office_translator/services/translation_service.py

"""
Translation Service Abstraction
Provides a unified interface for different translation providers
"""
from abc import ABC, abstractmethod
from typing import Optional, List
import requests
from deep_translator import GoogleTranslator, DeeplTranslator, LibreTranslator
from config import config


class TranslationProvider(ABC):
    """Abstract base class for translation providers"""
    
    @abstractmethod
    def translate(self, text: str, target_language: str, source_language: str = 'auto') -> str:
        """Translate text from source to target language"""
        pass


class GoogleTranslationProvider(TranslationProvider):
    """Google Translate implementation"""
    
    def translate(self, text: str, target_language: str, source_language: str = 'auto') -> str:
        if not text or not text.strip():
            return text
        
        try:
            translator = GoogleTranslator(source=source_language, target=target_language)
            return translator.translate(text)
        except Exception as e:
            print(f"Translation error: {e}")
            return text


class DeepLTranslationProvider(TranslationProvider):
    """DeepL Translate implementation"""
    
    def __init__(self, api_key: str):
        self.api_key = api_key
    
    def translate(self, text: str, target_language: str, source_language: str = 'auto') -> str:
        if not text or not text.strip():
            return text
        
        try:
            translator = DeeplTranslator(api_key=self.api_key, source=source_language, target=target_language)
            return translator.translate(text)
        except Exception as e:
            print(f"Translation error: {e}")
            return text


class LibreTranslationProvider(TranslationProvider):
    """LibreTranslate implementation"""
    
    def translate(self, text: str, target_language: str, source_language: str = 'auto') -> str:
        if not text or not text.strip():
            return text
        
        try:
            # LibreTranslator doesn't need API key for self-hosted instances
            translator = LibreTranslator(source=source_language, target=target_language, custom_url="http://localhost:5000")
            return translator.translate(text)
        except Exception as e:
            # Fail silently and return original text
            return text


class OllamaTranslationProvider(TranslationProvider):
    """Ollama LLM translation implementation"""
    
    def __init__(self, base_url: str = "http://localhost:11434", model: str = "llama3", vision_model: str = "llava"):
        self.base_url = base_url.rstrip('/')
        self.model = model
        self.vision_model = vision_model
    
    def translate(self, text: str, target_language: str, source_language: str = 'auto') -> str:
        if not text or not text.strip():
            return text
        
        try:
            prompt = f"Translate the following text to {target_language}. Return ONLY the translation, nothing else:\n\n{text}"
            
            response = requests.post(
                f"{self.base_url}/api/generate",
                json={
                    "model": self.model,
                    "prompt": prompt,
                    "stream": False
                },
                timeout=30
            )
            response.raise_for_status()
            result = response.json()
            return result.get("response", text).strip()
        except Exception as e:
            print(f"Ollama translation error: {e}")
            return text
    
    def translate_image(self, image_path: str, target_language: str) -> str:
        """Translate text within an image using Ollama vision model"""
        import base64
        
        try:
            # Read and encode image
            with open(image_path, 'rb') as img_file:
                image_data = base64.b64encode(img_file.read()).decode('utf-8')
            
            prompt = f"Extract all text from this image and translate it to {target_language}. Return ONLY the translated text, preserving the structure and formatting."
            
            response = requests.post(
                f"{self.base_url}/api/generate",
                json={
                    "model": self.vision_model,
                    "prompt": prompt,
                    "images": [image_data],
                    "stream": False
                },
                timeout=60
            )
            response.raise_for_status()
            result = response.json()
            return result.get("response", "").strip()
        except Exception as e:
            print(f"Ollama vision translation error: {e}")
            return ""
    
    @staticmethod
    def list_models(base_url: str = "http://localhost:11434") -> List[str]:
        """List available Ollama models"""
        try:
            response = requests.get(f"{base_url.rstrip('/')}/api/tags", timeout=5)
            response.raise_for_status()
            models = response.json().get("models", [])
            return [model["name"] for model in models]
        except Exception as e:
            print(f"Error listing Ollama models: {e}")
            return []


class WebLLMTranslationProvider(TranslationProvider):
    """WebLLM browser-based translation (client-side processing)"""
    
    def translate(self, text: str, target_language: str, source_language: str = 'auto') -> str:
        # WebLLM translation happens client-side in the browser
        # This is just a placeholder - actual translation is done by JavaScript
        # For server-side, we'll just pass through for now
        return text


class TranslationService:
    """Main translation service that delegates to the configured provider"""
    
    def __init__(self, provider: Optional[TranslationProvider] = None):
        if provider:
            self.provider = provider
        else:
            # Auto-select provider based on configuration
            self.provider = self._get_default_provider()
    
    def _get_default_provider(self) -> TranslationProvider:
        """Get the default translation provider from configuration"""
        # Always use Google Translate by default to avoid API key issues
        # Provider will be overridden per request in the API endpoint
        return GoogleTranslationProvider()
    
    def translate_text(self, text: str, target_language: str, source_language: str = 'auto') -> str:
        """
        Translate a single text string
        
        Args:
            text: Text to translate
            target_language: Target language code (e.g., 'es', 'fr', 'de')
            source_language: Source language code (default: 'auto' for auto-detection)
        
        Returns:
            Translated text
        """
        if not text or not text.strip():
            return text
        
        return self.provider.translate(text, target_language, source_language)
    
    def translate_batch(self, texts: list[str], target_language: str, source_language: str = 'auto') -> list[str]:
        """
        Translate multiple text strings
        
        Args:
            texts: List of texts to translate
            target_language: Target language code
            source_language: Source language code (default: 'auto')
        
        Returns:
            List of translated texts
        """
        return [self.translate_text(text, target_language, source_language) for text in texts]


# Global translation service instance
translation_service = TranslationService()