base

"""
Abstract base class for storage backends.
"""

from abc import ABC, abstractmethod
from pathlib import Path
from typing import List, Optional
from dataclasses import dataclass
from datetime import datetime


@dataclass
class RemoteFile:
    """Information about a remote file."""
    path: str
    size: int
    modified_time: datetime
    checksum: Optional[str] = None


class BaseBackend(ABC):
    """Abstract base class for storage backends."""
    
    @abstractmethod
    async def connect(self):
        """Initialize connection to the backend."""
        pass
    
    @abstractmethod
    async def disconnect(self):
        """Close connection to the backend."""
        pass
    
    @abstractmethod
    async def upload(self, local_path: Path, remote_path: str) -> bool:
        """
        Upload a file to the backend.
        
        Args:
            local_path: Path to local file
            remote_path: Destination path in backend
        
        Returns:
            True if successful
        """
        pass
    
    @abstractmethod
    async def download(self, remote_path: str, local_path: Path) -> bool:
        """
        Download a file from the backend.
        
        Args:
            remote_path: Path in backend
            local_path: Destination path locally
        
        Returns:
            True if successful
        """
        pass
    
    @abstractmethod
    async def delete(self, remote_path: str) -> bool:
        """
        Delete a file from the backend.
        
        Args:
            remote_path: Path to delete
        
        Returns:
            True if successful
        """
        pass
    
    @abstractmethod
    async def exists(self, remote_path: str) -> bool:
        """
        Check if a file exists in the backend.
        
        Args:
            remote_path: Path to check
        
        Returns:
            True if file exists
        """
        pass
    
    @abstractmethod
    async def list_files(self, prefix: str = "") -> List[RemoteFile]:
        """
        List files in the backend.
        
        Args:
            prefix: Path prefix to filter by
        
        Returns:
            List of RemoteFile objects
        """
        pass
    
    @abstractmethod
    async def get_file_info(self, remote_path: str) -> Optional[RemoteFile]:
        """
        Get information about a remote file.
        
        Args:
            remote_path: Path to file
        
        Returns:
            RemoteFile object or None if not found
        """
        pass