#!/bin/sh -e
# Display packages which depend on package

parser_definition() {
    setup REST help:usage -- "usage: ${0##*/} [options...] [pkg...]"
    flag tree -t --tree   -- "Also print indirect reverse dependencies"
    flag make -m --make   -- "Include make dependencies"
    global_options
}

. cpt-lib; set +f

[ "$1" ] || set -- "${PWD##*/}"

# 'cd' to the database directory as a simple way of
# stripping the path and performing a 'basename'.
cd "$sys_db"

get_revdep() {
    query="^$1\$"
    [ "$make" ] && query="$query\\|^$1 *make\$"
    grep "$query" -- */depends | while read -r pkg _; do
        printf '%s\n' "${pkg%%/*}"
    done
}

if [ "$tree" ]; then
    create_cache nobuild
    :> "$tmp_dir/processed"
    get_revdep "$1" > "$tmp_dir/dep"
    while ! diff -q "$tmp_dir/dep" "$tmp_dir/processed" >/dev/null 2>&1; do
        cp "$tmp_dir/dep" "$tmp_dir/dep.new"
        while read -r line; do
            grep -q "^$line\$" "$tmp_dir/processed" && continue
            get_revdep "$line" >> "$tmp_dir/dep.new"
            printf '%s\n' "$line" >> "$tmp_dir/processed"
        done < "$tmp_dir/dep"
        sort -u -o "$tmp_dir/dep" "$tmp_dir/dep.new"
        sort -u -o "$tmp_dir/processed" "$tmp_dir/processed"
    done
    cat "$tmp_dir/dep"
else
    get_revdep "$1"
fi