#!/bin/bash

function helpexit() {
    echo "Display file/folder sizes like 'du', but faster and actual byte sizes"
    echo "Returns only the size as number"
    echo "  -h       Human readable units"
    echo "  -s       Summary mode, otherwise each argument folder calculated separate"
    echo "  -c       Count files instead of summarizing sizes"
    echo "  -a       Display animation while counting"
    echo "  -f #     Format filesize to human readable. Command exits without scanning."
    echo "  --help   This help"
    exit
}
function filesize() {
# Return a human readable size from integer of bytes
# Usage:  filesize 10000

    [ "$1"  = "0" ] && {
        echo "0  B"
        return 0
    }

    awk 'BEGIN{ x = '$1'
        split("B kB MB GB TB PB EB ZB",type)
        for(i=7;y < 1;i--)
            y = x / (2^(10*i))
        str=int(y*10)/10 " " type[i+2]
        if (i==-1) { str = x "  B" }
        print str
    }' || return $?
}
function siprefix() {
# Return a SI prefixed string from integer

    [ "$1"  = "0" ] && {
        echo "0  "
        return 0
    }

    awk 'BEGIN{ x = '$1'
        split("_ k M G T P E Z",type)
        for(i=7;y < 1;i--)
            y = x / (10^(3*i))
        str=int(y*10)/10 " " type[i+2]
        if (i==-1) { str = x "  " }
        print str
    }' || return $?
}

function animate() {
  CHARS="|/-__-\\"
  i=0
  while true; do
    sleep 0.2
    printf "\r%s\r" ${CHARS:$i:1} >&2
    i=$(( (i + 1)%${#CHARS} ))
  done
}

function processfolder() {
   if [[ "$COUNT" -eq 1 ]]; then
     countfiles "$@"
   else
     displaysize "$@"
   fi
}

function countfiles() {
  SIZE=$( find "$@" -type f -printf %s"\n" 2>/dev/null | awk '{  sum += 1 } END { print int(sum)+0 }' )
  [[ "$HUMAN" -eq 1 ]] && {
    SIZE=$( siprefix "$SIZE" )
  }
  echo "${SIZE}"
}

function displaysize() {
  SIZE=$( find "$@" -type f -printf %s"\n" 2>/dev/null | awk '{  sum += $1 } END { print int(sum)+0 }' )
  [[ "$HUMAN" -eq 1 ]] && {
    SIZE=$( filesize "$SIZE" )
  }
  echo "$SIZE"
}

# Get options
what=()
for (( i=1; i<=$#; i++ )); do
  [[ "${!i}" = "-a" ]] && { ANIMATE=1; continue; }
  [[ "${!i}" = "-f" ]] && { FORMAT=1; ((i++)); FORMAT_VALUE=${!i}; continue; }
  [[ "${!i}" = "--help" ]] && helpexit
  [[ "${!i}" = "-h" ]] && { HUMAN=1; continue; }
  [[ "${!i}" = "-c" ]] && { COUNT=1; continue; }
  [[ "${!i}" = "-s" ]] && { SUMMARY=1; continue; }
  what+=( "${!i}" )
done
[[ -z "${what[@]}" ]] && what="."
# If formatting requested, do only that:
if [[ "$FORMAT" -eq 1 ]]; then
  if [[ -z "$FORMAT_VALUE" ]]; then
    echo -e "\nBytes argument missing\n\n"
    helpexit
  fi
  filesize $FORMAT_VALUE
  exit $?
fi

# If only one entry, dont print the name
[[ "${#what[@]}" -eq 1 ]] && SUMMARY=1

if [[ "$ANIMATE" -eq 1 ]]; then
  animate &
fi

if [[ "$SUMMARY" -eq 1 ]]; then
  # Display one line
  processfolder "${what[@]}"
else
  if [[ "$HUMAN" -eq 1 ]]; then
      FORMAT="%8s  %s\n"
  else
      FORMAT="%d\t%s\n"
  fi
  # One size for each argument
  for dir in "${what[@]}"; do
    printf "$FORMAT" "$( processfolder "$dir" )" "$dir"
  done
fi
if [[ "$ANIMATE" -eq 1 ]]; then
  kill %1
fi