import os
from pathlib import Path
from dataclasses import dataclass
from typing import List
from datetime import datetime


@dataclass
class FileInfo:
    """Data class to represent file information"""
    name: str
    path: str
    size: int
    file_type: str
    is_dir: bool
    modified_time: str

    @property
    def size_readable(self) -> str:
        """Convert size to human-readable format"""
        for unit in ['B', 'KB', 'MB', 'GB']:
            if self.size < 1024:
                return f"{self.size:.2f} {unit}"
            self.size /= 1024
        return f"{self.size:.2f} TB"


class FileSystemReader:
    """Handles reading file system information"""

    def __init__(self, root_path: str):
        self.root_path = Path(root_path)

    def get_files_and_folders(self) -> List[FileInfo]:
        """
        Read all files and folders from the root path

        Returns:
            List[FileInfo]: List of file information objects
        """
        items = []

        if not self.root_path.exists():
            return items

        try:
            for item in self.root_path.iterdir():
                try:
                    stat_info = item.stat()
                    file_info = FileInfo(
                        name=item.name,
                        path=str(item),
                        size=stat_info.st_size,
                        file_type=self._get_file_type(item),
                        is_dir=item.is_dir(),
                        modified_time=datetime.fromtimestamp(
                            stat_info.st_mtime
                        ).strftime("%Y-%m-%d %H:%M:%S")
                    )
                    items.append(file_info)
                except (PermissionError, OSError):
                    # Skip files/folders we can't read
                    continue

            # Sort: folders first, then by name
            items.sort(key=lambda x: (not x.is_dir, x.name.lower()))
            return items

        except PermissionError:
            return items

    def _get_file_type(self, path: Path) -> str:
        """
        Determine file type

        Args:
            path: Path object

        Returns:
            str: File type (Folder, or extension)
        """
        if path.is_dir():
            return "Folder"
        return path.suffix[1:].upper() if path.suffix else "File"