#!/usr/bin/env bash
# backup-prod-db.sh — 将线上(production)数据库 mysqldump 落盘到 deploy/backups/
#
# 与 sync-prod-db-to-local.sh 共用 SSH 隧道；仅导出，不覆盖本地库。
#
# 用法：
#   bash deploy/backup-prod-db.sh              # 交互确认
#   bash deploy/backup-prod-db.sh --yes      # 跳过确认
#   bash deploy/backup-prod-db.sh --dry-run  # 只打印计划
#
set -euo pipefail
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
cd "$SCRIPT_DIR"

LOCAL_CONTAINER="dukang-v1-mysql"
TUNNEL_PORT=6019
REMOTE_ENV_FILE="/opt/dukang/server/dukang-api/.env.production"
HOST_ALIAS="host.docker.internal"
ASSUME_YES=0
DRY_RUN=0

for arg in "$@"; do
  case "$arg" in
    --yes|-y) ASSUME_YES=1 ;;
    --dry-run) DRY_RUN=1 ;;
    --help|-h) sed -n '3,12p' "$0"; exit 0 ;;
    --tunnel-port=*) TUNNEL_PORT="${arg#*=}" ;;
    --container=*) LOCAL_CONTAINER="${arg#*=}" ;;
    --host-alias=*) HOST_ALIAS="${arg#*=}" ;;
    *) echo "未知参数: $arg" >&2; exit 2 ;;
  esac
done

if [[ -f deploy.env ]]; then
  # shellcheck disable=SC1091
  source deploy.env
fi
DEPLOY_HOST="${DEPLOY_HOST:?请在 deploy.env 配置 DEPLOY_HOST}"
DEPLOY_USER="${DEPLOY_USER:-root}"
DEPLOY_PORT="${DEPLOY_PORT:-22}"
SSH=(ssh -o StrictHostKeyChecking=accept-new -p "$DEPLOY_PORT")
if [[ -n "${DEPLOY_SSH_KEY:-}" ]]; then SSH+=(-i "$DEPLOY_SSH_KEY"); fi
TARGET="$DEPLOY_USER@$DEPLOY_HOST"

echo "==> 读取线上数据库配置 ($TARGET:$REMOTE_ENV_FILE)"
PARSED="$("${SSH[@]}" "$TARGET" bash -s <<'NODEEOF'
cat > /tmp/_parse_db.js <<'JSEOF'
const fs=require("fs");
const l=fs.readFileSync("/opt/dukang/server/dukang-api/.env.production","utf8").match(/^DATABASE_URL=(.*)$/m)[1].trim();
let u=l;
if((u[0]==='"'&&u[u.length-1]==='"')||(u[0]==="'"&&u[u.length-1]==="'"))u=u.slice(1,-1);
const U=new URL(u);
const b=s=>Buffer.from(s).toString("base64");
const path=U.pathname.replace(/^\//,"").split("?")[0];
process.stdout.write([b(decodeURIComponent(U.username)),b(U.hostname),U.port||"3306",b(path),b(decodeURIComponent(U.password))].join("|")+"\n");
JSEOF
node /tmp/_parse_db.js; rm -f /tmp/_parse_db.js
NODEEOF
)"
if [[ -z "$PARSED" ]]; then
  echo "无法读取远端 DATABASE_URL，中止。" >&2; exit 1
fi
IFS='|' read -r _U _H _P _DB _PASS <<< "$PARSED"
REMOTE_USER="$(echo "$_U" | base64 -d)"
REMOTE_HOST="$(echo "$_H" | base64 -d)"
REMOTE_PORT="$_P"
REMOTE_DB="$(echo "$_DB" | base64 -d)"
REMOTE_PASS="$(echo "$_PASS" | base64 -d)"

mkdir -p backups
OUT="backups/prod-${REMOTE_DB}-$(date +%Y%m%d-%H%M%S).sql"

echo
echo "备份计划:"
echo "  源(线上): $REMOTE_USER@$REMOTE_HOST:$REMOTE_PORT/$REMOTE_DB"
echo "  目标文件: $OUT"
echo "  隧道:      $TARGET -L $TUNNEL_PORT:$REMOTE_HOST:$REMOTE_PORT"
if [[ $DRY_RUN -eq 1 ]]; then
  echo "(dry-run) 已结束，未做任何修改。"
  exit 0
fi

if ! docker ps --format '{{.Names}}' | grep -qx "$LOCAL_CONTAINER"; then
  echo "本地容器 $LOCAL_CONTAINER 未运行。请先执行: cd deploy && docker compose up -d" >&2
  exit 1
fi

if [[ $ASSUME_YES -ne 1 ]]; then
  read -r -p "确认备份【线上 $REMOTE_DB】到 $OUT ? [y/N] " ans
  [[ "$ans" == "y" || "$ans" == "Y" ]] || { echo "已取消。"; exit 0; }
fi

CTL="/tmp/backup-prod-db-$$.sock"
echo "==> 建立 SSH 隧道"
"${SSH[@]}" -M -S "$CTL" -f -N -L "$TUNNEL_PORT:$REMOTE_HOST:$REMOTE_PORT" "$TARGET"

ready=0
for _ in 1 2 3 4 5 6 7 8 9 10; do
  if docker exec -e "MYSQL_PWD=$REMOTE_PASS" "$LOCAL_CONTAINER" \
        mysqladmin -h "$HOST_ALIAS" -P "$TUNNEL_PORT" -u "$REMOTE_USER" ping >/dev/null 2>&1; then
    ready=1; break
  fi
  sleep 1
done
if [[ $ready -ne 1 ]]; then
  echo "隧道未就绪，中止。" >&2
  "${SSH[@]}" -S "$CTL" -O exit "$TARGET" 2>/dev/null || true
  exit 1
fi

echo "==> mysqldump 导出中..."
docker exec -e "MYSQL_PWD=$REMOTE_PASS" "$LOCAL_CONTAINER" \
  mysqldump -h "$HOST_ALIAS" -P "$TUNNEL_PORT" -u "$REMOTE_USER" \
  --lock-tables=0 --add-drop-table --skip-triggers \
  --skip-routines --skip-events --column-statistics=0 --no-tablespaces --set-gtid-purged=OFF \
  --databases "$REMOTE_DB" > "$OUT"
RC=$?

"${SSH[@]}" -S "$CTL" -O exit "$TARGET" 2>/dev/null || true

if [[ $RC -ne 0 ]]; then
  echo "备份失败 (mysqldump 退出码 $RC)。" >&2
  exit 1
fi
echo "==> 备份完成 ✅ $OUT ($(wc -c < "$OUT") bytes)"
echo "    提示：请在阿里云 RDS 控制台再创建一次手动快照，作为整库回滚保险。"