# -----------------------------------------------------------------------------
# Author: Jiawei Liu
# Date: 2025-10-229
# -----------------------------------------------------------------------------
"""
Download script for NZMO
To run:
`python NewZealand_MO/download_script/download.py`
"""

import re
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
from urllib.parse import urljoin


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():
    base_url = "https://www.mathsolympiad.org.nz/resources"
    req_session = build_session()

    output_dir = Path(__file__).parent.parent / "raw"
    output_dir.mkdir(parents=True, exist_ok=True)

    resp = req_session.get(base_url)
    soup = BeautifulSoup(resp.text, "html.parser")

    nzmo_exams = soup.find_all(
        "a", href=lambda h: h and re.search(r"nzmo\d\_\d{4}\_solutions.pdf$", h)
    )
    nzmo_pdf_links = [urljoin(base_url, link["href"]) for link in nzmo_exams]

    for link in tqdm(nzmo_pdf_links):
        output_file = output_dir / f"en-{Path(link).name}"

        # Check if the file already exists
        if output_file.exists():
            continue

        pdf_resp = req_session.get(link)

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

        output_file.write_bytes(pdf_resp.content)


if __name__ == "__main__":
    main()