import json
import os
from pathlib import Path
from typing import Dict, Any, Optional
import logging

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


class DataService:
    def __init__(self, data_dir: str = "data"):
        """
        Initialize data service.
        
        Args:
            data_dir: Path to data directory (default: "data")
        """
        self.data_dir = Path(data_dir)
        
        if not self.data_dir.exists():
            raise ValueError(f"Data directory '{data_dir}' does not exist")
        
        logger.info(f"DataService initialized with directory: {self.data_dir}")
    
    def get_data(self, filename: str) -> Optional[Dict[str, Any]]:
        """
        Read and return complete data from JSON file.
        
        Args:
            filename: Name of JSON file (e.g., "GetCustomers.json")
            
        Returns:
            Dictionary with complete JSON data or None if error
        """
        file_path = self.data_dir / filename
        
        try:
            if not file_path.exists():
                logger.error(f"File not found: {file_path}")
                return None
            
            with open(file_path, 'r', encoding='utf-8') as f:
                data = json.load(f)
            
            logger.info(f"Successfully loaded data from {filename}")
            return data
            
        except json.JSONDecodeError as e:
            logger.error(f"Invalid JSON in {filename}: {e}")
            return None
        except Exception as e:
            logger.error(f"Error reading {filename}: {e}")
            return None