#   pdf-segmented: Generate PDFs using separate compression for foreground and background
#   Copyright (C) 2025  Lee Yingtong Li
#
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU Affero General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU Affero General Public License for more details.
#
#   You should have received a copy of the GNU Affero General Public License
#   along with this program.  If not, see <https://www.gnu.org/licenses/>.

from ..compression import CompressedPage
from ..input import InputPages
from ..util import assert_has_djvm, assert_has_djvumake

import os
import subprocess
import tempfile
from typing import Generator

def djvu_write_pages(
	input_pages: InputPages,
	compressed_pages: Generator[CompressedPage],
	output_file: str,
	tempdir: str
) -> None:
	
	assert_has_djvm('DjVu output requires DjVuLibre')
	assert_has_djvumake('DjVu output requires DjVuLibre')
	
	djvu_page_files = []
	
	try:
		# Write each page
		for compressed_page in compressed_pages:
			try:
				# Combine foreground and background
				_, page_djvu_file = tempfile.mkstemp(suffix='.djvu', dir=tempdir)
				
				# TODO: Handle case where empty background or foreground
				args = ['djvumake', page_djvu_file, 'INFO={},{},{}'.format(input_pages.width, input_pages.height, round(input_pages.dpi))]
				args.append('Sjbz={}'.format(compressed_page.fg.filename))
				args.append('BG44={}'.format(compressed_page.bg.filename))
				subprocess.run(args, check=True, capture_output=True)
				
				djvu_page_files.append(page_djvu_file)
			finally:
				# Clean up
				compressed_page.bg.cleanup()
				compressed_page.fg.cleanup()
		
		# Combine pages
		subprocess.run(['djvm', '-c', output_file] + djvu_page_files, check=True)
	finally:
		# Clean up
		for page_djvu_file in djvu_page_files:
			os.unlink(page_djvu_file)