/*
 * Copyright (c) 2007      Gustavo Pichorim Boiko <gustavo.boiko@kdemail.net>
 *
 *  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 "layoutmanager.h"
#include "randr.h"
#include "randrscreen.h"
#include "randroutput.h"
#include "outputgraphicsitem.h"

#include <QGraphicsScene>
#include <qmath.h>

LayoutManager::LayoutManager(RandRScreen *screen, QGraphicsScene *scene)
    : QObject(screen)
{
    m_screen = screen;
    m_scene = scene;
}

LayoutManager::~LayoutManager()
{
}

void LayoutManager::slotAdjustOutput(OutputGraphicsItem *output)
{
    QPointF p = output->pos();
    qreal nearest = m_scene->width() * m_scene->height();
    OutputGraphicsItem *selected = NULL;

    OutputGraphicsItem *mouseGrabber = dynamic_cast<OutputGraphicsItem*>(m_scene->mouseGrabberItem());
    // find the nearest item
    QList<QGraphicsItem *> itemList = m_scene->items();

    foreach(QGraphicsItem *current, itemList) {
        OutputGraphicsItem *cur = dynamic_cast<OutputGraphicsItem*>(current);
        if (cur == output || cur == mouseGrabber) {
            continue;
        }

        QPointF pos = cur->pos();
        qreal distance = (p.x() - pos.x())*(p.x()-pos.x()) + (p.y() - pos.y())*(p.y() - pos.y());
        if (distance <=nearest) {
            nearest = distance;
            selected  = cur;
        }
    }

    if (selected) {
        // find in which side this
        QRectF s = selected->boundingRect();
        QRectF i = output->boundingRect();

        s.translate(selected->scenePos());
        i.translate(output->scenePos());

        // calculate the distances
        qreal top = qAbs(i.top() - s.bottom());
        qreal bottom = qAbs(i.bottom() - s.top());
        qreal left = qAbs(i.left() - s.right());
        qreal right = qAbs(i.right() - s.left());

        // choose top
        if (top <= bottom && top <= left && top <= right) {
            output->setTop(selected);
            selected->setBottom(output);
        }
        // choose bottom
        else if (bottom < top && bottom <= left && bottom <= right) {
            output->setBottom(selected);
            selected->setTop(output);
        }
        // choose left
        else if (left < top && left < bottom && left <= right) {
            output->setLeft(selected);
            selected->setRight(output);
        }
        // choose right
        else {
            output->setRight(selected);
            selected->setLeft(output);
        }
    }

    // now visit all the outputs on the screen to adjust their positions
    // starting by the item selected to be the parent of the current item
    QList<OutputGraphicsItem *> visitedList;

    // FIXME: after adjusting the scene, we have to translate everything back to
    // the 0,0 position so that everything is onscreen
    output->setPos(0,0);
    // call a recursive function to adjust the outputs
    adjustScene(output, visitedList);
}

void LayoutManager::adjustScene(OutputGraphicsItem *current, QList<OutputGraphicsItem*> &visited)
{
    visited.append(current);

    OutputGraphicsItem *item;
    item = current->left();
    if (item && visited.indexOf(item) == -1) {
        item->setPos(current->x() - item->boundingRect().width(), current->y());
        adjustScene(item, visited);
    }

    item = current->right();
    if (item && visited.indexOf(item) == -1) {
        item->setPos(current->x() + current->boundingRect().width(), current->y());
        adjustScene(item, visited);
    }

    item = current->top();
    if (item && visited.indexOf(item) == -1) {
        item->setPos(current->x(), current->y() - item->boundingRect().height());
        adjustScene(item, visited);
    }

    item = current->bottom();
    if (item && visited.indexOf(item) == -1) {
        item->setPos(current->x(), current->y() + current->boundingRect().height());
        adjustScene(item, visited);
    }
}