"""Storage module for JSON file persistence.

This module provides the Storage class that handles reading and writing
todo items to a JSON file located at ~/.todo_cli/todos.json.
"""

import json
import os
from typing import List, Dict, Any


class Storage:
    """Handles persistent storage of todo items in a JSON file.

    Attributes:
        file_path: The absolute path to the JSON storage file.
    """

    def __init__(self, file_path: str = None) -> None:
        """Initialize Storage with a file path.

        If no file_path is provided, defaults to ~/.todo_cli/todos.json.

        Args:
            file_path: Optional custom path for the JSON file.
        """
        if file_path is None:
            home_dir = os.path.expanduser("~")
            self.file_path = os.path.join(home_dir, ".todo_cli", "todos.json")
        else:
            self.file_path = file_path

    def load(self) -> List[Dict[str, Any]]:
        """Load todo items from the JSON file.

        Returns:
            A list of dictionaries representing todo items.
            Returns an empty list if the file does not exist or is corrupted.
        """
        if not os.path.exists(self.file_path):
            return []

        try:
            with open(self.file_path, "r", encoding="utf-8") as f:
                data = json.load(f)
                if isinstance(data, list):
                    return data
                else:
                    return []
        except (json.JSONDecodeError, IOError):
            return []

    def save(self, data: List[Dict[str, Any]]) -> None:
        """Save a list of todo item dictionaries to the JSON file.

        Creates the directory structure if it does not exist.

        Args:
            data: A list of dictionaries representing todo items to persist.
        """
        directory = os.path.dirname(self.file_path)
        if directory:
            os.makedirs(directory, exist_ok=True)

        with open(self.file_path, "w", encoding="utf-8") as f:
            json.dump(data, f, indent=2, ensure_ascii=False)