#!/bin/bash
source $HOME/.bwda

# Usage function
usage(){
  echo "Usage: $(basename $0) files"
  echo " files                    files to be downloaded"
  echo " -c | --channel N         use N channels per file"
  echo " -n | --dry-run           print commands to stdout instead of executing them"
  echo " -P | --parallel N        transfer N files in parallel"
  echo " -h | --help              display this message"
}

# Get command line argument
nparallel=1
nchannel=1
flag_dryrun=false

POSITIONAL=()
while [[ $# -gt 0 ]]
do
key="$1"
case $key in
    -c|--channel)
    nchannel="$2"
    shift
    shift
    ;;
    -n|--dry-run)
    flag_dryrun=true
    shift
    ;;
    -P|--parallel)
    nparallel="$2"
    shift
    shift
    ;;
    -h|--help)
    usage
    exit 0
    shift
    ;;
    *)
    POSITIONAL+=("$1")
    shift
    ;;
esac
done
set -- "${POSITIONAL[@]}" # restore positional parameters

# Check if we got enough command line arguments
if [ $# -eq 0 ]; then
  usage
  exit -1
fi

# Get path to correct directory on bwda
ldir_target="$(realpath $PWD)"
if [[ $ldir_target == "${ldir_base}"* ]]; then
  dir_target=${ldir_target#"$ldir_base"}
else
  echo "Current directory is not located on LSDF!"
  echo "Is the base directory setting correct?"
  echo "ldir_base: $ldir_base"
  exit -2
fi
rdir_target="${rdir_base}/${dir_target}"

# Construct command
cmd="open sftp://${bwda_acc}@${bwda_url}\n"
cmd+="set cmd:parallel ${nparallel}\n"
cmd+="cd ${rdir_target}\n"
cmd+="lcd ${ldir_target}\n"
for file in $*; do
  cmd+="pget -n ${nchannel} $file\n"
done
cmd+="bye\n" 

# Print or execute commands
if [ "$flag_dryrun" == true ]; then
  printf "$cmd"
else
  tmpfile=$(mktemp)
  printf "$cmd" > $tmpfile
  lftp -f $tmpfile
  rm $tmpfile
fi