// Copyright (C) 2008  Lukas Lalinsky
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

#include <QGraphicsScene>
#include <QDebug>
#include "databasetable.h"
#include "databaserelation.h"

DatabaseRelation::DatabaseRelation(QGraphicsItem *parent)
	: DatabaseModelItem(parent), m_source(0), m_target(0)
{
	setFlag(ItemIsSelectable);
}

QRectF
DatabaseRelation::boundingRect() const
{
	return shape().boundingRect();
	//return QRectF(m_line.p1(), m_line.p2()).normalized();
}

QPainterPath
DatabaseRelation::shape() const
{
	QPainterPath path;
	path.moveTo(m_line.p1());
	path.lineTo(m_line.p2());
	path.addPolygon(m_arrowHead);
	QPen pen(QPen(QColor(0, 0, 0), 1));
	pen.setJoinStyle(Qt::MiterJoin);
	QPainterPathStroker ps;
	ps.setCapStyle(pen.capStyle());
	ps.setWidth(pen.widthF() + 0.3);
	ps.setJoinStyle(pen.joinStyle());
	ps.setMiterLimit(pen.miterLimit());
	return ps.createStroke(path);
}

void
DatabaseRelation::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
	Q_UNUSED(option);
	Q_UNUSED(widget);

	QPen pen(QPen(QColor(0, 0, 0), 1));
	pen.setJoinStyle(Qt::MiterJoin);
	painter->setPen(pen);
	painter->drawLine(m_line);
	painter->setBrush(pen.color());
	painter->drawPolygon(m_arrowHead);
}

void
DatabaseRelation::setSource(DatabaseTable *source)
{
	m_source = source;
	if (scene()) {
		updateLayout();
	}
}

void
DatabaseRelation::setTarget(DatabaseTable *target)
{
	m_target = target;
	if (scene()) {
		updateLayout();
	}
}

QVariant
DatabaseRelation::itemChange(GraphicsItemChange change, const QVariant &value)
{
	if (change == ItemSceneHasChanged) {
		updateLayout();
	}
	return QGraphicsItem::itemChange(change, value);
}

void
DatabaseRelation::updatePositions()
{
	updateLayout();
}

void
DatabaseRelation::updateLayout()
{
	if (!scene())
		return;

	prepareGeometryChange();

	QRectF rect1 = m_source->boundingRect().translated(m_source->pos());
	QRectF rect2 = m_target->boundingRect().translated(m_target->pos());

	QPointF p1 = rect1.center();
	QPointF p2 = rect2.center();
	m_line = QLineF(p1, p2);

	QPolygonF polygon;

	polygon = rect1;
	for (int i = 0; i < 4; i++) {
		QLineF line(polygon[i], polygon[(i+1)%4]);
		QPointF intersectionPoint;
		if (m_line.intersect(line, &intersectionPoint) == QLineF::BoundedIntersection) {
			m_line.setP1(intersectionPoint);
			break;
		}
	}

	polygon = rect2;
	for (int i = 0; i < 4; i++) {
		QLineF line(polygon[i], polygon[(i+1)%4]);
		QPointF intersectionPoint;
		if (m_line.intersect(line, &intersectionPoint) == QLineF::BoundedIntersection) {
			m_line.setP2(intersectionPoint);
			break;
		}
	}

	m_arrowHead.resize(3);
	m_arrowHead[0] = QPointF(0.0, 0.0);
	m_arrowHead[1] = QPointF(-4.5, 10.0);
	m_arrowHead[2] = QPointF(4.5, 10.0);
	QMatrix matrix;
	matrix.rotate(-m_line.angle() + 90);
	m_arrowHead = matrix.map(m_arrowHead);
	m_arrowHead.translate(m_line.p2());
}