#include "cbrll.h"
/* this library stores the screen in a variable referred to in functions as map
 * it takes the form of a 2 dimensional array of uint8_t
 * takes char storing the on/off positions of 8 points, in braille encoding
 * order, and prints the corresponding braille char
 * maps maximum size is 200x200 pixels, which works out to a 50 by 100 array
 */

void printbraille(uint8_t points) {
	/* outputs braille characters, the encoding for braile is:
	 * 1 4
	 * 2 5
	 * 3 6
	 * 7 8
	 * with the block being in U+2800 to U+28FF
	 * in utf8 that's encoded
	 * 1110xxxx 10xxxxxx 10xxxxxx
	 * [1110](0010) [10](1000)87 [10]654321
	 */
	printf("%c%c%c", 
		0b11100010, 
		0b10100000 | (points >> 6),
		0b10000000 | (points & 0b00111111));
}
/* prints the map, clears output before aswell*/
/*prints x1 to x2, y1 to y2 bytes of the map*/
void printmap( uint8_t x1, uint8_t x2, uint8_t y1, uint8_t y2 ) {
	uint8_t xi = x1;
	uint8_t yi = y1;
	/*terminal escape code to move the cursor to beginning of screen or 1,1*/
	printf("\033[1;1H");
	while (yi < y2) {
		xi = 0;
		while (xi < x2) {
			printbraille(map[xi][yi]);
			xi++;
		}
		printf("\n");
		yi++;
	}
}
/* sets a pixel in the map, converts x,y coordinates to braille order
 * if set is 0, then set it to 0
 * if 1, set to 1
 * if > 1, flip
 * does not throw errors
 */
void setpixel(uint8_t x, uint8_t y,uint8_t set) {
	/* anchor x and y coordinates, eg the index in map*/
	uint8_t ax;
	uint8_t ay;
	/*bitmask in braille order of the byte in mask*/
	uint8_t shift = 0x01;
	/* check if out of bounds, since the arguments are unsigned, don't have
	 * to check below 0, doesn't throw errors
	 */
	if ( (x >= 200 ) || (y >= 200) ) {
		return;
	}
	/* integer division rounds down, therefore dividing will always get the
	 * index
	 */
	ax = x/2;
	ay = y/4;
	/*
	 * maps to braille order based off of x and y offsets
	 * 1 4
	 * 2 5
	 * 3 6
	 * 7 8
	 */
	switch(x % 2) {
		case 0:
			switch (y % 4) {
				case 0:
					shift = shift << 0;
				break;
				case 1:
					shift = shift << 1;
				break;
				case 2:
					shift = shift << 2;
				break;
				case 3:
					shift = shift << 6;
				break;
			}
		break;
		case 1:
			switch (y % 4) {
				case 0:
					shift = shift << 3;
				break;
				case 1:
					shift = shift << 4;
				break;
				case 2:
					shift = shift << 5;
				break;
				case 3:
					shift = shift << 7;
				break;
			}
		break;
	}
	/* sets the bit based on set*/
	switch (set) {
		case 0:
			map[ax][ay] = map[ax][ay] & (~shift);
		break;
		case 1:
			map[ax][ay] = map[ax][ay] | shift;
		break;
		default:
			map[ax][ay] = ((~map[ax][ay]) & shift) | 
					((~shift) & map[ax][ay]);
		break;
	}
	return;
}
/*takes two points and draws a line between them, dot specifies that every nth x
 * point be drawn, if dot != 1, then a dotted line is drawn
 */
void drawline(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2, uint8_t dot) {
	/*temporary x and y for switching x1,y1 and x2,y1 if x1>x2*/
	uint8_t tv;
	/*number of x values to translate*/
	uint8_t dx;
	/*number of y values to translate*/
	uint8_t dy;
	/* for whether dy should be positive or negative, 1 pos, 0 neg*/
	uint8_t dir;
	/*drawin index*/
	uint8_t xi = 0;
	/*makes sure that x1 < x2, otherwise switch them arround*/
	if (x1 > x2) {
		tv = x1;
		x1 = x2;
		x2 = tv;
		tv = y1;
		y1 = y2;
		y2 = tv;
	}
	dx = x2 - x1;
	/*find absolute
	 * dir is used since i'm planning to port to a platform that may not
	 * have signed ints.
	 */
	if (y1 > y2) {
		dir = 0;
		dy = y1 - y2;
	} else {
		dir = 1;
		dy = y2 - y1;
	}
	/*
	 *For vertical Lines
	 * Uses xi as a y index now
	 */
	if (x1 == x2) {
		while (xi <= dy) {
			if (dir) {
				setpixel(x1, y1 + xi, 1);
			} else {
				setpixel(x1, y1 - xi, 1);
			}
			xi++;
		}
	}
	/*
	 * loop through x and draws y in line, dots done with modulus.
	 */
	while (xi <= (dx)) {
		if ((xi % dot) == 0) {
			if (dir) {
				setpixel(x1 + xi, y1 + ((dy/dx * xi)), 1);
			} else {
				setpixel(x1 + xi, y1 - ((dy/dx * xi)), 1);
			}
		}
		xi++;
	}
	
	return;	
}