#!/bin/sh
set -eu

SCRIPT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
INFRA_DIR=$(CDPATH= cd -- "$SCRIPT_DIR/.." && pwd)
PROJECT_DIR=$(CDPATH= cd -- "$INFRA_DIR/.." && pwd)
COMPOSE_FILE=${COMPOSE_FILE:-"$INFRA_DIR/docker-compose.prod.yml"}
BACKUP_ROOT=${BACKUP_ROOT:-"$PROJECT_DIR/backups"}
STAMP=$(date -u +%Y%m%dT%H%M%SZ)
TARGET="$BACKUP_ROOT/$STAMP"

mkdir -p "$TARGET"
TARGET=$(CDPATH= cd -- "$TARGET" && pwd)
case "$TARGET" in
  "$PROJECT_DIR"/*) ;;
  *) echo "拒绝写入项目目录之外的备份路径：$TARGET" >&2; exit 2 ;;
esac

POSTGRES_DB=${POSTGRES_DB:-ai_ticket_platform}
POSTGRES_USER=${POSTGRES_USER:-ai_ticket}
BACKUP_HELPER_IMAGE=${BACKUP_HELPER_IMAGE:-alpine:3.21}
RUNNING_APPLICATION_SERVICES=""
MINIO_WAS_RUNNING=false

cleanup() {
  MINIO_READY=true
  if [ "$MINIO_WAS_RUNNING" = "true" ]; then
    if ! docker compose -f "$COMPOSE_FILE" up -d --wait minio >/dev/null; then
      echo "备份结束后 MinIO 未恢复健康，应用服务保持停止" >&2
      MINIO_READY=false
    fi
  fi
  if [ "$MINIO_READY" = "true" ] && [ -n "$RUNNING_APPLICATION_SERVICES" ]; then
    docker compose -f "$COMPOSE_FILE" start $RUNNING_APPLICATION_SERVICES >/dev/null || true
  fi
}
trap cleanup EXIT INT TERM

RUNNING_SERVICES=$(docker compose -f "$COMPOSE_FILE" ps --services --filter status=running)
if printf '%s\n' "$RUNNING_SERVICES" | grep -qx "minio"; then
  MINIO_WAS_RUNNING=true
fi
if [ "${BACKUP_SKIP_APPLICATION_SERVICES:-false}" != "true" ]; then
  for service in backend worker beat; do
    if printf '%s\n' "$RUNNING_SERVICES" | grep -qx "$service"; then
      RUNNING_APPLICATION_SERVICES="$RUNNING_APPLICATION_SERVICES $service"
    fi
  done
  if [ -n "$RUNNING_APPLICATION_SERVICES" ]; then
    docker compose -f "$COMPOSE_FILE" stop $RUNNING_APPLICATION_SERVICES
  fi
fi
if [ "$MINIO_WAS_RUNNING" = "true" ]; then
  docker compose -f "$COMPOSE_FILE" stop minio
fi

docker compose -f "$COMPOSE_FILE" exec -T postgres \
  pg_dump -U "$POSTGRES_USER" -d "$POSTGRES_DB" --format=custom > "$TARGET/postgres.dump"
docker compose -f "$COMPOSE_FILE" exec -T postgres \
  pg_restore --list < "$TARGET/postgres.dump" > "$TARGET/postgres.contents"
MINIO_CONTAINER=$(docker compose -f "$COMPOSE_FILE" ps -q minio)
if [ -z "$MINIO_CONTAINER" ]; then
  echo "未找到 MinIO 容器" >&2
  exit 3
fi
docker run --rm \
  --volumes-from "$MINIO_CONTAINER" \
  -v "$TARGET:/backup" \
  "$BACKUP_HELPER_IMAGE" \
  tar -C /data -czf /backup/minio-data.tar.gz .

(
  cd "$TARGET"
  sha256sum postgres.dump postgres.contents minio-data.tar.gz > SHA256SUMS
)

cat > "$TARGET/manifest.txt" <<EOF
created_at=$STAMP
postgres_database=$POSTGRES_DB
postgres_user=$POSTGRES_USER
compose_file=$COMPOSE_FILE
EOF

cleanup
trap - EXIT INT TERM
echo "备份已创建并完成结构校验：$TARGET"