import gradio as gr
from huggingface_hub import InferenceClient
from typing import List, Tuple
import fitz  # PyMuPDF
from sentence_transformers import SentenceTransformer, util
import numpy as np
import faiss

client = InferenceClient("HuggingFaceH4/zephyr-7b-beta")

# Placeholder for the app's state
class MyApp:
    def __init__(self) -> None:
        self.documents = []
        self.embeddings = None
        self.index = None
        self.load_pdf("THEDIA1.pdf")
        self.build_vector_db()

    def load_pdf(self, file_path: str) -> None:
        """Extracts text from a PDF file and stores it in the app's documents."""
        doc = fitz.open(file_path)
        self.documents = []
        for page_num in range(len(doc)):
            page = doc[page_num]
            text = page.get_text()
            self.documents.append({"page": page_num + 1, "content": text})
        print("PDF processed successfully!")

    def build_vector_db(self) -> None:
        """Builds a vector database using the content of the PDF."""
        model = SentenceTransformer('all-MiniLM-L6-v2')
        self.embeddings = model.encode([doc["content"] for doc in self.documents])
        self.index = faiss.IndexFlatL2(self.embeddings.shape[1])
        self.index.add(np.array(self.embeddings))
        print("Vector database built successfully!")

    def search_documents(self, query: str, k: int = 3) -> List[str]:
        """Searches for relevant documents using vector similarity."""
        model = SentenceTransformer('all-MiniLM-L6-v2')
        query_embedding = model.encode([query])
        D, I = self.index.search(np.array(query_embedding), k)
        results = [self.documents[i]["content"] for i in I[0]]
        return results if results else ["No relevant documents found."]

app = MyApp()

def respond(
    message: str,
    history: List[Tuple[str, str]],
    system_message: str,
    max_tokens: int,
    temperature: float,
    top_p: float,
):
    system_message = (
        "You are a knowledgeable DBT (Dialectical Behavior Therapy) coach. You greet users warmly and ask questions like a real counselor. "
        "You are concise, respectful, and a good listener. You use the DBT book to guide users through DBT exercises and provide helpful information. "
        "When needed, you ask one follow-up question at a time to guide the user to ask appropriate questions. "
        "You avoid giving suggestions if any dangerous act is mentioned by the user and refer them to call someone or emergency services. "
        "Your responses are accurate and concise, and you maintain a professional and supportive tone throughout."
    )

    messages = [{"role": "system", "content": system_message}]

    for val in history:
        if val[0]:
            messages.append({"role": "user", "content": val[0]})
        if val[1]:
            messages.append({"role": "assistant", "content": val[1]})

    messages.append({"role": "user", "content": message})

    # RAG - Retrieve relevant documents
    try:
        retrieved_docs = app.search_documents(message)
        context = "\n".join(retrieved_docs)
        messages.append({"role": "system", "content": "Relevant documents: " + context})

        response = ""
        response_buffer = []
        for message in client.chat_completion(
            messages,
            max_tokens=max_tokens,
            stream=True,
            temperature=temperature,
            top_p=top_p,
        ):
            token = message.choices[0].delta.content
            response += token
            response_buffer.append(token)
            if token.endswith('.') or token.endswith('?'):
                yield ''.join(response_buffer)
                response_buffer = []

        if response_buffer:
            yield ''.join(response_buffer)

    except Exception as e:
        yield f"An error occurred: {str(e)}"

demo = gr.Blocks()

with demo:
    gr.Markdown("🧘‍♀️ **Dialectical Behaviour Therapy**")
    gr.Markdown(
        "‼️Disclaimer: This chatbot is based on a DBT exercise book that is publicly available. "
        "We are not medical practitioners, and the use of this chatbot is at your own responsibility.‼️"
    )
    
    chatbot = gr.ChatInterface(
        respond,
        examples=[
            ["I feel overwhelmed with work."],
            ["Can you guide me through a quick meditation?"],
            ["How do I stop worrying about things I can't control?"],
            ["What are some DBT skills for managing anxiety?"],
            ["Can you explain mindfulness in DBT?"],
            ["I am interested in DBT exercises"],
            ["I feel restless. Please help me."],
            ["I have destructive thoughts coming to my mind repetitively."]
        ],
        title='Dialectical Behaviour Therapy Assistant👩‍⚕️'
    )

if __name__ == "__main__":
    demo.launch()