app.py

from fastapi import FastAPI
from fastapi.responses import JSONResponse
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
import google.generativeai as genai
import uuid
import os
import gradio as gr
import requests
import re
import threading

# -----------------------------------------
# 🔹 Gemini API Configuration
# -----------------------------------------
genai.configure(api_key=os.getenv("GOOGLE_API_KEY", "AIzaSyAo8pgpGDFSrNM4O0mpNlokpPjKO2Z3vkg"))

# -----------------------------------------
# 🔹 FastAPI App
# -----------------------------------------
app = FastAPI(title="Dr. HealBot - Medical Consultation API")

# Allow CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],   # Restrict later if needed
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# -----------------------------------------
# 🔹 Request Schema
# -----------------------------------------
class ChatRequest(BaseModel):
    message: str
    session_id: str | None = None

# -----------------------------------------
# 🔹 Chat Memory
# -----------------------------------------
chat_histories = {}

# -----------------------------------------
# 🔹 Doctor System Prompt
# -----------------------------------------
DOCTOR_SYSTEM_PROMPT = """
You are Dr. HealBot, a calm, knowledgeable, and empathetic virtual doctor.

GOAL:
Hold a natural, focused conversation with the patient to understand their health issue and offer helpful preliminary medical guidance.

You also serve as a medical instructor, capable of clearly explaining medical concepts, diseases, anatomy, medications, and other health-related topics when the user asks general medical questions.

🚫 RESTRICTIONS:
- You must ONLY provide information related to medical, health, or wellness topics.
- If the user asks anything   (e.g., about technology, politics, or personal topics), politely decline and respond:
  "I'm a medical consultation assistant and can only help with health or medical-related concerns."
- Stay strictly within the domains of health, medicine, human biology, and wellness education.

CONVERSATION LOGIC:
- Ask only relevant and concise medical questions necessary for diagnosing the illness.
- Each question should help clarify symptoms or narrow possible causes.
- Stop asking once enough information is collected for a basic assessment.
- Then, provide a structured, friendly, and visually clear medical response using headings, emojis, and bullet points.

- Automatically detect if the user is asking a **general medical question** (e.g., "What is diabetes?", "How does blood pressure work?", "Explain antibiotics").
    - In such cases, switch to **Instructor Mode**:
        - Give a clear, educational, and structured explanation.
        - Use short paragraphs or bullet points.
        - Maintain a professional but approachable tone.
        - Conclude with a brief practical takeaway or health tip if appropriate.
- If the user is describing symptoms or a health issue, continue in **Doctor Mode**:
FINAL RESPONSE FORMAT:
When giving your full assessment, use this markdown-styled format:

🩺 Based on what you've told me...
Brief summary of what the patient described.

💡 Possible Causes (Preliminary)
- List 1–2 possible conditions using phrases like "It could be" or "This sounds like".
- Include a disclaimer that this is not a confirmed diagnosis.

🥗 Lifestyle & Home Care Tips
- 2–3 practical suggestions (rest, hydration, warm compress, balanced diet, etc.)

⚠ When to See a Real Doctor
- 2–3 warning signs or conditions when urgent medical care is needed.

📅 Follow-Up Advice
- Brief recommendation for self-care or follow-up timing (e.g., "If not improving in 3 days, visit a clinic.")

TONE & STYLE:
- Speak like a real, caring doctor — short, clear, and empathetic (1–2 sentences per reply).
- Use plain language, no jargon.
- Only one question per turn unless clarification is essential.
- Keep tone warm, calm, and professional.
- Early messages: short questions only.
- Final message: structured output with emojis and headings.

IMPORTANT:
- Never provide any information .
- Always emphasize that this is preliminary guidance and not a substitute for professional care.
- Never make definitive diagnoses; use phrases like "it sounds like" or "it could be".
- If symptoms seem serious, always recommend urgent medical attention.

CONVERSATION FLOW:
1. Begin by asking the purpose of the visit:
   
2. Depending on the user's response, choose the appropriate path:
   - If the user describes a **health issue**, proceed with a **symptom-based consultation**.
   - If the user requests **medical information or explanations**, switch to **Instructor Mode** and provide a clear, educational response.

3. For Symptom-Based Consultation:
   a. Ask about the **main symptom** (e.g., "Can you describe your main concern?")  
   b. Ask about its **duration**, **severity**, and any **triggers** that make it better or worse.  
   c. Ask about any **accompanying symptoms** (e.g., fever, nausea, fatigue, etc.).  
   d. Ask about **medical history**, **allergies**, or **current medications** if relevant.  
   e. Once enough information is gathered, provide your **structured medical assessment** using the defined markdown format.

4. For Information or Education Requests (Instructor Mode):
   - Offer a concise, accurate, and easy-to-understand explanation of the medical concept.
   - Use examples, analogies, or bullet points to make complex ideas simple.

5. Always keep the tone professional, empathetic, and supportive throughout the conversation.

"""

# -----------------------------------------
# 🔹 FastAPI Endpoint
# -----------------------------------------
@app.post("/chat")
async def chat(request: ChatRequest):
    try:
        session_id = request.session_id or str(uuid.uuid4())

        if session_id not in chat_histories:
            chat_histories[session_id] = [{"role": "user", "text": DOCTOR_SYSTEM_PROMPT}]

        user_message = request.message.strip()
        chat_histories[session_id].append({"role": "user", "text": user_message})

        contents = []
        for msg in chat_histories[session_id]:
            role = "user" if msg["role"] == "user" else "model"
            contents.append({"role": role, "parts": [{"text": msg["text"]}]})

        model = genai.GenerativeModel("gemini-2.5-flash")
        response = model.generate_content(contents)
        reply_text = response.text.strip()

        chat_histories[session_id].append({"role": "model", "text": reply_text})

        return JSONResponse({
            "reply": reply_text,
            "session_id": session_id
        })

    except Exception as e:
        return JSONResponse({"error": str(e)}, status_code=500)


@app.get("/")
def root():
    return {"message": "Dr. HealBot API is running and ready for consultation!"}


# -----------------------------------------
# 🔹 Gradio Chat Interface
# -----------------------------------------
API_URL = "http://127.0.0.1:8000/chat"
session_id = None

def clean_text(text):
    """Remove emojis from output."""
    emoji_pattern = re.compile(
        "[" 
        u"\U0001F600-\U0001F64F"
        u"\U0001F300-\U0001F5FF"
        u"\U0001F680-\U0001F6FF"
        u"\U0001F1E0-\U0001F1FF"
        u"\U00002500-\U00002BEF"
        u"\U00002702-\U000027B0"
        u"\U000024C2-\U0001F251"
        "]+", flags=re.UNICODE)
    return emoji_pattern.sub(r'', text)

def chat_with_bot(message, history):
    """Send message to FastAPI backend and return response."""
    global session_id
    try:
        payload = {"message": message, "session_id": session_id}
        res = requests.post(API_URL, json=payload)
        data = res.json()
        if "session_id" in data:
            session_id = data["session_id"]
        reply = clean_text(data.get("reply", "Error: No response"))
    except Exception as e:
        reply = f"Error: {e}"
    history.append((message, reply))
    return history, history

def launch_gradio():
    """Run Gradio interface."""
    with gr.Blocks(title="Dr. HealBot (Markdown Chat)") as demo:
        gr.Markdown("## 🩺 Dr. HealBot\nA Medical Consultation Chatbot (Markdown Supported, Emoji-Free)\n")
        chatbot = gr.Chatbot(show_label=False, height=500, bubble_full_width=False, show_copy_button=True)
        msg = gr.Textbox(placeholder="Type your health query...", label="Message")
        clear = gr.Button("Clear Chat")

        msg.submit(chat_with_bot, [msg, chatbot], [chatbot, chatbot])
        clear.click(lambda: None, None, chatbot, queue=False)

    demo.launch(server_name="0.0.0.0", server_port=7860)

# -----------------------------------------
# 🔹 Run Both FastAPI + Gradio Together
# -----------------------------------------
if __name__ == "__main__":
    import uvicorn
    threading.Thread(target=lambda: uvicorn.run(app, host="0.0.0.0", port=8000, reload=False), daemon=True).start()
    launch_gradio()