Magic Cube

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// Copyright 2020 Leszek Koltunski                                                               //

//                                                                                               //

// This file is part of Magic Cube.                                                              //

//                                                                                               //

// Magic Cube 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.                                                           //

//                                                                                               //

// Magic Cube 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 Magic Cube.  If not, see <http://www.gnu.org/licenses/>.                           //

///////////////////////////////////////////////////////////////////////////////////////////////////

package org.distorted.solvers;

import android.content.res.Resources;

import org.distorted.objectlib.main.ObjectType;

import org.distorted.objectlib.main.TwistyObject;

import org.distorted.main.R;

import org.distorted.screens.ScreenList;

import org.distorted.screens.RubikScreenSolver;

///////////////////////////////////////////////////////////////////////////////////////////////////

public class SolverMain implements Runnable

{

  private final Resources mRes;

  private final TwistyObject mObject;

///////////////////////////////////////////////////////////////////////////////////////////////////

  public SolverMain(Resources res, TwistyObject object)

    {

    mRes   = res;

    mObject= object;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

// certain objects have certain cubits locked - for example, the Cube3's centers of

// sides always have the same color.

// If a certain cubit is locked, return the color (index into it's FACE_COLORS array) it

// must have. Otherwise return -1.

  public static int cubitIsLocked(ObjectType object, int cubit)

    {

    if( object == ObjectType.CUBE_3 )

      {

      if( cubit==21 ) return 0; // center of the right  face

      if( cubit== 4 ) return 1; // center of the left   face

      if( cubit==15 ) return 2; // center of the up     face

      if( cubit==10 ) return 3; // center of the bottom face

      if( cubit==13 ) return 4; // center of the front  face

      if( cubit==12 ) return 5; // center of the back   face

      }

    return -1;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private void solveCube3(RubikScreenSolver solver)

    {

    String result;

    if( !org.distorted.solvers.cube3.Search.prepare(mRes) )

      result= "Error 9";

    else

      {

      String objectPosition = prepareCube3position();

      result = org.distorted.solvers.cube3.Search.solution(objectPosition, 24, 20);

      }

    if (result.contains("Error"))

      {

      switch (result.charAt(result.length() - 1))

        {

        case '1': result = mRes.getString(R.string.solver_cube3_error1); break;

        case '2': result = mRes.getString(R.string.solver_cube3_error2); break;

        case '3': result = mRes.getString(R.string.solver_cube3_error3); break;

        case '4': result = mRes.getString(R.string.solver_cube3_error4); break;

        case '5': result = mRes.getString(R.string.solver_cube3_error5); break;

        case '6': result = mRes.getString(R.string.solver_cube3_error6); break;

        case '7': result = mRes.getString(R.string.solver_cube3_error7); break;

        case '8': result = mRes.getString(R.string.solver_cube3_error8); break;

        case '9': result = mRes.getString(R.string.solver_cube3_error9); break;

        }

      solver.displayErrorDialog(result);

      }

    else

      {

      solver.setSolved(result);

      }

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

// order: Up --> Right --> Front --> Down --> Left --> Back

// (because the first implemented Solver - the two-phase Cube3 one - expects such order)

//

// Solved 3x3x3 Cube maps to "UUUUUUUUURRRRRRRRRFFFFFFFFFDDDDDDDDDLLLLLLLLLBBBBBBBBB"

//

// s : size of the cube; let index = a*s + b    (i.e. a,b = row,column)

//

// Up    :   index --> b<s-1 ? (s-1)*(s+4b)+a : 6*s*s -13*s +8 +a

// Right :   index --> 6*s*s - 12*s + 7 - index

// Front :   index --> if b==0  : s*s - 1 - index

//                     if b==s-1: 6*s*s -11*s +6 - index

//                     else

//                         a==0: s*s + s-1 + 4*(b-1)*(s-1) + 2*(s-2) + s

//                         else: s*s + s-1 + 4*(b-1)*(s-1) + 2*(s-1-a)

// Down  :   index --> b==0 ? (s-1-a) : s*s + s-1 + 4*(b-1)*(s-1) - a

// Left  :   index --> (s-1-a)*s + b

// Back  :   index --> if b==s-1: s*(s-1-a)

//                     if b==0  : 5*s*s -12*s + 8 + (s-1-a)*s

//                     else

//                        if a==s-1: s*s + 4*(s-2-b)*(s-1)

//                        else     : s*s + 4*(s-2-b)*(s-1) + s + (s-2-a)*2

  private String prepareCube3position()

    {

    StringBuilder objectString = new StringBuilder();

    int layers = mObject.getNumLayers();

    int len = layers*layers;

    int cubitIndex, row, col, color,face;

    final int RIGHT= 0;

    final int LEFT = 1;

    final int UP   = 2;

    final int DOWN = 3;

    final int FRONT= 4;

    final int BACK = 5;

    // 'I' - interior, theoretically can happen

    final char[] FACE_NAMES = { 'R', 'L', 'U', 'D', 'F', 'B', 'I'};

    face = UP;

    for(int i=0; i<len; i++)

      {

      row = i/layers;

      col = i%layers;

      cubitIndex = col<layers-1 ? (layers-1)*(layers+4*col) + row : 6*layers*layers - 13*layers + 8 + row;

      color = mObject.getCubitFaceColorIndex(cubitIndex,face);

      objectString.append(FACE_NAMES[color]);

      }

    face = RIGHT;

    for(int i=0; i<len; i++)

      {

      cubitIndex = 6*layers*layers - 12*layers +7 - i;

      color = mObject.getCubitFaceColorIndex(cubitIndex,face);

      objectString.append(FACE_NAMES[color]);

      }

    face = FRONT;

    for(int i=0; i<len; i++)

      {

      row = i/layers;

      col = i%layers;

      if( col==layers-1 ) cubitIndex = 6*layers*layers - 11*layers + 6 -i;

      else if(   col==0 ) cubitIndex = layers*layers - 1 - i;

      else

        {

        if( row==0 ) cubitIndex = layers*layers + layers-1 + 4*(col-1)*(layers-1) + 2*(layers-2) + layers;

        else         cubitIndex = layers*layers + layers-1 + 4*(col-1)*(layers-1) + 2*(layers-1-row);

        }

      color = mObject.getCubitFaceColorIndex(cubitIndex,face);

      objectString.append(FACE_NAMES[color]);

      }

    face = DOWN;

    for(int i=0; i<len; i++)

      {

      row = i/layers;

      col = i%layers;

      cubitIndex = col==0 ? layers-1-row : layers*layers + layers-1 + 4*(col-1)*(layers-1) - row;

      color = mObject.getCubitFaceColorIndex(cubitIndex,face);

      objectString.append(FACE_NAMES[color]);

      }

    face = LEFT;

    for(int i=0; i<len; i++)

      {

      row = i/layers;

      col = i%layers;

      cubitIndex = (layers-1-row)*layers + col;

      color = mObject.getCubitFaceColorIndex(cubitIndex,face);

      objectString.append(FACE_NAMES[color]);

      }

    face = BACK;

    for(int i=0; i<len; i++)

      {

      row = i/layers;

      col = i%layers;

      if( col==layers-1 ) cubitIndex = layers*(layers-1-row);

      else if(   col==0 ) cubitIndex = 5*layers*layers - 12*layers + 8 + (layers-1-row)*layers;

      else

        {

        if( row==layers-1 ) cubitIndex = layers*layers + 4*(layers-2-col)*(layers-1);

        else                cubitIndex = layers*layers + 4*(layers-2-col)*(layers-1) + layers + 2*(layers-2-row);

        }

      color = mObject.getCubitFaceColorIndex(cubitIndex,face);

      objectString.append(FACE_NAMES[color]);

      }

    return objectString.toString();

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private void interruptCube3()

    {

    org.distorted.solvers.cube3.Search.interrupt();

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  public void start()

    {

    Thread thr = new Thread(this);

    thr.start();

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  public void run()

    {

    RubikScreenSolver solver = (RubikScreenSolver) ScreenList.SVER.getScreenClass();

    if( mObject.getObjectType()== ObjectType.CUBE_3 )

      {

      solveCube3(solver);

      }

    else

      {

      solver.displayErrorDialog(mRes.getString(R.string.solver_generic_error1));

      }

    }

}