dock

#!/bin/bash
set -e -o pipefail

ENV_PASSTHROUGH=(
    TERM
    COLORTERM
    LANG
)

die() {
    [ "$#" -gt 0 ] && echo -e "\033[31m$*\033[0m" >&2
    exit 1
}

docker_cmd=(docker)
[ -w /var/run/docker.sock ] || docker_cmd=(sudo docker)

findimg() {
    local -a imgs
    readarray -t imgs < <("${docker_cmd[@]}" images --format='{{ printf "%s:%s" .Repository .Tag }}')

    declare -a match_prio
    local i
    for i in "${imgs[@]}"; do
        case "$i" in
            "$1") [ -z "${match_prio[1]}" ] && match_prio[1]="$i" ;;     # Exact match
            "$1":*) [ -z "${match_prio[2]}" ] && match_prio[2]="$i" ;;   # Repo match
            */"$1") [ -z "${match_prio[3]}" ] && match_prio[3]="$i" ;;   # Repo (last element) + Tag match
            */"$1":*) [ -z "${match_prio[4]}" ] && match_prio[4]="$i" ;; # Repo (last element) match
        esac
    done

    for i in "${match_prio[@]}"; do
        [ -n "$i" ] && echo "$i" && return 0
    done
}

IMG=archlinux:base-devel
BLACKLIST_DIRS=":/:/boot:/proc:/root:/run:/etc:/usr:/dev:/var:/home:/opt:/srv:/tmp:/mnt:/sys:$(realpath "$HOME"):"

cwd="$(realpath .)"
echo ":$BLACKLIST_DIRS:" | grep -qF ":$cwd:" && die "Refuse to run under protected directory: $cwd"

# Parse and generate additional docker arguments
docker_args=()

while [ "$#" -gt 0 ]; do
    case "$1" in
        --host) docker_args+=(--network host) ;;
        --gpu) docker_args+=(--gpus all) ;;
        --root) docker_args+=(--user root) ;;
        *) break ;;
    esac
    shift
done

[ -n "$1" ] && IMG=$(findimg "$1")
[ -z "$IMG" ] && die "image not found: $1"
shift || true

# Environment variables
for e in "${ENV_PASSTHROUGH[@]}"; do
    [ -z "${!e}" ] || docker_args+=(-e "$e=${!e}")
done

if [ -n "$TZ" ]; then
    docker_args+=(-e TZ="$TZ")
else
    tz=$(readlink -f /etc/localtime | sed -E 's|.*/zoneinfo/(posix/\|right/)?||')
    docker_args+=(-e TZ="${tz:-UTC}")
fi

# Mounts
docker_args+=(-v "$cwd:/cwd")
case "$IMG" in
    *archlinux*)
        [ -f "/etc/pacman.d/mirrorlist" ] && docker_args+=(-v /etc/pacman.d/mirrorlist:/etc/pacman.d/mirrorlist:ro)
        ;;
esac

set -x
exec "${docker_cmd[@]}" run -it --rm --workdir /cwd --tmpfs /tmp:exec --cpu-shares 512 \
    "${docker_args[@]}" \
    --entrypoint /bin/sh "$IMG" \
    -c "[ -x /bin/bash ] && exec /bin/bash || exec /bin/sh"