import os
import sys
import asyncio
import aiomysql
import subprocess
import datetime
import gzip
import shutil
from pathlib import Path

sys.path.insert(0, str(Path(__file__).parent.parent))

from config import settings

BACKUP_DIR = os.path.join(Path(__file__).parent.parent, "backups")
os.makedirs(BACKUP_DIR, exist_ok=True)

async def backup_database(name=None, compress=True):
    """备份MySQL数据库"""
    
    timestamp = datetime.datetime.now().strftime("%Y%m%d_%H%M%S")
    if name:
        backup_name = f"{name}_{timestamp}"
    else:
        backup_name = f"backup_{timestamp}"
    
    output_file = os.path.join(BACKUP_DIR, f"{backup_name}.sql")
    
    cmd = [
        "mysqldump",
        "-h", settings.db_host,
        "-P", str(settings.db_port),
        "-u", settings.db_user,
        f"-p{settings.db_password}",
        "--single-transaction",
        "--routines",
        "--triggers",
        "--events",
        settings.db_name
    ]
    
    try:
        print(f"开始备份数据库...")
        with open(output_file, 'w') as f:
            process = subprocess.Popen(
                cmd, 
                stdout=f,
                stderr=subprocess.PIPE
            )
            _, stderr = process.communicate()
            
        if process.returncode != 0:
            print(f"备份失败: {stderr.decode()}")
            if os.path.exists(output_file):
                os.remove(output_file)
            return False
        
        if compress:
            compressed_file = f"{output_file}.gz"
            print(f"压缩备份文件...")
            with open(output_file, 'rb') as f_in:
                with gzip.open(compressed_file, 'wb') as f_out:
                    shutil.copyfileobj(f_in, f_out)
            
            os.remove(output_file)  # 删除未压缩的SQL文件
            output_file = compressed_file
        
        file_size = os.path.getsize(output_file) / (1024 * 1024)  # 转换为MB
        print(f"备份完成: {output_file} ({file_size:.2f} MB)")
        return output_file
    
    except Exception as e:
        print(f"备份过程中出错: {e}")
        if os.path.exists(output_file):
            os.remove(output_file)
        return False

async def list_backups():
    """列出所有可用的备份文件"""
    if not os.path.exists(BACKUP_DIR):
        return []
    
    backups = [f for f in os.listdir(BACKUP_DIR) if f.endswith('.sql') or f.endswith('.sql.gz')]
    backups.sort(reverse=True)  # 按文件名排序，最新的在前面
    
    return backups

async def cleanup_old_backups(keep=10):
    """清理旧备份，仅保留指定数量的最新备份"""
    backups = await list_backups()
    
    if len(backups) <= keep:
        print(f"当前共有 {len(backups)} 个备份，未超过保留数量 {keep}，不需要清理")
        return
    
    to_delete = backups[keep:]
    print(f"将删除 {len(to_delete)} 个旧备份，保留 {keep} 个最新备份")
    
    for backup in to_delete:
        try:
            file_path = os.path.join(BACKUP_DIR, backup)
            os.remove(file_path)
            print(f"已删除: {backup}")
        except Exception as e:
            print(f"删除备份 {backup} 时出错: {e}")