/***************************************************************************
 *   Copyright (C) 2005 by Torben Nielsen   *
 *   torben@t-hoerup.dk   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#include "solution.h"
#include "queens.h"
#include "solutioncontainer.h"


Queens::Queens(GUIUpdate *par, SolutionContainer *sol, int set_size, bool set_debug) : QThread(), solution(set_size)
{
	parent = par;
	size = set_size;
	solution.setSize(size);
	debug = set_debug;
	solutions = sol;
}

bool Queens::solve()
{
	return solve(0, false);
}

void Queens::findAll()
{
	solve(0,true);
}

bool Queens::solve(int row, bool findAll)
{
	if (blocked == true)
		return false;
	for (int col=0; col<size; col++) {
		if (checkCols(row,col) == true && 
				checkCross1(row,col) == true && 
				checkCross2(row,col) == true) {

			solution.matrix[row][col] = true;
			
			if (row == (size-1) ) {
				if (!findAll)
					return true;
				else {
					solutions->addSolution( solution.copy() );
					parent->foundSolution();
				}
			}

			if ( solve(row+1,findAll) )
				return true;

			solution.matrix[row][col] = false;
		}
	}
	return false;
}


bool Queens::checkRows(int row, int col)
{
	for (int c=0; c<size; c++) {
		if (solution.matrix[row][c] == true)
			return false;
	}
		
	return true;
}

bool Queens::checkCols(int row, int col)
{
	for (int r=0; r<size; r++) {
		if (solution.matrix[r][col] == true)
			return false;
	}
	return true;
}

bool Queens::checkCross1(int row, int col)
{
	int r=row;
	int c=col;
	for (int i=0; i<size; i++) {
		if (solution.matrix[r][c] == true)
			return false;
		r++;
		c++;
		if ( r>(size-1) || c>(size-1) )
			break;		
	}
	r=row;
	c=col;
	for (int i=0; i<size;i++) {
		if (solution.matrix[r][c] == true)
			return false;
		r--;
		c--;
		if (r<0 || c<0)
			break;
	}
	return true;
}

bool Queens::checkCross2(int row, int col)
{
	int r=row;
	int c=col;
	for (int i=0; i<size; i++) {
		if (solution.matrix[r][c] == true)
			return false;
		r++;
		c--;
		if ( r>(size-1) || c<0 )
			break;
	}
	r=row;
	c=col;
	for (int i=0; i<size; i++) {
		if (solution.matrix[r][c] == true)
			return false;
		r--;
		c++;
		if (r<0 || c>(size-1))
			break;
	}
	return true;
}

void Queens::run()
{
	blocked = false;
	findAll();
	
	if (blocked == false)
		parent->finishedSearch();
}

void Queens::stop()
{
	blocked = true;
}