destroy() {
    test -n "$1" || return 1
    test -e "$1" || return 1

    echo -n "Sure want to destroy file '$1' with size $(du -hs "$1" | awk '{printf $1}') [y/N] "
    read -r response
    [[ $response == [yY] ]] && shred -zun 25 "$1"
}

lsl () {

    local DIR
    DIR="$1"
    
    if [ -z "$1" ]; then
        DIR="$(pwd)"
    fi

    ls -lhFA --color=always "${DIR}" | tail -n +2 | less -R
}

workon() {
    local ENV_NAME
    ENV_NAME="$1"

    if [ -z "$1" ]; then
        ENV_NAME=$(basename "$(pwd)")
    fi

    source /opt/pythonenv/"$ENV_NAME"/bin/activate
}


cl() {
    local DIR
    DIR="$*"

    if [ $# -lt 1 ]; then
        DIR="$HOME"
    fi

    cd "${DIR}" && ls -F --color=auto
}


va() {
    local activate_venv

    if [ -f "./venv/bin/activate" ]; then
        source "./venv/bin/activate"
        return 0
    fi

    activate_venv="$(find -P . -maxdepth 3 -type f -wholename '*/bin/activate' | sort | head -n 1)"

    if [ -n "$activate_venv" ]; then
        source "$activate_venv"
        return 0
    else
        echo "va: error: virtual environment not found, use python3 -m virtualenv venv" >&2
        return 1
    fi
}


extract () {
    if [ -z "$1" ]; then  # if string non-zero
        # display usage if no parameters given
        echo "extract: error: usage: extract <path/file_name>.<zip|rar|bz2|gz|tar|tbz2|tgz|Z|7z|xz|ex|tar.bz2|tar.gz|tar.xz>"
        return 2
    fi

    if ! [ -f "$1" ]; then   # if file not exist
        echo "extract: error: '$1' file does not exist" >&2
        return 1
    fi

    local NAME
    NAME=${1%%.*}  # removes extension from filename


    if [ -e "$NAME" ]; then
        echo "extract: error: '$NAME' exists" >&2
        return 1
    fi

    mkdir "$NAME" && cd "$NAME" || return 1

    case $1 in
        *.tar.bz2)  tar xjf      ../"$1" ;;
        *.tar.gz)   tar xzf      ../"$1" ;;
        *.tar.xz)   tar xJf      ../"$1" ;;
        *.lzma)     unlzma       ../"$1" ;;
        *.bz2)      bunzip2      ../"$1" ;;
        *.rar)      unrar x -ad  ../"$1" ;;
        *.gz)       gunzip       ../"$1" ;;
        *.tar)      tar xf       ../"$1" ;;
        *.tbz2)     tar xjf      ../"$1" ;;
        *.tgz)      tar xzf      ../"$1" ;;
        *.zip)      unzip        ../"$1" ;;
        *.Z)        uncompress   ../"$1" ;;
        *.7z)       7z x         ../"$1" ;;
        *.xz)       unxz         ../"$1" ;;
        *.exe)      cabextract   ../"$1" ;;
        *)          echo "extract: error: '$1' - unknown archive method" >&2 ;;
    esac
    cd ..
}


mcd () {
    mkdir -p "$1" && cd "$1" || return
}


# Syntax-highlight JSON strings or files
# Usage: `json '{"foo":42}'` or `echo '{"foo":42}' | json`
json() {
	if [ -t 0 ]; then # argument
		python -m json.tool <<< "$*" | pygmentize -l javascript
	else # pipe
		python -m json.tool | pygmentize -l javascript
	fi
}


# docker

# execute bash shell in running container
docker_ex() {
    docker exec -it $1 ${2:-bash}
}

# ips of docker containers
docker_ips() {
    local DOC IP OUT NAME PORT
    for DOC in $(docker ps -q | tr '\n' ' ')
    do
        IP="$(docker inspect --format='{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' "$DOC" 2>/dev/null)"
        PORT="$(docker inspect --format='{{range $p, $conf := .NetworkSettings.Ports}}{{(index $conf 0).HostPort}}{{end}}' "$DOC" 2>/dev/null)"
        NAME="$(docker inspect --format='{{.Name}}' "$DOC" 2>/dev/null)"
        OUT+="${NAME#"/"}"'\t'"$IP":"$PORT"'\n'
    done
    echo -e $OUT 2>/dev/null | column -t
}


py() {
    test -z "$@" && ipython -i -c "q = exit" || python3 $@
}

# toggle wireguard vpn with interface /etc/wireguard/wg0.conf
vpn() {
    local STATUS SERVICE CONFIG CONFIGFILE
    CONFIG="$1"

    test -z "$CONFIG" && CONFIG="wg0"

    CONFIGFILE="/etc/wireguard/$CONFIG.conf"

    test -e "$CONFIGFILE" || (echo "Config '$CONFIGFILE' not exists" >&2; return 1) && (

    SERVICE="wg-quick@$CONFIG.service"

    systemctl --quiet is-active "$SERVICE" && sudo systemctl stop "$SERVICE" || sudo systemctl start "$SERVICE"
    )
}

open() {
    test -e $1 || return 1
    nohup xdg-open $1 1>/dev/null 2>&1 &
}