# -----------------------------------------------------------------------------
# Author: Jiawei Liu
# Date: 2024-12-5
# -----------------------------------------------------------------------------
'''
Download script for Germany TST
To run: 
`python Germany_TST/download_script/download.py`
'''

import requests
from bs4 import BeautifulSoup
from tqdm import tqdm
from pathlib import Path
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry


def build_session(
    max_retries: int = 3,
    backoff_factor: int = 2,
    session: requests.Session = None
) -> requests.Session:
    """
    Build a requests session with retries

    Args:
        max_retries (int, optional): Number of retries. Defaults to 3.
        backoff_factor (int, optional): Backoff factor. Defaults to 2.
        session (requests.Session, optional): Session object. Defaults to None.
    """
    session = session or requests.Session()
    adapter = HTTPAdapter(max_retries=Retry(total=max_retries, backoff_factor=backoff_factor))
    session.mount("http://", adapter)
    session.mount("https://", adapter)
    session.headers.update({
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3"
    })

    return session


def main():
    """
    Download Germany TST (https://www.mathe-wettbewerbe.de/aufgaben#t-internationale-mathematik-olympiade)
    """
    output_dir = Path(__file__).parent.parent / "raw"
    output_dir.mkdir(parents=True, exist_ok=True)

    # Build a requests session with retries
    req_session = build_session()

    # Get all year list
    resp = req_session.get('https://www.mathe-wettbewerbe.de/aufgaben#t-internationale-mathematik-olympiade')
    soup = BeautifulSoup(resp.text, 'html.parser')
    germ_tst_list_ele = soup.find_all('article')[1]

    for sec_ele in tqdm(germ_tst_list_ele.find_all('section')):
        year = sec_ele.find('button').get_text(strip=True)
        resources = sec_ele.find_all('a')

        with_problems = [_['href'] for _ in resources if "Auswahlklausuren" in _.get_text(strip=True)]
        with_solutions = [_['href'] for _ in resources if "Lösungen" in _.get_text(strip=True)]

        # Give priority to download those with solution.
        if len(with_solutions) != 0:
            download_pdfs = with_solutions
        else:
            download_pdfs = with_problems

        for uri in download_pdfs:
            output_file = output_dir / f"de-{year}-{Path(uri).name}"

            # Skip if already downloaded
            if output_file.exists():
                continue

            pdf_resp = req_session.get("https://www.mathe-wettbewerbe.de" + uri)

            if pdf_resp.status_code != 200:
                print(f"Year {year} Failed to download: {uri}")
                continue

            output_file.write_bytes(pdf_resp.content)


if __name__ == "__main__":
    main()