Snake/src/SnakePkg/Board.java

package SnakePkg;

import java.util.Random;

/**
 * The game's board representation
 * @author Christos Choutouridis 8997
 */
public class Board {
   /** @name Constructors */
   /** @{ */
   /** Default ctor */
   Board () {
      N = M   =0;
      tiles   = null;
      snakes  = null;
      ladders = null;
      apples  = null;
   }
   
   /**
    * Main constructor
    * We make some simple input checking before memory allocation.
    * @note
    *    May throw BadBoardInput
    */
   Board (int N, int M, int numOfSnakes, int numOfLadders, int numOfApples) 
   throws BadBoardInput {
      // Input checking
      if (numOfApples + numOfLadders*2 + numOfSnakes*2 >= N*M/2)
         throw new BadBoardInput("Too many Apples, Snakes and ladders");
      // Init the board object
      setN (N);   // Input checked version (may throw)
      setM (M);   // Input checked version (may throw)
      tiles   = new int[N][M];
      snakes  = new Snake[numOfSnakes];
      ladders = new Ladder[numOfLadders];
      apples  = new Apple[numOfApples];
   }
   
   /**
    * Copy constructor. We make a deep copy of B and we trust B's
    * data to be valid
    * @note We don't use clone as long as we don't inherit Cloneable iface
    */
   Board (Board B) {
      this.N  = B.getN();
      this.M  = B.getM();
      tiles   = new int[N][M];
      snakes  = new Snake[B.getSnakes().length];
      ladders = new Ladder[B.getLadders().length];
      apples  = new Apple[B.getApples().length];
      // Copy B's guts
      for (int i =0 ; i<N ; ++i)
         for (int j =0 ; j<M ; ++j)
            tiles[i][j] = B.getTiles()[i][j];
      for (int i =0 ; i<B.getSnakes().length ; ++i)
         snakes[i] = B.getSnakes()[i];
      for (int i =0 ; i<B.getLadders().length ; ++i)
         ladders[i] = B.getLadders()[i];
      for (int i =0 ; i<B.getApples().length ; ++i)
         apples[i] = B.getApples()[i];
   }
   /** @} */
   
   /** @name Get/Set interface */
   /** @{ */
   
   /** Get value N */
   int getN () { return N; }
   /**
    * Set value N
    * @throws  BadBoardInput
    */
   void setN (int N) throws BadBoardInput {
      // Input checking
      if (N<=0)
         throw new BadBoardInput("N is zero or Less");
      this.N = N;
   }
   
   /** Get value M */
   int getM () { return M; }
   /**
    * Set value M
    * @throws  BadBoardInput
    */
   void setM (int M) throws BadBoardInput {
      // Input checking
      if (M<=0)
         throw new BadBoardInput("M is zero or Less");
      this.M = M;
   }

   /** Get reference to tiles */
   int[][] getTiles () { return tiles; }  
   
   /**
    * Set tiles (deep copy)
    * @param   tiles    Source of tiles to use
    * @throws  BadBoardInput
    */
   void setTiles (int[][] tiles) throws BadBoardInput {
      // Input checking
      if (tiles.length != N && tiles[0].length != M)
         throw new BadBoardInput("tiles size missmatch");
      // Check if we need allocation
      if (this.tiles == null)
         this.tiles = new int[N][M];
      // Assign values (deep copy)
      for (int i =0 ; i<N ; ++i)
         for (int j =0 ; j<M ; ++j)
            this.tiles[i][j] = tiles[i][j];
   }
   
   /** Get reference to snakes */
   Snake[] getSnakes() { return snakes; }
   /**
    * Set snakes (deep copy)
    * @param snakes  Source of snakes to use 
    * @throws BadBoardInput
    * @note Requires Snake copy contructor
    */
   void setSnakes(Snake[] snakes) throws BadBoardInput {
      // Check if we need allocation
      if (this.snakes == null)
         this.snakes = new Snake[snakes.length];
      // Input checking
      if (this.snakes.length != snakes.length)
         throw new BadBoardInput("snakes size missmatch");
      // Assign values (deep copy)
      for (int i =0 ; i<this.snakes.length ; ++i)
         this.snakes[i] = new Snake(snakes[i]);
   }
   
   /** Get reference to ladders */
   Ladder[] getLadders() { return ladders; }
   /**
    * Set ladders (deep copy)
    * @param ladders  Source of snakes to use 
    * @throws BadBoardInput
    * @note Requires Ladder copy contructor
    */
   void setLadders (Ladder[] ladders) throws BadBoardInput {
      // Check if we need allocation
      if (this.ladders == null)
         this.ladders = new Ladder[ladders.length];
      // Input checking
      if (this.ladders.length != ladders.length)
         throw new BadBoardInput("ladders size missmatch");
      // Assign values (deep copy)
      for (int i =0 ; i<this.ladders.length ; ++i)
         this.ladders[i] = new Ladder(ladders[i]);
   }
   
   /** Get reference to apples */
   Apple[] getApples() { return apples; }
   /**
    * Set apples (deep copy)
    * @param apples  Source of snakes to use 
    * @throws BadBoardInput
    * @note Requires Apple copy contructor
    */
   void setApples (Apple[] apples) throws BadBoardInput {
      // Check if we need allocation
      if (this.apples == null)
         this.apples = new Apple[apples.length];
      // Input checking
      if (this.apples.length != apples.length)
         throw new BadBoardInput("ladders size missmatch");
      // Assign values (deep copy)
      for (int i =0 ; i<this.apples.length ; ++i)
         this.apples[i] = new Apple(apples[i]);
   }
   /** @} */

   /** @name Exposed API members */
   /** @{ */
   
   
   /**
    * Create a playable board for the game
    */
   void createBoard () {
      _tile_numbering ();  // Create tile numbering
      _place_snakes ();    // Place snakes
      _place_apples ();    // Place Apples
      _place_ladders ();   // place ladders
   }

   /**
    * make and PRINT element boards
    */
   void createElementBoard () {
      String[][] elementBoardSnakes    = new String[N][M];
      String[][] elementBoardLadders   = new String[N][M];
      String[][] elementBoardApples    = new String[N][M];

      _makeElementSnakes (elementBoardSnakes);
      _makeElementLadders (elementBoardLadders);
      _makeElementApples (elementBoardApples);
      
      _printElement (elementBoardSnakes, "elementBoardSnakes");
      _printElement (elementBoardLadders, "elementBoardLadders");
      _printElement (elementBoardApples, "elementBoardApples");
   }
   /** @} */


   /** @name Private api */
   /**@{ */
   
   /**
    * @brief
    *    Create the tile numbering
    * We use a starting point the tile[0][0] and as finish point
    * the tile[N-1][M-1]
    */
   private void _tile_numbering () {
      for (int i=0, tile =1 ; i<N ; ++i) {
         if (i%2 == 0) {
            // Even row, go right
            for (int j=0 ; j<M ; ++j)
               tiles[i][j] = tile++;
         }
         else {
            // Odd row, go left
            for (int j=M-1 ; j>=0 ; --j)
               tiles[i][j] = tile++;
         }
      }
   }

   /**
    * @brief
    *    Place the snakes on the board
    * The only constrain at this point is that snake tails must be
    * below heads and in different tiles
    */
   private void _place_snakes () {
      int [] head = new int [snakes.length];    // temporary place holder for heads
      int [] tail = new int [snakes.length];    // temporary place holder for tails
      for (int i =0, tile =0 ; i<snakes.length ; ++i) {
         // Keep getting heads until they are different from the previous
         do
            tile = (int)(M + Math.random() * (N-1) * M);          // Don't use first row for heads
         while (_search (head, tile) >= 0);
         head[i] = tile;
         tail[i] = (int)(Math.random() * (head[i] - head[i]%M));  // Don't use heads row and up for tail
         snakes[i] = new Snake(i, head[i], tail[i]);              // Allocate snake
      }
   }

   /**
    * @brief
    *    Place apples on the board
    * At this point we have snakes. The constrains here are
    * that apples have to lie on different tiles and not in some
    * snake's head
    */
   private void _place_apples () {
      int [] apple_tiles = new int [apples.length];   // temporary placeholder for heads
      int [] snake_tiles = new int [snakes.length];   // array with snake head tiles
      for (int i =0 ; i<snakes.length ; ++i)          // Load snake head tiles
         snake_tiles[i] = snakes[i].getHeadId();

      for (int i =0, tile =0 ; i<apples.length ; ++i) {
         // Keep getting tiles until they are different from the previous
         // and not in some snake's head
         do
            tile = (int) (Math.random() * (N * M));
         while ((_search (apple_tiles, tile) >= 0) ||
                (_search (snake_tiles, tile) >= 0));
         apple_tiles[i] = tile;
         int points = (int)(Math.random() *10) * 5;      // get points
         boolean red = (boolean)(Math.random() >=0.5);   // get color
         // Allocate apple
         if (red)
            apples[i] = new Apple(i, tile, "red", points);
         else
            apples[i] = new Apple(i, tile, "black", -points);
      }
   }

   /**
    * @brief
    *    Place ladders on board
    * At this point we have snakes and apples.
    * @note
    *    We add a constrain for ladder so its up-setp has to be different from a
    *    snake's head tile. This ensures the each ladder and snake are independent 
    */
   private void _place_ladders () {
      int [] upstep   = new int [ladders.length];  // temporary place holder for up-steps
      int [] downstep = new int [ladders.length];  // temporary place holder for down-step
      int [] snake_tiles = new int [snakes.length];   // array with snake head tiles
      for (int i =0 ; i<snakes.length ; ++i)          // Load snake head tiles
         snake_tiles[i] = snakes[i].getHeadId();

      for (int i =0, tile =0 ; i<ladders.length ; ++i) {
         // Keep getting up-steps until they are different from the previous
         // and not in some snake's head
         do
            tile = (int)(M + Math.random() * (N-1) * M);          // Don't use first row for heads
         while ((_search (upstep, tile) >= 0) ||
                (_search (snake_tiles, tile) >= 0));
         upstep[i] = tile;
         downstep[i] = (int)(Math.random() * (upstep[i] - upstep[i]%M));
            //^ Don't use up-step row and up for down-step
         ladders[i] = new Ladder (i, upstep[i], downstep[i]);     // Allocate ladder
      }
   }

   /**
    * Make element array of snakes
    * @param elemSnakes
    */
   private void _makeElementSnakes (String[][] elemSnakes) {
      int [] head_tiles = new int [snakes.length];   // array with snake head tiles
      int [] tail_tiles = new int [snakes.length];   // array with snake head tiles
      int sn =-1;
      // Load snake head tiles
      for (int i =0 ; i<snakes.length ; ++i) {
         head_tiles[i] = snakes[i].getHeadId();
         tail_tiles[i] = snakes[i].getTailId();
      }

      // Search all tiles for snake heads and tails
      for (int i =0; i<N ; ++i) {
         for (int j =0 ; j<M ; ++j) {
            if ((sn = _search (head_tiles, tiles[i][j])) >= 0)
               elemSnakes[i][j] = "SH" + sn;
            else if ((sn = _search (tail_tiles, tiles[i][j])) >= 0)
               elemSnakes[i][j] = "ST" + sn;
            else
               elemSnakes[i][j] = "___";
         }
      }
   }

   /**
    * Make element array of ladders
    * @param elemLadders
    */
   private void _makeElementLadders (String[][] elemLadders) {
      int [] up_tiles   = new int [ladders.length];   // array with ladder up-step tiles
      int [] down_tiles = new int [ladders.length];   // array with ladder down-step tiles
      int sn =-1;
      // Load ladder tiles
      for (int i =0 ; i<ladders.length ; ++i) {
         up_tiles[i] = ladders[i].getUpStepId();
         down_tiles[i] = ladders[i].getDownStepId();
      }

      // Search all tiles for snake heads and tails
      for (int i =0; i<N ; ++i) {
         for (int j =0 ; j<M ; ++j) {
            if ((sn = _search (up_tiles, tiles[i][j])) >= 0)
               elemLadders[i][j] = "LU" + sn;
            else if ((sn = _search (down_tiles, tiles[i][j])) >= 0)
               elemLadders[i][j] = "LD" + sn;
            else
               elemLadders[i][j] = "___";
         }
      }
   }

   /**
    * Make element array of apples
    * @param elemApples
    */
   private void _makeElementApples (String[][] elemApples) {
      int [] red_tiles   = new int [apples.length];   // array with red apple tiles
      int [] black_tiles = new int [apples.length];   // array with black apple tiles
      int sn =-1;
      // Load apple tiles
      for (int i =0 ; i<apples.length ; ++i) {
         if (apples[i].getColor() == "red")
            red_tiles[i] = apples[i].getAppleTileId();
         else
            black_tiles[i] = apples[i].getAppleTileId();
      }

      // Search all tiles for snake heads and tails
      for (int i =0; i<N ; ++i) {
         for (int j =0 ; j<M ; ++j) {
            if ((sn = _search (red_tiles, tiles[i][j])) >= 0)
               elemApples[i][j] = "AR" + sn;
            else if ((sn = _search (black_tiles, tiles[i][j])) >= 0)
               elemApples[i][j] = "AB" + sn;
            else
               elemApples[i][j] = "___";
         }
      }
   }

   /**
    * Print element array
    * @param elem    The element array to print
    * @param caption The caption
    * @note
    *    As long as we use tiles[0][0] for first tile, this method
    *    has to print in reverse Y-axis order. For ex:
    *    16 15 14 13
    *    09 10 11 12
    *    08 07 06 05
    *    01 02 03 04
    */
   private void _printElement (String[][] elem, String caption) {
      System.out.print(caption);
      for (int i=N-1 ; i>=0 ; --i) {
         System.out.println("");
         System.out.print(" ");
         for (int j =0 ; j<M ; ++j)
            System.out.print(elem[i][j] + " ");
      }
      System.out.println("");
      System.out.println("");
   }

   /** Search algorithm
    * @param array   Array to search
    * @param elem    Element of type T to find inside of array
    * @return        The status of the operation
    *    @arg  -1    Element not found
    *    @arg  >=0   Element found
    */
   private int _search (int[] array, int elem) {
      for (int i=0 ; i<array.length ; ++i)
         if (elem == array[i])
            return i;
      return -1;
   }
   /**@} */
   
   /** @name Data members (private) */
   /** @{ */
   private int N;             //!< Board's row count
   private int M;             //!< Board's Column count
   private int[][]  tiles;    //!< Board's tiles
   private Snake[]  snakes;   //!< Board's snakes
   private Ladder[] ladders;  //!< Board's ladders
   private Apple[]  apples;   //!< Board's apples
   /** @} */
}

class BadBoardInput extends Exception {
   BadBoardInput() {}
   BadBoardInput(String str) { super(str); }
   //static final long SerialVersionUIDAdder = 0;
}