down.sh

#!/usr/bin/env bash
# Tear the rig down — DELETE the benchmark stack (+ its network stack, if present).
# Interactive + safe: pick the AWS account/region, SHOW which boxes will be destroyed,
# then require you to type the stack name to confirm. Nothing persists but the IaC in git.
#
#   ./down.sh                 # interactive
#   STACK=foo ./down.sh       # target a different stack
#   ASSUME_YES=1 ./down.sh    # no prompts (CI)
set -euo pipefail
ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# Reuse the operator's deploy.env (AWS_PROFILE / REGION / STACK) if present.
[ -f "$ROOT/deploy.env" ] && { set -a; . "$ROOT/deploy.env"; set +a; }
REGION="${REGION:-us-east-1}"; STACK="${STACK:-gw-bench}"; NET_STACK="${NET_STACK:-${STACK}-net}"
ASSUME_YES="${ASSUME_YES:-0}"

c(){ printf "\033[%sm%s\033[0m" "$1" "$2"; }
ok(){ echo "$(c 32 "✓") $*"; }; inf(){ echo "$(c 36 "•") $*"; }
warn(){ echo "$(c 33 "!") $*" >&2; }; die(){ echo "$(c 31 "✗") $*" >&2; exit 1; }
aws_(){ aws --region "$REGION" "$@"; }

# pick_one <title> <default> : "value|label" lines on stdin → numbered menu (stderr),
# chosen value (stdout). Enter = default. Honors ASSUME_YES (takes the default).
pick_one(){
  local title="$1" def="${2:-}"; local -a vals=() labels=(); local v l
  while IFS='|' read -r v l; do
    [ -n "$v" ] || continue
    case " ${vals[*]:-} " in *" $v "*) continue ;; esac
    vals+=("$v"); labels+=("${l:-$v}")
  done
  [ "${#vals[@]}" -gt 0 ] || { echo "$def"; return 0; }
  [ "$ASSUME_YES" = "1" ] && { echo "${def:-${vals[0]}}"; return 0; }
  { echo "$(c 1 "$title")"; local i mark
    for i in "${!vals[@]}"; do mark=""; { [ -n "$def" ] && [ "${vals[$i]}" = "$def" ]; } && mark=" $(c 32 '(current)')"
      printf "   %2d) %s%s\n" "$((i+1))" "${labels[$i]}" "$mark"; done; } >&2
  local ans; read -r -p "$(c 33 "?") choose 1-${#vals[@]}${def:+ (Enter=current)}: " ans </dev/tty || true
  [ -n "$ans" ] || { echo "${def:-${vals[0]}}"; return 0; }
  { [[ "$ans" =~ ^[0-9]+$ ]] && [ "$ans" -ge 1 ] && [ "$ans" -le "${#vals[@]}" ]; } || die "invalid selection '$ans'"
  echo "${vals[$((ans-1))]}"
}

del(){ # <stack>
  aws_ cloudformation describe-stacks --stack-name "$1" >/dev/null 2>&1 || { inf "stack '$1' not present — skipped"; return 0; }
  inf "deleting stack '$1'…"
  aws_ cloudformation delete-stack --stack-name "$1"
  aws_ cloudformation wait stack-delete-complete --stack-name "$1"
  ok "deleted '$1'"
}

command -v aws >/dev/null || die "aws CLI not found."
# Account / region — pick the right one (don't tear down the wrong environment).
if [ -z "${AWS_PROFILE:-}" ]; then
  profs="$(aws configure list-profiles 2>/dev/null || true)"
  [ -n "$profs" ] && { AWS_PROFILE="$(printf '%s\n' "$profs" | sed 's/$/|/' | pick_one "AWS profile (which account to tear down):" "default")"; export AWS_PROFILE; }
fi
REGION="$(printf '%s\n' \
  'us-east-1|us-east-1 (N. Virginia)' 'us-east-2|us-east-2 (Ohio)' 'us-west-2|us-west-2 (Oregon)' \
  'eu-west-1|eu-west-1 (Ireland)' 'eu-central-1|eu-central-1 (Frankfurt)' 'ap-southeast-1|ap-southeast-1 (Singapore)' \
  "${REGION}|${REGION} (current)" | pick_one "AWS region:" "$REGION")"
acct="$(aws_ sts get-caller-identity --query Account --output text 2>/dev/null)" || die "AWS credentials not working for profile '${AWS_PROFILE:-default}'."

aws_ cloudformation describe-stacks --stack-name "$STACK" >/dev/null 2>&1 \
  || die "stack '$STACK' not found in account $acct / $REGION — nothing to delete (right account/region/STACK?)."

# Show exactly what will be destroyed.
boxes="$(aws_ ec2 describe-instances \
  --filters "Name=tag:aws:cloudformation:stack-name,Values=$STACK" "Name=instance-state-name,Values=running,stopped,stopping,pending" \
  --query 'Reservations[].Instances[].[Tags[?Key==`Role`]|[0].Value,InstanceId,State.Name]' --output text 2>/dev/null || true)"
warn "about to DELETE stack '$STACK' (and '$NET_STACK' if present) in account $acct / region $REGION — these boxes go away:"
if [ -n "$boxes" ]; then printf '%s\n' "$boxes" | awk -F'\t' '{print "    "$1"  "$2"  ["$3"]"}'
else echo "    (no live instances found — the stack's resources are still deleted)"; fi

if [ "$ASSUME_YES" != "1" ]; then
  read -r -p "$(c 33 "?") type the stack name '$STACK' to confirm DELETE: " a </dev/tty || true
  [ "$a" = "$STACK" ] || die "aborted (got '$a', expected '$STACK')."
fi
del "$STACK"
del "$NET_STACK"
ok "teardown complete — account $acct / $REGION"