/*
* ============================================================================
*  Name     : CLocationExampleLocationEngine.cpp
*  Part of  : Location Example
*  Created  : 21.05.2007 by Forum Nokia
*  Description:
*  Version  : 1.0
*  Copyright: Nokia Corporation
* ============================================================================
*/

// INCLUDE FILES
#include <e32math.h>

#include "clocationexamplelocationengine.h"



// ---------------------------------------------------------
// CLocationExampleLocationEngine::NewL()
// ---------------------------------------------------------
//
CLocationExampleLocationEngine* CLocationExampleLocationEngine::NewL()
    {
    CLocationExampleLocationEngine* self = NewLC();
    CleanupStack::Pop(self);
	return self;
    }

// ---------------------------------------------------------
// CLocationExampleLocationEngine::NewLC()
// ---------------------------------------------------------
//
CLocationExampleLocationEngine* CLocationExampleLocationEngine::NewLC()
    {
    CLocationExampleLocationEngine* self = new (ELeave) CLocationExampleLocationEngine();
    CleanupStack::PushL(self);
    self->ConstructL();
    return self;
    }

// ---------------------------------------------------------
// CLocationExampleLocationEngine::ConstructL()
// ---------------------------------------------------------
//
void CLocationExampleLocationEngine::ConstructL()
    {
    } 

// ---------------------------------------------------------
// CLocationExampleLocationEngine::CLocationExampleLocationEngine()
// ---------------------------------------------------------
//
CLocationExampleLocationEngine::CLocationExampleLocationEngine() 
    {
    }   

// ---------------------------------------------------------
// CLocationExampleLocationEngine::~CLocationExampleLocationEngine()
// ---------------------------------------------------------
//
CLocationExampleLocationEngine::~CLocationExampleLocationEngine()
    {
    }


// ---------------------------------------------------------
// CLocationExampleLocationEngine::CalculateDistance()
// ---------------------------------------------------------
//
TReal CLocationExampleLocationEngine::CalculateDistanceL(const TCoordinate& aFrom, const TCoordinate& aTo) 
    {
    TReal result = 0;
    TReal val1 = 0;
    TReal val2 = 0;

    Math::Cos(val1,aFrom.Latitude()*KDectorad);
    Math::Cos(val2,aFrom.Longitude()*KDectorad);
    TReal aVal = val1 * val2;

    Math::Cos(val1,aTo.Latitude()*KDectorad);
    Math::Cos(val2,aTo.Longitude()*KDectorad);
    TReal bVal = val1 * val2;

    Math::Cos(val1,aFrom.Latitude()*KDectorad);
    Math::Sin(val2,aFrom.Longitude()*KDectorad);
    TReal cVal = val1 * val2;

    Math::Cos(val1,aTo.Latitude()*KDectorad);
    Math::Sin(val2,aTo.Longitude()*KDectorad);
    TReal dVal = val1 * val2;

    Math::Sin(val1,aFrom.Latitude()*KDectorad);
    Math::Sin(val2,aTo.Latitude()*KDectorad);
    TReal eVal = val1 * val2;

    TInt err = Math::ACos(result, (aVal*bVal) + cVal*dVal + eVal);
    User::LeaveIfError(err);

    result = result * KEarthRadius;


    return result;
    }   



// ---------------------------------------------------------
// CLocationExampleLocationEngine::GetDirectionL()
// Notice, that if you have two points laying at the same
// latitude than doesn't mean that bearing always be strict
// W or E (it will be so only if the latitude is 0), but 
// if two points at the same longitude than bearing always 
// be strict N or S
// ---------------------------------------------------------
//
TDesC& CLocationExampleLocationEngine::GetDirection(const TCoordinate& aFrom, const TCoordinate& aTo)
	{
	iDirection.Zero();
	TReal bearing;
    TReal from_lat,from_long,to_lat, to_long;
	TReal sin_a_lat, sin_b_lat, cos_a_lat, cos_b_lat, sin_dlon, cos_dlon;

	// Temp variables
    from_lat = aFrom.Latitude();
    from_long = aFrom.Longitude();
    to_lat = aTo.Latitude();
    to_long = aTo.Longitude();
	Math::Sin(sin_dlon, KDectorad*(to_long-from_long));
	Math::Cos(cos_b_lat, KDectorad*to_lat);
	Math::Sin(sin_a_lat, KDectorad*from_lat);
	Math::Sin(sin_b_lat, KDectorad*to_lat);
	Math::Cos(cos_a_lat, KDectorad*from_lat);
	Math::Cos(cos_b_lat, KDectorad*to_lat);
	Math::Cos(cos_dlon, KDectorad*(to_long-from_long));
	Math::ATan(bearing, sin_dlon*cos_b_lat, cos_a_lat*sin_b_lat-sin_a_lat*cos_b_lat*cos_dlon);
	
	// Add labels to iDirection based on bearing (-pi < bearing <= pi)
	TReal b2mod;
	// Make bearing positive and shifted by pi/8, so we can easy  find label by dividing 
	// shifted bearing by pi/4
	// e.g. N (-pi/8; pi/8) -> (0; pi/4)
	Math::Mod(b2mod, bearing+(2+0.125)*KPi, 2*KPi);
	TInt16 segment;
	Math::Int(segment, b2mod/(KPi/4));

	switch(segment)
    	{
    	case 0:
    		iDirection.Append(KNorth);break;
    	case 1:
    		iDirection.Append(KNorthEast);break;
    	case 2:
    		iDirection.Append(KEast);break;
    	case 3:
    		iDirection.Append(KSouthEast);break;
    	case 4:
    		iDirection.Append(KSouth);break;
    	case 5:
    		iDirection.Append(KSouthWest);break;
    	case 6:
    		iDirection.Append(KWest);break;
    	case 7:
    		iDirection.Append(KNorthWest);break;
    	default:
    		iDirection.Append(KInvalidDirection);break;
    	}
	return iDirection;
	}