Magic Cube

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

// Copyright 2023 Leszek Koltunski                                                               //

//                                                                                               //

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

//                                                                                               //

// Magic Cube is proprietary software licensed under an EULA which you should have received      //

// along with the code. If not, check https://distorted.org/magic/License-Magic-Cube.html        //

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

package org.distorted.solvers;

import android.content.res.Resources;

import org.distorted.main.R;

import org.distorted.objectlib.main.TwistyObject;

import org.distorted.screens.RubikScreenSolver;

import org.distorted.solvers.cube3.SolverSearch;

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

public class SolverCube3

{

  private final Resources mRes;

  private final TwistyObject mObject;

  private int mColorID;

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

  private int mapCubitToFace(int cubit, int face)

    {

    if( cubit<8 )

      {

      switch(face)

        {

        case 0: return 1;

        case 1: if( cubit==2 ) return 5;

                if( cubit==1 ) return 3;

                return 1;

        case 2: return cubit==7 ? 5 : 3;

        case 3: if( cubit==1 ) return 1;

                return cubit==4 ? 5 : 3;

        case 4: return cubit==7 ? 3 : 5;

        case 5: if( cubit==2 ) return 1;

                if( cubit==4 ) return 3;

                return 5;

        }

      }

    if( cubit>19 ) return 4;

    switch(face)

      {

      case 0: return cubit==15 || cubit==18 ? 3 : 5;

      case 1: return cubit==13 || cubit==16 ? 3 : 5;

      case 2: return cubit==10              ? 5 : 3;

      case 3: return cubit== 8              ? 3 : 5;

      case 4: return cubit== 9              ? 3 : 5;

      case 5: return cubit== 8              ? 5 : 3;

      }

    return -1;

    }

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

  private int checkPosition(String position)

    {

    int[] numColors = new int[6];

    int len = position.length();

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

      {

      char ch = position.charAt(i);

      switch(ch)

        {

        case 'R': numColors[0]++; break;

        case 'L': numColors[1]++; break;

        case 'U': numColors[2]++; break;

        case 'D': numColors[3]++; break;

        case 'F': numColors[4]++; break;

        case 'B': numColors[5]++; break;

        }

      }

    if( numColors[0]<9 ) { mColorID = R.string.color_yellow1; return numColors[0]; }

    if( numColors[1]<9 ) { mColorID = R.string.color_white1 ; return numColors[1]; }

    if( numColors[2]<9 ) { mColorID = R.string.color_blue1  ; return numColors[2]; }

    if( numColors[3]<9 ) { mColorID = R.string.color_green1 ; return numColors[3]; }

    if( numColors[4]<9 ) { mColorID = R.string.color_red1   ; return numColors[4]; }

    if( numColors[5]<9 ) { mColorID = R.string.color_orange1; return numColors[5]; }

    return -1;

    }

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

// 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"

  private String preparePosition()

    {

    StringBuilder objectString = new StringBuilder();

    final int R = 0;

    final int L = 1;

    final int U = 2;

    final int D = 3;

    final int F = 4;

    final int B = 5;

    // 'I' - interior, theoretically can happen

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

    final int[] U_INDEX = { 2,10, 6,17,22,19, 3,11, 7};

    final int[] R_INDEX = { 7,19, 6,15,20,14, 5,18, 4};

    final int[] F_INDEX = { 3,11, 7,13,24,15, 1, 9, 5};

    final int[] D_INDEX = { 1, 9, 5,16,23,18, 0, 8, 4};

    final int[] L_INDEX = { 2,17, 3,12,21,13, 0,16, 1};

    final int[] B_INDEX = { 6,10, 2,14,25,12, 4, 8, 0};

    for(int i=0; i<9; i++)

      {

      int face = mapCubitToFace(U_INDEX[i],U);

      int color = mObject.getCubitFaceStickerIndex(U_INDEX[i], face);

      objectString.append(FACE_NAMES[color]);

      }

    for(int i=0; i<9; i++)

      {

      int face = mapCubitToFace(R_INDEX[i],R);

      int color = mObject.getCubitFaceStickerIndex(R_INDEX[i], face);

      objectString.append(FACE_NAMES[color]);

      }

    for(int i=0; i<9; i++)

      {

      int face = mapCubitToFace(F_INDEX[i],F);

      int color = mObject.getCubitFaceStickerIndex(F_INDEX[i], face);

      objectString.append(FACE_NAMES[color]);

      }

    for(int i=0; i<9; i++)

      {

      int face = mapCubitToFace(D_INDEX[i],D);

      int color = mObject.getCubitFaceStickerIndex(D_INDEX[i], face);

      objectString.append(FACE_NAMES[color]);

      }

    for(int i=0; i<9; i++)

      {

      int face = mapCubitToFace(L_INDEX[i],L);

      int color = mObject.getCubitFaceStickerIndex(L_INDEX[i], face);

      objectString.append(FACE_NAMES[color]);

      }

    for(int i=0; i<9; i++)

      {

      int face = mapCubitToFace(B_INDEX[i],B);

      int color = mObject.getCubitFaceStickerIndex(B_INDEX[i], face);

      objectString.append(FACE_NAMES[color]);

      }

    return objectString.toString();

    }

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

// PUBLIC API

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

  public SolverCube3(Resources res, TwistyObject object)

    {

    mRes   = res;

    mObject= object;

    }

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

  public void solve(RubikScreenSolver solver)

    {

    String result;

    SolverSearch.prepare(mRes);

    String objectPosition = preparePosition();

    int check = checkPosition(objectPosition);

    if( check<0 )

      {

      result = SolverSearch.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_generic_edge_twist); break;

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

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

        }

      }

    else

      {

      String color = mRes.getString(mColorID);

      result = mRes.getString(R.string.solver_cube3_error1,check,color);

      solver.displayErrorDialog(result);

      }

    }

}