#include <vhex/display/font.h>
#include <vhex/display/draw/pixel.h>
#include <vhex/display/color.h>
#include <vhex/display/stack.h>

//---
// Kernel-level render API
//---

/* dfont_char_render() : */
void dfont_char_render(
	dsurface_t *surface,
	int glyph_idx,
	uint32_t *arg
) {
	uint32_t glyph_bitmap;
	uint32_t glyph_shift;
	int glyph_width;
	int glyph_size;
	font_t *font;
	int counter;
	int sx;
	int x;
	int y;

	x = arg[0];
	y = arg[1];

	/* generate font index / shift information */
	font = dfont_get();
	if (font->shape.prop == 1) {
		glyph_width = font->glyph.prop[glyph_idx].width;
		glyph_shift = font->glyph.prop[glyph_idx].shift;
		glyph_idx   = font->glyph.prop[glyph_idx].index;
		glyph_size  = glyph_width * font->glyph.height;
	} else {
		glyph_width = font->glyph.mono.width;
		glyph_size  = font->glyph.mono.storage_size;
		glyph_shift = glyph_size * glyph_idx;
		glyph_idx   = glyph_shift >> 8;
		glyph_shift = glyph_shift & 0xff;
	}

	/* drawing algo */
	//TODO: cache surface data (limit read/write)
	sx = x;
	counter = 0;
	glyph_shift = 0x80000000 >> glyph_shift;
	glyph_bitmap = font->glyph.data[glyph_idx];
	for (int i = 0; i < glyph_size; ++i)
	{
		if (glyph_bitmap & glyph_shift) {
			dpixel_render(surface, x, y, arg[4]);
		} else {
			dpixel_render(surface, x, y, arg[5]);
		}

		/* update font bitmap index / shift */
		glyph_shift >>= 1;
		if (glyph_shift == 0x00000000) {
			glyph_shift = 0x80000000;
			glyph_bitmap = font->glyph.data[++glyph_idx];
		}

		/* update bitmap position */
		x += 1;
		counter += 1;
		if (counter >= glyph_width) {
			counter = 0;
			x = sx;
			y += 1;
		}
	}
}

//---
// Dstack API
//---

/* dfont_char_dstack() : dstack wrapper */
void dfont_char_dstack(dsurface_t *surface, uint32_t *arg)
{
	font_t *font = dfont_get();
	uint32_t buff[6] = {
		arg[1], arg[2], 0, 0, arg[3], arg[4]
	};

	dfont_char_render(surface, dfont_glyph_index(font, arg[0]), buff);
}

//---
// User-level API
//---

/* dfont_char() : display one char */
void dfont_char(uint32_t n, int x, int y, int fg, int bg)
{
	dstack_add_action(
		DSTACK_CALL(
			&dfont_char_dstack,
			n,
			x, y,
			fg, bg
		),
		NULL,
		NULL
	);
}