#!/bin/bash

: << =cut

=head1 NAME

Power-Monitor using Shelly 3EM devices.

=head1 CONFIGURATION

Requires 'curl' and 'jq'.

=head1 AUTHOR

Kai Boenke

=head1 LICENSE

Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)

=back

=cut


#####
# Check prerequisites
###
if ! command -v "curl" > /dev/null 2>&1; then
  echo "curl is not installed or not in PATH." >&2
  exit -1
fi
if ! command -v "jq" > /dev/null 2>&1; then
  echo "jq is not installed or not in PATH." >&2
  exit -1
fi

#####
# Configuration
###
PLUGIN_NAME=${0##*/}
HOST_NAME=$(echo "$PLUGIN_NAME" | cut -d'_' -f2)

BASE_URL="http://${HOST_NAME}/emeter"
declare -A ENDPOINTS=(
  ["sensor_a"]="0/3em_data"
  ["sensor_b"]="1/3em_data"
  ["sensor_c"]="2/3em_data"
)
declare -A LABELS=(
  ["sensor_a"]="Phase A"
  ["sensor_b"]="Phase B"
  ["sensor_c"]="Phase C"
)

#####
# Handle Munin-Config
##
case $1 in
  config)
    # Power Consumption
    echo "multigraph shelly_power"
    echo "graph_title Power Consumption"
    echo "graph_vlabel watt [w]"
    echo "graph_category sensors"
    echo "graph_info Current power consumption for each phase."
    for sensor in "${!LABELS[@]}"; do
      echo "${sensor}_w.label ${LABELS[$sensor]}"
      echo "${sensor}_w.warning 800"
      echo "${sensor}_w.critical 1000"
    done
    # Voltages
    echo "multigraph shelly_voltage"
    echo "graph_title Voltages"
    echo "graph_vlabel volt [V]"
    echo "graph_category sensors"
    echo "graph_info Current voltages for each phase."
    for sensor in "${!LABELS[@]}"; do
      echo "${sensor}_v.label ${LABELS[$sensor]}"
      echo "${sensor}_v.warning 220:240"
      echo "${sensor}_v.critical 210:250"
    done
    # Power Factor
    echo "multigraph shelly_pf"
    echo "graph_title Power Factor"
    echo "graph_vlabel I/V"
    echo "graph_category sensors"
    echo "graph_info Current power factor for each phase."
    for sensor in "${!LABELS[@]}"; do
      echo "${sensor}_pf.label ${LABELS[$sensor]}"
    done
    exit 0;;
esac

#####
# Measurements
###

echo "multigraph shelly_power"
for sensor in "${!ENDPOINTS[@]}"; do
  url="${BASE_URL}/${ENDPOINTS[$sensor]}"
  response=$(curl -s "$url")
  if [ $? -eq 0 ]; then
    power=$(echo "$response" | jq -r '.power')
    echo "${sensor}_w.value ${power}"
  else
    echo "${sensor}_w.value U"
  fi
done

echo "multigraph shelly_voltage"
for sensor in "${!ENDPOINTS[@]}"; do
  url="${BASE_URL}/${ENDPOINTS[$sensor]}"
  response=$(curl -s "$url")
  if [ $? -eq 0 ]; then
    power=$(echo "$response" | jq -r '.voltage')
    echo "${sensor}_v.value ${power}"
  else
    echo "${sensor}_v.value U"
  fi
done

echo "multigraph shelly_pf"
for sensor in "${!ENDPOINTS[@]}"; do
  url="${BASE_URL}/${ENDPOINTS[$sensor]}"
  response=$(curl -s "$url")
  if [ $? -eq 0 ]; then
    power=$(echo "$response" | jq -r '.pf')
    echo "${sensor}_pf.value ${power}"
  else
    echo "${sensor}_pf.value U"
  fi
done