#include <QtGui>
#include <QtSql>

#include "sqltreemodel.h"

void doBranches( int id, const QString& name, int depth )
{
	int d = depth - 1;
	int n = qrand() % 10;
	QSqlQuery query;
	for ( int i = 0; i < n; i++ ) {
		QString str = name + QString('1' + i);
		query.exec( QString("INSERT INTO Object(ParentId, Name) VALUES(%1,'%2')").arg(id).arg(str) );
		query.exec( "SELECT last_insert_rowid()" );
		if ( query.first() && d ) {
			int ni = query.value(0).toInt();
			doBranches( ni, str, d );
		}
	}
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
	db.setDatabaseName(":memory:");
    if (!db.open()) {
		qFatal("Can't open database");
    }
	QSqlQuery query;
	query.exec("CREATE TABLE Object (Id integer primary key autoincrement, ParentId integer, Name varchar)");
	qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
	doBranches( 0, "Item", 3 );
	query.exec("CREATE INDEX ParentIdx ON Object(ParentId)");

	SqlTreeModel model(db);
    QTreeView view;
    view.setModel(&model);
    view.setWindowTitle(QObject::tr("SQL Tree Model"));
    view.show();
    return app.exec();
}

#include <QtGui>
#include <QtSql>

#include "sqltreemodel.h"

// Database access functions

QVariant SqlTreeModel::getData( int id, int column ) const 
{
	if ( column != 0 )
		return QVariant();
	QSqlQuery query(db);
	query.exec( QString("SELECT Name FROM Object WHERE Id = %1").arg(id) );
	if ( !query.next() ) 
		return QVariant();
	return query.value(0);	 
}

int SqlTreeModel::getParent( int id ) const 
{
	QSqlQuery query(db);
	query.exec( QString("SELECT ParentId FROM Object WHERE Id = %1").arg(id) );
	if ( !query.next() ) 
		return -1;
	return query.value(0).toInt();	 
}

int SqlTreeModel::getChildCount( int parent ) const 
{
	QSqlQuery query(db);
	query.exec( QString("SELECT count(*) FROM Object WHERE ParentId = %1").arg(parent) );
	if ( !query.next() )
		return 0;
	int cnt = query.value(0).toInt();
	return cnt;
}

int SqlTreeModel::getChild( int parent, int index ) const 
{
	QSqlQuery query(db);
	if ( !query.exec( QString("SELECT Id FROM Object WHERE ParentId = %1 ORDER BY Id").arg(parent) ) )
		return 0;
	int i = 0;
	while ( query.next() ) {
		if ( i == index ) {
			int id = query.value(0).toInt();
			return id;
		}
		++i;
	}
	return 0;
}

int SqlTreeModel::getChildIndex( int parent, int child ) const 
{
	QSqlQuery query(db);
	if ( !query.exec( QString("SELECT Id FROM Object WHERE ParentId = %1 ORDER BY Id").arg(parent) )  )
		return -1;
	int index = 0;
	while ( query.next() ) {
		int id = query.value(0).toInt();
		if ( id == child )
			return index;
		++index;
	}
	return -1;
}

//---------------------------------------------------

SqlTreeModel::SqlTreeModel(QSqlDatabase database, QObject *parent)
    : db(database), QAbstractItemModel(parent)
{
}


SqlTreeModel::~SqlTreeModel()
{
}


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


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

    if (role != Qt::DisplayRole)
        return QVariant();

	return getData( index.internalId(), index.column() );
}


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

    return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
}

QVariant SqlTreeModel::headerData(int section, Qt::Orientation orientation,
                               int role) const
{
    if (orientation == Qt::Horizontal && role == Qt::DisplayRole)
        return QString("Name");

    return QVariant();
}

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

    int parentId;

    if (!parent.isValid())
        parentId = 0;
    else
        parentId = parent.internalId();

    int childId = getChild(parentId, row);
    if (childId > 0)
        return createIndex(row, column, childId);
    else
        return QModelIndex();
}

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

    int childId = index.internalId();
    int parentId = getParent(childId);

    if (parentId <= 0)
        return QModelIndex();

	int row = getChildIndex(parentId, childId);
    return createIndex(row, 0, parentId);
}

int SqlTreeModel::rowCount(const QModelIndex &parent) const
{
    if (parent.column() > 0)
        return 0;

	int parentId;
    if (!parent.isValid())
        parentId = 0;
    else
        parentId = parent.internalId();

    return getChildCount(parentId);
}