#!/bin/bash

# Define the usage message
usage() {
  echo "Usage: $0 -u <url> [-w <warning>] [-c <critical>]"
  exit 3
}

# Parse the command-line arguments
while getopts "u:w:c:C:H:R:LhIp" opt; do
  case $opt in
  u)
    URL=$OPTARG
    ;;
  w)
    WARNING_LEVEL=$OPTARG
    ;;
  c)
    CRITICAL_LEVEL=$OPTARG
    ;;
  L)
    FOLLOW_REDIRECTS="-L"
    ;;
  C)
    CONTAINS=$OPTARG
    ;;
  I)
    INSECURE="--insecure"
    ;;
  H)
    HEADERS=$OPTARG
    ;;
  p)
    PRINT_ONLY=true
    ;;
  R)
    RESOLVE="--resolve $OPTARG"
    ;;
  h)
    usage
    ;;
  *)
    usage
    ;;
  esac
done

WARNING_LEVEL=${WARNING_LEVEL:-1}
CRITICAL_LEVEL=${CRITICAL_LEVEL:-2}
#FOLLOW_REDIRECTS=${FOLLOW_REDIRECTS:-""}

if [ -z "$URL" ]; then
  usage
fi

HEADER_ARGS=""
IFS=',' read -ra values <<<"$HEADERS"
for value in "${values[@]}"; do
  HEADER_ARGS+="-H '$value'"
done

CURL_CMD="-s -w '%{http_code}\n%{time_total}' $HEADER_ARGS $FOLLOW_REDIRECTS $INSECURE $RESOLVE $URL"

if $PRINT_ONLY; then
  echo "curl $CURL_CMD"
  exit 3
fi

TMP_ERROR_LOG=$(mktemp)
TMP_RESPONSE=$(mktemp)
RESPONSE=$(curl -v -o "$TMP_RESPONSE" "$CURL_CMD" 2>"$TMP_ERROR_LOG")

# shellcheck disable=SC2181
if [ $? -ne 0 ]; then
  echo "CRITICAL: curl failed!"
  echo "Error log:"
  cat "$TMP_ERROR_LOG"
  exit 2
fi
rm -rf "$TMP_ERROR_LOG"

RESPONSE_CODE=$(echo "$RESPONSE" | head -n 1)
RESPONSE_TIME=$(printf "%.2f" "$(echo "$RESPONSE" | tail -n 1)")

OUTPUT_MSG=""
OUTPUT_CODE=0

if [ $RESPONSE_CODE -eq 200 ] && [ "$(echo "$RESPONSE_TIME < $CRITICAL_LEVEL" | bc -l)" -eq 1 ]; then
  OUTPUT_MSG="OK: website is up and responded in $RESPONSE_TIME seconds."
elif [ $RESPONSE_CODE -eq 200 ] && [ "$(echo "$RESPONSE_TIME < $WARNING_LEVEL" | bc -l)" -eq 1 ]; then
  OUTPUT_MSG="WARNING: response time is slow ($RESPONSE_TIME seconds)."
  OUTPUT_CODE=1
elif [ $RESPONSE_CODE -eq 200 ]; then
  OUTPUT_MSG"CRITICAL: response time is very slow ($RESPONSE_TIME seconds)."
  OUTPUT_CODE=2
else
  OUTPUT_MSG="CRITICAL: website is not responding, returned $RESPONSE_CODE code."
  OUTPUT_CODE=2
fi

if [ ! -z ${CONTAINS+x} ]; then
  if ! grep -q "$CONTAINS" "$TMP_RESPONSE"; then
    OUTPUT_MSG+="\nCRITICAL: response did not contain required string!\nFound: $(cat "$TMP_RESPONSE")"
    OUTPUT_CODE=2
  else
    OUTPUT_MSG+="\nOK: response contained required string."
  fi
fi
rm -rf "$TMP_RESPONSE"

OUTPUT_MSG+=" | response_time=${RESPONSE_TIME}s;$WARNING_LEVEL;$CRITICAL_LEVEL;0"

echo -e "$OUTPUT_MSG"
exit $OUTPUT_CODE