function img2folder () (
    #set -x
    FLAG_DRYRUN=1
    FLAG_MOVE=0
    FLAG_SOURCE=
    FLAG_TARGET=

    function _print_help() {
        echo "Sort media files from a source dir and into a target dir"
        echo ""
        echo "Usage: img2folder <options> -s <source-dir> -t <target-dir>"
        echo "    -s <source-dir>  : source folder"
        echo "    -t <source-dir>  : target folder"
        echo "    -d               : no dry run"
        echo "    -m               : move instead of copy"
    }

    function _img_fn_2_exif () {
        file=$1
        file_name=$(basename ${file})
        file_name_prefix=${file_name%.*}

        if [ $FLAG_DRYRUN -eq 1 ]; then
            cmd=(echo)
        else
            cmd=()
        fi
        cmd+=(exiftool -overwrite_original -DateTimeOriginal=${file_name_prefix} ${file})
        echo ${cmd}
        "${cmd[@]}"
    }

    function _exif_to_isoformat () {
        current_exif=$1
        date_only=${current_exif#*Original*: }
        date_wo_colon=${date_only//:/}
        date_wo_ws=${date_wo_colon// /T}
        echo ${date_wo_ws}
    }

    function _is_same_file () {
        file1=$1
        file2=$2
        hash1=$(shasum $file1)
        hash2=$(shasum $file2)
        if [ "${hash1% *}" = "${hash2% *}" ]; then
            echo 1
        else
            echo 2
        fi
    }

    function _gen_target_file_path () {
        date=$1
        target_sort_dir=$2
        extension=$3
        suffix_c=$4
        datedirs=${date:0:4}"/"${date:4:2}
        filename=${date/T/-}
        suffix_f=$(printf "%04d" "$suffix_c")
        target_file_path=$target_path"/"$datedirs"/"$filename"-"$suffix_f"."$extension
        echo $target_file_path
    }

    # process input flags
    while true; do
        case $1 in
            -d)
                FLAG_DRYRUN=0
                shift;
                ;;
            -h)
                _print_help
                exit 0
                ;;
            -m)
                FLAG_MOVE=1
                shift;
                ;;
            -s)
                shift
                FLAG_SOURCE=$1
                shift
                ;;
            -t)
                shift
                FLAG_TARGET=$1
                shift
                ;;
            *)
                break
                ;;
        esac
    done

    # make sure input is correct
    if [ -z $FLAG_SOURCE ]; then
        echo "You need to specify a source directory"
        exit 1
    fi
    if [ -z $FLAG_TARGET ]; then
        echo "You need to specify a target directory"
        exit 1
    fi

    source_path=$(readlink -f ${FLAG_SOURCE})
    target_path=$(readlink -f ${FLAG_TARGET})
    if [ ! -d ${target_path} ]; then
        echo "Target directory ${target_path} does not exist"
        exit 1
    fi

    #set -x
    # main processing
    IFS=$'\n'
    for file in $(find ${source_path} -type f); do
        file_basename=$(basename $file)
        extension=${file_basename##*.}
        current_exif=$(exiftool -m -DateTimeOriginal ${file})
        if [ -z ${current_exif} ]; then
            _img_fn_2_exif ${file}
            exit_value=$?
            if [ $exit_value -ne 0 ]; then
                echo "Could not add Exif information, exit value was $exit_value, skipping"
                continue
            else
                current_exif=$(exiftool -m -DateTimeOriginal ${file})
            fi
        fi
        datetime=$(_exif_to_isoformat ${current_exif})

        # create target file path and make sure we dont generate duplicates
        target_exists=true
        suffix_c=0
        while $target_exists; do
            target_file_path=$(_gen_target_file_path ${datetime} ${target_path} ${extension} ${suffix_c})
            if [ -e $target_file_path ]; then
                if [ $(_is_same_file ${file} ${target_file_path}) -eq 1 ]; then
                    echo "Duplicate found, skipping ${file}."
                    break
                else
                    suffix_c=$((suffix_c+1))
                fi
            else
                target_exists=false
            fi
        done

        # create directory if needed
        target_dir_path=$(dirname ${target_file_path})
        if [ ! -d ${target_dir_path} ]; then
            if [ $FLAG_DRYRUN -eq 1 ]; then
                cmd=(echo)
            else
                cmd=()
            fi
            cmd+=(mkdir -p ${target_dir_path})
            echo ${cmd}
            "${cmd[@]}"
        fi

        # copy or move file
        if [ $FLAG_DRYRUN -eq 1 ]; then
            cmd=(echo)
        else
            cmd=()
        fi
        if [ $FLAG_MOVE -eq 1 ]; then
            cmd+=(mv)
        else
            cmd+=(cp)
        fi
        cmd+=($file $target_file_path)
        echo ${cmd}
        "${cmd[@]}"

    done

    # rm empty folders in source dir
    if [ $FLAG_MOVE -eq 1 ]; then
        for dir in $(find ${source_path} -type d); do
            if [ $FLAG_DRYRUN -eq 1 ]; then
                cmd=(echo)
            else
                cmd=()
            fi
            cmd+=(rmdir -p $dir)
            echo ${cmd}
            "${cmd[@]}"
        done
    fi

)