Code viewer for World: Complex World - Part I (by...
// Cloned by Tony Forde on 25 Oct 2021 from World "Complex World" by Starter user 
// Please leave this clone trail here.
 
// ==== Starter World =================================================================================================
// This code is designed for use on the Ancient Brain site. 
// This code may be freely copied and edited by anyone on the Ancient Brain site.
// To include a working run of this program on another site, see the "Embed code" links provided on Ancient Brain.
// ====================================================================================================================


// =============================================================================================
// More complex starter World 
// 3d-effect Maze World (really a 2-D problem) 
// Movement is on a semi-visible grid of squares 
//
// This more complex World shows:
// - Skybox
// - Internal maze (randomly drawn each time)
// - Enemy actively chases agent
// - Music/audio
// - 2D world (clone this and set show3d = false)
// - User keyboard control (clone this and comment out Mind actions to see)
// =============================================================================================


// =============================================================================================
// Scoring:
// Bad steps = steps where enemy is within one step of agent.
// Good steps = steps where enemy is further away. 
// Score = good steps as percentage of all steps.
//
// There are situations where agent is trapped and cannot move.
// If this happens, you score zero.
// =============================================================================================


// ===================================================================================================================
// === Start of tweaker's box ======================================================================================== 
// ===================================================================================================================

// The easiest things to modify are in this box.
// You should be able to change things in this box without being a JavaScript programmer.
// Go ahead and change some of these. What's the worst that could happen?


AB.clockTick       =  500;    

	// Speed of run: Step every n milliseconds. Default 500.
	
AB.maxSteps        = 1000;    

	// Length of run: Maximum length of run in steps. Default 1000.

AB.screenshotStep  = 50;   
  
	// Take screenshot on this step. (All resources should have finished loading.) Default 50.


//---- global constants: -------------------------------------------------------

	const show3d = true;						// Switch between 3d and 2d view (both using Three.js) 


 //const TEXTURE_WALL 	= '/uploads/starter/door.jpg' ;
 //const TEXTURE_MAZE 	= '/uploads/starter/latin.jpg' ;
 const TEXTURE_WALL 	= '/uploads/fordea23/black_marble.jpg' ;
 const TEXTURE_MAZE 	= '/uploads/fordea23/grey_marble.jpg' ;
 const TEXTURE_AGENT 	= '/uploads/fordea23/Mouse.jpg' ;
 const TEXTURE_ENEMY 	= '/uploads/fordea23/Cat.jpg' ; 
 const TEXTURE_PATH 	= '/uploads/fordea23/Green_Path.jpg'
 
 const SHOW_PATH = false;

// credits:
// http://commons.wikimedia.org/wiki/File:Old_door_handles.jpg
// https://commons.wikimedia.org/wiki/Category:Pac-Man_icons
// https://commons.wikimedia.org/wiki/Category:Skull_and_crossbone_icons
// http://en.wikipedia.org/wiki/File:Inscription_displaying_apices_(from_the_shrine_of_the_Augustales_at_Herculaneum).jpg

	const MUSIC_BACK  = '/uploads/starter/Defense.Line.mp3' ;
	const SOUND_ALARM = '/uploads/starter/air.horn.mp3' ;

// credits:
// http://www.dl-sounds.com/royalty-free/defense-line/
// http://soundbible.com/1542-Air-Horn.html 

const gridsize = 52;						// number of squares along side of world	   

const NOBOXES =  Math.trunc ( (gridsize * gridsize) / 3 );
		// density of maze - number of internal boxes
		// (bug) use trunc or can get a non-integer 

const squaresize = 100;					// size of square in pixels
const MAX_SEARCH = 20;

const MAXPOS = gridsize * squaresize;		// length of one side in pixels 
	
const SKYCOLOR 	= 0xddffdd;				// a number, not a string 

 
const startRadiusConst	 	= MAXPOS * 0.8 ;		// distance from centre to start the camera at
const maxRadiusConst 		= MAXPOS * 10  ;		// maximum distance from camera we will render things  

const diagonal = false;

// For A*:
var cols = gridsize - 2; // Grid size includes walls / edges hence - 2
var rows = cols;
var grid = new Array(cols);
var openSet = []; // Unvisited nodes
var closedSet = []; // Visited nodes
var start; // Start
var end; // End
var path = []; // Path to goal
var currentSquare;
var nextMovej;
var nextMovei;
var winnerj;
var winneri;
var breakCalculate = false;

//--- change ABWorld defaults: -------------------------------

ABHandler.MAXCAMERAPOS 	= maxRadiusConst ;

ABHandler.GROUNDZERO		= true;						// "ground" exists at altitude zero

//--- skybox: -------------------------------
// skybox is a collection of 6 files 
// x,y,z positive and negative faces have to be in certain order in the array 
// https://threejs.org/docs/#api/en/loaders/CubeTextureLoader 

// mountain skybox, credit:
// http://stemkoski.github.io/Three.js/Skybox.html

 const SKYBOX_ARRAY = [										 
                "/uploads/starter/dawnmountain-xpos.png",
                "/uploads/starter/dawnmountain-xneg.png",
                "/uploads/starter/dawnmountain-ypos.png",
                "/uploads/starter/dawnmountain-yneg.png",
                "/uploads/starter/dawnmountain-zpos.png",
                "/uploads/starter/dawnmountain-zneg.png"
                ];

// ===================================================================================================================
// === End of tweaker's box ==========================================================================================
// ===================================================================================================================


// You will need to be some sort of JavaScript programmer to change things below the tweaker's box.

//--- Mind can pick one of these actions -----------------

const ACTION_LEFT 			= 0;		   
const ACTION_RIGHT 			= 1;
const ACTION_UP 			= 2;		 
const ACTION_DOWN 			= 3;
const ACTION_STAYSTILL 		= 4;

// in initial view, (smaller-larger) on i axis is aligned with (left-right)
// in initial view, (smaller-larger) on j axis is aligned with (away from you - towards you)

// contents of a grid square

const GRID_BLANK 	= 0;
const GRID_WALL 	= 1;
const GRID_MAZE 	= 2;
 
var BOXHEIGHT;		// 3d or 2d box height 

var GRID 	= new Array(gridsize);			// can query GRID about whether squares are occupied, will in fact be initialised as a 2D array   

var theagent, theenemy, thepath, pathShape;
  
var wall_texture, agent_texture, enemy_texture, maze_texture, path_texture; 


// enemy and agent position on squares
var ei, ej, ai, aj, pi, pj;

var badsteps;
var goodsteps;


function loadResources()		// asynchronous file loads - call initScene() when all finished 
{
    // console.log('Load resources...')
	var loader1 = new THREE.TextureLoader();
	var loader2 = new THREE.TextureLoader();
	var loader3 = new THREE.TextureLoader();
	var loader4 = new THREE.TextureLoader();
	var loader5 = new THREE.TextureLoader();

	loader1.load ( TEXTURE_WALL, function ( thetexture )  		
	{
		thetexture.minFilter  = THREE.LinearFilter;
		wall_texture = thetexture;
		if ( asynchFinished() )	initScene();		// if all file loads have returned 
	});
		
	loader2.load ( TEXTURE_AGENT, function ( thetexture )  	 
	{
		thetexture.minFilter  = THREE.LinearFilter;
		agent_texture = thetexture;
		if ( asynchFinished() )	initScene();		 
	});	
	
	loader3.load ( TEXTURE_ENEMY, function ( thetexture )  
	{
		thetexture.minFilter  = THREE.LinearFilter;
		enemy_texture = thetexture;
		if ( asynchFinished() )	initScene();		 
	});
	
	loader4.load ( TEXTURE_MAZE, function ( thetexture )  
	{
		thetexture.minFilter  = THREE.LinearFilter;
		maze_texture = thetexture;
		if ( asynchFinished() )	initScene();		 
	});
	
	loader5.load ( TEXTURE_PATH, function ( thetexture )  
	{
		thetexture.minFilter  = THREE.LinearFilter;
		path_texture = thetexture;
		if ( asynchFinished() )	initScene();		 
	});	
}


function asynchFinished()		 // all file loads returned 
{
    // console.log('asynchFinished');
	if ( wall_texture && agent_texture && enemy_texture && maze_texture && path_texture )   return true; 
	else return false;
}	


//--- grid system -------------------------------------------------------------------------------
// my numbering is 0 to gridsize-1

	
function occupied ( i, j )		// is this square occupied
{
 if ( ( ei == i ) && ( ej == j ) ) return true;		// variable objects 
 if ( ( ai == i ) && ( aj == j ) ) return true;

 if ( GRID[i][j] == GRID_WALL ) return true;		// fixed objects	 
 if ( GRID[i][j] == GRID_MAZE ) return true;		 
	 
 return false;
}

function blockedByWall ( i, j )		// is this a wall
{
 if ( GRID[i][j] == GRID_WALL ) return true;		// fixed objects	 
 if ( GRID[i][j] == GRID_MAZE ) return true;		 
	 
 return false;
}

 
// translate my (i,j) grid coordinates to three.js (x,y,z) coordinates
// logically, coordinates are: y=0, x and z all positive (no negative)    
// logically my dimensions are all positive 0 to MAXPOS
// to centre everything on origin, subtract (MAXPOS/2) from all dimensions 

function translate ( i, j )			
{
	var v = new THREE.Vector3();
	
	v.y = 0;	
	v.x = ( i * squaresize ) - ( MAXPOS/2 );   		 
	v.z = ( j * squaresize ) - ( MAXPOS/2 );   	
	
	return v;
}


function initScene()		// all file loads have returned 
{
    //  console.log('Init scene...')
	 var i,j, shape, thecube;
	 
	// set up GRID as 2D array
	 
	 for ( i = 0; i < gridsize ; i++ ) 
		GRID[i] = new Array(gridsize);		 

	// set up walls
	 
	 for ( i = 0; i < gridsize ; i++ ) 
	  for ( j = 0; j < gridsize ; j++ ) 
		if ( ( i==0 ) || ( i==gridsize-1 ) || ( j==0 ) || ( j==gridsize-1 ) )
		{
			GRID[i][j] = GRID_WALL;		 
			shape    = new THREE.BoxGeometry ( squaresize, BOXHEIGHT, squaresize );			 
			thecube  = new THREE.Mesh( shape );
			thecube.material = new THREE.MeshBasicMaterial( { map: wall_texture } );
			
			thecube.position.copy ( translate(i,j) ); 		  	// translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 
			ABWorld.scene.add(thecube);
		}
		else 
   			GRID[i][j] = GRID_BLANK;

		
   // set up maze 
   
    for ( var c=1 ; c <= NOBOXES ; c++ )
	{
		i = AB.randomIntAtoB(1,gridsize-2);		// inner squares are 1 to gridsize-2
		j = AB.randomIntAtoB(1,gridsize-2);
			
		GRID[i][j] = GRID_MAZE ;
		
		shape    = new THREE.BoxGeometry ( squaresize, BOXHEIGHT, squaresize );			 
		thecube  = new THREE.Mesh( shape );
		thecube.material = new THREE.MeshBasicMaterial( { map: maze_texture } );		  

		thecube.position.copy ( translate(i,j) ); 		  	// translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 
		ABWorld.scene.add(thecube);		
	}
	 	 
   
	// set up enemy 
	// start in random location
	
	 do
	 {
	  i = AB.randomIntAtoB(1,gridsize-2);
	  j = AB.randomIntAtoB(1,gridsize-2);
	 }
	 while ( occupied(i,j) );  	  // search for empty square 

	 ei = i;
	 ej = j;
	 
	 shape    = new THREE.BoxGeometry ( squaresize, BOXHEIGHT, squaresize );			 
	 theenemy = new THREE.Mesh( shape );
 	 theenemy.material =  new THREE.MeshBasicMaterial( { map: enemy_texture } );
	 ABWorld.scene.add(theenemy);
	 drawEnemy();		  

	// set up agent 
	// start in random location
	
	 do
	 {
	  i = AB.randomIntAtoB(1,gridsize-2);
	  j = AB.randomIntAtoB(1,gridsize-2);
	 }
	 while ( occupied(i,j) );  	  // search for empty square 

	 ai = i;
	 aj = j;
 
	 shape    = new THREE.BoxGeometry ( squaresize, BOXHEIGHT, squaresize );			 
	 theagent = new THREE.Mesh( shape );
	 theagent.material =  new THREE.MeshBasicMaterial( { map: agent_texture } );
	 ABWorld.scene.add(theagent);
	 drawAgent(); 

  // finally skybox 
  // setting up skybox is simple 
  // just pass it array of 6 URLs and it does the asych load 
  
  	 ABWorld.scene.background = new THREE.CubeTextureLoader().load ( SKYBOX_ARRAY, 	function() 
	 { 
		ABWorld.render(); 
	 
		AB.removeLoading();
	
		AB.runReady = true; 		// start the run loop
	 });
 		
}
 
 
// --- draw moving objects -----------------------------------


function drawEnemy()		// given ei, ej, draw it 
{
	theenemy.position.copy ( translate(ei,ej) ); 		  	// translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 

	ABWorld.lookat.copy ( theenemy.position );	 		// if camera moving, look back at where the enemy is  
}


function drawAgent()		// given ai, aj, draw it 
{
	theagent.position.copy ( translate(ai,aj) ); 		  	// translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 

	ABWorld.follow.copy ( theagent.position );			// follow vector = agent position (for camera following agent)
}


// --- take actions -----------------------------------

function moveLogicalEnemy()
{ 
// move towards agent 
// put some randomness in so it won't get stuck with barriers 
 console.log('****** NEW MOVE...'); 
 console.log('Agent is at [row, col] [' + aj +  ', ' + ai + ']'); 
 console.log('Enemy is at [row, col] [' + ej +  ', ' + ei + ']'); 

 setupGrid();
 
 breakCalculate = false;
 
 // CalculateBestPath loops through all possible moves for the enemy, determines
 // the best path and the first move in that path.
 // The next move, on best path, is a move to square [row = nextMovej, col = nextMovei].
 while (breakCalculate === false) {    
      calculateBestPath();
 }

//  console.log('****** Next Move - row / col: ' + nextMovej + ' ,' + nextMovei);    
//  console.log('****** Winner - row / col: ' + winnerj + ' ,' + winneri);

 var i, j;
 
 // Rows:
 
 if ((typeof winnerj !== 'undefined') && (typeof winneri !== 'undefined')) {
    // Winner coordinates can be undefined: at start and if no possible path found e.g due to being blocked by wall
    j = winnerj;
    i = winneri;     
 }
 else {
     // If winner coordinates undefined (see above), go with previous best move. This prevents error.
    j = nextMovej;
    i = nextMovej;
 }

 console.log('****** BEST MOVE ==> row / col: ' + j + ' ,' + i);
 
 // If enemy is within one place of agent, hold back - in this Part I 
 // world we just want to home in on the agent without trapping in final move.
 // In world Part II, we make the final trapping move.
 if ( ( Math.abs(ei - ai) < 2 ) && ( Math.abs(ej - aj) < 2 ) ) {
    console.log('TOO CLOSE - HOLD BACK - WAIT FOR FINAL TRAP MOVE!');     
    console.log('[aj, ai] [' + aj +  ', ' + ai + ']'); 
    console.log('[ei, ei] [' + ej +  ', ' + ei + ']');     
    console.log('Math.abs(ei - ai) = ' + Math.abs(ei - ai));
    console.log('Math.abs(ej - aj) = ' + Math.abs(ej - aj));
 }
 else {
     // Otherwise, if not too close, keep homing in on agent.
     if ( ! occupied(i,j) )  	// if no obstacle then move
         {
          //console.log('No obstacle -- enemy can move.');     
          pi = i;
          pj = j;
         
          ei = i;
          ej = j;
          console.log('Enemy moves to moves to [row, col] [' + ej +  ', ' + ei + ']');
           
           if (SHOW_PATH) {
               
            // *** BUG 1: The code "ABWorld.scene.remove(pathScene)" seems to remove the path too quickly so you can't see the chosen path. 
            // Of course, if you leave it out, then the best paths accumulate on screen. Tried placing the remove path scene in different
            // locations  but same result, unfortunately.
            pathShape = new THREE.BoxGeometry ( squaresize, BOXHEIGHT, squaresize );			 
            thepath  = new THREE.Mesh( pathShape );
            thepath.material = new THREE.MeshBasicMaterial( { map: path_texture } );
            thepath.position.copy ( translate(pi,pj) ); 		  	// translate my (i,j) grid coordinates to three.js (x,y,z) coordinates 
            ABWorld.scene.add(thepath);  
            // *** Related to BUG 1:
            // ABWorld.scene.remove(thepath);    
           }
        
        }
         else
         {
             //console.log('Obstacle in the way - skip a turn.');
             console.log('Obstacle in the way - try another square.');
             
             if ( ei < ai ) i = AB.randomIntAtoB(ei, ei+1); 
             if ( ei == ai ) i = ei; 
             if ( ei > ai ) i = AB.randomIntAtoB(ei-1, ei); 
            
             if ( ej < aj ) j = AB.randomIntAtoB(ej, ej+1); 
             if ( ej == aj ) j = ej; 
             if ( ej > aj ) j = AB.randomIntAtoB(ej-1, ej); 
        
            if ( ! occupied(i,j) )  	// if no obstacle then move
             {
              //console.log('No obstacle -- enemy can move.');     
              ei = i;
              ej = j;
              console.log('Alternative enemy move to moves to [row, col] [' + ej +  ', ' + ei + ']');
             }
        
            //  //console.log('Obstacle in the way - skip a turn.');
            //  console.log('Obstacle in the way - try another square.');
         }
 }
}


function moveLogicalAgent( a )			// this is called by the infrastructure that gets action a from the Mind 
{ 
 var i = ai;
 var j = aj;		 

      if ( a == ACTION_LEFT ) 	i--;
 else if ( a == ACTION_RIGHT ) 	i++;
 else if ( a == ACTION_UP ) 		j++;
 else if ( a == ACTION_DOWN ) 	j--;

 if ( ! occupied(i,j) ) 
 {
  ai = i
 
  aj = j;
 }
}


// --- key handling --------------------------------------------------------------------------------------
// This is hard to see while the Mind is also moving the agent:
// AB.mind.getAction() and AB.world.takeAction() are constantly running in a loop at the same time 
// have to turn off Mind actions to really see user key control 

// we will handle these keys: 

var OURKEYS = [ 37, 38, 39, 40 ];

function ourKeys ( event ) { return ( OURKEYS.includes ( event.keyCode ) ); }
	

function keyHandler ( event )		
{
	if ( ! AB.runReady ) return true; 		// not ready yet 

   // if not one of our special keys, send it to default key handling:
	
	if ( ! ourKeys ( event ) ) return true;
	
	// else handle key and prevent default handling:
	
	if ( event.keyCode == 37 )   moveLogicalAgent ( ACTION_LEFT 	);   
    if ( event.keyCode == 38 )   moveLogicalAgent ( ACTION_DOWN  	); 	 
    if ( event.keyCode == 39 )   moveLogicalAgent ( ACTION_RIGHT 	); 	 
    if ( event.keyCode == 40 )   moveLogicalAgent ( ACTION_UP		);   
	
	// when the World is embedded in an iframe in a page, we want arrow key events handled by World and not passed up to parent 

	event.stopPropagation(); event.preventDefault(); return false;
}


// --- score: -----------------------------------


function badstep()			// is the enemy within one square of the agent
{
 if ( ( Math.abs(ei - ai) < 2 ) && ( Math.abs(ej - aj) < 2 ) ) return true;
 else return false;
}


function agentBlocked()			// agent is blocked on all sides, run over
{
 return ( 	occupied (ai-1,aj) 		&& 
		occupied (ai+1,aj)		&&
		occupied (  ai,aj+1)		&&
		occupied (  ai,aj-1) 	);		
} 


function updateStatusBefore(a)
// this is called before anyone has moved on this step, agent has just proposed an action
// update status to show old state and proposed move 
{
 var x 		= AB.world.getState();
 // x = step before [colAgent, rowAgent, colEnemy, rowEnemy]
 AB.msg ( " Step: " + AB.step + " &nbsp; x = (" + x.toString() + ") &nbsp; a = (" + a + ") " ); 
}


function   updateStatusAfter()		// agent and enemy have moved, can calculate score
{
 // new state after both have moved
 
 var y 		= AB.world.getState();
 // y = step after [colAgent, rowAgent, colEnemy, rowEnemy]
 var score = ( goodsteps / AB.step ) * 100; 

 AB.msg ( " &nbsp; y = (" + y.toString() + ") <br>" +
		" Bad steps: " + badsteps + 
		" &nbsp; Good steps: " + goodsteps + 
		" &nbsp; Score: " + score.toFixed(2) + "% ", 2 ); 
}


AB.world.newRun = function() 
{
    // console.log('New run...');
	AB.loadingScreen();

	AB.runReady = false;  

	badsteps = 0;	
	goodsteps = 0;

	
	if ( show3d )
	{
	 BOXHEIGHT = squaresize;
	 ABWorld.init3d ( startRadiusConst, maxRadiusConst, SKYCOLOR  ); 	
	}	     
	else
	{
	 BOXHEIGHT = 1;
	 ABWorld.init2d ( startRadiusConst, maxRadiusConst, SKYCOLOR  ); 		     
	}
	
	
	loadResources();		// aynch file loads		
							// calls initScene() when it returns 

	document.onkeydown = keyHandler;	
		 
};


AB.world.getState = function()
{
 var x = [ ai, aj, ei, ej ];
  return ( x );  
};


AB.world.takeAction = function ( a )
{
  //console.log('Take action...' + a);
  updateStatusBefore(a);			// show status line before moves 

  moveLogicalAgent(a);

  //if ( ( AB.step % 2 ) == 0 )		// slow the enemy down to every nth step
    moveLogicalEnemy();
   // *** Related to BUG 1: remove path scene below...
   // ABWorld.scene.remove(thepath); 

  if ( badstep() )  badsteps++;
  else   			goodsteps++;

   drawAgent();
   drawEnemy();
   updateStatusAfter();			// show status line after moves  
 

  if ( agentBlocked() )			// if agent blocked in, run over 
  {
	AB.abortRun = true;
	goodsteps = 0;			// you score zero as far as database is concerned 			 
	//musicPause();
	soundAlarm();
  }

};


AB.world.endRun = function()
{
  console.log('End run...');
  //musicPause(); 
  if ( AB.abortRun ) AB.msg ( " <br> <font color=red> <B> Agent trapped. Final score zero. </B> </font>   ", 3  );
  else    				AB.msg ( " <br> <font color=green> <B> Run over. </B> </font>   ", 3  );
};

 
AB.world.getScore = function()
{
    console.log('Get score...');
    // only called at end - do not use AB.step because it may have just incremented past AB.maxSteps
    
    var s = ( goodsteps / AB.maxSteps ) * 100;   // float like 93.4372778 
    var x = Math.round (s * 100);                // 9344
    return ( x / 100 );                          // 93.44
};


// --- music and sound effects ----------------------------------------

// TF: Switch off music
// var backmusic = AB.backgroundMusic ( MUSIC_BACK );

// function musicPlay()   { backmusic.play();  }
// function musicPause()  { backmusic.pause(); }

											 
function soundAlarm()
{
	var alarm = new Audio ( SOUND_ALARM );
	alarm.play();							// play once, no loop 
}

// --- The A* Stuff ---------------------------------------------------

function Spot(i, j) {
  this.i = i;
  this.j = j;
  this.f = 0;
  this.g = 0;
  this.h = 0;
  this.neighbors = []; // An array to store all neighbors of Spot
  this.previous = undefined;

  this.addNeighbors = function (grid) {
    var i = this.i;
    var j = this.j;

    // Neighbors' comparative grid positions depend on where current node
    // is on the grid, e.g. corner, edge, middle, etc... different options.
    // Below allows for non-diagonal travel, i.e. it only caters for:
    // 1. UP 2. DOWN 3. LEFT 4. RIGHT
    
    if (i < cols - 1) this.neighbors.push(grid[i + 1][j]);

    if (i > 0) this.neighbors.push(grid[i - 1][j]);

    if (j < rows - 1) this.neighbors.push(grid[i][j + 1]);

    if (j > 0) this.neighbors.push(grid[i][j - 1]);
    
    // Below allows for non-diagonal travel, i.e. it also caters for:
    // 5. TOP LEFT 6. TOP RIGHT 7. BOTTOM LEFT 8. BOTTOM RIGHT
    if (diagonal) {
      if (i > 0 && j > 0) this.neighbors.push(grid[i - 1][j - 1]);
      if (i < cols - 1 && j > 0) this.neighbors.push(grid[i + 1][j - 1]);
      if (i > 0 && j < rows - 1) this.neighbors.push(grid[i - 1][j + 1]);
      if (i < cols - 1 && j < rows - 1) this.neighbors.push(grid[i + 1][j + 1]);
    }
  };
}

function setupGrid() {
//   // TF: Initialise open and closed lists
//   openSet = [];
//   closedSet = []; 
  currentSquare = 1;
  // Making a 2D array
  for (var i = 0; i < cols; i++) grid[i] = new Array(rows);

  // Create a new object for each spot in the grid
  // so we can assign some values to, i.e. f, g and h values for starters
  for (var i = 0; i < cols; i++)
    for (var j = 0; j < rows; j++) grid[i][j] = new Spot(i, j);

  // Add the neighbors of the spot
  for (var i = 0; i < cols; i++)
    for (var j = 0; j < rows; j++) grid[i][j].addNeighbors(grid);

  start = grid[ei-1][ej-1];
  end = grid[ai-1][aj-1];

  openSet.push(start);

  //console.log(grid);
}

function calculateBestPath() {

 breakCalculate = false;
 //console.log('Calculate best path...');
    
  if (openSet.length > 0) {
    // While Open Set is not empty, keep going...

    var winner = 0; // Set the lowest, i.e. WINNING, index

    // Check which one is the lowest, i.e. current WINNER
    for (var i = 0; i < openSet.length; i++){
    //   console.log('Current check index: ' + i + ' -- Current check value : ' + openSet[i].f);
      if (openSet[i].f < openSet[winner].f) {
        winner = i;
        // console.log('Found new winner index: ' + i + ' better than index ' + winner);
        // console.log('Found new winner value: ' + openSet[i].f + ' better than vale ' + openSet[winner].f);
      }
    }

    var current = openSet[winner];

    // If current node equals END node, then we are done!
    if (current === end) {
      winnerj = null;
      winneri = null;
      console.log("FOUND BEST PATH!");
      //console.log('*** Next Move - row / col: ' + nextMovej + ' ,' + nextMovei);
      winnerj = nextMovej;
      winneri = nextMovei;
      //console.log('*** Winner - row / col: ' + winnerj + ' ,' + winneri);
      breakCalculate = true;
    }
    else
    {
        
    }
    // Else continue below...

    // Remove current node from Open Set
    removeFromArray(openSet, current);

    // And push current to Closed Set
    closedSet.push(current);

    // Evaluate all neighbors before pushing them to Open Set
    var neighbors = current.neighbors;
    
    for (var i = 0; i < neighbors.length; i++) {
      var neighbor = neighbors[i];

      // If Closed Set does NOT include the neighbor
      // AND it is NOT a wall
      if (!closedSet.includes(neighbor)) {

        // var xi = neighbor.i + 1; 
        // var xj = neighbor.j = 1;
        
        var tempG = current.g + 1;
        var newPath = false; // Default
        // Check if Open Set includes neighbor
        if (openSet.includes(neighbor)) {
          if (tempG < neighbor.g) {
            neighbor.g = tempG;
            newPath = true;
          }
        } else {
          neighbor.g = tempG;
          newPath = true;
          openSet.push(neighbor);
        }

        if (newPath) {
          // Only need to calulate heuristic if we've found a new path
          // Now assign a heuristic value to the neighbor, i.e. distance to end goal:
          neighbor.h = heuristic(neighbor, end);

          // Now calculate f(n) = g(n) + h(n):
          neighbor.f = neighbor.g + neighbor.h;
        //   console.log("current winner is square " + winner + 1);
        //   console.log("current winner has f(n) = " + openSet[winner].f);
        //   console.log("now check square " + currentSquare + " where..."); 
        //   console.log("g(" + currentSquare + ") = " + neighbor.g);
        //   console.log("h(" + currentSquare +  ") = " + neighbor.h);
        //   console.log("f(" + currentSquare +  ") = " + neighbor.f);
          currentSquare++;

          // Set current spot to be parent of the next one (in next for loop interation)
          neighbor.previous = current;
        }            
      }
    }
  } 
  else {
    console.log("No solution.");
    //noLoop();
    return;
    // No solution
  }

  path = [];
  var temp = current;
  path.push(temp);
  while (temp.previous) {
    // While there is a path history, i.e. previous node
    path.push(temp.previous);
    temp = temp.previous;
  }

   // Loop through path to find next move, i.e. which square to move to on the best path.
   for (var i =  path.length-1; i >= 0; i--) {
     var pathj = path[i].j+1;
     var pathi = path[i].i+1;
     //  console.log('Path - row, col: ' + path[i].j + ', ' + path[i].i);
     //console.log('Path - row, col: ' + pathj + ', ' + pathi);

     var firstIndex = path.length - 1;
     var nextMoveIndex;
    //  console.log('firstIndex: ' + firstIndex);
    //  console.log('Start - row / col: ' + path[firstIndex].j + ' ,' + path[firstIndex].i);
     if (firstIndex > 0) {
        nextMoveIndex = path.length - 2;
        nextMovej = path[nextMoveIndex].j+1;
        nextMovei = path[nextMoveIndex].i+1;
     }
     //console.log('Next Move - row / col: ' + nextMovej + ' ,' + nextMovei);
   }
}

function removeFromArray(arr, elt) {
  // Custom function to remove an object from an array.
  // Loop backwards through array.
  // Only reason for going backwards is if we delete something it shortens the array length.
  // So we could skip an element in the loop.
  for (var i = arr.length - 1; i >= 0; i--) if (arr[i] == elt) arr.splice(i, 1); // Splice deletes a particular element in an array at an index
}

function heuristic(a, b) {
  // Custom function to estimate distance from points a to b.
  var d;

  if (diagonal) {
    // Calculate the Euclidean or 2D distance for diagonal search
    d = dist(a.i, a.j, b.i, b.j);
  } else {
    // Calculate the "Manhattan" or "Taxi Cab" distance for non-diagonal search
    d = Math.abs(a.i - b.i) + Math.abs(a.j - b.j);
  }
  return d;
}