model.py

import os
os.environ["TRANSFORMERS_CACHE"] = "/tmp/hf-cache"
os.environ["HF_HOME"] = "/tmp/hf-home"

import nltk
nltk.download("punkt", download_dir="/tmp/nltk_data")

from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.cluster import KMeans
from sklearn.metrics.pairwise import cosine_similarity
from nltk.tokenize import sent_tokenize
from transformers import pipeline
import numpy as np
import logging
import re

# === Pipelines ===
summarizer = pipeline("summarization", model="google/pegasus-xsum")
qa_pipeline = pipeline(
    "question-answering",
    model="distilbert-base-cased-distilled-squad",
    tokenizer="distilbert-base-cased-distilled-squad"
)

emotion_model = pipeline("text-classification", model="j-hartmann/emotion-english-distilroberta-base", top_k=1)

# === Brief Summarization ===
def summarize_review(text, max_len=100, min_len=30):
    try:
        result = summarizer(text, max_length=max_len, min_length=min_len, do_sample=False)
        if result and isinstance(result, list) and "summary_text" in result[0]:
            return result[0]["summary_text"]
        else:
            logging.warning("Summarizer output malformed, falling back.")
            return text
    except Exception as e:
        logging.warning(f"Fallback to raw text due to summarization error: {e}")
        return text


# === Smart Summarization with Clustering ===
def smart_summarize(text, n_clusters=1):
    try:
        sentences = sent_tokenize(text)
        if len(sentences) <= 1:
            return text
        tfidf = TfidfVectorizer(stop_words="english")
        tfidf_matrix = tfidf.fit_transform(sentences)
        if len(sentences) <= n_clusters:
            return " ".join(sentences)
        kmeans = KMeans(n_clusters=n_clusters, random_state=42).fit(tfidf_matrix)
        summary_sentences = []
        for i in range(n_clusters):
            idx = np.where(kmeans.labels_ == i)[0]
            if not len(idx):
                continue
            avg_vector = np.asarray(tfidf_matrix[idx].mean(axis=0))
            sim = cosine_similarity(avg_vector, tfidf_matrix[idx].toarray())
            most_representative = sentences[idx[np.argmax(sim)]]
            summary_sentences.append(most_representative)
        return " ".join(sorted(summary_sentences, key=sentences.index))
    except Exception as e:
        logging.error(f"Smart summarize error: {e}")
        return text

# === Emotion Detection (Fixed) ===
def detect_emotion(text):
    if not text.strip():
        return "neutral"
    try:
        result = emotion_model(text, top_k=1)
        if isinstance(result, list) and isinstance(result[0], dict):
            return result[0]["label"]
        elif isinstance(result, dict) and "label" in result:
            return result["label"]
        else:
            return "neutral"
    except Exception as e:
        logging.warning(f"Emotion detection failed: {e}")
        return "neutral"
    
# === Follow-up Q&A ===
def answer_followup(text, question, verbosity="brief"):
    try:
        if not question:
            return "No question provided."
        if isinstance(question, list):
            answers = []
            for q in question:
                if not q.strip():
                    continue
                response = qa_pipeline({"question": q, "context": text})
                ans = response.get("answer", "")
                answers.append(f"**{q}** → {ans}" if verbosity.lower() == "detailed" else ans)
            return answers
        else:
            response = qa_pipeline({"question": question, "context": text})
            ans = response.get("answer", "")
            return f"**{question}** → {ans}" if verbosity.lower() == "detailed" else ans
    except Exception as e:
        logging.warning(f"Follow-up error: {e}")
        return "Sorry, I couldn't generate a follow-up answer."

# === Direct follow-up route handler ===
def answer_only(text, question):
    try:
        if not question:
            return "No question provided."
        return qa_pipeline({"question": question, "context": text}).get("answer", "No answer found.")
    except Exception as e:
        logging.warning(f"Answer-only failed: {e}")
        return "Q&A failed."

# === Explanation Generator ===
def generate_explanation(text):
    try:
        explanation = summarizer(text, max_length=60, min_length=20, do_sample=False)[0]["summary_text"]
        return f"🧠 This review can be explained as: {explanation}"
    except Exception as e:
        logging.warning(f"Explanation failed: {e}")
        return "⚠️ Explanation could not be generated."

# === Churn Risk Estimator ===
def assess_churn_risk(sentiment_label, emotion_label):
    if sentiment_label.lower() == "negative" and emotion_label.lower() in ["anger", "fear", "sadness", "frustrated"]:
        return "High Risk"
    return "Low Risk"

# === Pain Point Extractor ===
def extract_pain_points(text):
    common_issues = [
        "slow", "crash", "lag", "expensive", "confusing", "noisy", "poor", "rude",
        "unhelpful", "bug", "broken", "unresponsive", "not working", "error", "delay", "disconnect",
        "incomplete", "overpriced", "difficult", "conflict", "unclear", "inconsistent",
        "missing", "locked", "freeze", "freeze-up", "conflicting", "conflicting answers", "outdated"
    ]

    text_lower = text.lower()
    matches = [kw for kw in common_issues if re.search(rf"\b{re.escape(kw)}\b", text_lower)]
    return list(set(matches))[:5]

# === Industry Detector ===
def detect_industry(text):
    text = text.lower()
    if any(k in text for k in ["doctor", "hospital", "health", "pill", "med"]): return "Healthcare"
    if any(k in text for k in ["flight", "hotel", "trip", "booking"]): return "Travel"
    if any(k in text for k in ["bank", "loan", "credit", "payment"]): return "Banking"
    if any(k in text for k in ["gym", "trainer", "fitness", "workout"]): return "Fitness"
    if any(k in text for k in ["movie", "series", "stream", "video"]): return "Entertainment"
    if any(k in text for k in ["game", "gaming", "console"]): return "Gaming"
    if any(k in text for k in ["food", "delivery", "restaurant", "order"]): return "Food Delivery"
    if any(k in text for k in ["school", "university", "teacher", "course"]): return "Education"
    if any(k in text for k in ["insurance", "policy", "claim"]): return "Insurance"
    if any(k in text for k in ["property", "rent", "apartment", "house"]): return "Real Estate"
    if any(k in text for k in ["shop", "buy", "product", "phone", "amazon", "flipkart"]): return "E-commerce"
    return "Generic"

# === Product Category Detector ===
def detect_product_category(text):
    text = text.lower()
    if any(k in text for k in ["mobile", "smartphone", "iphone", "samsung", "phone"]): return "Mobile Devices"
    if any(k in text for k in ["laptop", "macbook", "notebook", "chromebook"]): return "Laptops"
    if any(k in text for k in ["tv", "refrigerator", "microwave", "washer"]): return "Home Appliances"
    if any(k in text for k in ["watch", "band", "fitbit", "wearable"]): return "Wearables"
    if any(k in text for k in ["app", "portal", "site", "website"]): return "Web App"
    return "General"