#!/bin/sh

set -e

find_root() {
   local topd
   if [ -z "${CLOUD_INIT_TOP_D}" ]; then
      topd=$(cd "$(dirname "${0}")" && cd .. && pwd)
   else
      topd=$(cd "${CLOUD_INIT_TOP_D}" && pwd)
   fi
   [ $? -eq 0 -a -f "${topd}/setup.py" ] || return
   ROOT_DIR="$topd"
}
fail() { echo "$0:" "$@" 1>&2; exit 1; }

if ! find_root; then
    fail "Unable to locate 'setup.py' file that should " \
         "exist in the cloud-init root directory."
fi

REQUIRES="$ROOT_DIR/Requires"

if [ ! -e "$REQUIRES" ]; then
    fail "Unable to find 'Requires' file located at '$REQUIRES'"
fi

# Filter out comments and empty lines
DEPS=$(sed -n -e 's,#.*,,' -e '/./p' "$REQUIRES") ||
   fail "failed to read deps from '${REQUIRES}'"
echo "$DEPS" | sort -d -f