//
// Open Service Platform
// Copyright (c) 2012 Samsung Electronics Co., Ltd.
//
// Licensed under the Apache License, Version 2.0 (the License);
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

/**
 * @file		FLoc_MathUtils.cpp
 * @brief		This is the implementation file for _MathUtils class.
 *
 * This file contains implementation of _MathUtils class.
 */

#include <math.h>
#include <FBaseDouble.h>
#include <FBaseSysLog.h>
#include <FBaseUtilMath.h>
#include <FLocLocation.h>
#include "FLoc_MathUtils.h"
#include "FLoc_RegionInfo.h"

using namespace Tizen::Base::Utility;
using namespace Tizen::Base;

namespace Tizen { namespace Locations
{

const double _MathUtils::PI = M_PI;
const double _MathUtils::PI2 = 2.0 * _MathUtils::PI;
const double _MathUtils::DEG2RAD = _MathUtils::PI / 180.0;
const double _MathUtils::RAD2DEG = 180.0 / _MathUtils::PI;
const double _MathUtils::HALFPI = 1.5707963267948966;
const double _MathUtils::CENTRE_LATITUDE = 0.0;

double
_MathUtils::CalculateOverlapRegion(const _RegionInfo& region, const Location& location)
{
	double overlapArea = 0;
	double distanceBtwCenters = region.GetCoordinate().GetDistanceTo(location.GetCoordinates());
	double regionRadius = region.GetRadius();
	double locationRadius = location.GetHorizontalAccuracy();
	double distanceBtwCentersSqr = distanceBtwCenters * distanceBtwCenters;
	double regionRadiusSqr = regionRadius * regionRadius;
	double locationRadiusSqr = locationRadius * locationRadius;

	// The circles are overlapping
	if (distanceBtwCenters <= Math::Abs(regionRadius - locationRadius))
	{
		overlapArea = locationRadius > regionRadius ? Math::GetPi() * regionRadiusSqr : Math::GetPi() * locationRadiusSqr;
	}
	else
	{
		double theta = Math::Acos((regionRadiusSqr + distanceBtwCentersSqr - locationRadiusSqr) / (2 * regionRadius * distanceBtwCenters));
		double phi = Math::Acos((locationRadiusSqr + distanceBtwCentersSqr - regionRadiusSqr) / (2 * locationRadius * distanceBtwCenters));

		overlapArea = regionRadiusSqr * (theta - Math::Sin(theta) * Math::Cos(theta)) + locationRadiusSqr * (phi - Math::Sin(phi) * Math::Cos(phi));
	}
	return overlapArea;
}

double
_MathUtils::GetShortestDistance(const Location& location, const Tizen::Base::Collection::IList& regionList)
{
	double minDistance = Double::GetMaxValue();
	int count = regionList.GetCount();

	for (int i = 0; i < count; i++)
	{
		const _RegionInfo* pRegionInfo = static_cast< const _RegionInfo* >(regionList.GetAt(i));
		if (pRegionInfo)
		{
			Coordinates regionCoordinate = pRegionInfo->GetCoordinate();
			double distance = abs(regionCoordinate.GetDistanceTo(location.GetCoordinates()) - pRegionInfo->GetRadius());

			if (minDistance > distance)
			{
				minDistance = distance;
			}
		}
	}

	SysSecureLog(NID_LOC, "Shortest distance from location (lat: %lf and lon: %lf) to the nearest region boundary is (%lf) meters", location.GetCoordinates().GetLatitude(), location.GetCoordinates().GetLongitude(), minDistance);
	return minDistance;
}
} } // Tizen::Locations