# -----------------------------------------------------------------------------
# Author: Jiawei Liu
# Date: 2024-12-10
# -----------------------------------------------------------------------------
'''
08-21 years: https://drive.google.com/file/d/0B2qYu535vGeQYUtUTzlOTldkR3c
Download Balkan MO problems with solution from 2008 to 2024.
'''

import os
import tempfile
import requests
from pathlib import Path
from tqdm import tqdm
from PyPDF2 import PdfReader, PdfWriter


def get_outline_ranges(pdf_reader: PdfReader):
    outlines = pdf_reader.outline

    # [[year, start_page, end_page], ...]
    outline_ranges = []
    for index, item in enumerate(outlines):
        year_range = [
            item.title,
            pdf_reader.get_page_number(item.page) + 1
        ]

        # get the end page
        if index + 1 < len(outlines):
            year_range.append(pdf_reader.get_page_number(outlines[index + 1].page))
        else:
            year_range.append(len(pdf_reader.pages))
        
        outline_ranges.append(year_range)

    return outline_ranges


def split_pdf(pdf_reader: PdfReader, outline_ranges: list, output_dir: Path):
    for title, start, end in tqdm(outline_ranges, desc="Splitting PDF"):
        pdf_writer = PdfWriter()
        for page_num in range(start - 1, end):
            pdf_writer.add_page(pdf_reader.pages[page_num])
        
        output_path = output_dir / f"en-{title.split("_")[-1]}-BMO.pdf"

        pdf_writer.write(output_path)


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

    # # Download the 08-21 years
    url = "https://drive.google.com/uc?id=0B2qYu535vGeQYUtUTzlOTldkR3c&export=download"
    response = requests.get(url)
    with tempfile.TemporaryFile() as f:
        f.write(response.content)
        print("08-21 years downloaded successfully.")

        reader = PdfReader(f)
        outline_ranges = get_outline_ranges(reader)
        split_pdf(reader, outline_ranges, output_dir)
    os.rename(output_dir / "en-2012-BMO.pdf", output_dir / "en-2012-BMO-solutions.pdf")

    # Download the 22-24 years
    urls = {
        "en-2012-BMO-problems": "https://artofproblemsolving.com/downloads/printable_post_collections/4084.pdf",
        "en-2022-BMO": "https://cdn.b3web.xyz/web/cms/optimizedBMO_2022_Problems_Solutions.pdf1652174033.pdf",
        "en-2023-BMO": "https://drive.google.com/uc?id=1lpcx_M-JLVLFMtZjFRngsAACtuSMPyfI&export=download",
        "en-2024-BMO": "https://bmo2024.org/wp-content/uploads/2024/05/BOM_englishSolutions.pdf"
    }

    for title, url in tqdm(urls.items(), desc="Downloading "):
        response = requests.get(url, headers={"User-Agent": "Mozilla/5.0"})
        output_path = output_dir / f"{title}.pdf"
        output_path.write_bytes(response.content)


if __name__ == "__main__":
    main()