#!/usr/bin/env bash
# PostgreSQL 自动备份脚本
# 用法:
#   手动: ./docker/backup.sh
#   自动: 由 docker compose backup 服务每日 02:00 执行
set -euo pipefail

BACKUP_DIR="${BACKUP_DIR:-/backups}"
PG_HOST="${PGHOST:-postgres}"
PG_PORT="${PGPORT:-5432}"
PG_USER="${PGUSER:-erp}"
PG_DB="${PGDATABSE:-erp}"
KEEP_DAYS="${KEEP_DAYS:-7}"
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
FILENAME="${PG_DB}_${TIMESTAMP}.sql.gz"
FILEPATH="${BACKUP_DIR}/${FILENAME}"

mkdir -p "${BACKUP_DIR}"

echo "[$(date -Iseconds)] 开始备份 ${PG_DB} → ${FILEPATH}"

if pg_dump \
    -h "${PG_HOST}" \
    -p "${PG_PORT}" \
    -U "${PG_USER}" \
    -d "${PG_DB}" \
    --format=plain \
    --no-owner \
    --no-privileges \
    | gzip > "${FILEPATH}"; then
    SIZE=$(du -h "${FILEPATH}" | cut -f1)
    echo "[$(date -Iseconds)] 备份完成: ${FILENAME} (${SIZE})"
else
    echo "[$(date -Iseconds)] 备份失败！" >&2
    rm -f "${FILEPATH}"
    exit 1
fi

# 清理过期备份
DELETED=$(find "${BACKUP_DIR}" -name "${PG_DB}_*.sql.gz" -mtime +${KEEP_DAYS} -delete -print | wc -l)
if [ "${DELETED}" -gt 0 ]; then
    echo "[$(date -Iseconds)] 已清理 ${DELETED} 个过期备份（>${KEEP_DAYS}天）"
fi