/* puzzle_partial.pde
   Written by Justin Hsia
   
   Implement the game mechanics of a 15 Puzzle
   Clicking "Reset" will return the board to the ordered state.
   
   Reset button and game board implemented.
   "Sliding" not in place yet - currently testing mousePressed()
*/

int boardX = 100;           // x-position of upper-left corner of game board
int boardY = 50;            // y-position of upper-left corner of game board
int[] tiles = new int[16];  // array to hold state of game board
int gridX, gridY;           // variables to detect grid coordinates when user clicks on game board


void setup() {
  size(400,400);            // drawing canvas size
  textAlign(CENTER);        // center align text (give coordinates for bottom center of where text will appear)
  background(0,100,100);    // dark turquoise
  reset();                  // use reset() function to initialize tiles[]
}

void draw() {
  drawReset();              // draw the reset button
  drawBoard();              // draw the game board
}

void mousePressed() {
  // detect clicking of Reset button
  if( mouseX >= 150 && mouseX <= 250 && mouseY >= 300 && mouseY <= 340 ) {
    println("Reset clicked");    // for testing purposes
    //reset();
  }
  // detect clicking on game board
  if( mouseX >= boardX && mouseX <= boardX+200 && mouseY >= boardY && mouseY <= boardY+200 ) {
    //println("Grid clicked");      // for testing purposes
    gridX = (mouseX-boardX)/50;   // x grid coordinate of clicked tile
    gridY = (mouseY-boardY)/50;   // y grid coordinate of clicked tile
    println("GridX = " + gridX);  // for testing purposes
    println("GridY = " + gridY);  // for testing purposes
  }
}

// draw the game board: grid of tiles
void drawBoard() {
  // draw border
  fill(0,100,200);
  rect(boardX,boardY,200,200);
  
  // draw tiles and tile numbers
  for(int i=0; i<4; i=i+1) {    // loop over columns (x grid position)
    for(int j=0; j<4; j=j+1) {  // loop over rows    (y grid position)
      if(tiles[4*j+i] > 0) {    // skip open square
        // draw tile
        fill(0,200,200);    // bright turquoise
        rect(boardX+2+50*i,boardY+2+50*j,46,46);
        // display tile number
        fill(255);          // white text
        text(tiles[4*j+i], boardX+2+50*i+23, boardY+2+50*j+30);
      }
    }
  }
}

// draw the reset button at the bottom (positioned arbitrarily)
void drawReset() {
  noFill();
  stroke(255);
  rect(width/2-50,300,100,40);
  textSize(32);
  fill(255);
  text("Reset", width/2, 330);
}

// reset tiles to be in order with open tile at position (0,0)
void reset() {
  for(int i=0; i<tiles.length; i=i+1) {
    tiles[i] = i;
  }
}