from PyPDF2 import PdfReader, PdfWriter
from PIL import Image
from pdf2image import convert_from_bytes


def get_first_page_pdf(filename, max_size=2048):
    def pdf_scale_page(page, size=297):
        """Scale page to specified size mm"""
        (w, h) = page.mediabox[2:]
        #  Units of measurement are not "points". The units of measurement are user defined and default to 1/72 inch. See section 4.2.1 Coordinate spaces of the PDF specification.
        # If we have a page width of 297 mm and at points 1 inch = 25.4 mm
        pmm = (1/72*25.4)
        ks = size / (float(max((w, h))) * pmm)
        page.scale_by(ks)
        return page

    reader = PdfReader(filename)
    page = reader.pages[0]
    scaled_page = pdf_scale_page(page, max_size)

    # Create BytesIO
    pdf_bytes = io.BytesIO()
    dst_pdf = PdfWriter()
    dst_pdf.add_page(scaled_page)
    dst_pdf.write(pdf_bytes)
    pdf_bytes.seek(0)

    image = convert_from_bytes(pdf_bytes.read())
    if isinstance(image, list):
        return image[0]
    return image

img = get_first_page_pdf("test_samples/20220303025923NHNE_20220222_Starhub_Order_Confirmation_by_Email.pdf", max_size=300)
img.save("invoice.jpg", "JPEG")