/*
randomly generated SUDOKU (unique numbers in 3x3 squares, in every row, and every column)
in C++, created by redve as test of his skills, BD
*/

// includes
#include <iostream>		// standard library, here it's just to print values
#include <cstdlib>		// randomize numbers
#include <time.h>		// RNG source

// set namespace
using namespace std;													// namespace std

bool CheckEverything(int** table, int random, int column, int row);		// Check is everything OK

bool CheckRows(int** table, int random, int column, int row);			// Check unique values in a row

bool CheckColumn(int** table, int random, int column, int row);			// Check unique values in a column

bool CheckSquares(int** table, int random, int column, int row);		// check unique values in 3x3 square

void ReturnValues(int** table);											// print values

void SetTo0(int** table);												// set table to 0

int SquareDetection(int x, int y);										// detect square

// main function
int main()
{
	int random = 0;					// bufor do losowania liczb przed wstawieniem ich do tabeli
	bool stop;						// variable to check
	int Counter = 0;				// Counter of critical errors

	// declare 2D table
	int** table = new int* [9];		// create pointer to pointers

	// create table
	for (int i = 0; i < 9; i++)		// create pointers
		table[i] = new int[9];		// make them pointers to ints

	// initiate RNG
	srand(time(NULL));				// start RNG

	// set table to 0
	SetTo0(table);

	// get a random numbers
	for (int row = 0; row < 9; row++) {											// go through rows
		for (int column = 0; column < 9; column++) {							// go through colums
			do {
				random = rand() % 9 + 1;										// random number to next table slot
				stop = true;
				stop = CheckEverything(table, random, column, row);				// Check if number repeats in current row, column, and square 3x3
				Counter++;														// increment every loop cycle
				if (Counter >= 1000) {											// if there were 1000 cycles without correct number
					Counter = 0;												// try fill new, clear table
					column = 0;													// set column to 0
					row = 0;													// set row to 0
					break;														// and break current cycle
				}
			} while (!stop);													// if CheckEverything is correct it returns TRUE, so try opposite argument
			table[row][column] = random;										// if everything is correct, fill these table slot
		}
	}

	// return values
	ReturnValues(table);	// print values of these table

	// exit program
	return 0;	// return integer
}

/*////////////////////////////////////////////////////////////////
							FUNCTIONS
////////////////////////////////////////////////////////////////*/

bool CheckRows(int** table, int random, int column, int row) {			// Check unique values in a row
	//cout << "================" << endl << "wartosc tabeli komorki: " << table[row][column] << endl << "aktualnie rozpatrywana liczba: " << random << endl << "aktualna kolumna: " << column << endl << "aktualny rzad: "<< row << endl << "==============" << endl;
	for (int i = 0; i < row; i++)
		if (random == table[i][column])									// if there were value like actually random number
			return false;												// find new value
	return true;														// default its true
}

bool CheckColumn(int** table, int random, int column, int row) {		// Check unique values in a column
	for (int i = 0; i < column; i++)
		if (random == table[row][i])									// if there were value like actually random number
			return false;												// find new value
	return true;														// default it's true
}

bool CheckSquares(int** table, int random, int column, int row) {		// check unique values in 3x3 square
	int square = SquareDetection(row, column);							// which field 3x3 it is
	int** square_values = new int* [9];									// create new 9 pointers table
	for (int i = 0; i < 9; i++)											// create 9x9 table
		square_values[i] = new int[9];
	square_values[square][(column % 3 + row % 3) % 9] = random;			// fill them with current random number
	for (int i = 0; i < (column % 3 + row % 3) % 9; i++)
		if (random = square_values[square][i])							// if there is same number in square 3x3
			return false;												// it's false
	return true;														// default it's true
}

void SetTo0(int** table) {				// set default values to 0

	for (int i = 0; i < 9; i++) 		// rows
		for (int j = 0; j < 9; j++) 	// columns
			table[i][j] = 0;			// set values to 0
}

void ReturnValues(int** table) {							// print values
	for (int row = 0; row < 9; row++) {					// rows
		for (int column = 0; column < 9; column++)		// column
			cout << table[row][column] << " ";			// print values
		cout << endl;									// go to the next row
	}
}

bool CheckEverything(int** table, int random, int column, int row) {							// check all statements
	if (CheckRows(table, random, column, row) && CheckColumn(table, random, column, row) && CheckSquares(table, random, column, row))
		return true;																			// everything is true
	else																						// if not
		return false;																			// it's not
}

int SquareDetection(int x, int y) {
	int square = 0;
	if ((x >= 0 && x <= 2) && (y >= 0 && y <= 2)) {
		square = 0;
	}
	if ((x >= 3 && x <= 5) && (y >= 0 && y <= 2)) {
		square = 3;
	}
	if ((x >= 6 && x <= 8) && (y >= 0 && y <= 2)) {
		square = 6;
	}
	if ((x >= 0 && x <= 2) && (y >= 3 && y <= 5)) {
		square = 1;
	}
	if ((x >= 3 && x <= 5) && (y >= 3 && y <= 5)) {
		square = 4;
	}
	if ((x >= 6 && x <= 8) && (y >= 3 && y <= 5)) {
		square = 7;
	}
	if ((x >= 0 && x <= 2) && (y >= 6 && y <= 8)) {
		square = 2;
	}
	if ((x >= 3 && x <= 5) && (y >= 6 && y <= 8)) {
		square = 5;
	}
	if ((x >= 6 && x <= 8) && (y >= 6 && y <= 8)) {
		square = 8;
	}
	return square;
}