#ifndef KNNMPINONBLOCKINGFUNCTIONDECLARATION_H_   /* Include guard */
#define KNNMPINONBLOCKINGFUNCTIONDECLARATION_H_

/*		Constants definitions		*/
#define MASTER				0	//task id of the master process
#define BLOCK_SENT			0	//index of request used for sending blocks in the requests array
#define BLOCK_RECEIVED		1	//index of request used for receiving blocks in the requests array

/*		Structs		*/
typedef struct neighbor{	//simple struct defining a point's neighbor
	double distance;		//distance between the two neighbors (points)
	int neighborId;			//index of the neighbor in the (complete) array of points
} neighbor;

/*		Global variables		*/
extern int numberOfPoints;		//number of the points knn should run for
extern int numberOfDimensions;	//number of dimensions of each point
extern int numberOfNeighbors;	//number of nearest neighbors that should be found for each point
extern int k;					//number of nearest neighbors requested by the user
extern char *pointsFilename;	//name of the binary file storing the coordinates of points
extern char *testFilename;		//name of binary file storing correct neighbors IDs array

/*		Functions declaration		*/

//Function getArguments is used to parse arguments provided to main
void getArguments(int argc	//arguments count
	, char** argv);			//arguments array

//Function init allocates memory for the arrays used and initializes them
void init(double ***pointsArray			//pointer to the array of points
	, double ***inBuffer				//pointer to the array used as input buffer for mpi
	, double ***outBuffer				//pointer to the array used as output buffer for mpi
	, neighbor ***sortedNeighborsArray	//pointer to the array holding the distances and ID's
	, int chunksize						//number of rows (points) to be allocated
	, int offset);						//process offset used when reading points from the file

//Function cMalloc allocates and returns a single block of continuous memory which can
//be indexed like a regular array, e.g. array[row][column]
double **cMalloc(int rows	//number of rows to be allocated
	, int columns);			//number of columns to be allocated

//Function readPointsArrayFromFile reads the coordinates of the points from a file and stores them
//in an array
int readPointsArrayFromFile(double ***array	//array that will hold the coordinates of the points
	, int chunksize							//number of rows (points) to be read
	, int offset);							//offset from which reading will start

//Function printArray iterates the values of an array printing them
void printArray(int rows	//number of array's rows
	, int columns			//number of array's columns
	, double ***array);		//array to be printed

//Function calculateDistances calculates the distances between all points in two different sets and
//adds the distance to sortedNeighborsArray
void calculateDistances(double ***firstPointsSet	//first pool of points coordinates
	, double ***secondPointsSet						//second pool of points coordinates
	, neighbor ***sortedNeighborsArray				//array that holds the distances
	, int chunksize									//number of points
	, int myOffset									//offset used for ID's of first pool's points
	, int indexOffset);								//offset used for ID's of seconds pool's points

//Function addDistance adds distances to sorted neighbors array sorted by the ID of the neighbor
void addDistance(neighbor ***sortedNeighborsArray	//array that holds the distances
	, int firstPointIndex							//Index of the first point in task's array
	, int firstPointId								//ID of the first point
	, int secondPointId								//ID of the second point
	, double pointsDistance);						//distance between the two points

//Function compare compares two neighbors using their distance fields, returns 0 if distances are
//equal, 1 if distance of first argument is greater and -1 otherwise
int compare (const void *a		//first neighbor
	, const void *b);			//second neighbor

//Function swapPointers swaps the memory blocks pointed to by two pointers
void swapPointers(double ***firstArray	//first memory block
	, double ***secondArray);			//second memory block

//Function test checks the validity of the solution based on correct results previously generated
//and stored in a text file
int test(neighbor ***sortedNeighborsArray	//array that holds the IDs
	, int chunksize							//number of points
	, int offset							//process offset
	, char *testFilename);					//name of text file storing correct neighbors IDs array

//Function cleanUp frees all memory previously allocated
void cleanUp(double ***pointsArray		//points array pointer
	, double ***inBuffer				//input buffer pointer
	, double ***outBuffer				//output buffer pointer
	, neighbor ***sortedNeighborsArray	//distanced array pointer
	, int chunksize);					//number of rows (points)

//Function abExit exits the program after checking for mpi initialization
void abExit(int exitCode);	//exit code to exit with

#endif // KNNMPINONBLOCKINGFUNCTIONDECLARATION_H_