#!/bin/sh
set -e
# tests all functions 3 times using numbers generated using $RPATH
# psh-prng is used here with my testing
# math is comparred to bc
fd() {
  m="$1"; n=1; while [ "$m" ]; do
    next="${m%?}"
    [ "$n" -eq "${#1}" ] && {
      echo "${m%next}"
      break
    }
    : $((n+=1)); m="$next"
  done
}
ran() {
  ran="$(${RPATH})"
  ran="${ran#0.}"
  until [ "${#ran}" -le 5 ]; do
    ran="${ran%?}"
  done
  echo "${ran}"
}
case "$1" in
  "") types="addition/add subtraction/sub multiplication/mul division/div" ;;
  *) types="$1"
esac
IFS=" "; for i in ${types}; do
  for n in 1 2; do
    ran="$(fd $(ran))"; : $((ran-=1)); until [ "$ran" -eq 1 -o "$ran" -eq 0 ]; do
      ran="$(fd $(ran))"; : $((ran-=1))
    done
    case $ran in
      0) ran=""; tn="$(ran).$(ran) $(ran)";;
      1) ran=""; tn="$(ran) $(ran).$(ran)"
         ran="$(fd $(ran))"; : $((ran-=1)); until [ "$ran" -eq 1 -o "$ran" -eq 0 ]; do
           ran="$(fd $(ran))"; : $((ran-=1))
         done
         case $ran in
           1) ran=""; tn="${tn% *}.$(ran) ${tn#* }"
         esac
    esac
    # use random number to determine if number will have decimal place
    case $i in
      *addition/add) op="+";;
      *subtraction/sub) op="-";;
      *multiplication/mul) op="*";;
      *division/div) op="/"
    esac
    aws="$(echo ${tn% *}${op}${tn#* } | bc -l)"; case "$(fd $aws)" in
      '.') aws="0${aws}"
    esac
    printf '  %s\n%s %s\n_____\nbc:  %s\n' "${tn% *}" "$op" "${tn#* }" "$aws"
    oaws="$aws"; aws="${aws%.*}${aws#*.}"
    [ "$aws" -ge 9223372036854775807 ] 2>/dev/null && {
      printf 'psh: too large...\n\n'
    } || printf 'psh: %s\n' "$(${i} ${tn% *} ${tn#* })"
    [ "$oaws" = "$(${i} ${tn% *} ${tn#* })" ] && {
      status=0
    } || status=1
    case "$status" in
      0) printf 'Correct!\n\n' ;;
      1) printf 'False..\n\n' && exit 1
    esac
  done
done