const container = Z.by_id('container');

function getRandomColor() {
  var letters = '0123456789ABCDEF';
  var color = '#';
  for (var i = 0; i < 6; i++) {
    color += letters[Math.floor(Math.random() * 16)];
  }
  return color;
}

for (let i = 0; i < 10000; ++i) {
	container.appendChild(Z.native('div', {
		innerText: i,
		className: 'image',
		style: {
			background: getRandomColor(),
			aspectRatio: '1 / ' + (Math.random() + 0.5),
		},
	}));
}

const zoom = new (class {
	constructor() {
		this.committed = 5;
		this.count = 5;
		container.style.gridTemplateColumns = `repeat(5, 1fr)`;
		container.classList.toggle('tiling', this.count != 1);
		this.por = { x: 0, y: 0 };
		this.eor = null;
		this.y_offset = 0;
	}

	update(delta, point) {
		this.count += delta;
		this.count = Math.min(Math.max(this.count, 1), 20);

		const scale = this.committed / this.count;

		const x = point.x - this.por.x;

		container.style.transform = `translate(${x}px, 0px) scale(${scale})`;
	}

	set point_of_reference(point) {
		const rect = container.getClientRects()[0];

		this.por = { x: point.x, y: point.y - rect.y };
		container.style.transformOrigin = `${this.por.x}px ${this.por.y}px`;
		this.eor = Z.document.shadowRoot.elementFromPoint(point.x, point.y);
		this.y_offset = this.eor.getBoundingClientRect().y;
	}

	commit() {
		console.log('commit');
		this.count = Math.round(this.count);
		container.style.gridTemplateColumns = `repeat(${this.count}, 1fr)`;
		container.classList.toggle('tiling', this.count != 1);
		container.style.transform = 'scale(1)';
		this.committed = this.count;

		void container.offsetHeight;

		const rect = this.eor.getBoundingClientRect();

		Z.document.scrollBy({
			top: rect.y - this.y_offset,
			behavior: 'instant',
		});
	}
});

Z.document.onwheel = (event) => {
	if (!event.ctrlKey) {
		return;
	}
	event.preventDefault();
	zoom.update(event.wheelDeltaY / 120, { x: 0, y: 0 });
	zoom.commit();
};

const pinch = new Pinch(Z.document);

pinch.onstart = (event) => {
	zoom.point_of_reference = event.point;
};

pinch.onpinch = (event) => {
	zoom.update(event.zoom_delta / 20, event.point);
};

pinch.onfinish = () => {
	zoom.commit();
};