OCR/backend/app/services/translation_service.py

"""
Tool_OCR - Translation Service (RESERVED)
Abstract interface and stub implementation for future translation feature
"""

from abc import ABC, abstractmethod
from typing import Dict, Optional, List
from enum import Enum
import logging


logger = logging.getLogger(__name__)


class TranslationEngine(str, Enum):
    """Supported translation engines"""
    OFFLINE = "offline"  # Argos Translate (offline)
    ERNIE = "ernie"  # Baidu ERNIE API
    GOOGLE = "google"  # Google Translate API
    DEEPL = "deepl"  # DeepL API


class LanguageCode(str, Enum):
    """Supported language codes"""
    CHINESE = "zh"
    ENGLISH = "en"
    JAPANESE = "ja"
    KOREAN = "ko"
    FRENCH = "fr"
    GERMAN = "de"
    SPANISH = "es"


class TranslationServiceInterface(ABC):
    """
    Abstract interface for translation services

    This interface defines the contract for all translation engine implementations.
    Future implementations should inherit from this class.
    """

    @abstractmethod
    def translate_text(
        self,
        text: str,
        source_lang: str,
        target_lang: str,
        **kwargs
    ) -> str:
        """
        Translate a single text string

        Args:
            text: Text to translate
            source_lang: Source language code
            target_lang: Target language code
            **kwargs: Engine-specific parameters

        Returns:
            str: Translated text
        """
        pass

    @abstractmethod
    def translate_document(
        self,
        markdown_content: str,
        source_lang: str,
        target_lang: str,
        preserve_structure: bool = True,
        **kwargs
    ) -> Dict[str, any]:
        """
        Translate a Markdown document while preserving structure

        Args:
            markdown_content: Markdown content to translate
            source_lang: Source language code
            target_lang: Target language code
            preserve_structure: Whether to preserve markdown structure
            **kwargs: Engine-specific parameters

        Returns:
            Dict containing:
                - translated_content: Translated markdown
                - metadata: Translation metadata (engine, time, etc.)
        """
        pass

    @abstractmethod
    def batch_translate(
        self,
        texts: List[str],
        source_lang: str,
        target_lang: str,
        **kwargs
    ) -> List[str]:
        """
        Translate multiple texts in batch

        Args:
            texts: List of texts to translate
            source_lang: Source language code
            target_lang: Target language code
            **kwargs: Engine-specific parameters

        Returns:
            List[str]: List of translated texts
        """
        pass

    @abstractmethod
    def get_supported_languages(self) -> List[str]:
        """
        Get list of supported language codes for this engine

        Returns:
            List[str]: List of supported language codes
        """
        pass

    @abstractmethod
    def validate_config(self) -> bool:
        """
        Validate engine configuration (API keys, model files, etc.)

        Returns:
            bool: True if configuration is valid
        """
        pass


class TranslationEngineFactory:
    """
    Factory for creating translation engine instances

    RESERVED: This is a placeholder for future implementation.
    When translation feature is implemented, this factory will instantiate
    the appropriate translation engine based on configuration.
    """

    @staticmethod
    def create_engine(
        engine_type: TranslationEngine,
        config: Optional[Dict] = None
    ) -> TranslationServiceInterface:
        """
        Create a translation engine instance

        Args:
            engine_type: Type of translation engine
            config: Engine-specific configuration

        Returns:
            TranslationServiceInterface: Translation engine instance

        Raises:
            NotImplementedError: Always raised (stub implementation)
        """
        raise NotImplementedError(
            "Translation feature is not yet implemented. "
            "This is a reserved placeholder for future development."
        )

    @staticmethod
    def get_available_engines() -> List[str]:
        """
        Get list of available translation engines

        Returns:
            List[str]: List of engine types (currently empty)
        """
        return []

    @staticmethod
    def is_engine_available(engine_type: TranslationEngine) -> bool:
        """
        Check if a specific engine is available

        Args:
            engine_type: Engine type to check

        Returns:
            bool: Always False (stub implementation)
        """
        return False


class StubTranslationService:
    """
    Stub translation service for API endpoints

    This service provides placeholder responses for translation endpoints
    until the feature is fully implemented.
    """

    @staticmethod
    def get_feature_status() -> Dict[str, any]:
        """
        Get translation feature status

        Returns:
            Dict with feature status information
        """
        return {
            "available": False,
            "status": "reserved",
            "message": "Translation feature is reserved for future implementation",
            "supported_engines": [],
            "planned_engines": [
                {
                    "type": "offline",
                    "name": "Argos Translate",
                    "description": "Offline neural translation",
                    "status": "planned"
                },
                {
                    "type": "ernie",
                    "name": "Baidu ERNIE",
                    "description": "Baidu AI translation API",
                    "status": "planned"
                },
                {
                    "type": "google",
                    "name": "Google Translate",
                    "description": "Google Cloud Translation API",
                    "status": "planned"
                },
                {
                    "type": "deepl",
                    "name": "DeepL",
                    "description": "DeepL translation API",
                    "status": "planned"
                }
            ],
            "roadmap": {
                "phase": "Phase 5",
                "priority": "low",
                "implementation_after": "Production deployment and user feedback"
            }
        }

    @staticmethod
    def get_supported_languages() -> List[Dict[str, str]]:
        """
        Get list of languages planned for translation support

        Returns:
            List of language info dicts
        """
        return [
            {"code": "zh", "name": "Chinese (Simplified)", "status": "planned"},
            {"code": "en", "name": "English", "status": "planned"},
            {"code": "ja", "name": "Japanese", "status": "planned"},
            {"code": "ko", "name": "Korean", "status": "planned"},
            {"code": "fr", "name": "French", "status": "planned"},
            {"code": "de", "name": "German", "status": "planned"},
            {"code": "es", "name": "Spanish", "status": "planned"},
        ]


# Example placeholder for future engine implementations:
#
# class ArgosTranslationEngine(TranslationServiceInterface):
#     """Offline translation using Argos Translate"""
#     def __init__(self, model_path: str):
#         self.model_path = model_path
#         # Initialize Argos models
#
#     def translate_text(self, text, source_lang, target_lang, **kwargs):
#         # Implementation here
#         pass
#
# class ERNIETranslationEngine(TranslationServiceInterface):
#     """Baidu ERNIE API translation"""
#     def __init__(self, api_key: str, api_secret: str):
#         self.api_key = api_key
#         self.api_secret = api_secret
#
#     def translate_text(self, text, source_lang, target_lang, **kwargs):
#         # Implementation here
#         pass