// toybox.js by Dante Scanline 2022
// UNIVERSAL PUBLIC DOMAIN LICENSE - This code and everything else in the universe is in the public domain

/// ------------

// CONFIGURATION VARIABLES, please change these!
const BUBBLE_IN = true; //makes the toys come in one at a time
const BUBBLE_DELAY = 250; // if bubbling in, how much time in miliseconds between each new toy. bigger number is slowe

const PUSH_SPEED = 3; // base amount that toys push each other, bigger number means quicker stronger pushing
const RANDOM_START_OFFSET = 200; // random distance from center in pixels where toys are spawned inside off

/// ------------

let toyContainer;
let items = []; // array of dom elements

// Fisher–Yates knuth shuffle
function shuffle(array) {
	let currentIndex = array.length,
		randomIndex;

	// While there remain elements to shuffle.
	while (currentIndex != 0) {
		// Pick a remaining element.
		randomIndex = Math.floor(Math.random() * currentIndex);
		currentIndex--;

		// And swap it with the current element.
		[array[currentIndex], array[randomIndex]] = [
			array[randomIndex],
			array[currentIndex],
		];
	}

	return array;
}

// reenable items sequentially for bubbling
function reEnable(index) {
	if (index > items.length - 1) {
		return;
	}

	items[index].domElement.style.display = "initial";

	setTimeout(() => {
		reEnable(index + 1);
	}, BUBBLE_DELAY);
}

// the object, with width height from DOM and then a position we set :)
class Toy {
	constructor(domElement) {
		this.domElement = domElement;
		this.domElement.style.position = "absolute";

		let rect = toyContainer.getBoundingClientRect();
		this.x = rect.width / 2 + 100 - Math.random() * 200;
		this.y = rect.height / 2 + 100 - Math.random() * 200;

		this.visualX = this.x;
		this.visualY = this.y;

		this.updateSize();
		this.updatePosition();
	}

	updatePosition() {
		this.visualX += (this.x - this.visualX) * 0.1;
		this.visualY += (this.y - this.visualY) * 0.1;
		this.domElement.style.left = `${this.x}px`;
		this.domElement.style.top = `${this.y}px`;
	}

	updateSize() {
		this.width = this.domElement.clientWidth;
		if (this.width == 0 || this.width == undefined) {
			console.error("no size for element yet");
		}
		this.height = this.domElement.clientHeight;
		if (this.width < 65 || this.height < 65) {
			this.domElement.style["z-index"] = "20";
		}
		this.domElement.style.marginLeft = `${-this.width / 2}px`;
		this.domElement.style.marginTop = `${-this.height / 2}px`;
		// this.domElement.style.transform = `translate(${-this.width / 2}px, ${-this.height / 2}px)`
	}

	pointOverlaps(xx, yy) {
		return (
			xx > this.x - this.width / 2 &&
			xx < this.x + this.width / 2 &&
			yy > this.y - this.height / 2 &&
			yy < this.y + this.height / 2
		);
	}

	toyOverlaps(otherToy) {
		const corners = [
			[otherToy.x - otherToy.width / 2, otherToy.y - otherToy.height / 2],
			[otherToy.x + otherToy.width / 2, otherToy.y - otherToy.height / 2],
			[
				otherToy.x - otherToy.height / 2,
				otherToy.y + otherToy.height / 2,
			],
			[otherToy.x + otherToy.width / 2, otherToy.y + otherToy.height / 2],
		];

		// check if the other toys corners are inside our rect
		for (let i = 0; i < corners.length; i++) {
			let pair = corners[i];
			if (this.pointOverlaps(pair[0], pair[1])) {
				return true;
			}
		}

		// edge case, where we are fit entirely inside the other rect, so check one of our points on them
		return otherToy.pointOverlaps(this.x, this.y);
	}

	getPushed(otherToy) {
		let distance = PUSH_SPEED;

		let centerX = this.x;
		let centerY = this.y;

		let otherCenterX = otherToy.x;
		let otherCenterY = otherToy.y;

		let angle = Math.atan2(centerY - otherCenterY, centerX - otherCenterX);

		let finalStrength = distance;

		// if the toy pushing us is roughly bigger than us, get pushed more to help offset some biasing
		if (
			otherToy.width + otherToy.height >
			(this.width + this.height) * 1.3
		) {
			finalStrength *= 3;
		}

		this.x += Math.cos(angle) * finalStrength;
		this.y += Math.sin(angle) * finalStrength;
		this.updatePosition();
	}
}

document.addEventListener("DOMContentLoaded", init);

function init() {
	toyContainer = document.querySelector("#toybox");
	let nodes = Array.from(toyContainer.childNodes);
	nodes = nodes.filter((node) => node.nodeType == 1);
	nodes = shuffle(nodes); // help prevent biases

	for (let i = 0; i < nodes.length; i++) {
		items.push(new Toy(nodes[i]));

		if (BUBBLE_IN) {
			if (i > 3) {
				items[i].domElement.style.display = "none";
			}
		}
	}

	if (BUBBLE_IN) {
		reEnable(3);
	}
	requestAnimationFrame(main);
}

function main() {
	items.map((item) => item.updateSize());

	for (let i = 0; i < items.length; i++) {
		const itemA = items[i];

		for (let k = 0; k < items.length; k++) {
			if (i == k) continue;

			const itemB = items[k];
			if (itemA.toyOverlaps(itemB)) {
				itemB.getPushed(itemA);
			}
		}
	}

	let rect = toyContainer.getBoundingClientRect();

	for (let i = 0; i < items.length; i++) {
		const itemA = items[i];
		if (itemA.x - itemA.width / 2 < 0) {
			itemA.x += 10;
			itemA.updatePosition();
		}
		if (itemA.y - itemA.height / 2 < 0) {
			itemA.y += 10;
			itemA.updatePosition();
		}
		if (itemA.x + itemA.width / 2 > rect.width) {
			itemA.x -= 10;
			itemA.updatePosition();
		}
		if (itemA.y + itemA.height / 2 > rect.height) {
			itemA.y -= 5;
			itemA.updatePosition();
		}
	}

	requestAnimationFrame(main);
}