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

log() {
  printf '[kill] %s\n' "$*"
}

usage() {
  cat <<'EOF'
Usage: ./kill.sh <id-or-name-prefix> [--signal SIGTERM|SIGKILL|...]

Sends a signal to the Firecracker process.
EOF
}

find_vm_json() {
  local query="$1"
  local vm_json match_count=0 match=""

  for vm_json in state/vms/*/vm.json; do
    [[ -f "$vm_json" ]] || continue
    local id name
    id="$(jq -r '.meta.id // empty' "$vm_json")"
    name="$(jq -r '.meta.name // empty' "$vm_json")"
    if [[ "$id" == "$query"* || "$name" == "$query"* ]]; then
      match="$vm_json"
      match_count=$((match_count + 1))
    fi
  done

  if (( match_count == 0 )); then
    log "no VM found for prefix: $query"
    exit 1
  fi
  if (( match_count > 1 )); then
    log "multiple VMs found for prefix: $query"
    exit 1
  fi

  printf '%s' "$match"
}

SIGNAL="TERM"
while [[ $# -gt 0 ]]; do
  case "$1" in
    --signal)
      SIGNAL="${2:-}"
      shift 2
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      if [[ -z "${QUERY:-}" ]]; then
        QUERY="$1"
        shift
        continue
      fi
      log "unknown option: $1"
      usage
      exit 1
      ;;
  esac
done

if [[ -z "$QUERY" || "$QUERY" == "-h" || "$QUERY" == "--help" ]]; then
  usage
  exit 1
fi

VM_JSON="$(find_vm_json "$QUERY")"
PID="$(jq -r '.meta.pid // empty' "$VM_JSON")"
API_SOCK="$(jq -r '.meta.api_sock // empty' "$VM_JSON")"
if [[ -z "$PID" ]]; then
  log "pid not found in $VM_JSON"
  exit 1
fi
if [[ -z "$API_SOCK" ]]; then
  log "api_sock not found in $VM_JSON"
  exit 1
fi

if ! ps -p "$PID" -o comm=,args= 2>/dev/null | rg -q "firecracker.*--api-sock $API_SOCK"; then
  log "pid $PID does not match a running VM"
  exit 1
fi

log "sending SIG$SIGNAL to pid $PID"
sudo kill "-$SIGNAL" "$PID"
log "signal sent"