#!/bin/bash

usage() {
cat << EOL
 Usage :

   $0 --crendentials CREDENTIALS --nodeid NODE_ID

   -c|--crendentials CREDENTIALS     # <user>:<password>
   -n|--nodeid       NODE_ID         # the <node_id> to check
EOL
}


return=0
nb_shards=0
nb_shards_max=0
nb_shards_avail=0
nb_shards_warn=0
nb_shards_crit=0
output=""

# If no argument then show usage
if [ "$#" -eq 0 ]; then
    usage
    exit 2
fi

while :; do
    case $1 in
        -h|-\?|--help)   # Call a "usage" function to display a synopsis, then exit.
            usage
            exit
            ;;
        -c|--crendentials)       # Takes an option argument, ensuring it has been specified.
            if [ -n "$2" ]; then
                CREDENTIALS="$2"
                shift
            else
                printf 'ERROR: "--crendentials" requires a non-empty option argument.\n' >&2
                exit 2
            fi
            ;;
        -n|--nodeid)       # Takes an option argument, ensuring it has been specified.
            if [ -n "$2" ]; then
                NODE_ID="$2"
                shift
            else
                printf 'ERROR: "--nodeid" requires a non-empty option argument.\n' >&2
                exit 2
            fi
            ;;
        -?*)
            printf 'WARNING: Unknown option (ignored): %s\n' "$1" >&2
            ;;
        *)               # Default case: If no more options then break out of the loop.
            break
    esac
    shift
done

if [ ! -e "/usr/bin/jq" ]; then
    printf "UNKNWON - jq is not installed"
    exit 3
fi

nb_shards=$(curl -s -k -u ${CREDENTIALS} https://127.0.0.1:9200/_cat/allocation/${NODE_ID}?h=shards)
nb_shards_max=$(curl -s -k -u ${CREDENTIALS} https://127.0.0.1:9200/_cluster/settings?flat_settings | jq -r ".persistent[]" )

nb_shards_avail=$(( $nb_shards_max - $nb_shards ))

if [ "$nb_shards_max" -ge "1000" ]; then
    nb_shards_warn=$(( $nb_shards_max / 100 ))
elif [ $nb_shards_max -ge 100 ]; then
    nb_shards_warn=$(( $nb_shards_max / 10 ))
else
    nb_shards_warn=10
fi

nb_shards_crit=$(( $nb_shards_warn / 4 ))

# debug…
# printf '%d out of %d, avail: %d, warn: %d, crit: %d' $nb_shards $nb_shards_max $nb_shards_avail $nb_shards_warn $nb_shards_crit

if [ "${nb_shards_avail}" -le "${nb_shards_crit}" ]; then
    printf "CRITICAL - %d USED / %d MAX" "${nb_shards}" "${nb_shards_max}"
    exit 2
elif [ "${nb_shards_avail}" -le "${nb_shards_warn}" ]; then
    printf "WARNING - %d USED / %d MAX" "${nb_shards}" "${nb_shards_max}"
    exit 1
elif [ "${nb_shards_avail}" -ge "${nb_shards_warn}" ]; then
    printf "OK - %d USED / %d MAX" "${nb_shards}" "${nb_shards_max}"
    exit 0
else
    printf "UNKNWON - %d USED / %d MAX" "${nb_shards}" "${nb_shards_max}"
    exit 3
fi