#!/bin/bash
# -*- sh -*-

: << =cut

=head1 NAME

  switchbotmeter - Munin plugin to monitor temperature and humidity with SwitchBot Meter

=head1 CONFIGURATION

  Obtain a token and deviceid for SwitchBot API. See the following website.
  https://github.com/OpenWonderLabs/SwitchBotAPI

=head1 ENVIRONMENT VARIABLES

  env.token    : Token to access SwitchBot API. (Required)
  env.deviceid : Device ID of SwitchBot Meter. (Required)
  env.interval : Interval in seconds for API access. (Optional, default is 0)
  env.tempunit : Temperature unit. (Optional, default is C)

=head1 NOTES

  The amount of SwitchBot API calls per day is limited to 1000 times.
  If munin-node executes this plugin every 5 minutes, the API will be called 288 times a day.
  You can use env.interval parameter to prevent frequent API access. For example, if you set
  env.interval 900, the API response will be cached to local file for 900 seconds(15 minutes).

=head1 AUTHOR

  K.Cima https://github.com/shakemid

=head1 LICENSE

  GPLv2
  SPDX-License-Identifier: GPL-2.0-only

=head1 Magic markers

  #%# family=contrib
  #%# capabilities=

=cut

. "${MUNIN_LIBDIR}/plugins/plugin.sh"

set -o nounset
set -o pipefail

# Token to access SwitchBot API
token=${token:?}

# Device ID of SwitchBot Meter
deviceid=${deviceid:?}

# Interval for API access (second)
interval=${interval:-0}

# Temperature unit
tempunit=${tempunit:-C}

config() {
    cat <<EOF
graph_title SwitchBot Meter ${deviceid}
graph_category sensors
graph_scale no
graph_vlabel Temp ${tempunit} / Humid %
graph_args --base 1000
temperature.label temperature
humidity.label humidity
EOF
}

fetch() {
    if [ "${interval}" -ne 0 ]; then
        time_now=$( date +%s )

        if [ -f "${MUNIN_STATEFILE}" ]; then
            time_modified=$( stat --format=%Y "${MUNIN_STATEFILE}" )
        else
            time_modified=0
        fi

        if [ $(( time_now - time_modified )) -le "${interval}" ]; then
            declare $( cat "${MUNIN_STATEFILE}" )
        else
            fetch_api
            echo "temperature=${temperature} humidity=${humidity}" > "${MUNIN_STATEFILE}"
        fi
    else
        fetch_api
    fi

    echo temperature.value "${temperature}"
    echo humidity.value "${humidity}"
}

fetch_api() {
    response=$( curl -s -H "Authorization:${token}" "https://api.switch-bot.com/v1.0/devices/${deviceid}/status" )

    statusCode=$( echo "${response}" | jq '.statusCode' )
    if [ "${statusCode}" -ne 100 ]; then
        echo Error with statusCode = "${statusCode}" 1>&2
        exit 1
    fi

    temperature=$( echo "${response}" | jq '.body.temperature' )
    humidity=$( echo "${response}" | jq '.body.humidity' )
}

# Main
case ${1:-} in
config)
    config
    if [ "${MUNIN_CAP_DIRTYCONFIG:-}" = "1" ]; then
        fetch
    fi
    ;;
*)
    fetch
    ;;
esac

exit 0