#!/usr/bin/env bash
# pre-change pg_dump — plan ds-s1-backend-1 E-3.
# A-1(migration 287) / B-4 backfill 적용 *전* 안전망. repo cp -p 가 아니라 진짜 DB 덤프.
#
# 사용 (GPU 서버, repo 루트에서):
#   bash scripts/s1_pre_change_backup.sh            # pre-A-1
#   bash scripts/s1_pre_change_backup.sh pre-b4     # pre-B-4 (라벨만 다름)
#
# 백업 위치 = repo 밖 (feedback_backup_outside_repo): $HOME/.local/share/ds-s1-backups/
set -euo pipefail

LABEL="${1:-pre-a1}"
DATE="$(date +%Y%m%d-%H%M%S)"
BACKUP_DIR="${BACKUP_DIR:-$HOME/.local/share/ds-s1-backups}"
mkdir -p "$BACKUP_DIR"
OUT="$BACKUP_DIR/pkm-${LABEL}-${DATE}.sql.gz"

echo "[s1-backup] pg_dump pkm → $OUT"
# 단일 pkm DB 덤프(pg_dumpall 아님). gzip 은 redirect(파일명 추측 함정 회피).
docker compose exec -T postgres pg_dump -U pkm -d pkm | gzip > "$OUT"

echo "[s1-backup] done: $(du -h "$OUT" | cut -f1)"
echo -n "[s1-backup] gzip 무결성: "
gzip -t "$OUT" && echo "OK"

echo
echo "[s1-backup] 롤백 옵션:"
echo "  (a) 287 컬럼만 되돌림(빠름): scripts/rollback_287.sql 수동 실행"
echo "  (b) 전체 복원: gunzip -c '$OUT' | docker compose exec -T postgres psql -U pkm -d pkm"
echo "[s1-backup] 보존 7일 권장. (DR-grade 검증은 ephemeral restore — D5 트랙, 본 안전망 범위 밖.)"