#!/bin/sh -e
#
# helper for update-motd

NO_ESM_MESSAGES=""

# poor mans force
if [ "$1" = "--force" ]; then
    NEED_UPDATE_CHECK=yes
else
    NEED_UPDATE_CHECK=no
fi

# check time when we did the last update check
stamp="/var/lib/update-notifier/updates-available"

# get list dir
StateDir="/var/lib/apt/"
ListDir="lists/"
eval "$(apt-config shell StateDir Dir::State)"
eval "$(apt-config shell ListDir Dir::State::Lists)"

# get dpkg status file
DpkgStatus="/var/lib/dpkg/status"
eval "$(apt-config shell DpkgStatus Dir::State::status)"

# get sources.list file
EtcDir="etc/apt/"
SourceList="sources.list"
eval "$(apt-config shell EtcDir Dir::Etc)"
eval "$(apt-config shell SourceList Dir::Etc::sourcelist)"

# let the actual update be asynchronous to avoid stalling apt-get
cleanup() { rm -f "$tmpfile"; }

# check if we have a list file or sources.list that needs checking
if [ -e "$stamp" ]; then
    if [ "$(find "/$StateDir/$ListDir" "/$EtcDir/$SourceList" "/$DpkgStatus" -type f -newer "$stamp" -print -quit)" ]; then
        NEED_UPDATE_CHECK=yes
    fi
else
    if [ "$(find "/$StateDir/$ListDir" "/$EtcDir/$SourceList" -type f -print -quit)" ]; then
        NEED_UPDATE_CHECK=yes
    fi
fi

tmpfile=""
trap cleanup EXIT
tmpfile=$(mktemp -p $(dirname "$stamp"))

# should we hide esm-related information in the output
no_esm_file="/var/lib/update-notifier/hide-esm-in-motd"
if [ -e "$no_esm_file" ]; then
    NO_ESM_MESSAGES="--no-esm-messages"
fi

# output something for update-motd
if [ "$NEED_UPDATE_CHECK" = "yes" ]; then
    {

        echo ""
        /usr/lib/update-notifier/apt-check --human-readable "$NO_ESM_MESSAGES"
        echo ""
    } > "$tmpfile"
    mv "$tmpfile" "$stamp"
    chmod +r "$stamp"
fi