndex);
                }
            }
        }
        while (!queue.isEmpty());
    }
}

QList<CSwordModuleInfo*> BtBookshelfTreeModel::checkedModules() const {
    typedef ModuleItemMap::const_iterator MMCI;

    QList<CSwordModuleInfo*> modules;
    for (MMCI it(m_modules.constBegin()); it != m_modules.constEnd(); it++) {
        if (it.value()->checkState() == Qt::Checked) {
            modules.append(it.key());
        }
    }
    return modules;
}

QVariant BtBookshelfTreeModel::parentData(BookshelfModel::ModuleItem *item,
                                          int role) const
{
    CSwordModuleInfo* m(item->moduleInfo());
    Q_ASSERT(m_sourceIndexMap.contains(m));
    return m_sourceModel->data(m_sourceIndexMap.value(m), role);
}

void BtBookshelfTreeModel::addModule(CSwordModuleInfo *module, bool checked) {
    if (m_modules.contains(module)) return;
    Grouping g(m_groupingOrder);
    addModule(module, QModelIndex(), g, checked);

    /**
      \bug Calling reset() shouldn't be necessary here, but omitting it will
           will break things like switching to a grouped layout or installing
           new modules. As a side effect, all attached views will also reset
           themselves.
    */
    reset();
}

void BtBookshelfTreeModel::addModule(CSwordModuleInfo *module,
                                     QModelIndex parentIndex,
                                     Grouping &intermediateGrouping,
                                     bool checked) {
    Q_ASSERT(module != 0);

    if (!intermediateGrouping.empty()) {
        QModelIndex newIndex;
        switch (intermediateGrouping.front()) {
            case GROUP_DISTRIBUTION:
                newIndex = getGroup<DistributionItem>(module, parentIndex);
                break;
            case GROUP_CATEGORY:
                newIndex = getGroup<CategoryItem>(module, parentIndex);
                break;
            case GROUP_LANGUAGE:
                newIndex = getGroup<LanguageItem>(module, parentIndex);
                break;
        }
        intermediateGrouping.pop_front();
        addModule(module, newIndex, intermediateGrouping, checked);
    }
    else {
        Item *parentItem(getItem(parentIndex));
        ModuleItem *newItem(new ModuleItem(module));
        newItem->setCheckState(checked ? Qt::Checked : Qt::Unchecked);
        const int newIndex(parentItem->indexFor(newItem));
        beginInsertRows(parentIndex, newIndex, newIndex);
        parentItem->insertChild(newIndex, newItem);
        m_modules.insert(module, newItem);
        endInsertRows();
        resetParentCheckStates(parentIndex);
    }
}

void BtBookshelfTreeModel::removeModule(CSwordModuleInfo *module) {
    if (!m_modules.contains(module)) return;

    Item *i(m_modules[module]);

    // Set i to be the lowest item (including empty groups) to remove:
    Q_ASSERT(i->parent() != 0);
    while (i->parent() != m_rootItem && i->parent()->children().size() <= 1) {
        i = i->parent();
    }
    Q_ASSERT(i != 0);
    Q_ASSERT(i->parent() != 0);

    // Remove item:
    int index(i->childIndex());
    QModelIndex parentIndex(getIndex(i->parent()));
    beginRemoveRows(parentIndex, index, index);
    i->parent()->deleteChildAt(index);
    m_modules.remove(module);
    endRemoveRows();
    resetParentCheckStates(parentIndex);
}

Item *BtBookshelfTreeModel::getItem(const QModelIndex &index) const {
    if (index.isValid()) {
        Item *item(static_cast<Item*>(index.internalPointer()));
        Q_ASSERT(item != 0);
        return item;
    }
    else {
        return m_rootItem;
    }
}

QModelIndex BtBookshelfTreeModel::getIndex(const BookshelfModel::Item *item) {
    Q_ASSERT(item != 0);

    QList<int> indexes;
    for (;;) {
        int i(item->childIndex());
        if (i < 0) break;
        indexes.append(i);
        item = item->parent();
    }

    QModelIndex i;
    while (!indexes.isEmpty()) {
        i = index(indexes.takeLast(), 0, i);
    }
    return i;
}

void BtBookshelfTreeModel::resetParentCheckStates(QModelIndex parentIndex) {
    for ( ; parentIndex.isValid(); parentIndex = parentIndex.parent()) {
        Item *parentItem(static_cast<Item*>(parentIndex.internalPointer()));
        Q_ASSERT(parentItem != 0);

        Qt::CheckState oldState(parentItem->checkState());
        bool haveCheckedChildren(false);
        bool haveUncheckedChildren(false);
        for (int i(0); i < parentItem->children().size(); i++) {
            Qt::CheckState state(parentItem->childAt(i)->checkState());
            if (state == Qt::PartiallyChecked) {
                haveCheckedChildren = true;
                haveUncheckedChildren = true;
                break;
            }
            else if (state == Qt::Checked) {
                haveCheckedChildren = true;
                if (haveUncheckedChildren) break;
            }
            else if (state == Qt::Unchecked) {
                haveUncheckedChildren = true;
                if (haveCheckedChildren) break;
            }
        }

        Qt::CheckState newState;
        if (haveCheckedChildren) {
            if (haveUncheckedChildren) {
                newState = Qt::PartiallyChecked;
            }
            else {
                newState = Qt::Checked;
            }
        }
        else {
            newState = Qt::Unchecked;
        }
        if (newState == oldState) break;

        parentItem->setCheckState(newState);
        emit dataChanged(parentIndex, parentIndex);
    } // for ( ; parentIndex.isValid(); parentIndex = parentIndex.parent())
}

void BtBookshelfTreeModel::moduleDataChanged(const QModelIndex &topLeft,
        const QModelIndex &bottomRight) {
    typedef BtBookshelfModel BM;
    static const BM::ModuleRole PR(BM::ModulePointerRole);

    Q_ASSERT(!topLeft.parent().isValid());
    Q_ASSERT(!bottomRight.parent().isValid());
    Q_ASSERT(topLeft.column() == 0 && bottomRight.column() == 0);

    for (int i(topLeft.row()); i <= bottomRight.row(); i++) {
        QModelIndex moduleIndex(m_sourceModel->index(i, 0, topLeft.parent()));
        QVariant data(m_sourceModel->data(moduleIndex, PR));
        CSwordModuleInfo *module((CSwordModuleInfo *) (data.value<void*>()));
        QModelIndex itemIndex(getIndex(m_modules[module]));
        Q_ASSERT(itemIndex.isValid());

        emit dataChanged(itemIndex, itemIndex);

        /*
          Also emit signals for parent items because the change might alter them
          as well, e.g. isHidden()
        */
        do {
            itemIndex = itemIndex.parent();
            emit dataChanged(itemIndex, itemIndex);
        } while (itemIndex.isValid());
    }
}

void BtBookshelfTreeModel::moduleInserted(const QModelIndex &parent, int start,
        int end) {
    typedef BtBookshelfModel BM;
    static const BM::ModuleRole PR(BM::ModulePointerRole);
    static const BM::ModuleRole HR(BM::ModuleHiddenRole);

    for (int i(start); i <= end; i++) {
        QModelIndex moduleIndex(m_sourceModel->index(i, 0, parent));
        QVariant data(m_sourceModel->data(moduleIndex, PR));
        CSwordModuleInfo *module((CSwordModuleInfo *) (data.value<void*>()));

        bool checked;
        if (m_defaultChecked == MODULE_HIDDEN) {
            checked = !m_sourceModel->data(moduleIndex, HR).toBool();
        } else {
            checked = (m_defaultChecked == CHECKED);
        }
        m_sourceIndexMap[module] = moduleIndex;
        addModule(module, checked);
    }
}

void BtBookshelfTreeModel::moduleRemoved(const QModelIndex &parent, int start,
        int end) {
    typedef BtBookshelfModel BM;
    static const BM::ModuleRole PR(BM::ModulePointerRole);

    for (int i(start); i <= end; i++) {
        QModelIndex moduleIndex(m_sourceModel->index(i, 0, parent));
        QVariant data(m_sourceModel->data(moduleIndex, PR));
        CSwordModuleInfo *module((CSwordModuleInfo *) (data.value<void*>()));

        removeModule(module);
        m_sourceIndexMap.remove(module);
    }
}

QDataStream &operator<<(QDataStream &os, const BtBookshelfTreeModel::Grouping &o) {
    os << o.size();
    Q_FOREACH(BtBookshelfTreeModel::Group g, o) {
        os << (int) g;
    }
    return os;
}

QDataStream &operator>>(QDataStream &is, BtBookshelfTreeModel::Grouping &o) {
    int s;
    is >> s;
    for (int i(0); i < s; i++) {
        int g;
        is >> g;
        o.append((BtBookshelfTreeModel::Group) g);
    }
    return is;
}