#ifndef gui_h
#define gui_h

#include "rect.h"

struct App;
struct Arena;
struct GUI;
struct Renderer;

typedef enum {
	gui_el_type_btn,
	gui_el_type_scrollable,
	gui_el_type_scrollbar
} GUI_El_Type;

typedef struct GUI_El {
	GUI_El_Type type;
	struct GUI_El* next;
	Rect r;
} GUI_El;

typedef struct {
	GUI_El el;
	char* text;
	int hover, active;
} GUI_Btn;

typedef struct {
	int x, y;
	short grabbed[2];
	short graboff[2];
} GUI_Scroll_State;

typedef struct {
	GUI_El el;
	GUI_Scroll_State* s;
	Rect handle;
	int h;
	int hover, active;
} GUI_Scrollbar;

typedef void (*GUI_Scrollable_Draw_Fn)(
	struct GUI*,
	struct Renderer*,
	const Rect*,
	const GUI_Scroll_State*
);

typedef struct {
	GUI_El el;
	GUI_Scrollable_Draw_Fn draw;
	GUI_Scroll_State* ss;
	int cs[2];
	int vp[2];
} GUI_Scrollable;

typedef struct GUI {
	const struct App* app;
	struct Arena* a;
	GUI_El* first, * prev;
	int cursor[2], pad;
} GUI;

int gui_text_width(const char* text, int len);
int gui_text_height(void);

void gui_begin(GUI* g, const struct App* app, struct Arena* a);
void gui_end(GUI* g, struct Renderer* r);
Rect gui_viewport(GUI* g);
Rect gui_cut_left(Rect* a, int v);
Rect gui_cut_right(Rect* a, int v);
Rect gui_cut_down(Rect* a, int v);
Rect gui_cut_up(Rect* a, int v);
int gui_btn(GUI* g, Rect r, const char* text);
void gui_scrollable(
	GUI* g,
	Rect r,
	const int* cs,
	GUI_Scroll_State* state,
	GUI_Scrollable_Draw_Fn fn
);
void gui_scrollbar(
	GUI* g,
	GUI_Scroll_State* state,
	Rect r,
	int diff,
	int horizontal
);

#endif