import io
import os

import pyocr.builders
from PIL import Image as PIL_Image
from pdfminer.converter import TextConverter
from pdfminer.layout import LAParams
from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
from pdfminer.pdfpage import PDFPage
from wand.image import Image

tool = pyocr.get_available_tools()[0]


def spdf2text(filepath, pages=None):
    ''''scan pdf to text'''
    if not os.path.isfile(filepath):
        raise ValueError("can not find the file {}".format(filepath))

    final_text = []

    image_pdf = Image(filename=filepath, resolution=300)
    image_jpeg = image_pdf.convert('jpeg')

    for i, img in enumerate(image_jpeg.sequence):
        if pages is None or (pages is not None and i in pages):
            img_page = Image(image=img)
            img = img_page.make_blob('jpeg')

            txt = tool.image_to_string(
                PIL_Image.open(io.BytesIO(img)),
                lang="chi_sim",
                builder=pyocr.builders.TextBuilder(),
            )
            final_text.append(txt)
    final_text = "\n".join(final_text)
    return final_text


def pdf2text(filepath, pages=None):
    with open(filepath, "rb") as fp:
        rsrcmgr = PDFResourceManager()
        retstr = io.StringIO()
        codec = 'utf-8'
        laparams = LAParams()
        device = TextConverter(rsrcmgr, retstr, codec=codec, laparams=laparams)
        interpreter = PDFPageInterpreter(rsrcmgr, device)
        for i, page in enumerate(PDFPage.get_pages(fp)):
            if pages is None or (pages is not None and i in pages):
                interpreter.process_page(page)
                data = retstr.getvalue()
    return data


def get_pdf_page_num(filepath):
    cnt = 0
    with open(filepath, "rb") as fp:
        for _ in PDFPage.get_pages(fp):
            cnt += 1
    return cnt


def route_pdf(filepath):
    page0 = pdf2text(filepath, [0])
    if len(page0) >= 50:
        return pdf2text(filepath)
    else:
        spage0 = spdf2text(filepath, [0])
        if len(page0) >= len(spage0):
            return pdf2text(filepath)
        else:
            return spdf2text(filepath)


if __name__ == '__main__':
    # filepath = r"D:\yx\1.pdf"
    filepath = r"D:\yx\scan_pdf\2.pdf"
    # print(pdf2text(filepath, pages=[0, 1, 2]))
    # print(get_pdf_page_num(filepath))

    print(route_pdf(filepath))