#ifndef ui_hpp
#define ui_hpp

#include "maths.hpp"
#include "video.hpp"

struct Arena;
struct UI {
	struct Rect {
		int x, y, w, h;
	};

	struct Element : Rect {
		enum class Type {
			label
		} type;
		Element* next;
		static int size(Type t);
	};

	struct Label : Element {
		char* text;
		int len;
		int x, y;
	};

	struct Vertex {
		float x, y, u, v, r, g, b, a;
	};

	Arena* arena;
	Device* device;
	Element* tree;
	Texture_Id atlas;
	Shader_Id shader;
	Vertex_Format_Id vertex_format;
	Buffer_Id mesh, config_buf;
	Sampler_Id sampler;
	struct UI_CBuffer {
		m4f projection;
	};
	struct {
		int vert_binding;
		int atlas_binding;
		int config_binding;
	} shader_info;

	static int text_width(const char* t);
	static int text_height(const char* t);

	static UI* create(Device* dev, Arena* a, Shader_Id sh);

	Element* create_element(Element::Type t);
	Label* create_label(const char* t, int x, int y);

	void init(Device* dev, Arena* a, Texture_Id atlas, Shader_Id sh);
	void destroy();
	void update(Arena* s);
	void render(Arena* s, Texture_Id target);

	int render_label(const Label* l, int off);
};

#endif