// ok, i want to write an extremely simple script that lets you click on tiles to change them. 

// width and size of grid
int tile_width = 50;
int L = 20;

// these are variables that we use to zoom in and out of the whole thing
float scale = 1;
int xOffset = 0;
int yOffset = 0;
float beta = 0.441;

// these are the spins
int[][] s = new int[L][L];

int score = 0;
int tries = 0;

PFont f;


void setup() {
  size(500,500);
  background(0, 0, 0);
 // s[0][0]=1;
 // s[0][1]=1;
 // s[1][1]=1;
//  println(s[0][0]);
  
  frameRate(60);
  // initialize all spins down. 
  for (int i =0; i<L; i=i+1) {
    for (int j =0; j<L; j = j+1) {
      s[i][j]=-1;
    }
  }
  
  f = createFont("Arial",16,true);
  
  drawLattice();
}

void draw() {

  // also turn off the zooming
  
  /*
  // see if we should be zooming in and out? 
  if ((keyPressed == true) && (key == 'A')) {
    scale *= 1.01;
  }
  if ((keyPressed == true) && (key == 'S')) {
    scale /= 1.01;
  }
  
  */
  // do the Ising thing -- with some small probability flip a spin all by itself
  int randX = (int) random(0,L);
  int randY = (int) random(0,L);
  
  // checking if metropolis wants to flip the spin: 
  if (checkSpin(randX,randY)==true) {
    s[randX][randY] = -s[randX][randY];
  }
  // now draw a square on the mouse
  int curr_x = gridLoc(mouseX);
  int curr_y = gridLoc(mouseY);
  

  //scale(scale);
  drawLattice();
  if (s[curr_x][curr_y]==-1) {
    fill(40);
  }
  else {
    fill(210);
  }
  rect(curr_x*tile_width,curr_y*tile_width,tile_width,tile_width);

  /*
  textFont(f,16);                  // STEP 3 Specify font to be used
  fill(100,100,255);                         // STEP 4 Specify font color 
  

  if (tries != 0) {
    text(nf(((float)score/tries)*100,0,1) + " % ",20,20); 
  }*/
  
  // that displays the score; let's leave that out. 
  

}

void drawLattice() {

  // draw the whole thing
  background(0, 0, 0);
  // now draw all the tiles. 
  fill(255);
  for (int i =0; i<L; i=i+1) {
    for (int j = 0; j<L; j=j+1) {
 
      if (s[i][j]==1) {
        rect(i*tile_width,j*tile_width,tile_width,tile_width);
      }
    }
  }
}

void mousePressed() {
  
  tries += 1;
  
  // figure out the location
  int curr_x = gridLoc(mouseX);
  int curr_y = gridLoc(mouseY);
  
  // flip the spin at that location 
  
  // check if the spin should be flipped
  if (checkSpin(curr_x,curr_y)==true) {
    // should flip it
    s[curr_x][curr_y] = -s[curr_x][curr_y];
    
    // store it as a success
    score += 1;
    
    // draw a green box
    fill(0,255,0);
  }
  
  else {
    // draw a red box!
    fill(255,0,0);
    
  }
  rect(curr_x*tile_width,curr_y*tile_width,tile_width,tile_width);
}

// returns the lattice point associated with a mouse movement
int gridLoc(int val) {
  return ((int) (val/(tile_width*scale)))%L;
}

boolean checkSpin(int i, int j) {
  
  // returns true if the spin should be flipped, false otherwise. 
  int deltaE = 2*(s[i][j])*(s[(i+1)%L][j]+s[(i+(L-1))%L][j]+s[i][(j+1)%L]+s[i][(j+(L-1))%L]);
  
  //int deltaE = 0;
  if (random(0,1)<exp(-beta*deltaE)) {
    return true;
  }
  return false;
}