import gradio as gr
from PyPDF2 import PdfReader
from bs4 import BeautifulSoup
import openai
import traceback
import requests
from io import BytesIO
from transformers import AutoTokenizer
import json
from datetime import datetime
import os
from openai import OpenAI
import re

# Cache for tokenizers to avoid reloading
tokenizer_cache = {}

# Global variables for providers
PROVIDERS = {
    "SambaNova": {
        "name": "SambaNova",
        "logo": "https://venturebeat.com/wp-content/uploads/2020/02/SambaNovaLogo_H_F.jpg",
        "endpoint": "https://api.sambanova.ai/v1/",
        "api_key_env_var": "SAMBANOVA_API_KEY",
        "models": [
            "Meta-Llama-3.1-70B-Instruct",
        ],
        "type": "tuples",
        "max_total_tokens": "50000",
    },
    "Hyperbolic": {
        "name": "hyperbolic",
        "logo": "https://www.nftgators.com/wp-content/uploads/2024/07/Hyperbolic.jpg",
        "endpoint": "https://api.hyperbolic.xyz/v1",
        "api_key_env_var": "HYPERBOLIC_API_KEY",
        "models": [
            "meta-llama/Llama-3.3-70B-Instruct",
            "meta-llama/Meta-Llama-3.1-405B-Instruct",
        ],
        "type": "tuples",
        "max_total_tokens": "50000",
    },
}


# Functions for paper fetching
def fetch_paper_info_neurips(paper_id):
    url = f"https://openreview.net/forum?id={paper_id}"
    response = requests.get(url)
    if response.status_code != 200:
        return None, None, None

    html_content = response.content
    soup = BeautifulSoup(html_content, 'html.parser')

    # Extract title
    title_tag = soup.find('h2', class_='citation_title')
    title = title_tag.get_text(strip=True) if title_tag else 'Title not found'

    # Extract authors
    authors = []
    author_div = soup.find('div', class_='forum-authors')
    if author_div:
        author_tags = author_div.find_all('a')
        authors = [tag.get_text(strip=True) for tag in author_tags]
    author_list = ', '.join(authors) if authors else 'Authors not found'

    # Extract abstract
    abstract_div = soup.find('strong', text='Abstract:')
    if abstract_div:
        abstract_paragraph = abstract_div.find_next_sibling('div')
        abstract = abstract_paragraph.get_text(strip=True) if abstract_paragraph else 'Abstract not found'
    else:
        abstract = 'Abstract not found'

    link = f"https://openreview.net/forum?id={paper_id}"
    return title, author_list, f"**Abstract:** {abstract}\n\n[View on OpenReview]({link})"


def fetch_paper_content_neurips(paper_id):
    try:
        url = f"https://openreview.net/pdf?id={paper_id}"
        response = requests.get(url)
        response.raise_for_status()
        pdf_content = BytesIO(response.content)
        reader = PdfReader(pdf_content)
        text = ""
        for page in reader.pages:
            text += page.extract_text()
        return text
    except:
        return None


def fetch_paper_content_arxiv(paper_id):
    try:
        url = f"https://arxiv.org/pdf/{paper_id}.pdf"
        response = requests.get(url)
        response.raise_for_status()
        pdf_content = BytesIO(response.content)
        reader = PdfReader(pdf_content)
        text = ""
        for page in reader.pages:
            text += page.extract_text()
        return text
    except Exception as e:
        print(f"Error fetching paper content: {e}")
        return None


def fetch_paper_info_paperpage(paper_id_value):
    def extract_paper_id(input_string):
        if re.fullmatch(r'\d+\.\d+', input_string.strip()):
            return input_string.strip()
        match = re.search(r'https://huggingface\.co/papers/(\d+\.\d+)', input_string)
        if match:
            return match.group(1)
        return input_string.strip()

    paper_id_value = extract_paper_id(paper_id_value)
    url = f"https://huggingface.co/api/papers/{paper_id_value}?field=comments"
    response = requests.get(url)
    if response.status_code != 200:
        return None, None, None
    paper_info = response.json()
    title = paper_info.get('title', 'No Title')
    authors_list = [author.get('name', 'Unknown') for author in paper_info.get('authors', [])]
    authors = ', '.join(authors_list)
    summary = paper_info.get('summary', 'No Summary')
    num_comments = len(paper_info.get('comments', []))
    num_upvotes = paper_info.get('upvotes', 0)
    link = f"https://huggingface.co/papers/{paper_id_value}"

    details = f"{summary}<br/>👍{num_comments} 💬{num_upvotes}<br/> <a href='{link}' " \
              f"target='_blank'>View on 🤗 hugging face</a>"
    return title, authors, details


def fetch_paper_content_paperpage(paper_id_value):
    def extract_paper_id(input_string):
        if re.fullmatch(r'\d+\.\d+', input_string.strip()):
            return input_string.strip()
        match = re.search(r'https://huggingface\.co/papers/(\d+\.\d+)', input_string)
        if match:
            return match.group(1)
        return input_string.strip()

    paper_id_value = extract_paper_id(paper_id_value)
    text = fetch_paper_content_arxiv(paper_id_value)
    return text


PAPER_SOURCES = {
    "neurips": {
        "fetch_info": fetch_paper_info_neurips,
        "fetch_pdf": fetch_paper_content_neurips
    },
    "paper_page": {
        "fetch_info": fetch_paper_info_paperpage,
        "fetch_pdf": fetch_paper_content_paperpage
    }
}


def create_chat_interface(provider_dropdown, model_dropdown, paper_content, hf_token_input, default_type,
                          provider_max_total_tokens):
    def get_fn(message, history, paper_content_value, hf_token_value, provider_name_value, model_name_value,
               max_total_tokens):
        provider_info = PROVIDERS[provider_name_value]
        endpoint = provider_info['endpoint']
        api_key_env_var = provider_info['api_key_env_var']
        max_total_tokens = int(max_total_tokens)

        tokenizer_key = f"{provider_name_value}_{model_name_value}"
        if tokenizer_key not in tokenizer_cache:
            tokenizer = AutoTokenizer.from_pretrained("meta-llama/Llama-3.2-1B-Instruct",
                                                      token=os.environ.get("HF_TOKEN"))
            tokenizer_cache[tokenizer_key] = tokenizer
        else:
            tokenizer = tokenizer_cache[tokenizer_key]

        if paper_content_value:
            context = f"The discussion is about the following paper:\n{paper_content_value}\n\n"
        else:
            context = ""

        context_tokens = tokenizer.encode(context)
        context_token_length = len(context_tokens)

        messages = []
        message_tokens_list = []
        total_tokens = context_token_length

        for user_msg, assistant_msg in history:
            user_tokens = tokenizer.encode(user_msg)
            messages.append({"role": "user", "content": user_msg})
            message_tokens_list.append(len(user_tokens))
            total_tokens += len(user_tokens)

            if assistant_msg:
                assistant_tokens = tokenizer.encode(assistant_msg)
                messages.append({"role": "assistant", "content": assistant_msg})
                message_tokens_list.append(len(assistant_tokens))
                total_tokens += len(assistant_tokens)

        message_tokens = tokenizer.encode(message)
        messages.append({"role": "user", "content": message})
        message_tokens_list.append(len(message_tokens))
        total_tokens += len(message_tokens)

        if total_tokens > max_total_tokens:
            available_tokens = max_total_tokens - (total_tokens - context_token_length)
            if available_tokens > 0:
                truncated_context_tokens = context_tokens[:available_tokens]
                context = tokenizer.decode(truncated_context_tokens)
                context_token_length = available_tokens
                total_tokens = total_tokens - len(context_tokens) + context_token_length
            else:
                context = ""
                total_tokens -= context_token_length
                context_token_length = 0

        while total_tokens > max_total_tokens and len(messages) > 1:
            removed_message = messages.pop(0)
            removed_tokens = message_tokens_list.pop(0)
            total_tokens -= removed_tokens

        final_messages = []
        if context:
            final_messages.append({"role": "system", "content": f"{context}"})
        final_messages.extend(messages)

        api_key = hf_token_value or os.environ.get(api_key_env_var)
        if not api_key:
            raise ValueError("API token is not provided.")

        client = OpenAI(
            base_url=endpoint,
            api_key=api_key,
        )

        try:
            completion = client.chat.completions.create(
                model=model_name_value,
                messages=final_messages,
                stream=True,
            )
            response_text = ""
            for chunk in completion:
                delta = chunk.choices[0].delta.content or ""
                response_text += delta
                yield response_text
        except json.JSONDecodeError as e:
            yield f"JSON decoding error: {e.msg}"
        except openai.OpenAIError as openai_err:
            yield f"OpenAI error: {openai_err}"
        except Exception as ex:
            yield f"Unexpected error: {ex}"

    chatbot = gr.Chatbot(label="Chatbot", scale=1, height=800, autoscroll=True)
    chat_interface = gr.ChatInterface(
        fn=get_fn,
        chatbot=chatbot,
        additional_inputs=[paper_content, hf_token_input, provider_dropdown, model_dropdown, provider_max_total_tokens],
        type="tuples",
    )
    return chat_interface, chatbot


def paper_chat_tab(paper_id, paper_from, paper_central_df):
    # A top-level button to "Chat with another paper" (visible only if paper_id is set)
    # We'll place it above everything
    chat_another_button = gr.Button("Chat with another paper", variant="primary", visible=False)

    # First row with two columns
    with gr.Row():
        # Left column: Paper selection and display
        with gr.Column(scale=1):
            todays_date = datetime.today().strftime('%Y-%m-%d')
            # Filter papers for today's date and having a paper_page
            selectable_papers = paper_central_df.df_prettified
            selectable_papers = selectable_papers[
                selectable_papers['paper_page'].notna() &
                (selectable_papers['paper_page'] != "") &
                (selectable_papers['date'] == todays_date)
                ]

            paper_choices = [(row['title'], row['paper_page']) for _, row in selectable_papers.iterrows()]
            paper_choices = sorted(paper_choices, key=lambda x: x[0])

            if not paper_choices:
                paper_choices = [("No available papers for today", "")]

            paper_select = gr.Dropdown(
                label="Select a paper to chat with: (from today's 🤗 hugging face paper page)",
                choices=[p[0] for p in paper_choices],
                value=paper_choices[0][0] if paper_choices else None
            )

            # Add a textbox for user to enter a paper_id (arxiv_id)
            paper_id_input = gr.Textbox(
                label="Or enter a 🤗 paper_id (arxiv_id) directly",
                placeholder="e.g. 1234.56789"
            )

            select_paper_button = gr.Button("Load this paper")

            # Paper info display
            content = gr.HTML(value="", elem_id="paper_info_card")

        # Right column: Provider and model selection
        with gr.Column(scale=1, visible=False) as provider_section:
            gr.Markdown("### LLM Provider and Model")
            provider_names = list(PROVIDERS.keys())
            default_provider = provider_names[0]

            default_type = gr.State(value=PROVIDERS[default_provider]["type"])
            default_max_total_tokens = gr.State(value=PROVIDERS[default_provider]["max_total_tokens"])

            provider_dropdown = gr.Dropdown(
                label="Select Provider",
                choices=provider_names,
                value=default_provider
            )

            hf_token_input = gr.Textbox(
                label=f"Enter your {default_provider} API token (optional)",
                type="password",
                placeholder=f"Enter your {default_provider} API token to avoid rate limits"
            )

            model_dropdown = gr.Dropdown(
                label="Select Model",
                choices=PROVIDERS[default_provider]['models'],
                value=PROVIDERS[default_provider]['models'][0]
            )

            logo_html = gr.HTML(
                value=f'<img src="{PROVIDERS[default_provider]["logo"]}" width="100px" />'
            )

            note_markdown = gr.Markdown(f"**Note:** This model is supported by {default_provider}.")

            paper_content = gr.State()

    # Now a new row, full width, for the chat
    with gr.Row(visible=False) as chat_row:
        with gr.Column():
            # Create chat interface below the two columns
            chat_interface, chatbot = create_chat_interface(provider_dropdown, model_dropdown, paper_content,
                                                            hf_token_input, default_type, default_max_total_tokens)

    def update_provider(selected_provider):
        provider_info = PROVIDERS[selected_provider]
        models = provider_info['models']
        logo_url = provider_info['logo']
        max_total_tokens = provider_info['max_total_tokens']

        model_dropdown_choices = gr.update(choices=models, value=models[0])
        logo_html_content = f'<img src="{logo_url}" width="100px" />'
        logo_html_update = gr.update(value=logo_html_content)
        note_markdown_update = gr.update(value=f"**Note:** This model is supported by {selected_provider}.")
        hf_token_input_update = gr.update(
            label=f"Enter your {selected_provider} API token (optional)",
            placeholder=f"Enter your {selected_provider} API token to avoid rate limits"
        )
        chatbot_reset = []
        return model_dropdown_choices, logo_html_update, note_markdown_update, hf_token_input_update, provider_info[
            'type'], max_total_tokens, chatbot_reset

    provider_dropdown.change(
        fn=update_provider,
        inputs=provider_dropdown,
        outputs=[model_dropdown, logo_html, note_markdown, hf_token_input, default_type, default_max_total_tokens,
                 chatbot],
        queue=False
    )

    def update_paper_info(paper_id_value, paper_from_value, selected_model, old_content):
        source_info = PAPER_SOURCES.get(paper_from_value, {})
        fetch_info_fn = source_info.get("fetch_info")
        fetch_pdf_fn = source_info.get("fetch_pdf")

        if not fetch_info_fn or not fetch_pdf_fn:
            return gr.update(value="<div>No information available.</div>"), None, []

        title, authors, details = fetch_info_fn(paper_id_value)
        if title is None and authors is None and details is None:
            return gr.update(value="<div>No information could be retrieved.</div>"), None, []

        text = fetch_pdf_fn(paper_id_value)
        if text is None:
            text = "Paper content could not be retrieved."

        card_html = f"""
        <div style="border:1px solid #ccc; border-radius:6px; background:#f9f9f9; padding:15px; margin-bottom:10px;">
            <center><h3 style="margin-top:0; text-decoration:underline;">You are talking with:</h3></center>
            <h3>{title}</h3>
            <p><strong>Authors:</strong> {authors}</p>
            <p>{details}</p>
        </div>
        """

        return gr.update(value=card_html), text, []

    def select_paper(paper_title, paper_id_val):
        # If user provided a paper_id_val (arxiv_id), use that
        if paper_id_val and paper_id_val.strip():
            # Check if it exists in df as a paper with paper_page not None
            df = paper_central_df.df_raw
            # We assume `arxiv_id` column exists in df (the user requested checking arxiv_id)
            # If not present, you must ensure `paper_central_df` has `arxiv_id` column.
            if 'arxiv_id' not in df.columns:
                return gr.update(value="<div>arxiv_id column not found in dataset</div>"), None

            found = df[
                (df['arxiv_id'] == paper_id_val.strip()) &
                df['paper_page'].notna() & (df['paper_page'] != "")
                ]

            if len(found) > 0:
                # We found a matching paper
                return paper_id_val.strip(), "paper_page"
            else:
                # Not found, show error in content
                # We can't directly show error from here. We'll return something that doesn't update states and rely on error message
                # Let's return empty paper_id and paper_from but we must also show error in content after this call
                return "", ""
        else:
            # fallback to dropdown selection
            for t, ppage in paper_choices:
                if t == paper_title:
                    return ppage, "paper_page"
            return "", ""

    select_paper_button.click(
        fn=select_paper,
        inputs=[paper_select, paper_id_input],
        outputs=[paper_id, paper_from]
    )

    # After the paper_id/paper_from are set, we update paper info
    paper_id_update = paper_id.change(
        fn=update_paper_info,
        inputs=[paper_id, paper_from, model_dropdown, content],
        outputs=[content, paper_content, chatbot]
    )

    def toggle_provider_visibility(paper_id_value):
        if paper_id_value and paper_id_value.strip():
            return gr.update(visible=True)
        else:
            return gr.update(visible=False)

    paper_id.change(
        fn=toggle_provider_visibility,
        inputs=[paper_id],
        outputs=[provider_section]
    )

    paper_id.change(
        fn=toggle_provider_visibility,
        inputs=[paper_id],
        outputs=[chat_row]
    )

    # Show/hide the "Chat with another paper" button
    # If paper_id is set, show it. If not, hide it.
    def toggle_chat_another_button(paper_id_value):
        if paper_id_value and paper_id_value.strip():
            return gr.update(visible=True)
        else:
            return gr.update(visible=False)

    paper_id.change(
        fn=toggle_chat_another_button,
        inputs=[paper_id],
        outputs=[chat_another_button]
    )

    # Button action to reset paper_id to None
    def reset_paper_id():
        # reset paper_id to ""
        return "", "neurips", gr.update(value="<div></div>")

    # When this button is clicked, we reset the paper_id and content
    chat_another_button.click(
        fn=reset_paper_id,
        outputs=[paper_id, paper_from, content]
    )

    # If user tried an invalid paper_id_input, no error was shown yet:
    # Actually we can show error message if no paper selected by updating after select_paper_button
    # The select_paper returns paper_id/paper_from. If empty means error:
    def check_paper_id_error(p_id, p_from):
        # If p_id is empty after clicking load, show error message
        if not p_id:
            return gr.update(value="<div style='color:red;'>No valid paper found for the given input.</div>")
        else:
            return gr.update()

    select_paper_button.click(
        fn=check_paper_id_error,
        inputs=[paper_id, paper_from],
        outputs=[content],
        queue=False
    )


def main():
    with gr.Blocks(css_paths="style.css") as demo:
        paper_id = gr.Textbox(label="Paper ID", value="")
        paper_from = gr.Radio(
            label="Paper Source",
            choices=["neurips", "paper_page"],
            value="neurips"
        )

        class MockPaperCentral:
            def __init__(self):
                import pandas as pd
                data = {
                    'date': [datetime.today().strftime('%Y-%m-%d')],
                    'paper_page': ['1234.56789'],
                    'arxiv_id': ['1234.56789'],  # adding arxiv_id column as user requested
                    'title': ['An Example Paper']
                }
                self.df_prettified = pd.DataFrame(data)

        paper_central_df = MockPaperCentral()

        paper_chat_tab(paper_id, paper_from, paper_central_df)

    demo.launch(ssr_mode=False)


if __name__ == "__main__":
    main()