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

shopt -s nullglob

format_count_unit() {
  local count="$1"
  local singular="$2"
  local plural="$3"

  if (( count == 1 )); then
    printf '%s %s ago' "$count" "$singular"
  else
    printf '%s %s ago' "$count" "$plural"
  fi
}

humanize_created_at() {
  local created_at="$1"
  local created_epoch elapsed

  if [[ -z "$created_at" ]]; then
    printf '%s' "-"
    return 0
  fi

  created_epoch="$(date -d "$created_at" +%s 2>/dev/null || true)"
  if [[ -z "$created_epoch" ]]; then
    printf '%s' "$created_at"
    return 0
  fi

  elapsed=$((NOW_EPOCH - created_epoch))
  if (( elapsed < 0 )); then
    elapsed=0
  fi

  if (( elapsed < 45 )); then
    printf '%s' "a few moments ago"
  elif (( elapsed < 90 )); then
    printf '%s' "about a minute ago"
  elif (( elapsed < 3600 )); then
    format_count_unit "$((elapsed / 60))" "minute" "minutes"
  elif (( elapsed < 5400 )); then
    printf '%s' "about an hour ago"
  elif (( elapsed < 86400 )); then
    format_count_unit "$((elapsed / 3600))" "hour" "hours"
  elif (( elapsed < 172800 )); then
    printf '%s' "1 day ago"
  elif (( elapsed < 604800 )); then
    format_count_unit "$((elapsed / 86400))" "day" "days"
  elif (( elapsed < 1209600 )); then
    printf '%s' "1 week ago"
  elif (( elapsed < 2592000 )); then
    format_count_unit "$((elapsed / 604800))" "week" "weeks"
  elif (( elapsed < 5184000 )); then
    printf '%s' "1 month ago"
  elif (( elapsed < 31536000 )); then
    format_count_unit "$((elapsed / 2592000))" "month" "months"
  elif (( elapsed < 63072000 )); then
    printf '%s' "1 year ago"
  else
    format_count_unit "$((elapsed / 31536000))" "year" "years"
  fi
}

statuses=()
ids=()
names=()
ips=()
created=()
max_name=4
max_ip=2
max_created=7
GREEN='\033[32m'
YELLOW='\033[33m'
RESET='\033[0m'
NOW_EPOCH="$(date +%s)"

for vm_json in state/vms/*/vm.json; do
  id="$(jq -r '.meta.id // empty' "$vm_json")"
  name="$(jq -r '.meta.name // empty' "$vm_json")"
  created_at="$(jq -r '.meta.created_at // empty' "$vm_json")"
  created_display="$(humanize_created_at "$created_at")"
  guest_ip="$(jq -r '.meta.guest_ip // empty' "$vm_json")"
  pid="$(jq -r '.meta.pid // empty' "$vm_json")"
  api_sock="$(jq -r '.meta.api_sock // empty' "$vm_json")"

  status="stopped"
  if [[ -n "$pid" && -n "$api_sock" ]]; then
    if ps -p "$pid" -o comm=,args= 2>/dev/null | rg -q "firecracker.*--api-sock $api_sock"; then
      status="running"
    fi
  fi

  short_id="${id:0:12}"
  statuses+=("$status")
  ids+=("$short_id")
  names+=("$name")
  ips+=("$guest_ip")
  created+=("$created_display")
  if (( ${#name} > max_name )); then
    max_name=${#name}
  fi
  if (( ${#guest_ip} > max_ip )); then
    max_ip=${#guest_ip}
  fi
  if (( ${#created_display} > max_created )); then
    max_created=${#created_display}
  fi
done

for i in "${!ids[@]}"; do
  color="$YELLOW"
  if [[ "${statuses[$i]}" == "running" ]]; then
    color="$GREEN"
  fi
  printf '%-10b %-12s %-*s %-*s %-*s\n' \
    "${color}[${statuses[$i]}]${RESET}" "${ids[$i]}" "$max_name" "${names[$i]}" "$max_ip" "${ips[$i]}" "$max_created" "${created[$i]}"
done