#!/bin/sh
# TODO: add duplicate checker to seeif a pkg is in multiple virtual pkgs

prog=$(basename $0)
usage() {
    echo "\
apkv: Quickly add and remove packages to/from Alpine virtual packages.

Usage:
    $prog add <packages> <virtual>
        Add <packages> to virtual package <virtual>. If the virtual package
        does not exist, it will be created.

    $prog del <packages> <virtual>
        Remove <packages> from virtual package <virtual>. Empty virtual
        packages are removed from world. The shorthand '$prog del * <virtual>' can
        be used to empty <virtual>.

    $prog list [-o | packages]
        List virtual packages and their contents.
            packages  List these virtual packages. If empty, list all.
            -o        Only list orphan packages that are not owned by any
                      virtual package. Orphans are automatically shown when
                      listing all packages.

    $prog help
        Show this help.

Virtual packages must be prefixed with a dot to be managed with apkv. Virtual
package names passed as arguments will automatically be prefixed with dots if
they are not present.

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, with the first being preferred:
    $prog add syslinux .virt
    $prog a syslinux virt
    $prog 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 [ $# -gt 0 ]; then
        # override reqs list for apkv add
        _list=$(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 $method in
    l*) method=list;;
    a*) method=add;;
    d*) method=del;;
    h*) usage; exit;;
    -*) usage; exit;;
    *)  [ -n "$method" ] && echo "Invalid method $method" >&2; usage; exit 1;;
esac

if [ "$method" = list ]; then
    if [ $# -eq 0 -o "$1" = '-o' ]; then
        if [ "$1" = '-o' -a $# -gt 1 ]; then
            echo "$method with -o switch does not accept arguments" >&2
            usage
            exit 1
        fi
        # ignore getopt's --, we don't care if an arg begins with - anyway
        [ "$1" = '--' ] && switch >/dev/null

        # OPTIMIZE: getting deps of virtual packages is slow, it would be
        #           great to use apk info -R from show_reqs in orphan loop
        all=$(apk info)
        # show packages if no args
        if [ $# -eq 0 ]; then
            for x in $(echo "$all" | grep '^\.'); do
                show_reqs "$(prepend_dot "$x")"
            done
        fi
        # set all child packages of virtual packages as owned
        for v in $(echo "$all" | grep '^\.'); do
            for c in $(apk info -R $v | tail +2 | grep -v '^\.'); do
                # NOTE: use tr because shell may not have ksh-derived ${c//}
                # XXX: package name may have illegal chars for variable name
                #      past those already replaced, and replacing chars may
                #      result in variable collision—but official apk repos do
                #      not have any packages that would cause issues
                eval "__$(echo $c | tr -s '.:-' _)=1"
            done
        done
        # check world against owned packages
        # TODO: notify user if package is in world and also a virtual package
        orphans=$(
            for x in $(cat /etc/apk/world | grep -v '^\.'); do
                eval "[ \${__$(
                         echo $x | tr -s '.:-' _ | tr -s '<>=' "\n" | head -1
                     )-0} -eq 0 ]" && echo $x
            done
        )
        if [ -z "$orphans" ]; then
            echo "No orphan packages found."
        else
            show_reqs orphans $orphans
        fi
    else
        for x in $*; do
            show_reqs "$(prepend_dot "$x")"
        done
    fi
    exit
fi

## 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
    # NOTE: $(echo) construct uses word splitting to remove newlines
    add) currpkgs="$(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"
    code=$?
else
    show_reqs "$virt" $currpkgs
    $sudo apk add -t "$virt" $currpkgs
    code=$?
    if [ $method = add -a $code -eq 0 ]; then
        # remove packages from world if they are being moved to a virtual one
        del=
        for x in $pkgs; do
            if apk info -e "$x" >/dev/null 2>&1; then
                del="$del $x"
            fi
        done
        if [ -n "$del" ]; then
            echo "Removing packages from world:$del"
            $sudo apk del $del
        fi
    fi
fi
# pass along sudo/apk exit code
exit $code

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