#!/bin/bash
# ============================================
# 丹阳公益婚恋服务平台 — PostgreSQL 备份脚本
# ============================================
# 用法：
#   ./scripts/backup.sh              # 备份全部数据库
#   ./scripts/backup.sh danyang_match  # 备份指定库
#   ./scripts/backup.sh --daily      # 仅保留最近7天的备份
# ============================================
set -euo pipefail

DB_NAME="${1:-danyang_match}"
BACKUP_DIR="${BACKUP_DIR:-/app/backups}"
RETENTION_DAYS="${RETENTION_DAYS:-30}"
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
BACKUP_FILE="${BACKUP_DIR}/${DB_NAME}_${TIMESTAMP}.sql.gz"

echo "[$(date '+%Y-%m-%d %H:%M:%S')] 开始备份: ${DB_NAME}"

# 创建备份目录
mkdir -p "${BACKUP_DIR}"

# 执行备份
pg_dump \
  -h "${DB_HOST:-postgres}" \
  -U "${DB_USER:-danyang}" \
  -d "${DB_NAME}" \
  --no-owner \
  --no-privileges \
  --clean \
  --if-exists \
  --inserts \
  | gzip > "${BACKUP_FILE}"

echo "[$(date '+%Y-%m-%d %H:%M:%S')] 备份完成: ${BACKUP_FILE}"
echo "[$(date '+%Y-%m-%d %H:%M:%S')] 文件大小: $(du -h "${BACKUP_FILE}" | cut -f1)"

# 清理过期备份
find "${BACKUP_DIR}" -name "${DB_NAME}_*.sql.gz" -mtime +${RETENTION_DAYS} -delete
echo "[$(date '+%Y-%m-%d %H:%M:%S')] 已清理 ${RETENTION_DAYS} 天前的备份"

# 保留最近 N 份（防止误删）
BACKUP_COUNT=$(ls -1 "${BACKUP_DIR}"/${DB_NAME}_*.sql.gz 2>/dev/null | wc -l)
if [ "${BACKUP_COUNT}" -gt 10 ]; then
  ls -1t "${BACKUP_DIR}"/${DB_NAME}_*.sql.gz | tail -n +11 | xargs rm -f
  echo "[$(date '+%Y-%m-%d %H:%M:%S')] 保留最近10份备份，其余已清理"
fi

echo "[$(date '+%Y-%m-%d %H:%M:%S')] 备份任务完成"