#!/bin/bash

# v1.0:
# - Initial release of the script
# v1.1 CHANGES:
# - Updated query for installed version to versionstring instead of version
# v1.2 CHANGES:
# - Updated nextcloud release check to actually get latest version from the release-url
# v1.3 CHANGES:
# - Added check for configured apache-user and basepath exist.
# v1.4 CHANGES:
# - added extra logic to deal with unresponsive or empty response from release-url
# v1.5 CHANGES:
# - added enhancement suggestion made by briand on checkmk forum to make the version-compare more granular
# v1.6 CHANGES:
# - Restructured and refined variables, also added additional comments per line of code
# v1.7 CHANGES:
# - Updated logic to also deal with higher installed version compared to release-url


# Current active version of the script
SCRIPT_VERSION=1.7

# Installation:
# This file should be place on a/the nextcloud host in /usr/lib/check_mk_agent/local
#
# (optional) if you want the check to run on a different schedule (like once per hour) put it in a subdirectory of above path
# named to the number of seconds of the interval wanted, so 3600/ for once an hour, 86400 for once per day.
#
# Also do not forget to make this file executable with chmod +x /usr/lib/check_mk_agent/local/nextcloud-updates.sh

# (c) Michael Honkoop <mhonkoop@comsolve.nl>

# License: GNU General Public License v2

######################
# Configurable Parameters
######################

# url to check releases against
RELEASEURL="https://download.nextcloud.com/server/releases/"

#basepath of Nextcloud's occ executable
BASEPATH="/var/www/nextcloud"

# set the correct user for running the commands (either apache or www-data, this depends on your Linux-Distribution)
APACHEUSER="www-data"

# Service name
SERVICE="NextCloud"

# Set how exact the version-comparison should be - enhancement suggested by briand at checkmk forum
#
# how many “.”-separated fields to compare:
#  3 → XX.YY.ZZ  (full)
#  2 → XX.YY     (major+minor)
#  1 → XX        (major only)
VERSION_FIELDS=2

######################
# The code below should not be changed, unless you know EXACTLY what you are doing.
# All configureable parameters are above this section.
######################

for COMMAND in sudo php jq curl; do
    if ! command -v "$COMMAND" >/dev/null 2>&1; then
        echo "2 \"$SERVICE\" - $SERVICE localcheck requires $COMMAND command to be installed"
        echo "2 \"$SERVICE Apps\" - $SERVICE localcheck requires $COMMAND command to be installed"
        exit 0
    fi
done

# check if configured apache user exists
if ! id -u "$APACHEUSER" >/dev/null 2>&1; then
    echo "2 \"$SERVICE\" - $SERVICE localcheck webserver user does not exist, check configuration!"
    echo "2 \"$SERVICE Apps\" - $SERVICE Apps localcheck webserver user does not exist, check configuration!"
    exit 0
fi

# check if configured basepath exists
if [ ! -d "$BASEPATH" ]; then
    echo "2 \"$SERVICE\" - $SERVICE localcheck could not find configured basepath, check configuration!"
    echo "2 \"$SERVICE Apps\" - $SERVICE Apps localcheck could not find configured basepath, check configuration!"
    exit 0
fi

# Get current installed Nextcloud version-information
# in v29.x.x version gives more detail, which is not given by the check on installed version, so switched to versionstring instead.

NCINSTALLED=$(sudo -u "$APACHEUSER" php "$BASEPATH"/occ status --output=json | jq -r '.versionstring // empty' | cut -d. -f1-"$VERSION_FIELDS")

# Get latest avaialble (core) version information from release-url
# In v29.x.x this has changed outputs <name-of-instance> <version>,
NCRELEASEDATA=$(curl -fsS --connect-timeout 5 --max-time 10 "$RELEASEURL" 2>/dev/null)
CURL_RC=$?

# If curl failed, report UNKNOWN
if [ "$CURL_RC" -ne 0 ]; then
    echo "3 \"$SERVICE\" - Unable to retrieve data from release-URL for $SERVICE Core (curl exit code $CURL_RC)"
    echo "3 \"$SERVICE Apps\" - No data received from release-URL, cannot determine latest release-version for $SERVICE Apps"
    exit 0
fi

# If the release URL returned an empty response, report UNKNOWN
if [ -z "$NCRELEASEDATA" ]; then
    echo "3 \"$SERVICE\" - No data received from release-URL, cannot determine latest release-version for $SERVICE Core"
    echo "3 \"$SERVICE Apps\" - No data received from release-URL, cannot determine latest release-version for $SERVICE Apps"
    exit 0
fi

# Extract all available Nextcloud release versions from the release data,
# sort them as versions and select the highest version.
NCAVAILABLE=$(printf '%s\n' "$NCRELEASEDATA" | grep -oE 'nextcloud-[0-9]+\.[0-9]+\.[0-9]+\.zip' | sed -E 's/^nextcloud-([0-9]+\.[0-9]+\.[0-9]+)\.zip$/\1/' | sort -V | tail -n1)

# Apply configured version-comparison granularity to the available version
NCAVAILABLE=$(printf '%s\n' "$NCAVAILABLE" | cut -d. -f1-"$VERSION_FIELDS")

# Compare installed and available versions.
if [ "$NCINSTALLED" = "$NCAVAILABLE" ]; then
    # Versions match, so check the actual Nextcloud core status.
    sudo -u "$APACHEUSER" php "$BASEPATH"/occ status -e >/dev/null 2>&1
    STATUS_RC=$?

    if [ "$STATUS_RC" -eq 0 ]; then
        echo "0 \"$SERVICE\" - $SERVICE Core is latest version ($NCAVAILABLE)"
    elif [ "$STATUS_RC" -eq 1 ]; then
        echo "1 \"$SERVICE\" - $SERVICE maintenance-mode is enabled"
    elif [ "$STATUS_RC" -eq 2 ]; then
        echo "2 \"$SERVICE\" - $SERVICE Core needs updating"
    else
        echo "3 \"$SERVICE\" - Unable to determine $SERVICE Core status (occ status exit code $STATUS_RC)"
    fi
# Installed version is lower than available version
elif [ "$(printf '%s\n%s\n' "$NCINSTALLED" "$NCAVAILABLE" | sort -V | head -n1)" = "$NCINSTALLED" ]; then
    echo "1 \"$SERVICE\" - A new $SERVICE Core version ($NCAVAILABLE) is available, running Core version is: $NCINSTALLED, please upgrade"
# Installed version is higher than available version (happens when a release is retracted)
else
    echo "2 \"$SERVICE\" - $SERVICE Core version ($NCAVAILABLE) is lower than the running Core version $NCINSTALLED, please investigate."
fi

APPRESULT=$(sudo -u "$APACHEUSER" php "$BASEPATH"/occ app:update --showonly)
APP_RC=$?

# If occ failed, report UNKNOWN
if [ "$APP_RC" -ne 0 ]; then
    echo "3 \"$SERVICE Apps\" - Unable to determine available app updates (occ app:update exit code $APP_RC)"
    exit 0
fi

# Check if all apps are up to date
if [[ "$APPRESULT" == *"All apps are up-to-date"* ]]; then
    echo "0 \"$SERVICE Apps\" - $SERVICE Apps all up to date"
    exit 0
else
    UPDATECOUNT=$(printf '%s\n' "$APPRESULT" | wc -l)
    echo "1 \"$SERVICE Apps\" - $UPDATECOUNT $SERVICE Apps require updates"
    exit 0
fi