/*
 * © Copyright 2014 – Urheberrechtshinweis
 * Alle Rechte vorbehalten / All Rights Reserved
 *
 * Programmcode ist urheberrechtlich geschuetzt.
 * Das Urheberrecht liegt, soweit nicht ausdruecklich anders gekennzeichnet, bei Frank Ebner.
 * Keine Verwendung ohne explizite Genehmigung.
 * (vgl. § 106 ff UrhG / § 97 UrhG)
 */

#ifndef GRIDNEIGHBORITERATOR_H
#define GRIDNEIGHBORITERATOR_H


/** allows iterating over all neighbors of one node */
class NeighborIter : std::iterator<std::input_iterator_tag, int> {

private:

	/** the grid the src-node belongs to */
	Grid<T>* grid;

	/** index of the source-node within its grid */
	int srcNodeIdx;

	/** index of the current neighbor [0:10] */
	int nIdx;

public:

	/** ctor */
	NeighborIter(const Grid<T>& grid, const int srcNodeIdx, const int nIdx) :
		grid((Grid<T>*)&grid), srcNodeIdx(srcNodeIdx), nIdx(nIdx) {;}

	/** next neighbor */
	NeighborIter& operator++() {++nIdx; return *this;}

	/** next neighbor */
	NeighborIter operator++(int) {NeighborIter tmp(*this); operator++(); return tmp;}

	/** compare with other iterator */
	bool operator==(const NeighborIter& rhs) {return srcNodeIdx == rhs.srcNodeIdx && nIdx == rhs.nIdx;}

	/** compare with other iterator */
	bool operator!=(const NeighborIter& rhs) {return srcNodeIdx != rhs.srcNodeIdx || nIdx != rhs.nIdx;}

	/** get the neighbor the iterator currently points to */
	T& operator*() {return (T&) grid->getNeighbor(srcNodeIdx, nIdx);}

};

/** allows for-each iteration over all neighbors of one node */
class NeighborForEach {
private:

	/** the grid the src-node belongs to */
	const Grid<T>& grid;

	/** index of the source-node within its grid */
	const int srcNodeIdx;

public:

	/** ctor */
	NeighborForEach(const Grid<T>& grid, const int srcNodeIdx) :
		grid(grid), srcNodeIdx(srcNodeIdx) {;}

	/** starting point */
	NeighborIter begin() {return NeighborIter(grid, srcNodeIdx, 0);}

	/** end point */
	NeighborIter end() {return NeighborIter(grid, srcNodeIdx, grid[srcNodeIdx]._numNeighbors);}

};

#endif // GRIDNEIGHBORITERATOR_H