#!/bin/bash

function usage() {
    cat << EOF
Usage: $0 [-hcCviIna]
Prune Docker resources.
If no option provided, defaults to -Cvn
Options:
    -h  Show this help and exits
    -c  Remove stopped containers
    -C  Remove all containers
    -v  Remove unused volumes
    -i  Remove unused images
    -I  Remove all images
    -n  Remove unused networks
    -a  All of the above, equivalent of -CvIn
EOF
    exit 0
}

function add_opt() {
    local RESULT

    RESULT="$(unset "1")"
    for o in "$@"; do
        if [ "$((RESULT & o))" == 0 ]; then
            RESULT="$((RESULT + o))"
        fi
    done
    echo "$RESULT"
}

if ! [ -w "/var/run/docker.sock" ] && [ "$EUID" != 0 ]; then
    exec sudo -- "$0" "$@"
fi

c=1
C=2
v=4
i=8
# I=16
n=32
# a="$((c + C + v + I + n))"

CLEAN=0
while getopts hcCviIna o; do
    case "$o" in
        h)
            usage
            ;;
        c)
            CLEAN="$(add_opt "$CLEAN" "$c")"
            ;;
        C)
            CLEAN="$(add_opt "$CLEAN" "$c" "$C")"
            ;;
        v)
            CLEAN="$(add_opt "$CLEAN" "$v")"
            ;;
        i)
            CLEAN="$(add_opt "$CLEAN" "$i")"
            ;;
        I)
            CLEAN="$(add_opt "$CLEAN" "$i")"
            IMG_OPT="-a"
            ;;
        n)
            CLEAN="$(add_opt "$CLEAN" "$n")"
            ;;
        a)
            CLEAN="$(add_opt "$CLEAN" "$c" "$C" "$v" "$i" "$n")"
            IMG_OPT="-a"
            ;;
        *)
            exit 1
            ;;
    esac
done

if [ "$CLEAN" == 0 ]; then
    CLEAN="$((C + v + n))"
fi

VALUES=(
    "$((c + i + v + n))"
    "$((c + i + n))"
    "$c"
    "$v"
    "$i"
    "$n"
)

CON="container"
PRUNE="prune -f"
COMMANDS=(
    "docker system  $PRUNE $IMG_OPT --volumes"
    "docker system  $PRUNE $IMG_OPT"
    "docker $CON    $PRUNE"
    "docker volume  $PRUNE"
    "docker image   $PRUNE $IMG_OPT"
    "docker network $PRUNE"
)

if [ "$((CLEAN & "$C"))" == "$C" ]; then
    docker "$CON" ls -aq | xargs docker "$CON" stop 2> /dev/null
fi

for idx in "${!VALUES[@]}"; do
    mask="${VALUES[$idx]}"

    if [ "$((CLEAN & mask))" == "$mask" ]; then
        bash -c "${COMMANDS[$idx]}"
        CLEAN="$((CLEAN - mask))"
    fi
done