#include <lib/display.h>
#include <kernel/types.h>

static const uint8_t kernel_font_bitmap[] = {
	0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee,
	0xee, 0xee, 0xee, 0xef, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x56, 0xaa, 0xaa, 0xaa, 0xaa,
	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xad,
	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
	0x55, 0x55, 0x55, 0x5e, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee,
	0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xee, 0xe0, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
	0x2a, 0x92, 0x11, 0x11, 0x28, 0x00, 0x00, 0x38, 0xbb, 0xab, 0xbb, 0xbb,
	0x80, 0x08, 0x23, 0x02, 0x57, 0x31, 0x52, 0x41, 0x22, 0x00, 0x01, 0x51,
	0x11, 0x54, 0x41, 0x55, 0x22, 0x27, 0x21, 0x04, 0x0a, 0xc4, 0x40, 0x82,
	0xae, 0x0e, 0x04, 0xa2, 0xee, 0xee, 0xe2, 0xee, 0x00, 0x80, 0x24, 0x00,
	0x1c, 0xd1, 0x41, 0x04, 0x08, 0x80, 0x11, 0x45, 0x04, 0x45, 0x45, 0x44,
	0x88, 0x9c, 0x80, 0x10, 0x2b, 0x09, 0x81, 0x10, 0x02, 0x01, 0x03, 0x8b,
	0xb8, 0xbb, 0x8b, 0xb8, 0x20, 0x82, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0c, 0xee,
	0xec, 0xee, 0xea, 0xee, 0xa8, 0xae, 0xee, 0xee, 0x6e, 0xaa, 0xaa, 0xae,
	0xe0, 0xe4, 0x05, 0x55, 0x15, 0x11, 0x14, 0x89, 0x51, 0xd5, 0x55, 0x55,
	0x09, 0x55, 0x55, 0x45, 0x10, 0x54, 0x0b, 0xb2, 0x2b, 0xba, 0xb9, 0x13,
	0x22, 0xaa, 0xba, 0xb3, 0x92, 0xaa, 0x91, 0x12, 0x10, 0x80, 0x55, 0x54,
	0x54, 0x45, 0x52, 0x25, 0x45, 0x55, 0x47, 0x51, 0x25, 0x57, 0x52, 0x44,
	0x11, 0x00, 0xca, 0xee, 0xce, 0x8e, 0xae, 0xca, 0xea, 0xae, 0x8e, 0xac,
	0x4e, 0x4a, 0xa4, 0xee, 0x0e, 0x0e, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x12, 0x00,
	0x90, 0x9a, 0x11, 0x23, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x19,
	0x30, 0x39, 0x14, 0x31, 0x52, 0x54, 0x00, 0x42, 0x76, 0x26, 0x35, 0x37,
	0x55, 0x55, 0x57, 0x22, 0x20, 0x70, 0x6c, 0x86, 0xee, 0x6c, 0xc4, 0xa4,
	0xea, 0xaa, 0xac, 0xc4, 0xaa, 0xa4, 0xa4, 0x84, 0x26, 0xe1, 0x55, 0x15,
	0x08, 0x54, 0x89, 0x89, 0x55, 0x58, 0xd0, 0x49, 0x55, 0xd4, 0x90, 0x88,
	0x99, 0xc1, 0xb1, 0x99, 0x93, 0x2b, 0xb2, 0x9a, 0xa9, 0x20, 0xa3, 0x19,
	0x92, 0xa9, 0x39, 0x93, 0x03, 0x80
};

void dascii(int x, int y, char const c)
{
	off_t bitmap_offset_x;
	off_t bitmap_offset_y;
	off_t vram_offset_y;
	int real_width;
	int real_height;
	uint8_t pixel_test;
	int pixel_cursor;
	int i;
	int j;

	// Calculate the charactere position (bitmap)
	bitmap_offset_y = (c / KERNEL_FONT_NB_CHAR_X) * (KERNEL_FONT_BITMAP_WIDTH * KERNEL_FONT_BITMAP_CHEIGHT);
	bitmap_offset_x = (c - ((c / KERNEL_FONT_NB_CHAR_X) * KERNEL_FONT_NB_CHAR_X)) * KERNEL_FONT_BITMAP_CWIDTH;

	// Set default size.
	real_width = KERNEL_FONT_REAL_WIDTH;
	real_height = KERNEL_FONT_REAL_HEIGHT;

	// Check X axis culling.
	if (x < 0)
	{
		bitmap_offset_x = bitmap_offset_x + x;
		real_width = KERNEL_FONT_REAL_WIDTH + x;
		x = 0;
	}
	else if (x + KERNEL_FONT_REAL_WIDTH >= DISPLAY_SCREEN_WIDTH)
		real_width = DISPLAY_SCREEN_WIDTH - x;

	// Check Y axis culling.
	if (y < 0)
	{
		real_height = KERNEL_FONT_REAL_HEIGHT + y;
		bitmap_offset_y = bitmap_offset_y + ((-y) * KERNEL_FONT_BITMAP_WIDTH);
		y = 0;
	}
	else if (y + KERNEL_FONT_REAL_HEIGHT >= DISPLAY_SCREEN_HEIGHT)
		real_height = DISPLAY_SCREEN_HEIGHT - y;

	// Check potential error.
	// @note we do not check real_height because the while() while do the job for us.
	if (real_width < 0)
		return;

	// Calculate VRAM buffer starting position.
	// @note:
	// 	The screen width size is always 128 and we
	// 	use 4-aligned Video RAM so 32 pixel per "slot"
	// 	and 128 / 32 = 4
	// 	y * 4 can be optimised by used shift operator
	// 	this is why we use y << 2 because 2^2 = 4.
	vram_offset_y = y << 2;

	// Draw character, pixer per pixel... (x_x)
	i = -1;
	while (++i < real_height)
	{
		j = -1;
		while (++j < real_width)
		{
			pixel_cursor = bitmap_offset_x + bitmap_offset_y + j;
			pixel_test = 0x80 >> (pixel_cursor & 0x07);
			if (pixel_test & kernel_font_bitmap[pixel_cursor >> 3])
			{
				VRAM[((x + j) >> 5) + vram_offset_y] |= 0x80000000 >> ((x + j) & 0x1f);
			}
		}
		bitmap_offset_y = bitmap_offset_y + KERNEL_FONT_BITMAP_WIDTH; 
		vram_offset_y = vram_offset_y + 4;
	}
}