from fastapi import FastAPI, BackgroundTasks
from pydantic import BaseModel
import httpx
from bs4 import BeautifulSoup
import asyncio
from datetime import datetime, timedelta

app = FastAPI()

class Notice(BaseModel):
    name: str
    link: str

# URL of the notice list page
url = 'https://www.durguniversity.ac.in/index.php/Home/Noticelist'

# Cache to store notices and the last updated timestamp
cache = {
    "notices": [],
    "last_updated": None
}

CACHE_TTL = timedelta(minutes=5)  # Cache Time-to-Live (5 minutes)

async def fetch_notices():
    """Fetch notices from the website and update the cache."""
    async with httpx.AsyncClient() as client:
        response = await client.get(url)

    if response.status_code != 200:
        print(f"Failed to retrieve content. Status code: {response.status_code}")
        return

    # Parse the HTML content using a faster parser like 'lxml'
    soup = BeautifulSoup(response.text, 'lxml')
    rows = soup.select('td a')  # Directly target <a> tags inside <td>

    # Process notices
    notice_list = []
    seen_links = set()

    for link_tag in rows:
        notice_link = link_tag.get('href', '').strip()
        notice_name = link_tag.text.strip()

        if notice_link and notice_link not in seen_links:
            seen_links.add(notice_link)
            notice_name = notice_name or f"Notice {len(notice_list) + 1}"
            notice_list.append({'name': notice_name, 'link': notice_link})

    # Update the cache
    cache["notices"] = notice_list[:50]  # Store top 50 notices
    cache["last_updated"] = datetime.utcnow()
    print("Cache updated.")

@app.on_event("startup")
async def startup_event():
    """Schedule the cache refresh task on application startup."""
    asyncio.create_task(cache_refresh_task())

async def cache_refresh_task():
    """Background task to refresh cache periodically."""
    while True:
        await fetch_notices()
        await asyncio.sleep(CACHE_TTL.total_seconds())

@app.get("/notices", response_model=list[Notice])
async def get_notices():
    """Serve notices from the cache."""
    if cache["last_updated"] and datetime.utcnow() - cache["last_updated"] < CACHE_TTL:
        # Serve cached data if it's still valid
        return cache["notices"]

    # If cache is expired or unavailable, fetch notices live
    await fetch_notices()
    return cache["notices"]