#!/bin/sh

fname=$(basename $0)

usage() {
  echo "$fname [options] [path]"
  echo 'Find the biggest size hog in given path

  Options:
    -h        Display help
    -r <val>  Size ratio for continuation
    -s        Print only size
    -p        Print only path
    -k        Print raw size (kbyte)
  '
}

get_dirsize_list() {
  du -d1 $1 2>/dev/null | sort -n
}

ratio=0.5
unset opt_s opt_p opt_k

duopt="xh"

while getopts ":hr:spk" opt
do
  case $opt in
    h)
      usage
      exit 0
      ;;
    r)
      if [ -z "$OPTARG" ]
      then
        echo "r needs an argument" >/dev/stderr
        exit 2
      fi
      ratio=$OPTARG
      ;;
    s)
      opt_s=y
      ;;
    p)
      opt_p=y
      ;;
    k)
      duopt="x"
      ;;
    *)
      echo "Unknown option: -$opt" >/dev/stderr
      exit 2
      ;;
  esac
done

[ -z "$opt_p" ] && [ -z "$opt_s" ] && opt_p=y opt_s=y

shift $((OPTIND-1))

list=""
pval=""
nval=""
cratio=""
dest=""

_step()
{
  list=$(get_dirsize_list $1)
  if [ "$(echo "$list" | wc -l)" = "1" ]
  then
    cratio=""
    return 0
  fi
  pval=$(echo "$list" | tail -n1)
  nval=$(echo "$list" | tail -n2 | head -n1)
  cratio=$(echo "scale=2;$(echo "$nval" | cut -f1)/$(echo "$pval" | cut -f1)" | bc 2>/dev/null)
  dest=$(echo "$nval" | cut -f2- | xargs basename 2>/dev/null)
}

path="."
[ -n "$1" ] && path=$1
if ! [ -d $path ]
then
  echo "Invalid path" >/dev/stderr
  exit 1
fi

_step $path

while [ -n "$cratio" ] && [ "1" -eq "$(echo "$cratio >= $ratio" | bc)" ]
do
  path="$path/$dest"
  _step $path
done

pval=$(get_dirsize_list $path | tail -n1)
nval=$(find $path -maxdepth 1 -type f -printf '%s %p\n' | awk '{print int(($1+1023)/1024)"\t"$2}' | sort -n | tail -n1)
cratio=$(echo "scale=2;$(echo "$nval" | cut -f1)/$(echo "$pval" | cut -f1)" | bc 2>/dev/null)

if [ -n "$cratio" ] && [ "1" -eq "$(echo "$cratio >= $ratio" | bc)" ]
then
  path="$path/$(echo "$nval" | cut -f2- | xargs basename)"
fi

[ -n "$opt_p" ] && printf "%s " "$path" | sed 's|^\./||;s|/./|/|' | tr -s '/'
[ -n "$opt_s" ] && printf "%s" "$(du -"$duopt"d0 "$path" | cut -f1)"
printf "\n"