#!/usr/bin/env bash

WARNING_THRESHOLD=10
CRITICAL_THRESHOLD=20

# Parse command line arguments
while getopts "w:c:" opt; do
  case $opt in
    w)
      WARNING_THRESHOLD="$OPTARG"
      ;;
    c)
      CRITICAL_THRESHOLD="$OPTARG"
      ;;
    \?)
      echo "Usage: check_iowait.sh [-w warning_threshold] [-c critical_threshold]"
      exit 1
      ;;
  esac
done

if ! command -v iostat &>/dev/null; then
  echo "UNKNOWN - iostat not found! Please install sysstat"
  exit -1
fi

if ! command -v iotop &>/dev/null; then
  echo "UNKNWON - iotop not found! Please install iotop"
  exit -1
fi

# Get iowait value
iowait=$(iostat -c | awk 'NR==4 {print $4}')

# Get process list header and top 3 processes causing iowait
header=$(iotop -b -n 1 -P -k -o | head -n 1)
top_processes=$(iotop -b -n 1 -P -k -o | tail -n +4 | head -n 3)

# Check if there are no processes causing iowait
if [ -z "$top_processes" ]; then
    top_processes="No processes causing significant iowait."
else
    top_processes="$header"$'\n'"$top_processes"
fi

iowait_str="- iowait: $iowait%"$'\n'"Top 3 processes causing iowait:"
perfdata="iowait=$iowait%;$WARNING_THRESHOLD;$CRITICAL_THRESHOLD;0;100"

# Check if iowait is above thresholds
if (( $(echo "$iowait > $CRITICAL_THRESHOLD" | bc -l) )); then
    echo "CRITICAL $iowait_str"
    echo "$top_processes | $perfdata"
    exit 2
elif (( $(echo "$iowait > $WARNING_THRESHOLD" | bc -l) )); then
    echo "WARNING $iowait_str"
    echo "$top_processes | $perfdata"
    exit 1
else
    echo -e "OK $iowait_str"
    echo "$top_processes | $perfdata"
    exit 0
fi