#!/bin/bash

set -e

docker_ps_opts=""
dry_run=false
hours="10"
verbose=false

OPTS="`getopt -l docker_ps_opts:,dry_run:,hours:,verbose: -- "$@"`"
while test $# -gt 1; do
    case $1 in
	--docker_ps_opts) docker_ps_opts="$2"; shift ;;
	--dry_run) dry_run="$2"; shift ;;
	--hours) hours="$2"; shift ;;
	--verbose) verbose="$2"; shift ;;
    esac
    shift
done

if $verbose; then
    set -x
fi

if [ "$hours" -lt "0" ]; then
    echo "ERROR: Refusing to delete containers that are $hours hours old"
    exit 1
fi

echo "Container report before:"
docker ps $docker_ps_opts

rm_containers=()
for container in $(docker ps --format "{{.ID}} {{.RunningFor}}" $docker_ps_opts | grep "hour\|day" | cut -d" " -f 1); do
    container_days="$(docker ps --format "{{.ID}} {{.RunningFor}}" $docker_ps_opts | grep "$container [0-9]\+ day" | cut -d" " -f 2)"
    if [ x"$container_days" = x"" ]; then container_days="0"; fi

    container_hours="$(docker ps --format "{{.ID}} {{.RunningFor}}" $docker_ps_opts | grep "$container [0-9]\+ hour" | cut -d" " -f 2)"
    if [ x"$container_hours" = x"" ]; then container_hours="0"; fi

    container_hours=$(($container_days*24 + $container_hours))
    if [ "$container_hours" -gt "$hours" ]; then
        rm_containers=("${rm_containers[@]}" $container)
    fi
done

status="0"
if [ ${#rm_containers[@]} != 0 ]; then
    echo "Removing containers: ${rm_containers[@]}"
    echo "Increasing exit code by 1 to indicate stale containers"
    status="$(($status+1))"
    if ! $dry_run; then
        for container in "${rm_containers[@]}"; do
            echo "Removing container $container"
            docker rm -f -v $container | cat
            echo "docker rm exit status: ${PIPESTATUS[0]}"
        done
    else
        echo "DRY_RUN: NOT REMOVING CONTAINERS"
    fi

    echo "Containers report after:"
    docker ps $docker_ps_opts
fi

if [ x"$(docker volume ls -q -f dangling=true)" != x"" ]; then
    echo "Removing dangling volumes"
    echo "Increasing exit code by 2 to indicate dangling volumes"
    status="$(($status+2))"
    if ! $dry_run; then
	docker volume ls -q -f dangling=true | xargs docker volume rm | cat
	echo "xargs docker volume rm exit status: ${PIPESTATUS[1]}"
    else
        echo "DRY_RUN: NOT REMOVING DANGLING VOLUMES"
    fi
fi

rm_images=()
for image in $(docker images -q -f dangling=true); do
    if ! docker ps -a --format "{{.Image}}" | grep -q $image; then
	rm_images=("${rm_images[@]}" $image)
    fi
done

if [ ${#rm_images[@]} != 0 ]; then
    echo "Removing unused images"
    echo "Increasing exit code by 4 to indicate unused images"
    status="$(($status+4))"
    if ! $dry_run; then
	for image in "${rm_images[@]}"; do
	    docker rmi $image | cat
	    echo "docker rmi exit status: ${PIPESTATUS[0]}"
	done
    else
        echo "DRY_RUN: NOT REMOVING UNTAGGED IMAGES"
    fi
fi

exit $status