#!/bin/bash
#NOTE, because bash arrays are just string delimited by space, we will not be
#using space as our empty character but .
rawbuff=()
function load_raw () {
	while read -r line; do
		if [ "$line" = "END_RAW" ]; then
			return
		else
			rawbuff=("${rawbuff[@]}" "$line")
		fi
	done
}
function load_point() {
	read -r x
	read -r y
	read -r c
	line=${rawbuff[$y]}
	#construct a sed prompt that replaces the xth character
	prompt="s/^\(.\{$x\}\).\(.*\)$/\1$c\2/"
	rawbuff[$y]=$(echo "$line" | sed "$prompt")
}
function print_raw () {
	for line in "${rawbuff[@]}"; do
		echo "$line"
	done
}
function canvas() {
	read -r w
	read -r h
	ln=""
	i=0
	while [ $i -lt $w ];do
		ln="$ln."
		i=$(($i + 1))
	done
	j=0
	while [ $j -lt $h ]; do
		rawbuff=("${rawbuff[@]}" "$ln")
		j=$(($j+1))
	done
}

#prints a single braille at $1=x $2=y
function print_sin_braille() {
#NOTE, for optimization purposes, this only works if the buffer consits of 1s
#and 0s
#bit to braille 
#
#0 3
#1 4
#2 5
#6 7
#reverse 
#(1,3)(0,3)(1,2)(1,1)(1,0)(0,2)(0,1)(0,0)

	b0=${rawbuff[((0+4*$2))]:((0+2*$1)):1}
	b1=${rawbuff[((1+4*$2))]:((0+2*$1)):1}
	b2=${rawbuff[((2+4*$2))]:((0+2*$1)):1}
	b3=${rawbuff[((0+4*$2))]:((1+2*$1)):1}
	b4=${rawbuff[((1+4*$2))]:((1+2*$1)):1}
	b5=${rawbuff[((2+4*$2))]:((1+2*$1)):1}
	b6=${rawbuff[((3+4*$2))]:((0+2*$1)):1}
	b7=${rawbuff[((3+4*$2))]:((1+2*$1)):1}

	#ors it with the utf-8 hex value of the empty braille character
	#the two spaces assume aht the encoding is utf-8, convoluted bitwise OR
	#and coversion between character and number stuff
	echo "obase=16;$(( 2#$b7${b6}00$b5$b4$b3$b2$b1$b0 | 0xE2A080 ))"|bc | xxd --reverse -ps
}

function print_braille() {
	#I do the lazy thing and just test the first line
	w=${#rawbuff[0]}
	h=${#rawbuff[@]}
	#conver to braille coords, we do not want to try to print incomplete
	#characters because they will break with our optimization, so rounding
	#down is good
	w=$((w/2))
	h=$((h/4))
	i=0
	j=0
	while [ $i -lt $h ]; do
		j=0
		while [ $j -lt $w ]; do
			print_sin_braille $j $i
			j=$(($j+1))
		done
		#just want a new line
		echo
		i=$(($i+1))
	done
}
while read -r line; do
	if [ "$line" = "LOAD_RAW" ]; then
		load_raw
	elif [ "$line" = "LOAD_POINT" ]; then
		load_point
	elif [ "$line" = "PRINT_RAW" ]; then
		print_raw
	elif [ "$line" = "CANVAS" ]; then
		canvas
	elif [ "$line" = "PRINT_BRAILLE" ]; then
		print_braille
	elif [ "$line" = "END" ]; then
		exit
	fi
done