Code viewer for World: A* Lettuce (World 1)
// Cloned by Tristan Everitt on 26 Oct 2022 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 = 100; // 100;

// Speed of run: Step every n milliseconds. Default 100.

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)


// Pool Water. CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
// Source: https://www.publicdomainpictures.net/en/view-image.php?image=126102&picture=pool-water
const TEXTURE_WALL = '/uploads/tristan/water.jpg';

// Der Kothaufen-Emoji (💩) (englisch: pile of poo)
// Source: https://de.wikipedia.org/wiki/Kothaufen-Emoji
// Licence: Apache License 2.0

// I, MarcusObal, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/>, via Wikimedia Commons
// Source: https://commons.wikimedia.org/wiki/File:FIRE_01.JPG
const TEXTURE_MAZE = ['/uploads/tristan/water.jpg', '/uploads/tristan/poo.png', '/uploads/starter/door.jpg', '/uploads/starter/latin.jpg', '/uploads/tristan/fire.jpg'];


// Liz Truss official portrait is licensed under the United Kingdom Open Government Licence v3.0.
// https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
// Source: https://commons.wikimedia.org/wiki/File:Liz_Truss_official_portrait.jpg
const TEXTURE_AGENT = '/uploads/tristan/truss.jpg';

// Lettuce by Nick Youngson CC BY-SA 3.0 Alpha Stock Images
// Source: https://www.picserver.org/photo/32776/Lettuce.html
// Licence: Creative Commons 3 - CC BY-SA 3.0
// Attribution: Alpha Stock Images - http://alphastockimages.com/
// Original Author: Nick Youngson - link to - http://www.nyphotographic.com/
const TEXTURE_ENEMY = '/uploads/tristan/lettuce.jpg';

// 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


// ROYALTY-FREE “BENNY HILL THEME” STYLE ALTERNATIVE
// Source: http://toolofgod.com/my-music/royalty-free-benny-hill-theme-style-alternative/
const MUSIC_BACK = '/uploads/tristan/Benny-Hill-Theme-style-Royalty-free.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 = 30; // 30;						// number of squares along side of world

const NOBOXES = Math.trunc((gridsize * gridsize) / 4);
// 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 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


//--- 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"
//];

// Union Square Skybox - https://opengameart.org/content/urban-skyboxes
// This is the work of Emil Persson, aka Humus. http://www.humus.name
// These were previously under a custom licence, but he re-licensed them to CC-BY-3.0.
const SKYBOX_ARRAY = [
    "/uploads/tristan/union-square-posx.jpg",
    "/uploads/tristan/union-square-negx.jpg",
    "/uploads/tristan/union-square-posy.jpg",
    "/uploads/tristan/union-square-negy.jpg",
    "/uploads/tristan/union-square-posz.jpg",
    "/uploads/tristan/union-square-negz.jpg"
];


// space skybox, credit:
// http://en.spaceengine.org/forum/21-514-1
// x,y,z labelled differently

/*
 const SKYBOX_ARRAY = [
                "/uploads/starter/sky_pos_z.jpg",
                "/uploads/starter/sky_neg_z.jpg",
                "/uploads/starter/sky_pos_y.jpg",
                "/uploads/starter/sky_neg_y.jpg",
                "/uploads/starter/sky_pos_x.jpg",
                "/uploads/starter/sky_neg_x.jpg"
                ];
*/


// urban photographic skyboxes, credit:
// http://opengameart.org/content/urban-skyboxes

/*
 const SKYBOX_ARRAY = [
                "/uploads/starter/posx.jpg",
                "/uploads/starter/negx.jpg",
                "/uploads/starter/posy.jpg",
                "/uploads/starter/negy.jpg",
                "/uploads/starter/posz.jpg",
                "/uploads/starter/negz.jpg"
                ];
*/


// ===================================================================================================================
// === 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;


let BOXHEIGHT;		// 3d or 2d box height

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

let theagent, theenemy;

let wall_texture, agent_texture, enemy_texture, maze_texture_0, maze_texture_1, maze_texture_2, maze_texture_3, maze_texture_4;


// enemy and agent position on squares
//et ei, ej, ai, aj;
let enemy = new Node();
let agent = new Node();

let badsteps;
let goodsteps;


function loadResources()		// asynchronous file loads - call initScene() when all finished
{
    let loader1 = new THREE.TextureLoader();
    let loader2 = new THREE.TextureLoader();
    let loader3 = new THREE.TextureLoader();
    let loader_maze0 = new THREE.TextureLoader();
    let loader_maze1 = new THREE.TextureLoader();
    let loader_maze2 = new THREE.TextureLoader();
    let loader_maze3 = new THREE.TextureLoader();
    let loader_maze4 = 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();
    });

    loader_maze0.load(TEXTURE_MAZE[0], function (thetexture) {
        thetexture.minFilter = THREE.LinearFilter;
        maze_texture_0 = thetexture;
        if (asynchFinished()) initScene();
    });

    loader_maze1.load(TEXTURE_MAZE[1], function (thetexture) {
        thetexture.minFilter = THREE.LinearFilter;
        maze_texture_1 = thetexture;
        if (asynchFinished()) initScene();
    });

    loader_maze2.load(TEXTURE_MAZE[2], function (thetexture) {
        thetexture.minFilter = THREE.LinearFilter;
        maze_texture_2 = thetexture;
        if (asynchFinished()) initScene();
    });

    loader_maze3.load(TEXTURE_MAZE[3], function (thetexture) {
        thetexture.minFilter = THREE.LinearFilter;
        maze_texture_3 = thetexture;
        if (asynchFinished()) initScene();
    });

    loader_maze4.load(TEXTURE_MAZE[4], function (thetexture) {
        thetexture.minFilter = THREE.LinearFilter;
        maze_texture_4 = thetexture;
        if (asynchFinished()) initScene();
    });

}


function asynchFinished()		 // all file loads returned
{
    return !!(wall_texture && agent_texture && enemy_texture && maze_texture_0 && maze_texture_1 && maze_texture_2 && maze_texture_3 && maze_texture_4);
}


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


function occupied(i, j)		// is this square occupied
{
    const variableObjects = isEnemy(i, j) || isAgent(i, j);
    return variableObjects || fixedObject(i, j);
}

function fixedObject(i, j) {
    const outsideBoundary = i >= gridsize || j >= gridsize;
    return outsideBoundary || GRID[i][j] === GRID_WALL || GRID[i][j] === GRID_MAZE;
}

// 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) {
    let 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
{
    let 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
    const maze_texture = [maze_texture_0, maze_texture_1, maze_texture_2, maze_texture_3, maze_texture_4];
    for (let 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);
        const texture = maze_texture[AB.randomIntAtoB(0, maze_texture.length - 1)];
        thecube.material = new THREE.MeshBasicMaterial({map: 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

    enemy.i = i;
    enemy.j = j;

    shape = new THREE.BoxGeometry(squaresize, BOXHEIGHT + 300, 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

    agent.i = i;
    agent.j = j;

    shape = new THREE.BoxGeometry(squaresize, BOXHEIGHT + 150, 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(translateNode(enemy)); 		  	// 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(translateNode(agent)); 		  	// 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() {
    useAStarSearch ? aStarEnemyMove() : legacyEnemyMove();
}

function legacyEnemyMove() {

// move towards agent
// put some randomness in so it won't get stuck with barriers

    let i, j;
    if (enemy.i < agent.i) i = AB.randomIntAtoB(enemy.i, enemy.i + 1);
    if (enemy.i === agent.i) i = enemy.i;
    if (enemy.i > agent.i) i = AB.randomIntAtoB(enemy.i - 1, enemy.i);

    if (enemy.j < agent.j) j = AB.randomIntAtoB(enemy.j, enemy.j + 1);
    if (enemy.j === agent.j) j = enemy.j;
    if (enemy.j > agent.j) j = AB.randomIntAtoB(enemy.j - 1, enemy.j);

    if (!occupied(i, j))  	// if no obstacle then move, else just miss a turn
    {
        enemy.i = i;
        enemy.j = j;
    }
}

function moveLogicalAgent(a)			// this is called by the infrastructure that gets action a from the Mind
{
    let i = agent.i;
    let j = agent.j;

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

    if (!sittingDuck && !occupied(i, j)) {
        agent.i = i;
        agent.j = 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:

let 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
{
    return (Math.abs(enemy.i - agent.i) < 2) && (Math.abs(enemy.j - agent.j) < 2);
}

function agentBlocked()			// agent is blocked on all sides, run over
{
    let count = 0;
    let obstacles = [];
    if (occupied(agent.i - 1, agent.j)) {
        count++;
        obstacles.push(occupiedBy(agent.i - 1, agent.j));
    }
    if (occupied(agent.i + 1, agent.j)) {
        count++;
        obstacles.push(occupiedBy(agent.i + 1, agent.j));
    }
    if (occupied(agent.i, agent.j + 1)) {
        count++;
        obstacles.push(occupiedBy(agent.i, agent.j + 1));
    }
    if (occupied(agent.i, agent.j - 1)) {
        count++;
        obstacles.push(occupiedBy(agent.i, agent.j - 1));
    }

    const blocked = obstacles.length === 4;
    if (consoleLogs && blocked) {
        let o = '';
        obstacles.forEach(obstacle => {
            o += ' ' + obstacle
        });
        console.log('Agent blocked by: ' + o);

    }
    return blocked;
}


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
{
    let x = AB.world.getState();
    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

    let y = AB.world.getState();
    let 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 () {
    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 () {
    let x = [agent.i, agent.j, enemy.i, enemy.j];
    return (x);
};


AB.world.takeAction = function (a) {
    updateStatusBefore(a);			// show status line before moves

    moveLogicalAgent(a);

    if ((AB.step % enemyNthStep) === 0) {		// slow the enemy down to every nth step
        moveLogicalEnemy();
    }


    if (badstep()) {
        badsteps++;
    } else {
        goodsteps++;
    }
    drawAgent();
    drawEnemy();
    updateStatusAfter();			// show status line after moves


    if (agentBlocked() || agentCaught())			// 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 () {
    musicPause();
    const r = agentCaught() ? 'caught' : 'trapped';
    if (AB.abortRun) AB.msg(" <br> <font color=red> <B> Agent " + r + ". Final score zero. </B> </font>   ", 3);
    else AB.msg(" <br> <font color=green> <B> Run over. </B> </font>   ", 3);
};


AB.world.getScore = function () {
    // only called at end - do not use AB.step because it may have just incremented past AB.maxSteps

    let s = (goodsteps / AB.maxSteps) * 100;   // float like 93.4372778
    let x = Math.round(s * 100);                // 9344
    return (x / 100);                          // 93.44
};


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

let backmusic = AB.backgroundMusic(MUSIC_BACK);

function musicPlay() {
    backmusic.play();
}

function musicPause() {
    backmusic.pause();
}


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

// ==================== [START] Tristan's parameters ====================
// [7] Change the enemy to use A* to make a move.

const useAStarSearch = true;
const useHeuristic = true; // false: h(n) = 0
const bestFirst = false; // true: f(n) = h(n);  false:  f(n) = g(n) + h(n)

// ///////////////////////////////////////////

// [6] Diagonal moves off: Change the World so the enemy cannot make diagonal moves. This makes obstacles much harder.

const diagonal = false;

// ///////////////////////////////////////////

// [10] Prove it is A* by drawing the paths on screen.

const drawAStarPath = true; // Draws the best path found by A*
const drawAStarClosedSet = true; // Draw the points added to the closed set
const drawAStarOpenSet = true; // Draw the points added to the open set, excluding the best path.

// ///////////////////////////////////////////

const gameEndsWhenAgentCaught = true;
const enemyNthStep = 2;
const sittingDuck = false; // No moving target used for debugging.
const consoleLogs = false;

// ==================== [END] Tristan's parameters ====================

// ==================== [START] Tristan's functions ====================

function findMinimumNode(set) {
    // Best next option
    let winner = 0;

    for (let i = 0; i < set.length; i++) {
        winner = set[i].f < set[winner].f ? i : winner;
    }

    return set[winner];
}

function isFinalNode(source, target) {
    return source.i === target.i && source.j === target.j;
}

function removeNode(set, n) {
    set.splice(indexOfNode(set, n), 1);
}

function aStarEnemyMove() {
    clearPlanOfAttack();
    const planOfAttack = aStarMove(enemy, agent);
    if (planOfAttack.bestPath && planOfAttack.bestPath.length > 0) {
        const nextMove = planOfAttack.bestPath[0];
        drawPlanOfAttack(planOfAttack);

        if(consoleLogs) {
            console.log('[aStarEnemyMove] enemy=[' + enemy.i + ', ' + enemy.j + '] agent=[' + agent.i + ', ' + agent.j + '] nextMove: [' + nextMove.i + ', ' + nextMove.j + ', h=' + nextMove.h + ', g=' + nextMove.g + ', f=' + nextMove.f + ']');
        }

        enemy.i = nextMove.i;
        enemy.j = nextMove.j;
    } else if(consoleLogs) {
        console.log('[aStarEnemyMove] enemy=[' + enemy.i + ', ' + enemy.j + '] agent=[' + agent.i + ', ' + agent.j + '] nextMove: none');
    }
}

function indexOfNode(collection, node) {
    return collection.findIndex(e => e.i === node.i && e.j === node.j);
}

function containsNode(collection, node) {
    return indexOfNode(collection, node) >= 0;
}

function aStarMove(subject, destination) {
    let openSet = [];
    let closedSet = [];
    openSet.push(subject);

    let current = createNode(subject.i, subject.j);

    while (openSet.length > 0) {
        current = findMinimumNode(openSet);
        if (isFinalNode(current, destination)) {
            let c = current;
            let path = [];
            // Build path from end to start
            while (c.previous) {
                path.push(c);
                c = c.previous;
            }
            current.bestPath = path.reverse();
            current.openSet = openSet;
            current.closedSet = closedSet;
            return current;
        }

        removeNode(openSet, current);
        closedSet.push(current);
        let neighbours = examineValidNeighbours(current);
        neighbours.forEach(neighbour => {
            const validMove = !containsNode(closedSet, neighbour);
            if (validMove) {
                const g = (bestFirst ? 0 : current.g);
                const h = heuristic(neighbour, current);
                const tempG = g + h;
                // Is this a better path than before?
                let optimal = false;
                if (!containsNode(openSet, neighbour)) {
                    optimal = true;
                    neighbour.h = heuristic(neighbour, destination);
                    openSet.push(neighbour);
                } else if (tempG < neighbour.g) {
                    optimal = true;
                }

                // Yes, it's a better path
                if (optimal) {
                    neighbour.g = tempG;
                    neighbour.h = heuristic(neighbour, destination);
                    neighbour.f = neighbour.g + neighbour.h;
                    neighbour.previous = current;
                }
            }
        });
    }

    if(consoleLogs) {
        console.log('No path found');
    }

    // Add empty defaults
    current.bestPath = [];
    current.openSet = [];
    current.closedSet = [];

    return current;
}

function examineValidNeighbours(subject) {
    let i = subject.i;
    let j = subject.j;
    let neighbours = [];

    if (!fixedObject(i + 1, j)) {
        neighbours.push(createNode(i + 1, j));
    }
    if (!fixedObject(i - 1, j)) {
        neighbours.push(createNode(i - 1, j));
    }
    if (!fixedObject(i, j + 1)) {
        neighbours.push(createNode(i, j + 1));
    }
    if (!fixedObject(i, j - 1)) {
        neighbours.push(createNode(i, j - 1));
    }

    if (diagonal)
        // diagonals are also neighbours:
    {
        if (!fixedObject(i - 1, j - 1)) {
            neighbours.push(createNode(i - 1, j - 1));
        }
        if (!fixedObject(i + 1, j - 1)) {
            neighbours.push(createNode(i + 1, j - 1));
        }
        if (!fixedObject(i - 1, j + 1)) {
            neighbours.push(createNode(i - 1, j + 1));
        }
        if (!fixedObject(i + 1, j + 1)) {
            neighbours.push(createNode(i + 1, j + 1));
        }
    }

    return neighbours;
}

function heuristic(a, b) {
    if (useHeuristic) {
        return diagonal ? euclideanDistance(a, b) : Math.abs(a.i - b.i) + Math.abs(a.j - b.j);
    } else {
        return 0;
    }
}

function euclideanDistance(a, b) {
    //http://en.wikipedia.org/wiki/Euclidean_distance
    return Math.sqrt(Math.pow((a.i - b.i), 2) + Math.pow((a.j - b.j), 2));
}


function createNode(i, j) {
    const n = new Node();
    n.i = i;
    n.j = j;
    return n;
}

function Node() {
    // Location
    this.i = null;
    this.j = null;
    this.previous = null;

    // f, g, and h values for A*
    this.f = 0;
    this.g = 0;
    this.h = 0;
}

function drawPlanOfAttack(planOfAttack) {
    if (drawAStarPath) {
        const points = [];
        planOfAttack.bestPath.forEach(node => {
            // translate my (i,j) grid coordinates to three.js (x,y,z) coordinates
            points.push(translateNode(node));
        });

        // A yellow diamond
        const meshParams = {color: 0xffff00};
        const radius = 20;
        const widthSegments = 32;
        const heightSegments = 32;
        showSpheres(points, meshParams, radius, widthSegments, heightSegments);
    }

    drawOpenSet(planOfAttack);
    drawClosedSet(planOfAttack);
}

function drawOpenSet(planOfAttack) {
    if (drawAStarOpenSet) {
        const points = [];
        planOfAttack.openSet.forEach(node => {
            if (!(isEnemy(node.i, node.j) || isAgent(node.i, node.j))) {
                // translate my (i,j) grid coordinates to three.js (x,y,z) coordinates
                points.push(translateNode(node));
            }
        });

        // A blue sphere
        const meshParams = {color: 0x0b5394};
        const radius = 12;
        const widthSegments = 10;
        const heightSegments = 2;
        showSpheres(points, meshParams, radius, widthSegments, heightSegments);
    }
}

function drawClosedSet(planOfAttack) {
    if (drawAStarClosedSet) {
        const points = [];
        planOfAttack.closedSet.forEach(node => {
            if (!(isEnemy(node.i, node.j) || isAgent(node.i, node.j))) {
                // translate my (i,j) grid coordinates to three.js (x,y,z) coordinates
                points.push(translateNode(node));
            }
        });

        // A red diamond
        const meshParams = {color: 0xe06666};
        const radius = 12;
        const widthSegments = 10;
        const heightSegments = 2;
        showSpheres(points, meshParams, radius, widthSegments, heightSegments);
    }
}

let meshCleanup = [];

function showSpheres(points, meshParameters, radius, widthSegments, heightSegments) {
    // Remove first and last from list since they are the enemy/agent
    points.shift();
    points.pop();
    points.forEach(point => {
        const geometry = new THREE.SphereGeometry(radius, widthSegments, heightSegments);
        const material = new THREE.MeshBasicMaterial(meshParameters);
        const mesh = new THREE.Mesh(geometry, material);

        meshCleanup.push(mesh);

        ABWorld.scene.add(mesh);
        mesh.position.copy(point);
    });

}

function clearPlanOfAttack() {
    meshCleanup.forEach(mesh => {
        ABWorld.scene.remove(mesh);
    });

    meshCleanup = [];
}

function occupiedBy(i, j) {
    if (i >= gridsize || j >= gridsize) {
        return 'boundary';
    } else if (GRID[i][j] === GRID_WALL) {
        return 'wall';
    } else if (GRID[i][j] === GRID_MAZE) {
        return 'pillar';
    } else if (enemy.i === i && enemy.j === j) {
        return 'enemy';
    } else {
        return '';
    }
}

function translateNode(n) {
    return translate(n.i, n.j);
}

function isEnemy(i, j) {
    return enemy.i === i && enemy.j === j;
}

function isAgent(i, j) {
    return agent.i === i && agent.j === j;
}

function agentCaught()			// agent is caught by enemy
{
    return gameEndsWhenAgentCaught && agent.i === enemy.i && agent.j === enemy.j;
}

// ==================== [END] Tristan's functions ====================