#include <QPainter>
#include "common/coordinates.h"
#include "common/rectc.h"
#include "common/wgs84.h"
#include "downloader.h"
#include "config.h"
#include "onlinemap.h"


#define TILE_SIZE     256
#define EPSILON       1e-6

static QPointF ll2m(const Coordinates &c)
{
	return QPointF(c.lon(), rad2deg(log(tan(M_PI_4 + deg2rad(c.lat())/2.0))));
}

static Coordinates m2ll(const QPointF &p)
{
	return Coordinates(p.x(), rad2deg(2.0 * atan(exp(deg2rad(p.y()))) - M_PI_2));
}

static QPoint mercator2tile(const QPointF &m, int z)
{
	QPoint tile;

	tile.setX((int)(floor((m.x() + 180.0) / 360.0 * (1<<z))));
	tile.setY((int)(floor((1.0 - (m.y() / 180.0)) / 2.0 * (1<<z))));

	return tile;
}

static qreal zoom2scale(int zoom)
{
	return (360.0/(qreal)((1<<zoom) * TILE_SIZE));
}

static int scale2zoom(qreal scale)
{
	return (int)(log2(360.0/(scale * (qreal)TILE_SIZE)) + EPSILON);
}


OnlineMap::OnlineMap(const QString &name, const QString &url,
  const Range &zooms, const RectC &bounds, const Authorization &authorization,
  QObject *parent) : Map(parent), _name(name), _zooms(zooms), _bounds(bounds),
  _valid(false)
{
	QString dir(TILES_DIR + "/" + _name);

	_zoom = _zooms.max();

	_tileLoader = new TileLoader(this);
	_tileLoader->setUrl(url);
	_tileLoader->setDir(dir);
	_tileLoader->setAuthorization(authorization);
	connect(_tileLoader, SIGNAL(finished()), this, SIGNAL(loaded()));

	if (!QDir().mkpath(dir)) {
		_errorString = "Error creating tiles dir";
		return;
	}

	_valid = true;
}

QRectF OnlineMap::bounds() const
{
	return QRectF(ll2xy(_bounds.topLeft()), ll2xy(_bounds.bottomRight()));
}

int OnlineMap::limitZoom(int zoom) const
{
	if (zoom < _zooms.min())
		return _zooms.min();
	if (zoom > _zooms.max())
		return _zooms.max();

	return zoom;
}

int OnlineMap::zoomFit(const QSize &size, const RectC &rect)
{
	if (!rect.isValid())
		_zoom = _zooms.max();
	else {
		QRectF tbr(ll2m(rect.topLeft()), ll2m(rect.bottomRight()));
		QPointF sc(tbr.width() / size.width(), tbr.height() / size.height());
		_zoom = limitZoom(scale2zoom(qMax(sc.x(), -sc.y())));
	}

	return _zoom;
}

qreal OnlineMap::resolution(const QRectF &rect) const
{
	qreal scale = zoom2scale(_zoom);

	return (WGS84_RADIUS * 2.0 * M_PI * scale / 360.0
	  * cos(2.0 * atan(exp(deg2rad(-rect.center().y() * scale))) - M_PI/2));
}

int OnlineMap::zoomIn()
{
	_zoom = qMin(_zoom + 1, _zooms.max());
	return _zoom;
}

int OnlineMap::zoomOut()
{
	_zoom = qMax(_zoom - 1, _zooms.min());
	return _zoom;
}

void OnlineMap::draw(QPainter *painter, const QRectF &rect, bool block)
{
	qreal scale = zoom2scale(_zoom);

	QPoint tile = mercator2tile(QPointF(rect.topLeft().x() * scale,
	  -rect.topLeft().y() * scale), _zoom);
	QPoint tl = QPoint((int)floor(rect.left() / (qreal)TILE_SIZE)
	  * TILE_SIZE, (int)floor(rect.top() / TILE_SIZE) * TILE_SIZE);

	QList<Tile> tiles;
	QSizeF s(rect.right() - tl.x(), rect.bottom() - tl.y());
	for (int i = 0; i < ceil(s.width() / TILE_SIZE); i++)
		for (int j = 0; j < ceil(s.height() / TILE_SIZE); j++)
			tiles.append(Tile(QPoint(tile.x() + i, tile.y() + j), _zoom));

	if (block)
		_tileLoader->loadTilesSync(tiles);
	else
		_tileLoader->loadTilesAsync(tiles);

	for (int i = 0; i < tiles.count(); i++) {
		Tile &t = tiles[i];
		QPoint tp(tl.x() + (t.xy().x() - tile.x()) * TILE_SIZE,
		  tl.y() + (t.xy().y() - tile.y()) * TILE_SIZE);
		if (t.pixmap().isNull())
			painter->fillRect(QRect(tp, QSize(TILE_SIZE, TILE_SIZE)),
			  _backgroundColor);
		else
			painter->drawPixmap(tp, t.pixmap());
	}
}

QPointF OnlineMap::ll2xy(const Coordinates &c) const
{
	qreal scale = zoom2scale(_zoom);
	QPointF m = ll2m(c);
	return QPointF(m.x() / scale, m.y() / -scale);
}

Coordinates OnlineMap::xy2ll(const QPointF &p) const
{
	qreal scale = zoom2scale(_zoom);
	return m2ll(QPointF(p.x() * scale, -p.y() * scale));
}