#!/usr/bin/env python3.7
# coding=utf-8

''' Combine multiple hOCR files. '''

from argparse import ArgumentParser
from lxml import html


parser = ArgumentParser(description='Combine multiple hOCR files.')
parser.add_argument(
    '-i', '--input-file',
    help='Input file',
    nargs='+',
    required=True
)
parser.add_argument(
    '-o', '--output-file',
    help='Output file',
    required=True
)
args = parser.parse_args()


for input_file in args.input_file:
    input_files = []
    if input_file.startswith('@'):
        with open(input_file[1:], 'r') as f:
            input_files += [x for x in f.read().split("\n") if x != '']
    else:
        input_files.append(input_file)
if len(input_files) == 0:
    exit(1)


hocr = html.parse(input_files[0])
hocr_body = hocr.find('body')
for input_file in input_files[1:]:
    for ocr_page in html.parse(input_file).findall('//div[@class="ocr_page"]'):
        hocr_body.append(ocr_page)


with open(args.output_file, 'wb') as f:
    hocr.write(f, encoding='UTF-8', method='html')