grapher

#!/bin/bash
clear
while getopts "d:r:" opt; do 
	case $opt in
		r ) detail=$OPTARG ;;
		d ) 
			domainStart=${OPTARG%:*}
			domainEnd=${OPTARG#*:}
			;;
	esac
done

calc() {
	result=$(echo "$1" | bc | sed '/\./ s/\.\{0,1\}0\{1,\}$//')
	shift 1

	local OPTIND
	
	while getopts 'a' opt; do
		case $opt in
			a ) absolute=1;;
		esac
	done

	
	
	if [[ absolute -eq '1' ]]; then
		result=${result#-}
	fi

	echo $result
}

fill() {
	length=$1
	char=$2

	for i in $(seq 0 $length); do
		echo $char 
	done
}

#result = indices of digits found in array

findI() {
	declare -a array=(${@:1:$(($# - 1))})	
	declare -i digit="${@: -1}"

	declare -a indices=()
	declare -i i=0
	declare resultIndex=0

	for element in ${array[@]}; do
		if [[ $element -eq $digit ]]; then

			indices[$resultIndex]="$i"

			((resultIndex++))
		fi

		((i++))
	done

	echo ${indices[@]}
}

#equation=$(./series '+ (z *  ((x ^ y)/y!))' -y 'y+2;3' -z 'z * -1;-1' -d 3)
equation=$(cat < /dev/stdin)

zoom=$(calc "1/$detail")
domainRange=$(calc "$domainEnd - $domainStart" -a)

declare -i pos_res
declare -i neg_res

pos_res=$(calc "$zoom * $domainEnd" -a)
neg_res=$(calc "$zoom * $domainStart" -a)

declare -i res=$(calc "$zoom * $domainRange")

ratio=$(calc "$res / $domainRange")

for i in $(seq $res); do
	x=$(calc "($i - $neg_res)/$ratio")

	point=$(calc "${equation//'x'/$x}")
	point=$(calc "$point * $zoom")
	point=$(printf "%.0f" $point)
	points[i]=$point
done



declare -a line

#fill line with '*' and '+' on y axis
for i in $(seq $res); do
 	blank[i]='.'
 	blank[$neg_res]='+'
done


#file line with '-'
declare -a axis
axis=(`fill $res '+'`) 

for y in $(seq $pos_res -1 -$neg_res); do
 	line=("${blank[@]}")

 	if [[ y -eq 0 ]]; then 
 		line=("${axis[@]}")			
 	fi

 	declare -a indices=(`findI "${points[@]}" $y`)

 	if [[ -n $indices ]]; then
		for index in ${indices[@]}; do
 			line[$index]='#'
		 done
 	fi

  	echo "${line[@]}"
done