#!/bin/bash
if [ -z "$4" ]; then
    printf "Usage: %s package distro arch mail\n" `basename $0`;
    exit 1
fi

PKG="$1"
DISTRO="$2"
ARCH="$3"
MAIL="$4"

if [ ! -f "${HOME}/.${PKG}-version" ]; then
    touch "${HOME}/.${PKG}-version"
fi

wget -O - -q "http://packages.debian.org/${DISTRO}/${ARCH}/${PKG}/download" \
  | grep -o "${PKG}_[^_]\+_${ARCH}.deb" \
  | uniq \
  | head -n 1 \
  | sed -e 's/[^_]*_//' -e 's/_.*//' \
  > ${HOME}/.${PKG}-version.new

diff -q ${HOME}/.${PKG}-version.new ${HOME}/.${PKG}-version > /dev/null \
  || diff -u ${HOME}/.${PKG}-version ${HOME}/.${PKG}-version.new \
     | mail -s "New ${PKG} in ${DISTRO}/${ARCH}" "${MAIL}"

mv -f ${HOME}/.${PKG}-version.new ${HOME}/.${PKG}-version