#!/bin/bash
# SPDX-FileCopyrightText: 2022 Frank Doepper
#
# SPDX-License-Identifier: GPL-3.0-only

set -o pipefail
declare -A h # header array
# default (empty) action, to be overridden in config
action () {
  :
}
wrap () {
  local IFS=
  "$@" | while read l
  do
    echo "$n $l"
  done
}
setheader () {
  local IFS==
  set $1
  h[$1]=$2
}
checktimeout () {
  if [ $(date +%s) -gt $toolate ]
  then
    exit 1
  fi
}
delay () {
  sleep 2
}
checkshaandmoveorexit () {
  sha=$1
  src=$2
  dst=$3
  if [ "$sha" ] && sha1=$(sha1sum "$src" | awk '{print$1}')
  then
    if [ "$sha1" = "$sha" ]
    then
      echo "$n $src sha1 ok"
      wrap mv -v "$src" "$dst"
      wrap action "$dst"
      exit
    else
      echo "$n $src sha1 FALSCH"
      # keine action, aber ACK
      exit 0
    fi
  else
    # keine sha, auch gut
    wrap mv -v "$src" "$dst"
    wrap action "$dst"
    exit
  fi
}
while [ "x$1" != x ]
do
  case $1 in
    -f) f=$2;shift ;; # filename
    -m) m=$2;shift ;; # mime type
    -h) setheader "$2";shift ;; # headers
    -n) n=$2;shift ;; # seq number
    -r) r=$2;shift ;; # routing key
    -d) dest=$2;shift ;; # file destination dir
    -c) . $2 || exit;shift ;; # config snippet
    -p) prio=$2;shift ;; # priority
    -t) t=$2;shift ;; # timestamp
    -R) redeliv=$2;shift ;; # redelivered message
  esac
  shift
done
trap "rm -f -- \"$f\"" 0 1 2 3 15
if [ "${h[chunkSize]}" -a "${h[fileSize]}" ]
then
  : ${maxwait:=20}
  : ${dest:=/tmp/files}
  : ${temp:=$dest/.tmp}
  mkdir -p $dest
  mkdir -p $temp
  begin=$(date +%s)
  toolate=$((begin+maxwait))
  if [ "${h[chunkSize]}" = "${h[fileSize]}" ]
  then
    # einteilig
    wrap cp -v "$f" "$temp/${h[fileName]}"
    checkshaandmoveorexit "${h[sha1]}" "$temp/${h[fileName]}" "$dest/${h[fileName]}"
  elif [ "${h[chunkIndex]}" ]
  then
    # mehrteilig
    wrap cp -v "$f" "$temp/${h[fileName]}.part${h[chunkIndex]}"
    if [ "${h[chunkCount]}" = "${h[chunkIndex]}" ]
    then
      # letzter Teil
      # 
      until checktimeout; [ -f "$temp/${h[fileName]}.part" ]
      do
        for i in `seq 1 ${h[chunkCount]}`
        do
          if ! [ -f "$temp/${h[fileName]}.part$i" ]
          then
            # einer fehlt. versuch beenden. warten bis der da ist. nochmal probieren.
            rm -f "$temp/${h[fileName]}.part"
            delay
            break
          fi
          # ls -l "$temp/${h[fileName]}.part$i"
          cat "$temp/${h[fileName]}.part$i" >> "$temp/${h[fileName]}.part"
        done
      done
      # warten, bis die Prozesse der anderen Teile sich beendet und ihre
      # Datei entfernt haben und keine *.part* mehr da sind
      wrap mv -v "$temp/${h[fileName]}.part" "$temp/${h[fileName]}"
      rm -f -- "$temp/${h[fileName]}.part${h[chunkIndex]}"
      until checktimeout; [ "$(echo "$temp/${h[fileName]}.part"*)" = "$temp/${h[fileName]}.part*" ]
      do
        delay
      done
      checkshaandmoveorexit "${h[sha1]}" "$temp/${h[fileName]}" "$dest/${h[fileName]}"
    else
      # nicht letzter Teil
      # erst ACKen, wenn alle Teile da sind und zusammengesetzt sind.
      until checktimeout; [ -f "$temp/${h[fileName]}" ]
      do
        delay
      done
      rm -f -- "$temp/${h[fileName]}.part${h[chunkIndex]}"
    fi
  fi
else
  # keine headerdaten, normal!
  wrap action "$f"
  exit
fi

exit 0