package lib.ui.elements;

class RootElement implements IUIElement {
	private var children:Array<IUIElement> = [];
	private final eventManager:UIEventManager = new UIEventManager();
	private var title:String = "";

	public function new(?children:Array<IUIElement>) {
		if (children == null) {
			children = [];
		} else {
			this.children = children;
		}
	}

	public function getEventHandlers():UIEvents {
		return eventManager.getEventHandlers();
	}

	public function setChildren(children:Array<IUIElement>) {
		this.children = children;
	}

	public function render(bounds:Pos):Canvas {
		var canvas = new Canvas();
		var offset = new Pos({x: 0, y: 0});

		if (hasTitle()) {
			var title = new TextElement(this.title);
			var halfWidth = Math.floor(bounds.x / 2) - Math.floor(this.title.length / 2);
			canvas.combine(title.render(bounds), {x: halfWidth, y: offset.y});
			offset = new Pos({x: 0, y: 1});
		}

		this.eventManager.clearMap();

		for (child in children) {
			var childCanvas = child.render(bounds);
			var bounds = childCanvas.getBounds();
			bounds.offset(offset);

			this.eventManager.addMapElement(child, bounds);
			canvas.combine(childCanvas, offset);

			offset = new Pos({x: 0, y: offset.y + bounds.getHight() + 1});
		}

		return canvas;
	}

	public function setTitle(title:String) {
		this.title = title;
	}

	private inline function hasTitle():Bool {
		return title != "";
	}
}