// Interface for the road component classes - Intersection and RoadSegment.
// CSE143 Spring '01
// Homework 6

#ifndef _INTERSECTION_H
#define _INTERSECTION_H

#include "road_chunk.h"
#include "position.h"

const int Entry = 0;
const int Exit = 1;

int swapEntryExit(int entryOrExit);

// Forward declaration to avoid circular #includes.
class RoadSegment;

// Intersection: models a simple road intersection.
// Connects up to 8 road segments (objects of class RoadSegment),
// two on each direction (N,S,E,W), one incoming traffic, one outgoing.
// Controls traffic from each incoming road segment to outgoing segments.
// This is a subclass of SimObject, so it supports basic simulation operations.
class Intersection : public RoadChunk {
public:
	// Construct an uninitialized intersection
	Intersection();

	// Construct an intersection centered at the specified position
	Intersection(Position center);

	// Destructor: does NOT deallocate any of the segments, but does deallocate
	// the vehicle(s) currently in the intersection (if any).
	virtual ~Intersection();

	// Draw the intersection on the screen.
	// Precondition: the intersection was initialized with a position.
	virtual void draw(GP142Display& gp);
	virtual void tick();

	// Set the position of the intersection.
	// This must be done before any other operation (unless the position was
	// set using the constructor).
	// Precondition: the position was not set yet.
	virtual void setCenter(Position pos);

	// Connects the given road segment at the given direction, and updates the
	// intersection's dimensions accordingly. The argument entryOrExit should
	// be one of the constants ENTRY or EXIT, and specifies whether the segment
	// is an entry to the intersection or an exit from it.
	// Precondition: the intersection was positioned already.
	virtual void connectRoad(RoadSegment *roadSeg, Direction dir, int entryOrExit);

	// Returns the x or y coordinate at the intersection's border on the
	// specified direction. E.g. if dir = NORTH, returns the y value for the
	// northern border of the intersection; if dir = EAST, returns the x value
	// for the eastern border.
	virtual int Intersection::getBorder(Direction dir) const;

	// Returns the center of this intersection
	virtual Position getCenter() const;

private:
	Position center;
	RoadSegment *segments[NumDirections][2]; 
									// Road segments connected to this
									// intersection

	// Private copy constructor: prevents copying intersections.
	Intersection(const Intersection& other) {}
	// Private assinment operator: prevents assignment of Intersections.
	operator =(const Intersection& other) {}
};

#endif // end of file