import time
import requests
from bs4 import BeautifulSoup
import re

# URL to scrape
url = "https://campusonline.uni-ulm.de/CoronaNG/user/userDetails.html?cvid=18456614"

# Cookie to include in the request
cookie = "JSESSIONID=5729EE2B769FE54D4663C1B7620E4B43"

# Headers for the GET request
headers = {
    "User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:124.0) Gecko/20100101 Firefox/124.0",
    "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8",
    "Accept-Language": "en-GB,en;q=0.5",
    "Accept-Encoding": "gzip, deflate, br",
    "Referer": "https://campusonline.uni-ulm.de/CoronaNG/user/userDetails.html?cvid=18456614",
    "Connection": "keep-alive",
    "Cookie": cookie,
    "Upgrade-Insecure-Requests": "1",
    "Sec-Fetch-Dest": "document",
    "Sec-Fetch-Mode": "navigate",
    "Sec-Fetch-Site": "same-origin",
    "Sec-Fetch-User": "?1",
    "Pragma": "no-cache",
    "Cache-Control": "no-cache"
}

def make_post_request(url, headers, payload, max_retries=3):
    retries = 0
    while retries < max_retries:
        try:
            response = requests.post(url, headers=headers, data=payload)
            response.raise_for_status()  # Raise an exception for 4xx or 5xx status codes
            return response
        except requests.exceptions.RequestException as e:
            print(f"Error occurred during POST request: {str(e)}")
            retries += 1
            if retries < max_retries:
                print(f"Retrying in 5 seconds... (Attempt {retries+1}/{max_retries})")
                time.sleep(5)
            else:
                print("Max retries reached. Exiting.")
                exit(1)

while True:
    try:
        print("Scraping...")
        # Send GET request to the URL with the specified headers
        response = requests.get(url, headers=headers)
        response.raise_for_status()  # Raise an exception for 4xx or 5xx status codes

        # Parse the HTML content using BeautifulSoup
        soup = BeautifulSoup(response.content, "html.parser")

        # Find the <tr> element with class "dbu"
        tr_elements = soup.find_all("tr", class_="dbu")

        for tr_element in tr_elements:
            th_element = tr_element.find("th")
            if th_element and "Max. Teilnehmer" in th_element.text:
                # Extract the max and current participant numbers
                td_element = tr_element.find("td")
                participant_info = td_element.text.strip()

                # regex to find the numbers in a string like "10 (aktuell 10)"
                regex = r"(\d+) \(aktuell (\d+)\)"
                match = re.search(regex, participant_info)
                if match:
                    max_participants = int(match.group(1))
                    current_participants = int(match.group(2))
                    print("Max participants:", max_participants, "; Current participants:", current_participants)
                else:
                    print("Failed to parse participant info:", participant_info)
                    continue

                # Check if there is a free spot
                if current_participants < max_participants:
                    # Send POST request to participate
                    post_url = "https://campusonline.uni-ulm.de/CoronaNG/user/userDetails.html"
                    payload = "id=18456649&command=participate"
                    post_headers = headers.copy()
                    post_headers["Content-Type"] = "application/x-www-form-urlencoded"
                    post_headers["Content-Length"] = str(len(payload))
                    post_headers["Origin"] = "https://campusonline.uni-ulm.de"

                    post_response = make_post_request(post_url, post_headers, payload)

                    if post_response.status_code == 200:
                        print("Successfully participated!")
                        exit(0)
                    else:
                        print("Failed to participate. Status code:", post_response.status_code)
                        exit(1)
                else:
                    print("No free spots available.")
                break
        else:
            print("Participant information not found.")

    except requests.exceptions.RequestException as e:
        print(f"Error occurred during GET request: {str(e)}")

    print(f'Current Time: {time.strftime("%H:%M:%S")}. Sleeping for 30 seconds...')
    time.sleep(30)