#!/bin/sh

usage() {
    echo "\
apkv: Quickly add and remove packages to/from Alpine virtual packages.

Usage:
    $0 add <packages> <virtual>
        Add <packages> to virtual package <virtual>. If the virtual package
        does not exist, it will be created.
    $0 del <packages> <virtual>
        Remove <packages> from virtual package <virtual>. Empty virtual
        packages are removed from world. The shorthand '$0 del * <virtual>' can
        be used to empty <virtual>.
    $0 list [packages]
        List all or specific virtual packages and their contents.
    $0 help
        Show this help.

Virtual packages must be prefixed with a dot to be managed with apkv. If one is
not present, it will be added automatically.

Methods can be shortened to their closest unambiguous forms, e.g. a, d, or l.
However, due to implementation specifics, any string starting with those forms
will work; that functionality is unspecified and is not guaranteed.

For example, the following are equivalent:
    $0 add syslinux .virt
    $0 a syslinux virt
    $0 abcdefg syslinux .virt

"
}

prepend_dot() {
    case $1 in
        .*) printf "$1";;
        *)  printf ".$1";;
    esac
}

show_reqs() {
    _pkg="$1"
    shift >/dev/null
    [ -z "$_pkg" ] && return 1
    if [ $# -gt 0 ]; then
        _list=$(echo "$(for x do echo $x; done)" | sort | uniq)
    else
        apk info -e "$_pkg" >/dev/null || return 1
        _list=$(apk info -R "$_pkg" | awk 'NR > 1 && NF' | sort)
    fi
    echo -e "\e[1m$_pkg\e[0m:" $_list
}

method="$1"
shift >/dev/null
case $method in
    l*) for x in ${*:-$(apk info | grep '^\.')}; do
            show_reqs "$(prepend_dot "$x")"
        done
        exit;;
    a*) method=add;;
    d*) method=del;;
    h*) usage; exit;;
    -*) usage; exit;;
    *)  [ -n "$method" ] && echo "Invalid method $method" >&2; usage; exit 1;;
esac

## add/del
# get and validate packages
pkgs=
virt=
for x; do
    if [ -n "$pkgs" ]; then
        pkgs="$pkgs $virt"
    elif [ -n "$virt" ]; then
        pkgs=$virt
    fi
    virt=$x
done
if [ -z "$pkgs" ]; then
    echo 'Not enough arguments' >&2
    usage
    exit 1
fi
virt=$(prepend_dot $virt)
# exit if database locked (99) or no package found to delete from (1)
apk info -e "$virt" >/dev/null
code=$?
if [ $code -eq 99 -o \( $method = del -a $code -ne 0 \) ]; then
    exit $code
fi

# we have validated our args, so let's prepare to run apk: get sudo command if
# it exists and we are not already root
# TODO: support doas
if [ "$(id -u)" != 0 ] && command -v sudo >/dev/null 2>&1; then
    sudo=$(command -v sudo)
fi

# handle quick delete shorthand mentioned in help
if [ $method = del -a '*' = "$pkgs" ]; then
    $sudo apk del "$virt"
    exit $?
fi

currpkgs=$(apk info -R "$virt" | awk 'NR > 1 && NF')
case $method in
    # $(echo) construct is to use word splitting to normalize whitespace
    add) currpkgs="$(echo $currpkgs) $pkgs";;
    del) # XXX: there's probably a more efficient way to do this
         for x in $pkgs; do
             currpkgs=$(echo "$currpkgs" | grep -vFiw $x)
         done;;
esac

if [ -z "$currpkgs" ]; then
    # virtual package is empty
    $sudo apk del "$virt"
else
    show_reqs "$virt" $currpkgs
    $sudo apk add -t "$virt" $currpkgs
fi
# pass along sudo/apk exit code
exit $?

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