var cellWidth = 50;
var columns = 0;
var rows = 0;
var grid = [];
//var currentCell;
var cellStack = [];
var frontier = [];
var explored = [];
var currentNode = {};
var maze = {};

function setup() {
  var canvas = createCanvas(500, 500);
  canvas.parent('sketch-holder');
  maze = new Maze(width, height, cellWidth);
  frameRate(60);

  rows = floor(width / cellWidth);
  columns = floor(height / cellWidth);

  for (let y = 0; y < rows; y++) {
    for (var x = 0; x < columns; x++) {
      grid.push(new Cell(x, y, cellWidth));
    }
  }

  //currentCell = grid[0];
  grid[0].visited = true;
  grid[0].selected = true;
  cellStack.push(grid[0]);
}

function draw() {
  background(220);

  for (var i = 0; i < grid.length; i++) {
    grid[i].show();
  }
  
  if(cellStack.length > 0){
  	//Build the maze
	let currentCell = cellStack.pop();
	//currentCell.visited = true;
  	let nextCell = getNeighbors(currentCell);
  	
  	if(nextCell){
	   	cellStack.push(currentCell);
	  	currentCell.Selected = false;
	  	currentCell.visited = true;
	  	nextCell.visited = true;
	  	nextCell.selected = true;
  		removeWalls(currentCell, nextCell);
  		cellStack.push(nextCell);

  	} else cellStack.pop();
  	
  	currentCell.selected = false;
  }
  else if (cellStack.length == 0 && frontier.length == 0 && explored.length == 0){
	for (var i = 0; i < grid.length; i++) {
		grid[i].visited = false;
	}
	
	print("Maze generation done");
	
	grid[index(0, 0)].selected = true;
	grid[index(0, 0)].visited = true;
	grid[index(0, 0)].searched = true;
	grid[index(0, 0)].start = true;
	currentNode = grid[index(0, 0)];
	
	frontier.push(grid[index(0, 0)]);
	frameRate(5);
  }
  else if (cellStack.length == 0 && frontier.length > 0){
    currentNode.selected = false;
	currentNode = frontier.shift();
	
	let neighbors = getAllNeighbors(currentNode);
	
	currentNode.searched = true;
	currentNode.selected = true;
	
	for(let index = 0; index < neighbors.length; index++){
		frontier.push(neighbors[index]);
		neighbors[index].parent = currentNode;
	}
	
	explored.push(currentNode);
	
	if(currentNode.x == 9 && currentNode.y == 9)
		//currentNode.end = true;
		frontier = [];	
  }
  else{
  	tmp = explored.pop();
  	
  	while (tmp.parent != undefined) {
  		tmp.finalPath = true;
  		tmp = tmp.parent;
  	}
  	grid[index(0, 0)].finalPath = true;
  	
	for (var i = 0; i < grid.length; i++) {
    	grid[i].show();
  	}
  	
  	
  	print("Maze search done");
  	noLoop();
  }
}

function index(x, y) {
  if (x < 0 || y < 0 || x > columns - 1 || y > rows - 1) return -1;
  return x + y * columns;
}

function removeWalls(a, b) {
  var x = a.x - b.x;
  var y = a.y - b.y;
  
  if (x === -1) {
	a.setRight = false;
	b.setLeft = false;
  } else if (x === 1) {
	a.setLeft = false;
	b.setRight = false;
  }

  if (y === -1) {
	a.setBottom = false;
	b.setTop = false;
  } else if (y === 1) {
	a.setTop = false;
	b.setBottom = false;
  }
}

function getAllNeighbors(cell){
	var Neighbors = [];
	
	var top = grid[index(cell.x, cell.y - 1)];
	var left = grid[index(cell.x - 1, cell.y)];
	var bottom = grid[index(cell.x, cell.y + 1)];
	var right = grid[index(cell.x + 1, cell.y)];
	
    if (top && !top.searched && !cell.top) {
      Neighbors.push(top);
    }
    if (left && !left.searched && !cell.left) {
      Neighbors.push(left);
    }
    if (right && !right.searched && !cell.right) {
      Neighbors.push(right);
    }
    if (bottom && !bottom.searched && !cell.bottom) {
      Neighbors.push(bottom);
    }
    
    return shuffle(Neighbors);
}

function getNeighbors(cell){
	var visited = [];
	
	var top = grid[index(cell.x, cell.y - 1)];
	var left = grid[index(cell.x - 1, cell.y)];
	var bottom = grid[index(cell.x, cell.y + 1)];
	var right = grid[index(cell.x + 1, cell.y)];
	
    if (top && !top.visited) {
      visited.push(top);
    }
    if (left && !left.visited) {
      visited.push(left);
    }
    if (right && !right.visited) {
      visited.push(right);
    }
    if (bottom && !bottom.visited) {
      visited.push(bottom);
    }
    
    if(visited.length == 1) 
    	return visited[0];
    else if (visited.length > 1)
      	return visited[floor(random(0, visited.length))];
    else 
    	return undefined;
}