#!/usr/bin/env bash

# 在线备份脚本共用函数。仅供 scripts/backup-online.sh、archive-binlog.sh 和
# restore-online.sh source，不要单独执行。

BACKUP_ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
BACKUP_COMPOSE_FILE="${BACKUP_ROOT_DIR}/deploy/docker-compose.prod.yml"
BACKUP_ENV_FILE="${BACKUP_ROOT_DIR}/backend/.env"
BACKUP_XTRABACKUP_IMAGE="${XTRABACKUP_IMAGE:-percona/percona-xtrabackup:8.4}"

backup_log() {
  printf '[backup] %s\n' "$*" >&2
}

backup_error() {
  printf '[backup] ERROR: %s\n' "$*" >&2
}

backup_require_cmd() {
  if ! command -v "$1" >/dev/null 2>&1; then
    backup_error "缺少命令：$1"
    exit 1
  fi
}

backup_env_value() {
  local key="$1"
  awk -F= -v key="${key}" '$1 == key { sub(/^[^=]*=/, ""); print; exit }' "${BACKUP_ENV_FILE}"
}

backup_require_env() {
  local key="$1"
  local value
  value="$(backup_env_value "${key}")"
  if [[ -z "${value}" ]]; then
    backup_error "${BACKUP_ENV_FILE} 缺少或未填写 ${key}"
    exit 1
  fi
  printf '%s' "${value}"
}

backup_compose() {
  docker compose --env-file "${BACKUP_ENV_FILE}" -f "${BACKUP_COMPOSE_FILE}" "$@"
}

backup_mysql_container_id() {
  local cid
  cid="$(backup_compose ps -q mysql 2>/dev/null || true)"
  if [[ -z "${cid}" ]]; then
    backup_error "MySQL 容器未运行"
    exit 1
  fi
  printf '%s' "${cid}"
}

backup_mysql_network() {
  local network
  network="$(docker inspect -f '{{range $k, $v := .NetworkSettings.Networks}}{{$k}}{{end}}' "$1")"
  if [[ -z "${network}" ]]; then
    backup_error "无法读取 MySQL Docker 网络"
    exit 1
  fi
  printf '%s' "${network}"
}

backup_mysql_root_query() {
  backup_compose exec -T mysql sh -c \
    'MYSQL_PWD="$MYSQL_ROOT_PASSWORD" mysql -uroot --protocol=socket -N -B "$MYSQL_DATABASE" -e "$1"' \
    sh "$1"
}

backup_validate_dir() {
  local dir="$1"
  if [[ "${dir}" != /data/* || "${dir}" == "/data" ]]; then
    backup_error "备份目录必须是 /data 之下的具体绝对路径，当前值：${dir}"
    exit 1
  fi
}

backup_lock_or_exit() {
  local path="$1"
  local wait_seconds="${2:-${BACKUP_LOCK_WAIT_SECONDS:-0}}"
  backup_require_cmd flock
  mkdir -p "$(dirname "${path}")"
  exec 9>"${path}"
  if [[ ! "${wait_seconds}" =~ ^[0-9]+$ ]]; then
    backup_error "锁等待时间必须是非负整数：${wait_seconds}"
    exit 1
  fi
  if ! flock -w "${wait_seconds}" 9; then
    backup_error "已有同类备份任务在执行，拒绝并发运行"
    exit 1
  fi
}

backup_server_uuid() {
  local value
  value="$(backup_mysql_root_query 'SELECT @@server_uuid;' 2>/dev/null || true)"
  if [[ ! "${value}" =~ ^[0-9A-Fa-f-]{36}$ ]]; then
    backup_error "无法读取 MySQL server_uuid"
    exit 1
  fi
  printf '%s' "${value,,}"
}

backup_binlog_index() {
  local filename="$1"
  if [[ "${filename}" =~ ^mysql-bin\.([0-9]{6,})$ ]]; then
    printf '%d' "$((10#${BASH_REMATCH[1]}))"
    return
  fi
  backup_error "不支持的 binlog 文件名：${filename}"
  exit 1
}

backup_sha256() {
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$1" | awk '{print $1}'
    return
  fi
  shasum -a 256 "$1" | awk '{print $1}'
}

backup_file_size() {
  if [[ "$(uname)" == 'Darwin' ]]; then
    stat -f%z "$1"
  else
    stat -c%s "$1"
  fi
}

backup_encrypt_file() {
  local source="$1"
  local destination="$2"
  local passphrase
  passphrase="$(backup_require_env BACKUP_PASSPHRASE)"
  BACKUP_PASSPHRASE="${passphrase}" openssl enc -aes-256-cbc -pbkdf2 -iter 600000 -salt \
    -pass env:BACKUP_PASSPHRASE \
    -in "${source}" \
    -out "${destination}"
  unset passphrase
}

backup_decrypt_file() {
  local source="$1"
  local destination="$2"
  local passphrase
  passphrase="$(backup_require_env BACKUP_PASSPHRASE)"
  BACKUP_PASSPHRASE="${passphrase}" openssl enc -d -aes-256-cbc -pbkdf2 -iter 600000 \
    -pass env:BACKUP_PASSPHRASE \
    -in "${source}" \
    -out "${destination}"
  unset passphrase
}

backup_oss_upload() {
  local source="$1"
  local destination="$2"
  local kms_key_id
  kms_key_id="$(backup_env_value BACKUP_KMS_KEY_ID)"
  if [[ -n "${kms_key_id}" ]]; then
    ossutil cp "${source}" "${destination}" \
      --encryption KMS --kms-master-key-id "${kms_key_id}"
    return
  fi
  # 未配置 KMS 时依赖 Bucket 已启用的 OSS 托管服务器端加密；备份载荷仍会先经过客户端加密。
  ossutil cp "${source}" "${destination}"
}

backup_validate_oss_uri() {
  local uri="$1"
  if [[ ! "${uri}" =~ ^oss://[A-Za-z0-9][A-Za-z0-9._-]*$ ]]; then
    backup_error "BACKUP_OSS_URI 必须是 oss://bucket 格式，当前值：${uri}"
    exit 1
  fi
}

backup_oss_download() {
  local source="$1"
  local destination="$2"
  ossutil cp "${source}" "${destination}"
}

backup_write_complete_marker() {
  local path="$1"
  local payload_name="$2"
  local payload_sha256="$3"
  local payload_size="$4"
  local server_uuid="$5"
  {
    printf 'format_version=1\n'
    printf 'created_at=%s\n' "$(date -Iseconds)"
    printf 'server_uuid=%s\n' "${server_uuid}"
    printf 'payload=%s\n' "${payload_name}"
    printf 'payload_sha256=%s\n' "${payload_sha256}"
    printf 'payload_size_bytes=%s\n' "${payload_size}"
  } > "${path}"
}