from pathlib import Path

import httpx
import pymupdf  # type: ignore

# where to save / load data
DATA_DIR = Path.cwd() / "data"

# URLs of the raw PDFs to download
RAW_PDF_URLS = [
    "https://www.ebooksgratuits.com/ebooksfrance/moliere-oeuvres_completes_1.pdf",
    "https://www.ebooksgratuits.com/ebooksfrance/moliere-oeuvres_completes_2.pdf",
]


def download_pdf(url: str, output_path: str) -> None:
    """Download a PDF from the given URL and save it to the specified output path."""
    with httpx.stream("GET", url, follow_redirects=True) as response:
        response.raise_for_status()  # ensure we got a 200 OK
        with open(output_path, "wb") as f:
            for chunk in response.iter_bytes():
                f.write(chunk)


def detect_toc(doc: pymupdf.Document) -> tuple[int, int]:
    """Detect the table of contents in the first quarter of the document.

    Args:
        doc: A pymupdf Document object representing the PDF document.

    Returns:
        A tuple containing the start and end page indices of the TOC.
        If no TOC is found, returns (-1, -1).
    """
    start = -1
    end = -1
    i = 0

    for page in doc[: len(doc) // 4]:
        if page.get_links():
            start = i
            break
        i += 1

    if start == -1:
        print("No table of contents found in the first quarter of the document.")
        return -1, -1  # no TOC found

    for page in doc[start : len(doc) // 4]:
        if not page.get_links():
            end = i
            break
        i += 1

    if end == -1:
        end = len(doc) // 4

    print(f"Table of contents detected from page {start} to {end}.")
    return start, end


def main():
    # make sure data directory exists
    DATA_DIR.mkdir(parents=True, exist_ok=True)

    # download raw PDFs if they don't already exist
    paths = []
    for url in RAW_PDF_URLS:
        filename = url.split("/")[-1]
        output_path = DATA_DIR / filename
        paths.append(output_path)
        if not output_path.exists():
            print(f"Downloading {filename}...")
            download_pdf(url, output_path)
        else:
            print(f"{filename} already exists, skipping download.")

    # overwrite tinymoliere.txt if it exists
    if (DATA_DIR / "tinymoliere.txt").exists():
        (DATA_DIR / "tinymoliere.txt").unlink()

    # process each PDF and write into a .txt file
    for path in paths:
        with open(path, "rb") as f:
            doc = pymupdf.open(f)

            # detect toc in first quarter of the document
            _, toc_end = detect_toc(doc)

            # compute a clip to remove headers / footers on every pages
            rect = doc[0].bound()
            new_rect = pymupdf.Rect(
                rect.x0, rect.y0 + 60, rect.x1, rect.y1 - 60
            )

            # we ignore the last page
            for page in doc[toc_end:-1]:
                page_text = page.get_text(clip=new_rect)
                with open(DATA_DIR / "tinymoliere.txt", "a") as f:
                    f.write(page_text)


if __name__ == "__main__":
    main()