/* ************************************************************************** */
/*                                                                            */
/*  ML_horizontal_line.c                                                      */
/*  | Project : libmonochrome                                                 */
/*                                                                            */
/*  By: Pierre "PierrotLL" Le Gall <legallpierre89@gmail.com>                 */
/*  Last updated: 2011/11/22                                                  */
/*                                                                            */
/* ************************************************************************** */

#include <monochrome/internals.h>

void ML_horizontal_line(int y, int x1, int x2, ML_Color color)
{
	if (y & ~63 || (x1 < 0 && x2 < 0) || (x1 > 127 && x2 > 127))
		return;

	int i;
    char checker;
    char* vram = ML_vram_address();
	
	if (x1 > x2) {
		i = x1;
		x1 = x2;
		x2 = i;
	}
	if (x1 < 0)
		x1 = 0;
	if (x2 > 127)
		x2 = 127;
	switch (color) {
		case ML_BLACK:
			if (x1 >> 3 != x2 >> 3) {
				vram[(y << 4) + (x1 >> 3)] |= 255 >> (x1 & 7);
				vram[(y << 4) + (x2 >> 3)] |= 255 << (7 - (x2 & 7));
				for (i = (x1 >> 3) + 1 ; i < x2 >> 3; i++)
					vram[(y << 4) + i] = 255;
			} else
				vram[(y << 4) + (x1 >> 3)] |= (255 >> (x1 % 8 + 7 - x2 % 8))
					<< (7 - (x2 & 7));
			break;
		case ML_WHITE:
			if (x1 >> 3 != x2 >> 3) {
				vram[(y << 4) + (x1 >> 3)] &= 255 << (8 - (x1 & 7));
				vram[(y << 4) + (x2 >> 3)] &= 255 >> (1 + (x2 & 7));
				for (i = (x1 >> 3) + 1; i < x2 >> 3; i++)
					vram[(y << 4) + i] = 0;
			} else
				vram[(y << 4) + (x1 >> 3)] &= (255 << (8 - (x1 & 7)))
					| (255 >> (1 + (x2 & 7)));
			break;
		case ML_XOR:
			if (x1 >> 3 != x2 >> 3) {
				vram[(y << 4) + (x1 >> 3)] ^= 255 >> (x1 & 7);
				vram[(y << 4) + (x2 >> 3)] ^= 255 << (7 - (x2 & 7));
				for (i = (x1 >> 3) + 1; i < (x2 >> 3); i++)
					vram[(y << 4) + i] ^= 255;
			} else
				vram[(y << 4) + (x1 >> 3)] ^= (255 >> ((x1 & 7) + 7 - (x2 & 7)))
					<< (7 - (x2 & 7));
			break;
		case ML_CHECKER:
			checker = (y & 1 ? 85 : 170);
			if (x1 >> 3 != x2 >> 3) {
				vram[(y << 4) + (x1 >> 3)] &= 255 << (8 - (x1 & 7));
				vram[(y << 4) + (x2 >> 3)] &= 255 >> (1 + (x2 & 7));
				vram[(y << 4) + (x1 >> 3)] |= checker & 255 >> (x1 & 7);
				vram[(y << 4) + (x2 >> 3)] |= checker & 255 << (7 - (x2 & 7));
				for (i = (x1 >> 3) + 1; i < x2 >> 3; i++)
					vram[(y << 4) + i] = checker;
			} else {
				vram[(y << 4) + (x1 >> 3)] &= (255 << (8 - (x1 & 7)))
					| (255 >> (1 + (x2 & 7)));
				vram[(y << 4) + (x1 >> 3)] |= checker
					& (255 >> (x1 % 8 + 7 - x2 % 8)) << (7 - (x2 & 7));
			}
			break;
		default:
			break;
	}
}