#!/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 in addition 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))
        if (i==-1) { printf( "%d~B", x) }
        if (i>-1) { printf( "%0.1f%s", y, type[i+2]) }
    }' || 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))
        if (i==-1) { printf( "%d~#", x) }
        if (i>-1) { printf( "%0.1f%s", y, type[i+2]) }
    }' || return $?
}

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

function processfolder() {

  if [[ "$ANIMATE" -eq 1 ]]; then
    SIZECOUNT=( $( \
      find "$@" -type f -printf %s"\n" 2>/dev/null | \
      awk '{  sum += $1; count += 1; printf "      %dMb/%d#\r", sum/(1024*1024), count > "/dev/stderr" } END { printf("%0.f	 %0.f",sum+0, count+0)}' \
    ) )
    echo -e -n "\033[K" >&2
  else
    SIZECOUNT=( $( find "$@" -type f -printf %s"\n" 2>/dev/null | awk '{  sum += $1; count += 1 } END { printf("%0.f	 %0.f",sum+0, count+0)}' ) )
  fi

  SIZE=${SIZECOUNT[0]}

  [[ "$HUMAN" -eq 1 ]] && {
    SIZE=$( filesize "$SIZE" )
  }
  [[ "$COUNT" -eq 1 ]] && {
    COUNTS=${SIZECOUNT[1]}
    [[ "$HUMAN" -eq 1 ]] && {
      COUNTS=$( siprefix "$COUNTS" )
    }
  }
  echo -e "$SIZE\t$COUNTS"
}

function formatter() {
    cat - | xargs printf "$FORMAT" | sed -e 's,~B, B,' -e 's,~#, #,'
}
# Get options
what=()
for (( i=1; i<=$#; i++ )); do
  [[ "${!i}" = "-f" ]] && { FORMAT=1; ((i++)); FORMAT_VALUE=${!i}; continue; }
  [[ "${!i}" = "--help" ]] && helpexit

  [[ "${!i}" = "-"* ]] && {
    [[ "${!i}" =~ -.*a ]] && { ANIMATE=1; }
    [[ "${!i}" =~ -.*h ]] && { HUMAN=1; }
    [[ "${!i}" =~ -.*c ]] && { COUNT=1; }
    [[ "${!i}" =~ -.*s ]] && { SUMMARY=1; }
    continue
  }
  what+=( "${!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 | sed 's,~B, B,'
  exit $?
fi

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

if [[ "$ANIMATE" -eq 1 ]]; then
  trap 'trap - SIGTERM && kill -- -$$' EXIT SIGINT SIGTERM
  animate &
fi
[[ "$HUMAN" -eq 1 ]] && NUMFORMAT="%7s "
[[ "$HUMAN" -ne 1 ]] && NUMFORMAT="%d\t"
[[ "$COUNT" -eq 1 ]] && NUMBERS="$NUMFORMAT$NUMFORMAT"
[[ "$COUNT" -ne 1 ]] && NUMBERS="$NUMFORMAT"
[[ "SUMMARY" -eq 1 ]] && FORMAT="$NUMBERS\n"
[[ "SUMMARY" -ne 1 ]] && FORMAT="$NUMBERS"


if [[ "$SUMMARY" -eq 1 ]]; then
  # Display one line
  processfolder "${what[@]}" | formatter
else
  # One size for each argument
  for ((i=0; i<"${#what[@]}"; i++)); do
    processfolder "${what[$i]}" | formatter
    echo "${what[$i]}"
  done
fi

if [[ "$ANIMATE" -eq 1 ]]; then
  trap - EXIT SIGINT SIGTERM
  kill %1
fi