"""
阿里云OSS工具类
"""
import os
import uuid
from datetime import datetime
from django.conf import settings

try:
    import oss2
    OSS_AVAILABLE = True
except ImportError:
    OSS_AVAILABLE = False


class OSSClient:
    """阿里云OSS客户端"""
    
    _instance = None
    
    def __new__(cls):
        if cls._instance is None:
            cls._instance = super().__new__(cls)
            cls._instance._initialized = False
        return cls._instance
    
    def __init__(self):
        if self._initialized:
            return
        
        if not OSS_AVAILABLE:
            self.bucket = None
            self._initialized = True
            return
            
        oss_config = settings.ALIYUN_OSS
        if not oss_config.get('ACCESS_KEY_ID'):
            self.bucket = None
            self._initialized = True
            return
        
        auth = oss2.Auth(
            oss_config['ACCESS_KEY_ID'],
            oss_config['ACCESS_KEY_SECRET']
        )
        self.bucket = oss2.Bucket(
            auth,
            oss_config['ENDPOINT'],
            oss_config['BUCKET_NAME']
        )
        self.custom_domain = oss_config.get('CUSTOM_DOMAIN', '')
        self._initialized = True
    
    def upload_file(self, file_obj, folder='uploads'):
        """
        上传文件
        :param file_obj: 文件对象
        :param folder: 存储文件夹
        :return: 文件URL
        """
        if not self.bucket:
            raise Exception('OSS未配置')
        
        # 生成唯一文件名
        ext = os.path.splitext(file_obj.name)[1] if hasattr(file_obj, 'name') else ''
        filename = f"{datetime.now().strftime('%Y%m%d')}/{uuid.uuid4().hex}{ext}"
        key = f"{folder}/{filename}"
        
        # 上传文件
        self.bucket.put_object(key, file_obj)
        
        # 返回URL
        if self.custom_domain:
            return f"https://{self.custom_domain}/{key}"
        return f"https://{settings.ALIYUN_OSS['BUCKET_NAME']}.{settings.ALIYUN_OSS['ENDPOINT']}/{key}"
    
    def delete_file(self, file_url):
        """
        删除文件
        :param file_url: 文件URL
        """
        if not self.bucket:
            return
        
        # 从URL提取key
        key = file_url.split('/')[-2] + '/' + file_url.split('/')[-1]
        self.bucket.delete_object(key)


def get_oss_client():
    """获取OSS客户端单例"""
    return OSSClient()