src/infrastructure/stt/provider_factory.py

"""Factory for creating STT provider instances."""

import logging
from typing import Dict, Type, Optional

from ..base.stt_provider_base import STTProviderBase
from .whisper_provider import WhisperSTTProvider
from .parakeet_provider import ParakeetSTTProvider
from ...domain.exceptions import SpeechRecognitionException

logger = logging.getLogger(__name__)


class STTProviderFactory:
    """Factory for creating STT provider instances with availability checking and fallback logic."""

    _providers: Dict[str, Type[STTProviderBase]] = {
        "whisper": WhisperSTTProvider,
        "parakeet": ParakeetSTTProvider
    }

    _fallback_order = ["whisper", "parakeet"]

    @classmethod
    def create_provider(cls, provider_name: str) -> STTProviderBase:
        """
        Create an STT provider instance by name.

        Args:
            provider_name: Name of the provider to create

        Returns:
            STTProviderBase: The created provider instance

        Raises:
            SpeechRecognitionException: If provider is not available or creation fails
        """
        provider_name = provider_name.lower()
        
        if provider_name not in cls._providers:
            raise SpeechRecognitionException(f"Unknown STT provider: {provider_name}")

        provider_class = cls._providers[provider_name]
        
        try:
            provider = provider_class()
            
            if not provider.is_available():
                raise SpeechRecognitionException(f"STT provider {provider_name} is not available")
            
            logger.info(f"Created STT provider: {provider_name}")
            return provider
            
        except Exception as e:
            logger.error(f"Failed to create STT provider {provider_name}: {str(e)}")
            raise SpeechRecognitionException(f"Failed to create STT provider {provider_name}: {str(e)}") from e

    @classmethod
    def create_provider_with_fallback(cls, preferred_provider: str) -> STTProviderBase:
        """
        Create an STT provider with fallback to other available providers.

        Args:
            preferred_provider: The preferred provider name

        Returns:
            STTProviderBase: The created provider instance

        Raises:
            SpeechRecognitionException: If no providers are available
        """
        # Try preferred provider first
        try:
            return cls.create_provider(preferred_provider)
        except SpeechRecognitionException as e:
            logger.warning(f"Preferred STT provider {preferred_provider} failed: {str(e)}")

        # Try fallback providers
        for provider_name in cls._fallback_order:
            if provider_name.lower() == preferred_provider.lower():
                continue  # Skip the preferred provider we already tried
                
            try:
                logger.info(f"Trying fallback STT provider: {provider_name}")
                return cls.create_provider(provider_name)
            except SpeechRecognitionException as e:
                logger.warning(f"Fallback STT provider {provider_name} failed: {str(e)}")
                continue

        raise SpeechRecognitionException("No STT providers are available")

    @classmethod
    def get_available_providers(cls) -> list[str]:
        """
        Get list of available STT providers.

        Returns:
            list[str]: List of available provider names
        """
        available = []
        
        for provider_name, provider_class in cls._providers.items():
            try:
                provider = provider_class()
                if provider.is_available():
                    available.append(provider_name)
            except Exception as e:
                logger.debug(f"Provider {provider_name} not available: {str(e)}")
                
        return available

    @classmethod
    def get_provider_info(cls, provider_name: str) -> Optional[dict]:
        """
        Get information about a specific provider.

        Args:
            provider_name: Name of the provider

        Returns:
            Optional[dict]: Provider information or None if not found
        """
        provider_name = provider_name.lower()
        
        if provider_name not in cls._providers:
            return None

        provider_class = cls._providers[provider_name]
        
        try:
            provider = provider_class()
            return {
                "name": provider.provider_name,
                "available": provider.is_available(),
                "supported_languages": provider.supported_languages,
                "available_models": provider.get_available_models() if provider.is_available() else [],
                "default_model": provider.get_default_model() if provider.is_available() else None
            }
        except Exception as e:
            logger.debug(f"Failed to get info for provider {provider_name}: {str(e)}")
            return {
                "name": provider_name,
                "available": False,
                "error": str(e)
            }

    @classmethod
    def register_provider(cls, name: str, provider_class: Type[STTProviderBase]) -> None:
        """
        Register a new STT provider.

        Args:
            name: Name of the provider
            provider_class: The provider class
        """
        cls._providers[name.lower()] = provider_class
        logger.info(f"Registered STT provider: {name}")


# Legacy compatibility - create an ASRFactory alias
class ASRFactory:
    """Legacy ASRFactory for backward compatibility."""
    
    @staticmethod
    def get_model(model_name: str = "parakeet") -> STTProviderBase:
        """
        Get STT provider by model name (legacy interface).
        
        Args:
            model_name: Name of the model/provider to use
            
        Returns:
            STTProviderBase: The provider instance
        """
        # Map legacy model names to provider names
        provider_mapping = {
            "whisper": "whisper",
            "parakeet": "parakeet",
            "faster-whisper": "whisper"
        }
        
        provider_name = provider_mapping.get(model_name.lower(), model_name.lower())
        
        try:
            return STTProviderFactory.create_provider(provider_name)
        except SpeechRecognitionException:
            # Fallback to any available provider
            logger.warning(f"Requested provider {provider_name} not available, using fallback")
            return STTProviderFactory.create_provider_with_fallback(provider_name)