translator.py

from transformers import pipeline, AutoTokenizer, AutoModelForSeq2SeqLM
import torch

class ImprovedTranslator:
    def __init__(self):
        """Initialize translator with multiple model options"""
        self.device = 0 if torch.cuda.is_available() else -1
        self.models = {}
        self.current_model = "nllb"  # Default model
        
    def load_model(self, model_type="nllb"):
        """Load translation model based on type"""
        if model_type == "nllb" and "nllb" not in self.models:
            # NLLB (No Language Left Behind) - Meta's multilingual model
            # Better quality, supports 200+ languages
            self.models["nllb"] = pipeline(
                "translation",
                model="facebook/nllb-200-distilled-600M",
                device=self.device,
                torch_dtype=torch.float16 if torch.cuda.is_available() else torch.float32
            )
            
        elif model_type == "mbart" and "mbart" not in self.models:
            # mBART - Good for Indonesian
            self.models["mbart"] = pipeline(
                "translation",
                model="facebook/mbart-large-50-many-to-many-mmt",
                device=self.device
            )
            
        elif model_type == "opus" and "opus" not in self.models:
            # Original Helsinki-NLP (fallback)
            self.models["opus"] = {
                "id_en": pipeline("translation", model="Helsinki-NLP/opus-mt-id-en", device=self.device),
                "en_id": pipeline("translation", model="Helsinki-NLP/opus-mt-en-id", device=self.device)
            }
            
        elif model_type == "t5" and "t5" not in self.models:
            # T5-based Indonesian model
            self.models["t5"] = pipeline(
                "translation",
                model="google/flan-t5-base",
                device=self.device
            )
    
    def translate_with_nllb(self, text, direction):
        """Translate using NLLB model"""
        if "nllb" not in self.models:
            self.load_model("nllb")
            
        if direction == "ID → EN":
            src_lang = "ind_Latn"  # Indonesian
            tgt_lang = "eng_Latn"  # English
        else:
            src_lang = "eng_Latn"  # English  
            tgt_lang = "ind_Latn"  # Indonesian
            
        result = self.models["nllb"](
            text,
            src_lang=src_lang,
            tgt_lang=tgt_lang,
            max_length=512
        )
        return result[0]['translation_text']
    
    def translate_with_mbart(self, text, direction):
        """Translate using mBART model"""
        if "mbart" not in self.models:
            self.load_model("mbart")
            
        if direction == "ID → EN":
            # mBART format
            text = f">>en<< {text}"  # Target English
        else:
            text = f">>id<< {text}"  # Target Indonesian
            
        result = self.models["mbart"](text)
        return result[0]['translation_text']
    
    def translate_with_opus(self, text, direction):
        """Translate using original Helsinki-NLP model"""
        if "opus" not in self.models:
            self.load_model("opus")
            
        if direction == "ID → EN":
            return self.models["opus"]["id_en"](text)[0]['translation_text']
        else:
            return self.models["opus"]["en_id"](text)[0]['translation_text']

# Global translator instance
translator = ImprovedTranslator()

def translate(text, direction, model_type="nllb"):
    """
    Main translation function
    
    Args:
        text (str): Text to translate
        direction (str): "ID → EN" or "EN → ID" 
        model_type (str): "nllb", "mbart", "opus", or "t5"
    """
    try:
        if model_type == "nllb":
            return translator.translate_with_nllb(text, direction)
        elif model_type == "mbart":
            return translator.translate_with_mbart(text, direction)
        elif model_type == "opus":
            return translator.translate_with_opus(text, direction)
        else:
            # Default to NLLB if unknown model
            return translator.translate_with_nllb(text, direction)
            
    except Exception as e:
        print(f"Translation error with {model_type}: {e}")
        # Fallback to OPUS if other models fail
        if model_type != "opus":
            return translator.translate_with_opus(text, direction)
        else:
            return f"Translation failed: {str(e)}"

# Wrapper untuk kompatibilitas dengan kode lama
def translate_simple(text, direction):
    """Simple wrapper for backward compatibility"""
    return translate(text, direction, "nllb")