#include "aplos.h"

#define FOREGROUND 0x442A13
#define BACKGROUND 0xE3DFD7

static struct framebuffer *fb;
static volatile uint32_t *fb_mem;

static uint32_t row;
static uint32_t col;

static void screen_clear(void);
static int print_fmt(char8_t *, va_list);

void
screen_init(struct framebuffer *framebuffer)
{
	fb = framebuffer;
	fb_mem = fb->addr;
	screen_clear();

	font_init();
}

void
screen_draw_pixel(uint32_t x, uint32_t y, uint32_t c)
{
	fb_mem[x + y * (fb->pitch/4)] = c;
}

void
print(char8_t *fmt, ...)
{
	va_list args;
	va_start(args, fmt);

	int n;
	for(char8_t *p = fmt; *p; p += utf8_char_length(p)){
		switch(*p){
		default:
print_char:
			font_draw(p, row, col, BACKGROUND, FOREGROUND);
			col++;
			break;
		case '\n':
			row++;
			col = 0;
			break;
		case '%':
			n = print_fmt(p, args);
			if(n == 0)
				goto print_char;
			while(n-- > 1)
				p += utf8_char_length(p);
			break;
		}
	}
	va_end(args);
}

static void
screen_clear(void)
{
	for(uint64_t y = 0; y < fb->height; y++){
		for(uint64_t x = 0; x < fb->width; x++){
			fb_mem[x + y * (fb->pitch/4)] = BACKGROUND;
		}
	}
}

static int
print_fmt(char8_t *fmt, va_list args)
{
	char8_t digits[] = u8"0123456789ABCDEF";
	char8_t *prefixes[17] = {0};
	char8_t buf[65];
	char8_t *p = &buf[nelem(buf)-1];

	prefixes[2] = u8"0b";
	prefixes[8] = u8"0o";
	prefixes[16] = u8"0x";

	*p = 0;

#define UINT(spec, n, base, min, type) 		\
	if(utf8_cmp_n(fmt, spec, 2+n) == 0){	\
		type v = va_arg(args, type);	\
		int w = min;			\
		do{				\
			p--;			\
			*p = digits[v%base];	\
			v = v / base;		\
			if(w)			\
				w--;		\
		}while(v || w);			\
		if(prefixes[base])		\
			print(prefixes[base]);	\
		print(p);			\
		return 2+n;			\
	}

#define UINTS(bits, n, type)		\
	UINT(u8"%b" #bits, n, 2, 0, type)	\
	UINT(u8"%o" #bits, n, 8, 0, type)	\
	UINT(u8"%u" #bits, n, 10, 0, type)	\
	UINT(u8"%x" #bits, n, 16, 0, type)	\

	UINTS(64, 2, uint64_t);
	UINTS(32, 2, uint32_t);
	UINTS(16, 2, int);
	UINTS(8,  1, int);

	UINT(u8"%p", 0, 16, 16, uintptr_t);

	return 0;
}