#!/bin/bash
# moves a directory and then links it back
# good for moving directories from one partition to another but without changing any settings

module_load copy
module_load path
module_load confirm

mvlnbk () {

    # Show usage and exit with status
    help () {
        echo 'usage: mvlnbk -h,-r <source_path, full or relative> <destination_parent_dir> <optional, alternate directory name> -- <copy options>'
    }

    if [[ $1 == "-h" ]]; then help; return; fi

    local co; 
    local dr="echo " 
    
    if [[ $1 == "-r" ]]; then 
      co="-r"; unset dr; shift; 
      else
      echo this will be a dry run, use -r to actually run the command
    fi

    if [[ $# -lt 2 ]]; then  help; return 1; fi

    # Check for directories
    if [[ ! -d "$1" ]]; then
    echo source $1 not a valid directory
    help
    return 2
    fi  

    if [[ ! -d "$2" ]]; then
    echo destination $2 not a valid directory
    help; return 3
    fi  

    # Get paths
    local src=$(abs_path "${1%/}")
    local psrc="$(dirname $src)"
    local dest=$(abs_path "${2%/}")
    local dir=$(basename $src)
    local ddir=${3:-$dir}
  
    local use_sudo
    if [[ $(stat -c %u "$psrc") != "$UID" ]]; then
     echo $psrc not owned by current user $USER 
     echo elevating to sudo
     use_sudo="sudo "
     co+=" -s"
    fi 

    if confirm do you want to move $src to $dest/$ddir and link back; then 
        if $dr copy $co -m -i $src $dest/$ddir; then
        echo directory copied successfully
            echo moving source to temporary directory  $src-tmp
            if $dr $use_sudo mv $src $src-tmp; then
                echo success, creating link back now
                if $dr $use_sudo ln -s "$dest/$ddir" "$src"; then
                    if [[ ! $dr ]]; then
                        echo success
                        echo destination $dest/$ddir
                        ls -la $dest/$ddir
                        echo from link at $src
                        ls -la $src
                        ls -Lla $src
                        if confirm -s Was the move and link back succesfull; then
                            echo deleting the temporary directory $src-tmp
                            $dr $use_sudo rm -rf $src-tmp
                        else 
                            echo restoring $src from $src-tmp
                            $dr $use_sudo rm $src 
                            $dr $use_sudo mv $src-tmp  $src
                        fi
                    fi    
                fi  
            else
            echo failed to move source to temporary directory so not creating link back  
            fi     
        else
        echo rsync copy failed, aborting link back 
        fi

    else
        echo aborting move and link back
    fi

}

# # if script was executed then call the function
(return 0 2>/dev/null) || mvlnbk $@