"""阿里云 OSS 存储服务"""
from datetime import timedelta
from typing import BinaryIO, Optional
from urllib.parse import urlparse
import os

import oss2
from app.config import get_settings


class OSSStorageService:
    """阿里云 OSS 存储服务"""

    def __init__(self):
        settings = get_settings()
        auth = oss2.Auth(
            settings.OSS_ACCESS_KEY_ID,
            settings.OSS_ACCESS_KEY_SECRET
        )
        self.bucket = oss2.Bucket(
            auth,
            settings.OSS_ENDPOINT,
            settings.OSS_BUCKET_NAME
        )
        self.bucket_name = settings.OSS_BUCKET_NAME
        self.public_url = f"https://{settings.OSS_BUCKET_NAME}.{settings.OSS_ENDPOINT}"
        self.local_url_prefix = os.getenv("GENERATED_FILES_URL_PREFIX", "/generated-files")

    def _is_local_generated_url(self, storage_key_or_url: str) -> bool:
        parsed = urlparse(storage_key_or_url)
        path = parsed.path if parsed.scheme else storage_key_or_url
        return path.startswith(f"{self.local_url_prefix}/")

    def upload_file(
        self,
        file_or_path,
        storage_key: str,
        content_type: str = "application/octet-stream",
    ) -> str:
        """
        上传文件到 OSS
        
        Args:
            file_or_path: 文件对象或本地文件路径
            storage_key: 存储键（文件路径）
            content_type: 内容类型
        
        Returns:
            文件公网 URL
        """
        try:
            # 如果是字符串路径，从本地文件上传
            if isinstance(file_or_path, str):
                self.bucket.put_object_from_file(
                    storage_key,
                    file_or_path,
                    headers={'Content-Type': content_type}
                )
            else:
                # 文件对象
                file_or_path.seek(0)
                self.bucket.put_object(
                    storage_key,
                    file_or_path,
                    headers={'Content-Type': content_type}
                )
            
            return f"{self.public_url}/{storage_key}"
        except Exception as e:
            raise Exception(f"Failed to upload file to OSS: {e}")

    def get_url(self, storage_key: str) -> str:
        """获取文件公网 URL"""
        return f"{self.public_url}/{storage_key}"

    def get_download_url(self, storage_key_or_url: str, expires_seconds: int = 3600) -> str:
        """
        获取文件下载签名 URL（用于私有文件）
        
        Args:
            storage_key_or_url: 存储键或完整 URL
            expires_seconds: 过期时间（秒）
        
        Returns:
            签名 URL
        """
        if self._is_local_generated_url(storage_key_or_url):
            return storage_key_or_url
        storage_key = self._normalize_storage_key(storage_key_or_url)
        try:
            return self.bucket.sign_url('GET', storage_key, expires_seconds)
        except Exception:
            return self.get_url(storage_key)

    def _normalize_storage_key(self, storage_key_or_url: str) -> str:
        """从 URL 中提取存储键"""
        if storage_key_or_url.startswith("http://") or storage_key_or_url.startswith("https://"):
            parsed = urlparse(storage_key_or_url)
            # 移除开头的 /
            return parsed.path.lstrip("/")
        return storage_key_or_url.lstrip("/")

    def download_file(self, storage_key: str, local_path: str):
        """
        从 OSS 下载文件到本地
        
        Args:
            storage_key: 存储键
            local_path: 本地文件路径
        """
        try:
            os.makedirs(os.path.dirname(local_path), exist_ok=True)
            self.bucket.get_object_to_file(storage_key, local_path)
        except Exception as e:
            raise Exception(f"Failed to download file from OSS: {e}")

    def delete_file(self, storage_key: str):
        """
        删除 OSS 文件
        
        Args:
            storage_key: 存储键
        """
        try:
            self.bucket.delete_object(storage_key)
        except Exception as e:
            print(f"Error deleting file from OSS: {e}")

    def file_exists(self, storage_key: str) -> bool:
        """
        检查文件是否存在
        
        Args:
            storage_key: 存储键
        
        Returns:
            是否存在
        """
        return self.bucket.object_exists(storage_key)


# 向后兼容的服务类名
MinIOService = OSSStorageService


_storage_service = None


def get_storage_service() -> OSSStorageService:
    """获取存储服务实例（全局单例）"""
    global _storage_service
    if _storage_service is None:
        _storage_service = OSSStorageService()
    return _storage_service


# 向后兼容的别名
def get_minio_service() -> OSSStorageService:
    """向后兼容：返回 OSS 服务（已替换 MinIO）"""
    return get_storage_service()