import os
from threading import Thread
from typing import Iterator

import gradio as gr
import spaces
import torch
from transformers import AutoModelForCausalLM, AutoTokenizer, TextIteratorStreamer, TextStreamer
from llama_index.core.prompts.prompts import SimpleInputPrompt
from llama_index.llms.huggingface import HuggingFaceLLM
from llama_index.legacy.embeddings.langchain import LangchainEmbedding
#from langchain.embeddings.huggingface import HuggingFaceEmbeddings # This import should now work
from langchain_huggingface import HuggingFaceEmbeddings
from sentence_transformers import SentenceTransformer

from llama_index.core import set_global_service_context, ServiceContext

from llama_index.core import VectorStoreIndex, download_loader, Document # Import Document
from pathlib import Path
import fitz  # PyMuPDF

MAX_MAX_NEW_TOKENS = 2048
DEFAULT_MAX_NEW_TOKENS = 512
MAX_INPUT_TOKEN_LENGTH = int(os.getenv("MAX_INPUT_TOKEN_LENGTH", "4096"))
DEFAULT_SYS_PROMPT = """\
"""

DESCRIPTION = """\
# Test Chat Information System for MEPO 2024 courtesy of Dr. Dancy & THiCC Lab

Duplicated, then modified from [llama-2 7B example](https://huggingface.co/spaces/huggingface-projects/llama-2-7b-chat)
"""

LICENSE = """
<p/>

---
As a derivate work of [Llama-2-7b-chat](https://huggingface.co/meta-llama/Llama-2-7b-chat) by Meta,
this demo is governed by the original [license](https://huggingface.co/spaces/huggingface-projects/llama-2-7b-chat/blob/main/LICENSE.txt) and [acceptable use policy](https://huggingface.co/spaces/huggingface-projects/llama-2-7b-chat/blob/main/USE_POLICY.md).
"""

SYSTEM_PROMPT = """<s>[INST] <<SYS>>

    <</SYS>>"""

def read_pdf_to_documents(file_path):
    doc = fitz.open(file_path)
    documents = []
    for page_num in range(len(doc)):
        page = doc.load_page(page_num)
        text = page.get_text()
        documents.append(Document(text=text)) # Now Document is defined
    return documents

# Function to update the global system prompt
def update_system_prompt(new_prompt):
    global SYSTEM_PROMPT
    SYSTEM_PROMPT = new_prompt
    query_wrapper_prompt = SimpleInputPrompt("{query_str} [/INST]")
    return "System prompt updated."

@spaces.GPU(duration=240)
def query_model(question):
    llm = HuggingFaceLLM(
        context_window=4096,
        max_new_tokens=256,
        system_prompt=SYSTEM_PROMPT,
        query_wrapper_prompt=query_wrapper_prompt,
        model=model,
        tokenizer=tokenizer
    )
    #embeddings = LangchainEmbedding(HuggingFaceEmbeddings(model_name="all-MiniLM-L6-v2"))
    service_context = ServiceContext.from_defaults(chunk_size=1024, llm=llm, embed_model=embeddings)
    set_global_service_context(service_context)

    response = query_engine.query(question)
    # formatted_response = format_paragraph(response.response)
    return response.response

def format_paragraph(text, line_length=80):
    words = text.split()
    lines = []
    current_line = []
    current_length = 0

    for word in words:
        if current_length + len(word) + 1 > line_length:
            lines.append(' '.join(current_line))
            current_line = [word]
            current_length = len(word) + 1
        else:
            current_line.append(word)
            current_length += len(word) + 1

    if current_line:
        lines.append(' '.join(current_line))

    return '\n'.join(lines)

if not torch.cuda.is_available():
    DESCRIPTION += "We won't be able to run this space! We need GPU processing"


if torch.cuda.is_available():
    model_id = "meta-llama/Llama-2-7b-chat-hf"
    model = AutoModelForCausalLM.from_pretrained(model_id, torch_dtype=torch.float16, device_map="auto")
    tokenizer = AutoTokenizer.from_pretrained(model_id)
    tokenizer.use_default_system_prompt = False
    # Throw together the query wrapper
    query_wrapper_prompt = SimpleInputPrompt("{query_str} [/INST]")
    llm = HuggingFaceLLM(context_window=4096,
                     max_new_tokens=256,
                     system_prompt=SYSTEM_PROMPT,
                     query_wrapper_prompt=query_wrapper_prompt,
                     model=model, tokenizer=tokenizer)
    embeddings = LangchainEmbedding(HuggingFaceEmbeddings(model_name="all-MiniLM-L6-v2"))
    service_context = ServiceContext.from_defaults(chunk_size=1024, llm=llm, embed_model=embeddings)
    set_global_service_context(service_context)
    file_path = Path("files/Full Pamplet.pdf")
    documents = read_pdf_to_documents(file_path)
    index = VectorStoreIndex.from_documents(documents)
    query_engine = index.as_query_engine()


update_prompt_interface = gr.Interface(
    fn=update_system_prompt,
    inputs=gr.Textbox(lines=5, placeholder="Enter the system prompt here...", label="System Prompt", value=SYSTEM_PROMPT),
    outputs=gr.Textbox(label="Status"),
    title="System Prompt Updater",
    description="Update the system prompt used for context."
)

# Create Gradio interface for querying the model
query_interface = gr.Interface(
    fn=query_model,
    inputs=gr.Textbox(lines=2, placeholder="Enter your question here...", label="User Question"),
    outputs=gr.Textbox(label="Response"),
    title="Document Query Assistant",
    description="Ask questions based on the content of the loaded pamphlet."
)

# Combine the interfaces
combined_interface = gr.TabbedInterface([update_prompt_interface, query_interface], ["Update System Prompt", "Query Assistant"])

# Launch the combined interface
#combined_interface.launch()

"""
@spaces.GPU(duration=240)
def generate(
    message: str,
    chat_history: list[tuple[str, str]],
    system_prompt: str,
    max_new_tokens: int = MAX_MAX_NEW_TOKENS,
    temperature: float = 0.6,
    top_p: float = 0.9,
    top_k: int = 50,
    repetition_penalty: float = 1.2,
) -> Iterator[str]:
    conversation = []
    if system_prompt:
        conversation.append({"role": "system", "content": system_prompt})
    for user, assistant in chat_history:
        conversation.extend([{"role": "user", "content": user}, {"role": "assistant", "content": assistant}])
    conversation.append({"role": "user", "content": message})

    input_ids = tokenizer.apply_chat_template(conversation, return_tensors="pt")
    if input_ids.shape[1] > MAX_INPUT_TOKEN_LENGTH:
        input_ids = input_ids[:, -MAX_INPUT_TOKEN_LENGTH:]
        gr.Warning(f"Trimmed input from conversation as it was longer than {MAX_INPUT_TOKEN_LENGTH} tokens.")
    input_ids = input_ids.to(model.device)

    streamer = TextIteratorStreamer(tokenizer, timeout=10.0, skip_prompt=True, skip_special_tokens=True)
    generate_kwargs = dict(
        {"input_ids": input_ids},
        streamer=streamer,
        max_new_tokens=max_new_tokens,
        do_sample=True,
        top_p=top_p,
        top_k=top_k,
        temperature=temperature,
        num_beams=1,
        repetition_penalty=repetition_penalty,
    )
    t = Thread(target=model.generate, kwargs=generate_kwargs)
    t.start()

    outputs = []
    for text in streamer:
        outputs.append(text)
        yield "".join(outputs)


chat_interface = gr.ChatInterface(
    fn=generate,
    additional_inputs=[
        gr.Textbox(label="System prompt", lines=6),
        gr.Slider(
            label="Max new tokens",
            minimum=1,
            maximum=MAX_MAX_NEW_TOKENS,
            step=1,
            value=DEFAULT_MAX_NEW_TOKENS,
        ),
        gr.Slider(
            label="Temperature",
            minimum=0.1,
            maximum=4.0,
            step=0.1,
            value=0.6,
        ),
        gr.Slider(
            label="Top-p (nucleus sampling)",
            minimum=0.05,
            maximum=1.0,
            step=0.05,
            value=0.9,
        ),
        gr.Slider(
            label="Top-k",
            minimum=1,
            maximum=1000,
            step=1,
            value=50,
        ),
        gr.Slider(
            label="Repetition penalty",
            minimum=1.0,
            maximum=2.0,
            step=0.05,
            value=1.2,
        ),
    ],
    stop_btn=None,
    examples=[
        ["Hello there! How are you doing?"],
        ["Can you explain briefly to me what is the Python programming language?"],
        ["Explain the plot of Cinderella in a sentence."],
        ["How many hours does it take a man to eat a Helicopter?"],
        ["Write a 100-word article on 'Benefits of Open-Source in AI research'"],
    ],
)
"""

with gr.Blocks(css="style.css") as demo:
    gr.Markdown(DESCRIPTION)
    #chat_interface.render()
    combined_interface.render()
    gr.Markdown(LICENSE)

if __name__ == "__main__":
    demo.queue(max_size=20).launch()