# app_environment.py - Production-grade environment configuration
"""
Production environment configuration for OmniBiMol Streamlit app.

Provides clean environment handling to separate development/debug output
from production-ready user-facing UI.

Usage:
    from app_environment import AppEnvironment
    env = AppEnvironment()
    
    if env.is_development():
        # Show debug UI elements
    
    if env.should_show_backend_status():
        render_backend_status_badge()
"""

import os
import logging
from typing import Optional

logger = logging.getLogger(__name__)


class AppEnvironment:
    """
    Manages application environment configuration.
    
    Separates development/debug UI from production user-facing UI.
    """
    
    # Environment modes
    DEVELOPMENT = "development"
    PRODUCTION = "production"
    
    def __init__(self):
        """Initialize environment configuration from APP_ENV variable."""
        # Default to production for safety
        self.env = os.getenv("APP_ENV", self.PRODUCTION).strip().lower()
        
        # Validate environment
        if self.env not in {self.DEVELOPMENT, self.PRODUCTION}:
            logger.warning(
                f"Invalid APP_ENV='{self.env}'. Valid values: "
                f"'{self.DEVELOPMENT}', '{self.PRODUCTION}'. Defaulting to '{self.PRODUCTION}'."
            )
            self.env = self.PRODUCTION
        
        logger.info(f"OmniBiMol running in {self.env} mode")
    
    def is_development(self) -> bool:
        """Check if running in development mode."""
        return self.env == self.DEVELOPMENT
    
    def is_production(self) -> bool:
        """Check if running in production mode."""
        return self.env == self.PRODUCTION
    
    def should_show_backend_status(self) -> bool:
        """
        Determine if backend status badge should be shown.
        
        Returns:
            True in development mode, False in production.
        """
        return self.is_development()
    
    def should_show_debug_ui(self) -> bool:
        """
        Determine if debug/development UI elements should be visible.
        
        Includes:
        - Backend routing details
        - Environment labels
        - Debug status indicators
        - Internal error details
        
        Returns:
            True in development mode, False in production.
        """
        return self.is_development()
    
    def should_expose_errors(self) -> bool:
        """
        Determine if raw errors should be exposed in UI.
        
        Returns:
            True in development mode, False in production (user-friendly messages only).
        """
        return self.is_development()
    
    def get_user_message(self, internal_error: Optional[str] = None) -> str:
        """
        Get user-friendly message, hiding internal details in production.
        
        Args:
            internal_error: The actual error for logging purposes
        
        Returns:
            Production: Generic user message
            Development: Full error details
        """
        if self.is_production():
            return "Processing request... Some data could not be loaded. Results may be partial."
        else:
            return internal_error or "An error occurred."
    
    def log_debug(self, message: str, **kwargs) -> None:
        """Log debug message (visible in logs, not UI)."""
        logger.debug(message, extra=kwargs)
    
    def log_info(self, message: str, **kwargs) -> None:
        """Log info message."""
        logger.info(message, extra=kwargs)
    
    def log_error(self, message: str, **kwargs) -> None:
        """Log error message."""
        logger.error(message, extra=kwargs)


# Global singleton instance
_app_environment: Optional[AppEnvironment] = None


def get_environment() -> AppEnvironment:
    """
    Get or create the global app environment instance.
    
    Returns:
        AppEnvironment singleton
    """
    global _app_environment
    if _app_environment is None:
        _app_environment = AppEnvironment()
    return _app_environment