MazeCell.pde

import java.util.List;

public class MazeCell {
  private int col;
  private int row;
  private boolean[] walls;
  boolean visited;

  public MazeCell(String s) {
    String[] pieces = s.split(":");
  assert pieces != null && pieces.length == 4 :
    String.format("MazeCell.fromString(%s) bad input", s);

    col = Integer.parseInt(pieces[0]);
    row = Integer.parseInt(pieces[1]);

    int bits = Integer.parseInt(pieces[2], 16);
    walls = new boolean[4];
    for (int i = 0; i < walls.length; i++) {
      walls[i] = ((bits >> i) & 1) == 1;
    }
    visited = (pieces[3].equals("T"));
  }

  public MazeCell(int col, int row) {
    this.col = col;
    this.row = row;
    this.walls = new boolean[] { true, true, true, true };
    this.visited = false;
  }

  public int getCol() {
    return col;
  }

  public int getRow() {
    return row;
  }

  public boolean getWall(Wall wall) {
    return walls[wall.ordinal()];
  }

  public void setWall(Wall wall, boolean value) {
    walls[wall.ordinal()] = value;
  }

  public boolean isVisited() {
    return visited;
  }

  public void setVisited(boolean visited) {
    this.visited = visited;
  }

  private void removeWall(MazeCell next) {
    int colDiff = next.getCol() - getCol();
    int rowDiff = next.getRow() - getRow();

    if (colDiff == 1) {
      setWall(Wall.EAST, false);
      next.setWall(Wall.WEST, false);
    } else if (colDiff == -1) {
      setWall(Wall.WEST, false);
      next.setWall(Wall.EAST, false);
    } else if (rowDiff == 1) {
      setWall(Wall.SOUTH, false);
      next.setWall(Wall.NORTH, false);
    } else if (rowDiff == -1) {
      setWall(Wall.NORTH, false);
      next.setWall(Wall.SOUTH, false);
    }
  }

  public MazeCell getRandomUnvisitedNeighbor(Maze maze) {
    ArrayList<MazeCell> neighbors = new ArrayList<MazeCell>();
    if (row > 0 && !maze.grid[col][row - 1].visited) { // top neighbor
      neighbors.add(maze.grid[col][row - 1]);
    }
    if (col < maze.cols - 1 && !maze.grid[col + 1][row].visited) { // right neighbor
      neighbors.add(maze.grid[col + 1][row]);
    }
    if (row < maze.rows - 1 && !maze.grid[col][row + 1].visited) { // bottom neighbor
      neighbors.add(maze.grid[col][row + 1]);
    }
    if (col > 0 && !maze.grid[col - 1][row].visited) { // left neighbor
      neighbors.add(maze.grid[col - 1][row]);
    }
    if (neighbors.size() > 0) {
      int r = floor(random(0, neighbors.size()));
      return neighbors.get(r);
    } else {
      return null;
    }
  }

  public String toString() {
    int bits = 0;
    for (int i = 0; i < walls.length; i++) {
      if (walls[i]) {
        bits |= 1 << i;
      }
    }
    return String.format("%d:%d:%S:%.1B", col, row, Integer.toHexString(bits), visited);
  }
}

enum Wall {
  NORTH,
    EAST,
    SOUTH,
    WEST;
}