import gradio as gr
import requests
from datetime import datetime, timezone

API_URL = "https://huggingface.co/api/daily_papers"

class PaperManager:
    def __init__(self, papers_per_page=10):
        self.papers_per_page = papers_per_page

    def fetch_papers(self, page=1):
        try:
            response = requests.get(f"{API_URL}?page={page}&limit={self.papers_per_page}")
            response.raise_for_status()
            data = response.json()
            papers = sorted(data, key=lambda x: x.get('paper', {}).get('upvotes', 0), reverse=True)
            
            # Update total_pages based on the 'X-Total-Pages' header if available
            total_pages = int(response.headers.get('X-Total-Pages', 1))
            
            return papers, total_pages
        except requests.RequestException as e:
            print(f"Error fetching papers: {e}")
            return None, 1

    def format_paper(self, paper):
        title = paper.get('title', 'No title')
        url = f"https://huggingface.co/papers/{paper['paper'].get('id', '')}"
        authors = ', '.join([author.get('name', '') for author in paper['paper'].get('authors', [])])
        upvotes = paper.get('paper', {}).get('upvotes', 0)
        comments = paper.get('numComments', 0)
        published_time = datetime.fromisoformat(
            paper.get('publishedAt', datetime.now(timezone.utc).isoformat()).replace('Z', '+00:00')
        )
        time_ago = (datetime.now(timezone.utc) - published_time).days
        
        return f"""<div style='border-bottom: 1px solid #eee; padding: 10px 0;'>
        <a href='{url}' target='_blank' style='color: #000; text-decoration: none; font-weight: bold;'>{title}</a>
        <div style='font-size: 0.8em; color: #666; margin-top: 5px;'>
        {upvotes} upvotes | by {authors} | {time_ago} days ago | {comments} comments
        </div>
        </div>"""

    def render_papers(self, papers):
        if not papers:
            return "<div>No papers available for this page.</div>"
        
        return "".join([self.format_paper(paper) for paper in papers])

    def search_papers(self, papers, query):
        if not query:
            return self.render_papers(papers)
        
        filtered_papers = [paper for paper in papers if query.lower() in paper.get('title', '').lower()]
        return self.render_papers(filtered_papers)

css = """
html, body {
    height: 100%;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #f0f0f0;
}
.container {
    font-family: Arial, sans-serif;
    max-width: 800px;
    width: 100%;
    background-color: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
.paper-list { 
    max-height: 400px; 
    overflow-y: auto;
    border: 1px solid #eee;
    border-radius: 5px;
    padding: 10px;
    margin-bottom: 10px;
}
.search-row {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}
.title {
    text-align: center;
    color: #333;
}
.footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 10px;
}
"""

paper_manager = PaperManager()

def initialize():
    papers, total_pages = paper_manager.fetch_papers(page=1)
    html = paper_manager.render_papers(papers)
    return html, 1, total_pages, papers  # paper_list, current_page, total_pages, papers

def refresh_papers(current_page, query):
    papers, total_pages = paper_manager.fetch_papers(page=1)
    if query:
        html = paper_manager.search_papers(papers, query)
    else:
        html = paper_manager.render_papers(papers)
    return html, 1, total_pages, papers

def search_papers(query, papers):
    html = paper_manager.search_papers(papers, query)
    return html

def change_page(direction, current_page, total_pages, papers, query):
    if direction == "next" and current_page < total_pages:
        new_page = current_page + 1
    elif direction == "prev" and current_page > 1:
        new_page = current_page - 1
    else:
        new_page = current_page  # No change if limits are reached

    papers, total_pages = paper_manager.fetch_papers(page=new_page)
    if query:
        html = paper_manager.search_papers(papers, query)
    else:
        html = paper_manager.render_papers(papers)
    return html, new_page, total_pages, papers

demo = gr.Blocks(css=css)

with demo:
    with gr.Column(elem_classes=["container"]):
        gr.Markdown("# Daily Papers - HackerNews Style", elem_classes=["title"])
        with gr.Row(elem_classes=["search-row"]):
            search_input = gr.Textbox(label="Search papers", placeholder="Enter search term...")
            refresh_button = gr.Button("Refresh")
        paper_list = gr.HTML(elem_classes=["paper-list"])
        
        with gr.Row(elem_classes=["footer"]):
            prev_button = gr.Button("Previous Page")
            page_info = gr.Markdown("Page 1 of 1")
            next_button = gr.Button("Next Page")
        
        # Hidden states
        current_page_state = gr.State(1)
        total_pages_state = gr.State(1)
        papers_state = gr.State([])

        # Initialize the app
        demo.load(initialize, outputs=[paper_list, current_page_state, total_pages_state, papers_state])

        # Search functionality
        search_input.submit(search_papers, inputs=[search_input, papers_state], outputs=[paper_list])
        search_input.change(search_papers, inputs=[search_input, papers_state], outputs=[paper_list])

        # Refresh functionality
        refresh_button.click(refresh_papers, 
                             inputs=[current_page_state, search_input], 
                             outputs=[paper_list, current_page_state, total_pages_state, papers_state])

        # Previous Page
        prev_button.click(change_page, 
                          inputs=["prev", current_page_state, total_pages_state, papers_state, search_input], 
                          outputs=[paper_list, current_page_state, total_pages_state, papers_state])

        # Next Page
        next_button.click(change_page, 
                          inputs=["next", current_page_state, total_pages_state, papers_state, search_input], 
                          outputs=[paper_list, current_page_state, total_pages_state, papers_state])

demo.launch()