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

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# shellcheck disable=SC1091
source "${SCRIPT_DIR}/common.sh"

STEP="fault-inject"
B_SIDE_SERVICE="blitz-b-side-omnid.service"
ROS_SERVICE="blitz-ros-receiver.service"

main_pid_for_service() {
  local service_name="$1"
  systemctl show --property MainPID --value "${service_name}"
}

wait_for_service_pid_change() {
  local service_name="$1"
  local previous_pid="$2"
  local timeout_sec="${3:-10}"
  local waited=0
  local current_pid=""

  while (( waited < timeout_sec )); do
    current_pid="$(main_pid_for_service "${service_name}")"
    if [[ -n "${current_pid}" && "${current_pid}" != "0" && "${current_pid}" != "${previous_pid}" ]]; then
      printf '%s\n' "${current_pid}"
      return 0
    fi
    sleep 1
    waited=$(( waited + 1 ))
  done

  return 1
}

require_running_pid() {
  local service_name="$1"
  local pid

  pid="$(main_pid_for_service "${service_name}")"
  if [[ -z "${pid}" || "${pid}" == "0" ]]; then
    blitz_log "${STEP}" "lookup-pid" "failure" "service=${service_name}" 1
    exit 1
  fi
  printf '%s\n' "${pid}"
}

write_fault_flag() {
  local flag_name="$1"
  local flag_path="${BLITZ_RUNTIME_DIR}/${flag_name}"
  printf '%s\n' "$(date +%s)" > "${flag_path}"
  blitz_log "${STEP}" "flag-on" "success" "path=${flag_path}" 0
}

clear_fault_flag() {
  local flag_name="$1"
  local flag_path="${BLITZ_RUNTIME_DIR}/${flag_name}"
  rm -f "${flag_path}"
  blitz_log "${STEP}" "flag-off" "success" "path=${flag_path}" 0
}

blitz_load_boot_env
blitz_require_root "${STEP}"
blitz_prepare_runtime_dir

case "${1:-}" in
  bside-crash)
    target_pid="$(require_running_pid "${B_SIDE_SERVICE}")"
    blitz_log "${STEP}" "bside-crash" "start" "service=${B_SIDE_SERVICE} pid=${target_pid}" 0
    kill -9 "${target_pid}"
    if restarted_pid="$(wait_for_service_pid_change "${B_SIDE_SERVICE}" "${target_pid}")"; then
      blitz_log "${STEP}" "bside-crash" "success" "old_pid=${target_pid} new_pid=${restarted_pid}" 0
    else
      blitz_log "${STEP}" "bside-crash" "failure" "old_pid=${target_pid} restart_not_observed_within=10s" 1
      exit 1
    fi
    ;;
  bside-process-freeze)
    target_pid="$(require_running_pid "${B_SIDE_SERVICE}")"
    blitz_log "${STEP}" "bside-process-freeze" "start" "service=${B_SIDE_SERVICE} pid=${target_pid}" 0
    kill -STOP "${target_pid}"
    blitz_log "${STEP}" "bside-process-freeze" "success" "service=${B_SIDE_SERVICE} pid=${target_pid}" 0
    ;;
  bside-video-thread-stall)
    write_fault_flag "fault-injection-bside-video-thread-stall"
    ;;
  bside-control-thread-stall)
    write_fault_flag "fault-injection-bside-control-thread-stall"
    ;;
  ros-crash)
    target_pid="$(require_running_pid "${ROS_SERVICE}")"
    blitz_log "${STEP}" "ros-crash" "start" "service=${ROS_SERVICE} pid=${target_pid}" 0
    kill -9 "${target_pid}"
    if restarted_pid="$(wait_for_service_pid_change "${ROS_SERVICE}" "${target_pid}")"; then
      blitz_log "${STEP}" "ros-crash" "success" "old_pid=${target_pid} new_pid=${restarted_pid}" 0
    else
      blitz_log "${STEP}" "ros-crash" "failure" "old_pid=${target_pid} restart_not_observed_within=10s" 1
      exit 1
    fi
    ;;
  ros-freeze)
    target_pid="$(require_running_pid "${ROS_SERVICE}")"
    blitz_log "${STEP}" "ros-freeze" "start" "service=${ROS_SERVICE} pid=${target_pid}" 0
    kill -STOP "${target_pid}"
    blitz_log "${STEP}" "ros-freeze" "success" "service=${ROS_SERVICE} pid=${target_pid}" 0
    ;;
  network-down)
    if [[ "${BLITZ_WATCHDOG_ALLOW_FAULT_INJECTION}" != "1" ]]; then
      blitz_log "${STEP}" "network-down" "failure" "set BLITZ_WATCHDOG_ALLOW_FAULT_INJECTION=1 first" 1
      exit 1
    fi
    case "${2:-}" in
      on)
        write_fault_flag "fault-injection-network-down"
        ;;
      off)
        clear_fault_flag "fault-injection-network-down"
        ;;
      *)
        echo "usage: $0 network-down on|off" >&2
        exit 2
        ;;
    esac
    ;;
  *)
    cat <<'EOF'
usage:
  blitz-fault-inject.sh bside-crash
  blitz-fault-inject.sh bside-process-freeze
  blitz-fault-inject.sh bside-video-thread-stall
  blitz-fault-inject.sh bside-control-thread-stall
  blitz-fault-inject.sh ros-crash
  blitz-fault-inject.sh ros-freeze
  blitz-fault-inject.sh network-down on|off
EOF
    exit 2
    ;;
esac