#!/usr/bin/env zsh
if [ -f "${0%/*}/.pacman-init" ];then
    . "${0%/*}/.pacman-init"
else
    echo "Missing init file" && exit 1
fi

# Note: we really need to use an array for this one, so Bourne shells will not
# work.

_printhelp()
{

    cat <<EOF
Usage: ${1##*/} [-a|-h|-q] [-r] PACKAGES

Display package dependencies. Output contains no double and is alphabetically
sorted. It will only work for repos packages by default.

  -a:  Uses Yaourt queries instead of repos database. It slows down query but allow displaying size of any packages not available in repos.
  -h:  Show this help.
  -r:  Call function recursively.
  -q:  Uses installed packages database instead of repos database. It speeds up queries and allows displaying size of local packages not available in repos.
EOF
}

CMD="pacman -Si"
OPT_REC=0
SEP=": "

while getopts ":ahrq" opt; do
    case $opt in
        a)
            CMD="yaourt -Si"
            ;;
        h)
            _printhelp "$0"
            exit 1
            ;;
        r)
            OPT_REC=1
            ;;
        q)
            CMD="pacman -Qi"
            ;;
        ?)
            _printhelp "$0"
            exit 1
            ;;
        :)
            echo "Missing argument."
            _printhelp "$0"
            exit 1
            ;;
    esac
done

shift $(($OPTIND - 1))

if [ $# -eq 0 ]; then
    echo "Missing argument."
    _printhelp "$0"
    exit 1
fi

if [ $OPT_REC -eq 0 ]; then
    eval "${CMD} $@ 2>/dev/null" | awk -F "$SEP" -v filter="$pacman_deps" \
        '$0 ~ filter {gsub(/[>=<][^ ]*/,"",$2) ; gsub(/ +/,"\n",$2) ; print $2}' \
        | sort -u
else
    ## Recursive dependencies.

    ## Store the complete DB into a variable to speed up access.
    FULLDEPLIST=$(eval "${CMD}" | grep "${pacman_name}\|${pacman_deps}" | sed -n "/${pacman_name}/{s/.*: \(.*\)/\1:/;h;n;s/${pacman_deps}.*: //;s/[>=<][^ ]*//g;H;x;s/\n//;p}")

    ## Note: using an array is important for Ksh/Zsh compatibility.
    DEPLIST=()

    ## Check if argument $1 is in DEPLIST.
    _not_in_array()
    {
        if [ ${#DEPLIST} -eq 0 ]; then
            return 0
        else
            for j in ${DEPLIST[*]}; do
                if [ "$j" = "$1" ]; then
                    return 1
                fi
            done
            return 0
        fi
    }

    ## This function calls recursively over the dependencies. It stops whenever
    ## a package has already be handled, or when it has no dependency. Note:
    ## 'grep | cut' is a little faster than 'sed' for simple stuff. Since it is
    ## a loop, it is quite a performance boost.
    _pacman_deps_rec()
    {
        SUBDEPLIST=()
        for i ; do
            SUBDEPLIST=(${SUBDEPLIST[*]} $(echo "$FULLDEPLIST" | grep "^$i\s*:" | cut -d':' -f2))
        done

        for i in ${SUBDEPLIST[*]} ; do
            if [ ! "$i" = "$pacman_deps_none" ] && _not_in_array "$i" ; then
                DEPLIST=(${DEPLIST[*]} "$i")
                _pacman_deps_rec "$i"
            fi
        done
    }

    for i ; do
        _pacman_deps_rec "$@"
    done

    ## There might be duplicates, so we remove them with the '-u' parameter of
    ## sort.
    echo "${DEPLIST[*]}" | sed 's/ /\n/g' | sort -u
fi