class Maze{
	constructor(mazeWidth, mazeHeight, cellWidth){
		this.columns = floor(mazeWidth / cellWidth);
		this.rows = floor(mazeHeight / cellWidth);
		this.width = mazeWidth;
		this.height = mazeHeight;
		this.cellWidth = cellWidth;
		this.workingStack = [];
		this.grid = [];
		
	    for (let y = 0; y < this.rows; y++) {
			for (var x = 0; x < this.columns; x++) {
		  		this.grid.push(new Cell(x, y, this.cellWidth));
			}
	    }
	    
	    this.grid[this.index(0,0)].visited = true;
	    this.grid[this.index(0,0)].selected = true;
	    this.workingStack.push(this.grid[this.index(0,0)]);
	}
	
	getStartingCell(){
		return this.grid[0];
	}
	
	getEndingCell(){
		return this.grid[this.index(9, 9)];
	}
	
	updateMazeDisplay(){
	  for (let i = 0; i < this.grid.length; i++) {
		this.grid[i].show();
	  }
	}
	
	resetMazeState(){
		for (let i = 0; i < this.grid.length; i++){
			this.grid[i].visited = false;
			this.grid[i].color = this.grid[i].defaultColor;
			this.grid[i].parent = undefined;
		}
	}
	
	buildNextCell(selectedColor = [50, 175, 50]){
	  	//Build the maze
		let currentCell = this.workingStack.pop();
		
	  	let nextCell = this.getNeighbors(currentCell);
	  	
	  	if(nextCell){
		   	this.workingStack.push(currentCell);
		  	currentCell.color = currentCell.defaultColor;
		  	currentCell.visited = true;
		  	nextCell.visited = true;
		  	nextCell.color = selectedColor;
	  		this.removeWalls(currentCell, nextCell);
	  		this.workingStack.push(nextCell);
	  	} 
	  	else 
	  		this.workingStack.pop();
	  	
	  	currentCell.color = currentCell.defaultColor;
	}
	
	get mazeGenDone() {
		return this.workingStack.length == 0;
	}
	
	getNeighbors(cell){
		let visited = [];
		
		let top = this.grid[this.index(cell.x, cell.y - 1)];
		let left = this.grid[this.index(cell.x - 1, cell.y)];
		let bottom = this.grid[this.index(cell.x, cell.y + 1)];
		let right = this.grid[this.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;
	}
	
	getLegalMoves(cell){
		let neighbors = [];
		
		let top = this.grid[this.index(cell.x, cell.y - 1)];
		let left = this.grid[this.index(cell.x - 1, cell.y)];
		let bottom = this.grid[this.index(cell.x, cell.y + 1)];
		let right = this.grid[this.index(cell.x + 1, cell.y)];
		
		if (top && !top.visited && !cell.top) {
		  neighbors.push(top);
		}
		if (left && !left.visited && !cell.left) {
		  neighbors.push(left);
		}
		if (right && !right.visited && !cell.right) {
		  neighbors.push(right);
		}
		if (bottom && !bottom.visited && !cell.bottom) {
		  neighbors.push(bottom);
		}
		
		return shuffle(neighbors);
	}
	
	removeWalls(a, b) {
		let x = a.x - b.x;
		let 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;
		}
	}

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