/**
 * @file Board.java
 *
 * @author Christos Choutouridis AEM:8997
 * @email  cchoutou@ece.auth.gr
 */

package net.hoo2.auth.labyrinth;

import java.util.function.IntFunction;

/**
 * @brief
 *    This class is the representation of the games's board
 *
 * The board is the square arrangement of the tiles. This class is also
 * the owner of the tile and supply objects.
 */
public class Board {
   /** @name Constructors */
   /** @{ */

   /**
    * The empty constructor for default initialization
    */
   protected Board() {
      this.N = this.S = this.W = 0;
      this.tiles = null;
      this.supplies =null;
   }

   /**
    * The main constructor for the application
    * @param N    The size of each edge of the board
    * @param S    The number of supplies on the board
    * @param W    The number of walls on the board
    */
   protected Board(int N, int S, int W) {
      assert (W>= 4*N-1 && W<=(3*N*N+1)/2 )
         : "Boards walls has to be in the range [4N-1, (3N^2+1)/2]";

      this.N   = Session.boardSize = N;
      this.S   = S;
      this.W   = W;
      tiles    = new Tile[N*N];
      supplies = new Supply[S];
   }

   /**
    * Deep copy constructor
    * @param b    The board to copy
    *
    * @note
    *    The lack of value semantics in java is (in author's opinion) one of the greatest
    *    weakness of the language and one of the reasons why it will never be a language
    *    to care about. To quote Alexander Stepanof's words in "elements of programming" section 1.5:
    *    "Assignment is a procedure that takes two objects of the same type and makes the first
    *    object equal to the second without modifying the second".
    *    In this class we try to cope with this situation knowing that we can not do anything about
    *    assignment operator. We just add value semantics to the copy constructor and go on with our lifes...
    */
   protected Board(Board b) {
      // Copy primitives
      this.N   = b.N;
      this.S   = b.S;
      this.W   = b.W;
      // Clone arrays
      this.tiles     = b.tiles.clone();
      this.supplies  = b.supplies.clone();
   }
   /** @} */

   /** @name Supply's main application interface */
   /** @{ */

   protected void createTiles() {
      int wallPool = W;
      wallPool -= createBasicTileWalls ();
      createInnerWalls(wallPool);
   }

   protected void createSupplies(int theseusTile, int minotaurTile) {
      ShuffledRange rand = new ShuffledRange(0, N*N);
      for (int tileId, i=0 ; i<supplies.length ; ++i) {
         do
            tileId = rand.get();
         while (tileId == theseusTile || tileId == minotaurTile);
         supplies[i] = new Supply(i, tileId);
      }
   }

   protected void createBoard(int theseusTile, int minotaurTile) {
      createTiles();
      createSupplies(theseusTile, minotaurTile);
   }

   protected String[][] getStringRepresentation(int theseusTile, int minotaurTile) {
      String[][] frame = new String[2*N+1][N];

      for (int row=0 ; row<N ; ++row) {
         int col;
         for (col =0 ; col<N-1 ; ++col)
            renderTile(frame, row, col, theseusTile, minotaurTile);
         renderSentinelTile(frame, row, col, theseusTile, minotaurTile);
      }
      return frame;
   }

   protected void printBoard (String[][] sBoard) {
      for (int i=sBoard.length-1 ; i>=0 ; --i) {
         for (String it : sBoard[i])
            System.out.print(it);
         System.out.println();
      }
   }

   int size() { return N; }

   /** @} */

   /**
    * @name Accessor/Mutator interface
    * @note
    *    Please consider not to use mutator interface. Its the abstraction killer :(
    */
   /** @{ */
   protected int getN()    { return N; }
   protected int getS()    { return S; }
   protected int getW()    { return W; }
   /**
    * @note Use it with care. Any use of this function results to what Sean Parent calls "incidental data-structure".
    * <a href="https://github.com/sean-parent/sean-parent.github.io/blob/master/better-code/03-data-structures.md"> see also here</a>
    * @return  Reference to inner tiles array.
    */
   protected Tile[] getTiles()      { return tiles; }
   /**
    * @note Use it with care. Any use of this function results to what Sean Parent calls "incidental data-structure".
    * <a href="https://github.com/sean-parent/sean-parent.github.io/blob/master/better-code/03-data-structures.md"> see also here</a>
    * @return  Reference to inner supplies array.
    */
   protected Supply[] getSupplies() { return supplies; }

   protected void setN(int N)  { this.N = N; }
   protected void setS(int S)  { this.S = S; }
   protected void setW(int W)  { this.W = W; }

   /**
    * @param tiles   Reference to tiles that we want to act as replacement for the inner tiles array.
    * @note    Use with care.
    * Any call to this function will probably add memory for the garbage collector.
    */
   protected void setTiles(Tile[] tiles)           { this.tiles = tiles; }
   /**
    * @param supplies   Reference to supplies that we want to act as replacement for the inner supplies array.
    * @note    Use with care.
    * Any call to this function will probably add memory for the garbage collector.
    */
   protected void setSupplies(Supply[] supplies)   { this.supplies= supplies; }
   /** @} */

   private int createBasicTileWalls () {
      int tileCount =0;
      // Create basic tiles and outer walls
      for (int i =0 ; i< tiles.length ; ++i) {
         int r = Position.toRow(i);
         int c = Position.toCol(i);
         boolean up    = (r == N-1)          ? true : false;
         boolean down  = (r == 0 && c != 0)  ? true : false;
         boolean left  = (c == 0)            ? true : false;
         boolean right = (c == N-1)          ? true : false;
         tileCount += ((up?1:0) + (down?1:0) + (left?1:0) + (right?1:0));
         tiles[i] = new Tile (i, up, down, left, right);
      }
      return tileCount;
   }

   private int createInnerWalls (int wallPool) {
   // Create inner walls for the rest of the desired walls
      ShuffledRange randTiles = new ShuffledRange(0, N*N);
      for (int tileId, i =0 ; i<wallPool ; ++i) {
         // randomly pick a tile with less than 2 walls
         do {
            tileId = randTiles.get();
            if (tileId == Const.noTileId)
               return 0;
         } while (tiles[tileId].hasWalls() >= 2);  //XXX: Predicate : can put wall
         // Randomly pick a not used direction in that tile
         ShuffledRange randDirections = new ShuffledRange(Direction.Begin, Direction.Step, Direction.End);
         Position tilePos = new Position(tileId);
         int dir;
         do
            dir = randDirections.get();
         while (tiles[tileId].hasWall(dir));
         switch (dir) {
            case Direction.UP:
               tiles[tileId].setWalls(true, false, false, false);
               tiles[Position.toID(tilePos.getRow()+1, tilePos.getCol())].setWalls(false, true, false, false);
               break;
            case Direction.DOWN:
               tiles[tileId].setWalls(false, true, false, false);
               tiles[Position.toID(tilePos.getRow()-1, tilePos.getCol())].setWalls(true, false, false, false);
               break;
            case Direction.LEFT:
               tiles[tileId].setWalls(false, false, true, false);
               tiles[Position.toID(tilePos.getRow(), tilePos.getCol()-1)].setWalls(false, false, false, true);
               break;
            case Direction.RIGHT:
               tiles[tileId].setWalls(false, false, false, true);
               tiles[Position.toID(tilePos.getRow(), tilePos.getCol()+1)].setWalls(false, false, true, false);
               break;
         }
      }
      return 0;
   }

   private String getTileBody (int row, int col, int theseusTile, int minotaurTile) {
      int tileId = Position.toID(row, col);
      boolean T = (tileId == theseusTile) ? true : false;
      boolean M = (tileId == minotaurTile) ? true : false;
      int S = tiles[tileId].hasSupply(supplies);

      if      (T && !M)    return " T ";
      else if (M && !T)    return " M ";
      else if (T && M)     return "T+M";
      else if (S != Const.noSupply)
         return String.format("s%02d", S+1);
      else                 return "   ";
   }

   private void renderTile(String[][] frame, int row, int col, int theseusTile, int minotaurTile) {
      IntFunction<Integer> toframe = (r)->{ return 2*r+1; };

      int tileId = Position.toID(row, col);
      frame[toframe.apply(row)+1][col] = tiles[tileId].hasWall(Direction.UP)   ? "+---" : "+   ";
      frame[toframe.apply(row)  ][col] = (tiles[tileId].hasWall(Direction.LEFT)? "|" : " ")
                                       + getTileBody(row, col, theseusTile, minotaurTile);
      frame[toframe.apply(row)-1][col] = tiles[tileId].hasWall(Direction.DOWN) ? "+---" : "+   ";
   }


   private void renderSentinelTile(String[][] frame, int row, int col, int theseusTile, int minotaurTile ) {
      IntFunction<Integer> toframe = (r)->{ return 2*r+1; };

      int tileId = Position.toID(row, col);
      frame[toframe.apply(row)+1][col] = tiles[tileId].hasWall(Direction.UP)   ? "+---+" : "+   +";
      frame[toframe.apply(row)  ][col] = (tiles[tileId].hasWall(Direction.LEFT)? "|" : " ")
                                       + getTileBody(row, col, theseusTile, minotaurTile)
                                       + (tiles[tileId].hasWall(Direction.RIGHT)? "|" : " ");
      frame[toframe.apply(row)-1][col] = tiles[tileId].hasWall(Direction.DOWN) ? "+---+" : "+   +";
   }

   /** @name Class data */
   /** @{ */
   private int    N;          /**< The size of each edge of the board */
   private int    S;          /**< The number of the supplies on the board */
   private int    W;          /**< The number of walls on the board */
   private Tile[] tiles;      /**< Array to hold all the tiles for the board */
   private Supply[] supplies; /**< Array to hold all the supplies on the board */
   /** @} */
}