import java.io.*;
import java.net.*;
import java.awt.*;

public class Grid {

    Graphics g;                    // graphics environment for the grid
	int size, cellSize;            // number per row, and size of cells
    final char OFF = ' ', ON = '*', 
               EX = 'X', OH = 'O'; // state of a cell
	char[][] cells;                // all cell values for the grid
	int dX = 6;                    // distance of the grid, in cells,
	int dY = 15;                   // from upperleft corner of the frame
    boolean gridError;

    public int row, col; // row and column of last mouse click in the grid 
                         // (-1, -1) means click was outside the grid
    int i, j;
    Color current_color;
    static BufferedReader input;
    static boolean iseof = false;

  // Initialize an empty grid in the given graphics environment
  public Grid (Graphics gg, int s, int cs, int horizontal) {
	 g = gg;
     size = s;
     cellSize = cs;
     dX = horizontal;
     cells = new char[s][s];
	 for (int i=0; i<size; i++)
		for (int j=0; j<size; j++)
			cells[i][j] = OFF;
	 gridError = false;
	 row = col = -1;             // no cell selected yet
	 current_color = Color.black;
	 showGrid();
  }

  // Load the grid with values retrieved from the given text file
  public void loadFromFile (String fileName){
     try {
       URL UF = new URL(fileName);
       InputStream in = UF.openStream();
       input = new BufferedReader(new InputStreamReader(in));       
       for (int i=0; i<size; i++) {
         String s = readString();
         for (int j=0; j<s.length(); j++)
           switch(s.charAt(j)) {
           case ON: case OFF: case EX: case OH: 
              cells[j][i] = s.charAt(j);
           }
       }
       showGrid();
     }
     catch (MalformedURLException e) {
        System.out.println("File not found: MalformedURLException");
     }
     catch (IOException e) {
        System.out.println("File not found: IOException");
     }
  }
  
  public static String readString () {
    String s = "";
    if (iseof) return null;
    System.out.flush();
    try { 
      s=input.readLine();
    }
    catch (IOException e) {
      System.exit(-1);
    }
    if (s==null) {
      iseof=true; 
      return "";
    }
    return s;
  }
  
  public void showGrid() {
     g.setColor(Color.black);
	 for (i=0; i<=size; i++)     // draw vertical lines
	    g.drawLine(cellSize*(i+dX), cellSize*dY, cellSize*(i+dX), cellSize*(size+dY));
	 for (j=0; j<=size; j++)     // draw horizontal lines
	    g.drawLine(cellSize*dX, cellSize*(j+dY), cellSize*(size+dX), cellSize*(j+dY));
	 for (i=0; i<size; i++)      // display each cell's value
	    for (j=0; j<size; j++) 
	       drawCell(i, j);
  }
  
  public void clearGrid () {
	 for (i=0; i<size; i++)          // clear the grid and redisplay it
	    for (j=0; j<size; j++) 
	       set(i, j, OFF);
	 row = col = -1;
	 current_color = Color.black;
  }

  public void drawCell (int r, int c) {
  // displays the contents of a single cell, at row r, column c in the grid
	 if (0<=r && r<size && 0<=c && c<size) {
		gridError = false;
		switch (cells[r][c]) {
			case OFF: g.setColor(Color.white);
					  g.fillRect(cellSize*(r+dX)+1, cellSize*(c+dY)+1, 
					             cellSize-1, cellSize-1);
					  g.setColor(current_color);
				      break;
			case ON:  g.setColor(current_color);
					  g.fillRect(cellSize*(r+dX)+1, cellSize*(c+dY)+1, 
					             cellSize-1, cellSize-1);
					  break;
			case EX:  g.setColor(Color.white);
					  g.fillRect(cellSize*(r+dX)+1, cellSize*(c+dY)+1, 
					             cellSize-1, cellSize-1);
					  g.setColor(current_color);
				      g.drawLine(cellSize*(r+dX)+2, cellSize*(c+dY)+2, 
				                 cellSize*(r+1+dX)-2, cellSize*(c+1+dY)-2);
				      g.drawLine(cellSize*(r+dX)+2, cellSize*(c+1+dY)-2, 
				                 cellSize*(r+1+dX)-2, cellSize*(c+dY)+2);
					  break;
			case OH:  g.setColor(Color.white);
					  g.fillRect(cellSize*(r+dX)+1, cellSize*(c+dY)+1, 
					             cellSize-1, cellSize-1);
					  g.setColor(current_color);
				      g.drawOval(cellSize*(r+dX)+2, cellSize*(c+dY)+2, 
				                 cellSize-3, cellSize-3);
					  break;
		}
	}
	else
		gridError = true;
  }
  
  public void cellColor (Color c) {
     current_color = c;
  }

  public boolean inGrid (int x, int y) {
  // determines whether the point x-y in the Frame is in the grid.
  // If so, set the values of row and col appropriately and return
  // true.  Otherwise, x-y is not in the grid, so set row and col 
  // to -1 and return false.
    row = (x - cellSize*dX) / cellSize;
    col = (y - cellSize*dY) / cellSize;
    if (0 <= x - cellSize*dX && row < size && 
        0 <= y - cellSize*dY && col < size)
      return true; 
    else {
      row = col = -1;
      return false;
    }
  }

  public boolean equals (int r, int c, char val) {
  // test to see if cell row r, column c is equal to val
    if (0<=r && r<size && 0<=c && c<size && (val==OFF || val==ON || val==EX || val==OH)) {
      if (cells[r][c] == val)
         return true;
      else return false;
    }
    else {
      gridError = true;
      return false;
    } 
  }

  public void set (int r, int c, char val) {
  // set the cell in row r, column c to val
    if (0<=r && r<size && 0<=c && c<size && (val==OFF || val==ON || val==EX || val==OH)) {
      cells[r][c] = val;
      drawCell(r, c);
    }
    else 
      gridError = true;  
  }

  public char get (int r, int c) {
  // return the value of the cell in row r, column c
    if (0<=r && r<size && 0<=c && c<size) 
      return cells[r][c];
    else 
      return OFF;  
  }

}