#!/bin/bash

# ============================================
# LinkShare Blog - 数据库备份脚本
# ============================================
# 用途: 自动备份 PostgreSQL 数据库
# 用法: ./scripts/backup.sh [backup_name]
# 示例: ./scripts/backup.sh daily

set -e

# 配置
BACKUP_DIR="/backups"
DB_CONTAINER="blog-postgres"
DB_NAME="linkshare"
DB_USER="blog"
RETENTION_DAYS=7

# 参数处理
BACKUP_NAME=${1:-"auto_$(date +%Y%m%d_%H%M%S)"}
BACKUP_FILE="$BACKUP_DIR/${BACKUP_NAME}.sql.gz"

# 颜色定义
GREEN='\033[0;32m'
RED='\033[0;31m'
NC='\033[0m'

log_info() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# 创建备份目录
mkdir -p "$BACKUP_DIR"

# 检查数据库容器
if ! docker ps | grep -q "$DB_CONTAINER"; then
    log_error "数据库容器 '$DB_CONTAINER' 未运行"
    exit 1
fi

# 执行备份
log_info "开始备份数据库: $DB_NAME"
log_info "备份文件: $BACKUP_FILE"

if docker exec "$DB_CONTAINER" pg_dump -U "$DB_USER" "$DB_NAME" 2>/dev/null | gzip > "$BACKUP_FILE"; then
    BACKUP_SIZE=$(du -h "$BACKUP_FILE" | cut -f1)
    log_info "备份成功: $BACKUP_SIZE"
    
    # 记录备份信息
    echo "Backup: $BACKUP_NAME" >> "$BACKUP_DIR/backup.log"
    echo "Date: $(date '+%Y-%m-%d %H:%M:%S')" >> "$BACKUP_DIR/backup.log"
    echo "Size: $BACKUP_SIZE" >> "$BACKUP_DIR/backup.log"
    echo "File: $BACKUP_FILE" >> "$BACKUP_DIR/backup.log"
    echo "---" >> "$BACKUP_DIR/backup.log"
    
    # 清理旧备份
    log_info "清理 $RETENTION_DAYS 天前的旧备份..."
    find "$BACKUP_DIR" -name "*.sql.gz" -mtime +$RETENTION_DAYS -delete 2>/dev/null || true
    
    log_info "备份完成！"
    
    # 输出备份文件列表
    echo ""
    echo "可用的备份:"
    ls -lh "$BACKUP_DIR"/*.sql.gz 2>/dev/null || echo "无备份文件"
    
    exit 0
else
    log_error "备份失败"
    rm -f "$BACKUP_FILE"
    exit 1
fi