app.py

import gradio as gr
from transformers import AutoModelForCausalLM, AutoTokenizer
import torch

class MentalHealthChatbot:
    def __init__(self, model_path="hemhemoh/Gemma-2-2b-it-wazobia-wellness-bot"):
        self.model = AutoModelForCausalLM.from_pretrained(model_path)
        self.tokenizer = AutoTokenizer.from_pretrained(model_path)
        
        # Comprehensive system instruction
        self.predefined_instruction = (
            "CORE THERAPEUTIC GUIDELINES:\n"
            "1. Professional Role: You are an advanced AI mental health support assistant, "
            "trained to provide compassionate, culturally sensitive, and professional psychological support.\n"
            "2. Communication Principles:\n"
            "   - Listen actively and empathetically\n"
            "   - Validate the user's emotions without judgment\n"
            "   - Provide support that is culturally nuanced (English, Yoruba, Igbo, Hausa)\n"
            "   - Maintain professional boundaries\n"
            "3. Response Strategy:\n"
            "   - Use a warm, supportive, and non-threatening tone\n"
            "   - Ask open-ended, reflective questions\n"
            "   - Offer practical coping strategies\n"
            "   - Avoid direct medical diagnosis\n"
            "4. Safety Protocol:\n"
            "   - If user expresses thoughts of self-harm or suicide, respond with immediate compassion and provide crisis resource information\n"
            "   - Never minimize the user's feelings\n"
            "   - Encourage professional help when issues seem complex\n"
            "5. Linguistic Flexibility:\n"
            "   - Respond in the language of the user\n"
            "   - Use culturally appropriate language and metaphors\n"
        )

    def prepare_prompt(self, message, history):
        # Construct conversation history
        conversation_context = ""
        for user_input, assistant_response in history:
            if user_input:
                conversation_context += f"User: {user_input}\n"
            if assistant_response:
                conversation_context += f"Assistant: {assistant_response}\n"
        
        # Combine system instruction, conversation history, and new message
        full_prompt = (
            f"{self.predefined_instruction}\n"
            f"CONVERSATION HISTORY:\n{conversation_context}\n"
            f"CURRENT USER MESSAGE:\n{message}\n"
            f"ASSISTANT'S COMPASSIONATE RESPONSE:"
        )
        
        return full_prompt

    def respond(
        self,
        message,
        history,
        max_tokens=512,
        temperature=0.2,
        top_p=0.5
    ):
        # Prepare the comprehensive prompt
        full_prompt = self.prepare_prompt(message, history)
        
        # Tokenize the prompt
        inputs = self.tokenizer(full_prompt, return_tensors="pt", padding=True, truncation=True)
        
        outputs = self.model.generate(
            **inputs,
            max_length=max(512, inputs["input_ids"].shape[1] + max_tokens)
            temperature=temperature,
            top_p=top_p,
            no_repeat_ngram_size=3,
            do_sample=True
        )
        
        # Decode the response
        response = self.tokenizer.decode(outputs[0], skip_special_tokens=True)
        
        # Optional: Post-processing to extract only the assistant's response
        if "ASSISTANT'S COMPASSIONATE RESPONSE:" in response:
            response = response.split("ASSISTANT'S COMPASSIONATE RESPONSE:")[-1].strip()
        
        yield response

def main():
    chatbot = MentalHealthChatbot()
    
    demo = gr.ChatInterface(
        chatbot.respond,
        additional_inputs=[
            gr.Slider(minimum=1, maximum=512, value=170, step=1, label="Max new tokens"),
            gr.Slider(minimum=0.1, maximum=1.0, value=0.2, step=0.1, label="Temperature"),
            gr.Slider(minimum=0.1, maximum=1.0, value=0.8, step=0.05, label="Top-p (nucleus sampling)"),
        ],
        title="Mental Health Support Chatbot",
        description="An AI assistant providing compassionate, culturally sensitive mental health support."
    )
    
    demo.launch()

if __name__ == "__main__":
    main()