import os
import shutil
from fastapi import UploadFile
from datetime import datetime
from pathlib import Path
from typing import Optional
from ..core.config import settings
from .logger import logger

class FileStorage:
    def __init__(self):
        self.upload_dir = Path("uploads")
        self.upload_dir.mkdir(exist_ok=True)
        
        # Create subdirectories for different file types
        self.image_dir = self.upload_dir / "images"
        self.document_dir = self.upload_dir / "documents"
        self.image_dir.mkdir(exist_ok=True)
        self.document_dir.mkdir(exist_ok=True)

    async def save_file(
        self,
        file: UploadFile,
        category: str = "documents",
        max_size: int = 10 * 1024 * 1024  # 10MB default
    ) -> Optional[str]:
        try:
            # Validate file size
            file.file.seek(0, os.SEEK_END)
            size = file.file.tell()
            file.file.seek(0)
            
            if size > max_size:
                raise ValueError(f"File size exceeds maximum limit of {max_size/1024/1024}MB")
            
            # Generate unique filename
            timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
            filename = f"{timestamp}_{file.filename}"
            
            # Determine storage directory based on category
            if category == "images":
                save_dir = self.image_dir
                allowed_types = {".jpg", ".jpeg", ".png", ".gif"}
            else:
                save_dir = self.document_dir
                allowed_types = {".pdf", ".doc", ".docx", ".txt"}
            
            # Validate file type
            file_ext = Path(file.filename).suffix.lower()
            if file_ext not in allowed_types:
                raise ValueError(f"File type {file_ext} not allowed")
            
            # Save file
            file_path = save_dir / filename
            with file_path.open("wb") as buffer:
                shutil.copyfileobj(file.file, buffer)
            
            return str(file_path.relative_to(self.upload_dir))
        
        except Exception as e:
            logger.error(f"File upload error: {str(e)}")
            return None

    async def delete_file(self, file_path: str) -> bool:
        try:
            full_path = self.upload_dir / file_path
            if full_path.exists():
                full_path.unlink()
                return True
            return False
        except Exception as e:
            logger.error(f"File deletion error: {str(e)}")
            return False

    def get_file_url(self, file_path: str) -> str:
        """Generate URL for accessing the file"""
        return f"/uploads/{file_path}"

file_storage = FileStorage()