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/*

*

* This file is part of QMapControl,

* an open-source cross-platform map widget

*

* Copyright (C) 2007 - 2008 Kai Winter

*

* This program 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 3 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 Lesser General Public License for more details.

*

* You should have received a copy of the GNU Lesser General Public License

* along with QMapControl. If not, see <http://www.gnu.org/licenses/>.

*

* Contact e-mail: kaiwinter@gmx.de

* Program URL   : http://qmapcontrol.sourceforge.net/

*

*/

#include "googlesatmapadapter.h"

#include <math.h>

namespace qmapcontrol

{

    GoogleSatMapAdapter::GoogleSatMapAdapter()

            : TileMapAdapter("kh.google.com", "/kh?n=404&v=8&t=trtqtt", 256, 0, 19)

    {

        // name = "googlesat";

        numberOfTiles = pow(2, current_zoom+0.0);

        coord_per_x_tile = 360. / numberOfTiles;

        coord_per_y_tile = 180. / numberOfTiles;

    }

    GoogleSatMapAdapter::~GoogleSatMapAdapter()

    {

    }

    QString GoogleSatMapAdapter::getHost() const

    {

        int random = qrand() % 4;

        return QString("kh%1.google.com").arg(random);

    }

    QPoint GoogleSatMapAdapter::coordinateToDisplay(const QPointF& coordinate) const

    {

        //double x = ((coordinate.x()+180)*(tilesize*numberOfTiles/360));

        //double y = (((coordinate.y()*-1)+90)*(tilesize*numberOfTiles/180));

        qreal x = (coordinate.x()+180.) * (numberOfTiles*mytilesize)/360.;              // coord to pixel!

        //double y = -1*(coordinate.y()-90) * (numberOfTiles*tilesize)/180.;    // coord to pixel!

        qreal y = (getMercatorYCoord(coordinate.y())-M_PI) * -1 * (numberOfTiles*mytilesize)/(2*M_PI);  // coord to pixel!

        return QPoint(int(x), int(y));

    }

    QPointF GoogleSatMapAdapter::displayToCoordinate(const QPoint& point) const

    {

        //double lon = ((point.x()/tilesize*numberOfTiles)*360)-180;

        //double lat = (((point.y()/tilesize*numberOfTiles)*180)-90)*-1;

        qreal lon = (point.x()*(360./(numberOfTiles*mytilesize)))-180.;

        //double lat = -(point.y()*(180./(numberOfTiles*tilesize)))+90;

        //qreal lat = getMercatorLatitude(point.y()*-1*(2*M_PI/(numberOfTiles*tilesize)) + M_PI);

        qreal lat = lat *180./M_PI;

        return QPointF(lon, lat);

    }

    qreal GoogleSatMapAdapter::getMercatorLatitude(qreal YCoord) const

    {

        //http://welcome.warnercnr.colostate.edu/class_info/nr502/lg4/projection_mathematics/converting.html

        if (YCoord > M_PI) return 9999.;

        if (YCoord < -M_PI) return -9999.;

        qreal t = atan(exp(YCoord));

        qreal res = (2.*(t))-(M_PI/2.);

        return res;

    }

    qreal GoogleSatMapAdapter::getMercatorYCoord(qreal lati) const

    {

        qreal lat = lati;

        // conversion degre=>radians

        qreal phi = M_PI * lat / 180;

        qreal res;

        //double temp = Math.Tan(Math.PI / 4 - phi / 2);

        //res = Math.Log(temp);

        res = 0.5 * log((1 + sin(phi)) / (1 - sin(phi)));

        return res;

    }

    void GoogleSatMapAdapter::zoom_in()

    {

        current_zoom+=1;

        numberOfTiles = pow(2, current_zoom+0.0);

        coord_per_x_tile = 360. / numberOfTiles;

        coord_per_y_tile = 180. / numberOfTiles;

    }

    void GoogleSatMapAdapter::zoom_out()

    {

        current_zoom-=1;

        numberOfTiles = pow(2, current_zoom+0.0);

        coord_per_x_tile = 360. / numberOfTiles;

        coord_per_y_tile = 180. / numberOfTiles;

    }

    bool GoogleSatMapAdapter::isValid(int x, int y, int z) const

    {

        if ((x>=0 && x < numberOfTiles) && (y>=0 && y < numberOfTiles) && z>=0)

        {

            return true;

        }

        return false;

    }

    QString GoogleSatMapAdapter::query(int i, int j, int z) const

    {

        return getQ(-180+i*coord_per_x_tile,

                    90-(j+1)*coord_per_y_tile, z);

    }

    QString GoogleSatMapAdapter::getQ(qreal longitude, qreal latitude, int zoom) const

    {

        qreal xmin=-180;

        qreal xmax=180;

        qreal ymin=-90;

        qreal ymax=90;

        qreal xmoy=0;

        qreal ymoy=0;

        QString location="t";

        //Google uses a latitude divided by 2;

        qreal halflat = latitude;

        for (int i = 0; i < zoom; i++)

        {

            xmoy = (xmax + xmin) / 2;

            ymoy = (ymax + ymin) / 2;

            if (halflat >= ymoy) //upper part (q or r)

            {

                ymin = ymoy;

                if (longitude < xmoy)

                { /*q*/

                    location+= "q";

                    xmax = xmoy;

                }

                else

                {/*r*/

                    location+= "r";

                    xmin = xmoy;

                }

            }

            else //lower part (t or s)

            {

                ymax = ymoy;

                if (longitude < xmoy)

                { /*t*/

                    location+= "t";

                    xmax = xmoy;

                }

                else

                {/*s*/

                    location+= "s";

                    xmin = xmoy;

                }

            }

        }

        return QString("/kh?n=404&v=24&t=%1").arg(location);

    }

}