/// ==============================================================================================
/// Author:         Eric Ho
/// Date:           Jan 24, 2015
/// Class:          CSE142
/// TA:             Christina Polyukh
/// Assignment:     #3B
/// Description:    This class will draw an cafe wall illusion, exactly as in the prompt.
/// ==============================================================================================

import java.awt.*;

public class CafeWall
{
   public static final int MORTAR_HEIGHT = 2;   // The distance, in pixels, separating the rows of a grid.
                                                // Represents the mortar glueing bricks together in a real wall.

   public static void main(String[] args)
   {
      //-- Set up the panel to draw on
           DrawingPanel panel = new DrawingPanel(650, 400);
           Graphics pen = panel.getGraphics();
           panel.setBackground(Color.GRAY);

      //-- Draw the 2 row of boxes, as in the prompt
           drawRowOfBoxes(  0,  0, 4, 20, pen);
           drawRowOfBoxes( 50, 70, 5, 30, pen);

      //-- Draw the 4 grid of boxes, as in the prompt
           drawGridOfBoxes(  10, 150, 4, 25,  0, pen);
           drawGridOfBoxes( 250, 200, 3, 25, 10, pen);
           drawGridOfBoxes( 425, 180, 5, 20, 10, pen);
           drawGridOfBoxes( 400,  20, 2, 35, 35, pen);
   }



   //
   //   Method: Draws a grid of boxes, using drawRowOfBoxes, with mortar between each row.
   //   Parameters:
   //      int x, y     - starting coordinates; the top left corner of the grid
   //      int pairs    - number of pairs of boxes in each row. Also determines the number of rows.
   //      int size     - size of each box, in pixels
   //      int offset   - the horizontal offset between alternating rows, in pixels
   //      Graphics pen - graphics to draw with
   //
   public static void drawGridOfBoxes(int x, int y, int pairs, int size, int offset, Graphics pen)
   {
      for (int row = 0; row < (2 * pairs); row ++)  // Draws (2 * pairs) rows of boxes
      {
         int rowX = x + (row % 2) * offset;             // Starting X for this row. Adds offset to even numbered rows.
         int rowY = y + row * (size + MORTAR_HEIGHT);   // Starting Y for this row. Adds height to leave mortar between rows.

         drawRowOfBoxes(rowX, rowY, pairs, size, pen);
      }
   }



   //
   //   Method: Draws a row of boxes, using drawPairOfBoxes.
   //   Parameters:
   //      int x, y     - starting coordinates; the top left corner of the row
   //      int pairs    - number of pairs of boxes in the row
   //      int size     - size of each box, in pixels
   //      Graphics pen - graphics to draw with
   //
   public static void drawRowOfBoxes(int x, int y, int pairs, int size, Graphics pen)
   {
      for (int loop = 0; loop < pairs; loop ++)     // Draws (pairs) pairs of boxes
      {
         int pairX = x + (2 * loop * size);         // Starting X coordinate for the pair of boxes.

         drawPairOfBoxes(pairX, y, size, pen);
      }
   }



   //
   //   Method: Draws a pair of boxes, one black with a blue X across it,
   //           one white of the same size directly to the right of it.
   //   Parameter:
   //      int x, y     - starting coordinates; the top left corner of the black box
   //      int size     - size of each box, in pixels
   //      Graphics pen - graphics to draw with.
   //
   public static void drawPairOfBoxes(int x, int y, int size, Graphics pen)
   {
      //-- Draw a black box
           pen.setColor(Color.BLACK);
           pen.fillRect(x, y, size, size);

      //-- Draw a blue X over the black box
           pen.setColor(Color.BLUE);
           pen.drawLine(x, y, x + size, y + size);
           pen.drawLine(x, y + size, x + size, y);

      //-- Draw a white box
           pen.setColor(Color.WHITE);
           pen.fillRect(x + size, y, size, size);
   }
}