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


class Config:
    _instance = None
    _config_data = None

    def __new__(cls):
        if cls._instance is None:
            cls._instance = super().__new__(cls)
        return cls._instance

    def __init__(self):
        if self._config_data is None:
            self._load_config()

    def _load_config(self):
        config_path = os.path.join(os.path.dirname(__file__), '..', 'config', 'config.json')
        config_path = os.path.abspath(config_path)
        
        try:
            with open(config_path, 'r') as f:
                self._config_data = json.load(f)
        except FileNotFoundError:
            # Default config if file doesn't exist
            self._config_data = {
                'nats': {
                    'url': 'nats://localhost:4222',
                    'connection_timeout': 30,
                    'max_reconnect_attempts': 10
                }
            }
        except json.JSONDecodeError as e:
            raise ValueError(f"Invalid JSON in configuration file: {e}")

    def get(self, key: str, default: Any = None) -> Any:
        keys = key.split('.')
        value = self._config_data
        
        for k in keys:
            if isinstance(value, dict) and k in value:
                value = value[k]
            else:
                return default
        
        return value

    @property
    def nats_url(self) -> str:
        return os.getenv('NATS_URL') or self.get('nats.url', 'nats://localhost:4222')

    @property
    def nats_connection_timeout(self) -> int:
        return self.get('nats.connection_timeout', 30)

    @property
    def nats_max_reconnect_attempts(self) -> int:
        return self.get('nats.max_reconnect_attempts', 10)

    def get_local_services(self) -> list:
        """Get list of services that should run on this node"""
        systemd_services = self.get('auto_upgrade.systemd_services', [])
        local_services = []
        for systemd_service in systemd_services:
            service_name = systemd_service.replace('vi-', '').replace('.service', '')
            local_services.append(service_name)
        return local_services
    
    def is_service_enabled(self, service_name: str) -> bool:
        """Check if a service is enabled on this node"""
        return service_name in self.get_local_services()

    @property
    def project_root(self) -> Path:
        """Get the project root directory"""
        return Path(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
    
    @property
    def data_dir(self) -> Path:
        """Get the data directory for databases"""
        data_path = os.getenv('DATA_DIR', str(self.project_root / 'data'))
        data_dir = Path(data_path)
        data_dir.mkdir(exist_ok=True, parents=True)
        return data_dir


config = Config()

# Database paths
SHORT_TERM_DB = config.data_dir / 'memory_active.db'
LONG_TERM_DB = config.data_dir / 'memory_archive.db'