src/model_utils.py

import streamlit as st
from transformers import AutoTokenizer, AutoModelForSequenceClassification, pipeline
from underthesea import word_tokenize
# from src.text_preprocessor import preprocess_text 

MODEL_NAME = "ndyah2020/phobert-base-v2-vsmec-finetuned"
# MODEL_NAME = "wonrax/phobert-base-vietnamese-sentiment" # 

@st.cache_resource
def load_sentiment_pipeline():
    try:
        tokenizer = AutoTokenizer.from_pretrained(MODEL_NAME, use_fast=False)
        model = AutoModelForSequenceClassification.from_pretrained(MODEL_NAME)

        sentiment_pipeline = pipeline(
            "sentiment-analysis",
            model=model,
            tokenizer=tokenizer,
            truncation=True,
            max_length=256,
        )

        st.success("✅ Mô hình (local) đã sẵn sàng!")
        return sentiment_pipeline

    except Exception as e:
        st.error(f"❌ Lỗi khi tải mô hình local: {e}")
        return None


def predict_sentiment(text: str, sentiment_pipeline):
    if not text or sentiment_pipeline is None:
        return "Lỗi", 0.0

    try:
        segmented_text = " ".join(word_tokenize(text))
        result = sentiment_pipeline(segmented_text)[0]
        label_map = {
            "NEG": "NEGATIVE",
            "POS": "POSITIVE",
            "NEU": "NEUTRAL"
        }

        raw_label = result["label"].upper()
        confidence = float(result["score"])
        
        CONFIDENCE_THRESHOLD = 0.5 
        if confidence < CONFIDENCE_THRESHOLD:
            # Nếu độ tin cậy quá thấp, ép về Trung tính
            label = label_map["NEU"]
            label += " (không rõ)"
        
        else:
            # Nếu độ tin cậy đủ cao, dùng nhãn dự đoán
            label = label_map.get(raw_label, "Không xác định")
            
            if confidence >= 0.85:
                label += " (rất rõ)"
            elif confidence >= 0.7:
                label += " (khá rõ)"
            else:
                label += " (hơi nhẹ)"

        return label, confidence

    except Exception as e:
        print(f"Lỗi khi dự đoán: {e}")
        return "Lỗi", 0.0