# -----------------------------------------------------------------------------
# Author: Jiawei Liu
# Date: 2024-11-22
# -----------------------------------------------------------------------------
'''
Download EGMO data

Notes:
2012 and 2014, the pdf with solutions was downloaded to the official homepage.

To run: 
`python EGMO/download_script/download.py`
'''

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


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.egmo.org/egmos/"

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

    req_session = build_session()

    resp = req_session.get(base_url)
    soup = BeautifulSoup(resp.text, "html.parser")
    egmo_list_ele = soup.find("table", class_="egmo-list")

    for year_a_ele in tqdm(egmo_list_ele.select("tr > td:nth-child(2) > a")):
        year = year_a_ele.get_text(strip=True)

        year_page_url = urljoin(base_url, year_a_ele["href"])
        html_resp = req_session.get(year_page_url)
        html_soup = BeautifulSoup(html_resp.text, "html.parser")

        solution_pdf = html_soup.find_all("a", href=lambda h: "solutions" in h.lower() and h.lower().endswith(".pdf"))
        problem_day1_pdf = html_soup.find("a", href=lambda h: "english" in h.lower() and "day1" in h.lower() and h.lower().endswith(".pdf"))
        problem_day2_pdf = html_soup.find("a", href=lambda h: "english" in h.lower() and "day2" in h.lower() and h.lower().endswith(".pdf"))

        # download solution pdf
        if solution_pdf:
            for sp in solution_pdf:
                sp_url = urljoin(year_page_url, sp["href"])

                output_file = output_dir / f"en-{year}-{sp_url.split("/")[-1]}"
                if output_file.exists():
                    continue

                sp_resp = req_session.get(sp_url)
                if sp_resp.status_code != 200:
                    print(f"Year {year}, Failed to download {sp_url}")
                    continue

                output_file.write_bytes(sp_resp.content)
        else:
            # if no solution pdf, download problem pdf
            # day1 pdf
            if problem_day1_pdf:
                p_d1_url = urljoin(year_page_url, problem_day1_pdf["href"])

                output_file = output_dir / f"en-{year}-{p_d1_url.split('/')[-1]}"
                if output_file.exists():
                    continue

                p_d1_resp = req_session.get(p_d1_url)
                if p_d1_resp.status_code != 200:
                    print(f"Year {year}, Failed to download {p_d1_url}")
                    continue

                output_file.write_bytes(p_d1_resp.content)

            # day2 pdf
            if problem_day2_pdf:
                p_d2_url = urljoin(year_page_url, problem_day2_pdf["href"])

                output_file = output_dir / f"en-{year}-{p_d2_url.split('/')[-1]}"
                if output_file.exists():
                    continue

                p_d2_resp = req_session.get(p_d2_url)
                if p_d2_resp.status_code != 200:
                    print(f"Year {year}, Failed to download {p_d2_url}")
                    continue

                output_file.write_bytes(p_d2_resp.content)


if __name__ == "__main__":
    main()