models/space_b.py

# MentalQA – Arabic Mental Health Assistant (chat + classifier)

import torch
from transformers import (
    AutoTokenizer, AutoModelForCausalLM,
    AutoModelForSequenceClassification, pipeline
)

CHAT_REPO = "yasser-alharbi/MentalQA"
CLASSIFIER_REPO = "yasser-alharbi/MentalQA-Classification"

# Load chat model
chat_tok = AutoTokenizer.from_pretrained(CHAT_REPO, use_fast=False)
chat_model = AutoModelForCausalLM.from_pretrained(
    CHAT_REPO,
    torch_dtype="auto",
    device_map="auto",
    low_cpu_mem_usage=True,
)

# Load classifier
clf_tok = AutoTokenizer.from_pretrained(CLASSIFIER_REPO)
clf_model = AutoModelForSequenceClassification.from_pretrained(CLASSIFIER_REPO)

device_idx = 0 if torch.cuda.is_available() else -1
clf_pipe = pipeline("text-classification", model=clf_model, tokenizer=clf_tok, device=device_idx)

label_map = {
    "LABEL_0": "A",  # تشخيص
    "LABEL_1": "B",  # علاج
    "LABEL_2": "C",  # تشريح
    "LABEL_3": "D",  # وبائيات
    "LABEL_4": "E",  # نمط حياة
    "LABEL_5": "F",  # مقدم خدمة
    "LABEL_6": "G",  # أخرى
}

SYSTEM_MSG = (
    "أنت مساعد ذكي للصحة النفسية اسمه MentalQA. "
    "لا تذكر اسمك أو منصة عملك إلا إذا سُئلت صراحةً عن هويتك."
)

def classify_question(text: str, threshold: float = 0.5) -> str:
    pred = max(clf_pipe(text), key=lambda x: x["score"])
    return label_map.get(pred["label"], "G") if pred["score"] >= threshold else "G"

def build_prompt(question: str, final_qt: str) -> str:
    return (
        f"{SYSTEM_MSG}\n\n"
        f"final_QT: {final_qt}\n\n"
        f"سؤال المستخدم:\n{question}\n\n"
        "اكتب فقرة واحدة مفصّلة لا تقل عن ثلاث جمل مترابطة، بعد أن تفكّر خطوة بخطوة.\n"
        "الإجابة النهائية:\n"
    )

def generate_mentalqa_answer(question: str, threshold: float = 0.5) -> str:
    final_qt = classify_question(question, threshold)
    prompt = build_prompt(question, final_qt)

    chat_input = chat_tok.apply_chat_template(
        [{"role": "system", "content": SYSTEM_MSG},
         {"role": "user", "content": prompt}],
        add_generation_prompt=True,
        return_tensors="pt"
    ).to(chat_model.device)

    gen_output = chat_model.generate(
        chat_input,
        max_new_tokens=128,
        do_sample=True,
        temperature=0.6,
        top_p=0.95,
        repetition_penalty=1.15,
        no_repeat_ngram_size=2,
        pad_token_id=chat_tok.eos_token_id,
        eos_token_id=chat_tok.eos_token_id,
    )[0]

    answer = chat_tok.decode(gen_output[chat_input.shape[1]:], skip_special_tokens=True)
    return answer.strip()