from re import match
from typing import List, Optional

from scrapthechan.parser import Parser
from scrapthechan.fileinfo import FileInfo

__all__ = ["LainchanParser"]


class LainchanParser(Parser):
	"""JSON parser for lainchan.org image board.
	JSON structure is identical to 4chan.org's, so this parser is just inherited
	from 4chan.org's parser and only needed things are redefined.
	"""

	__url_thread_json = "https://lainchan.org/{board}/res/{thread}.json"
	__url_file_link = "https://lainchan.org/{board}/src/{filename}"

	def __init__(self, board: str, thread: str,
				 skip_posts: Optional[int] = None) -> None:
		posts = self._get_json(self.__url_thread_json.format(board=board, \
			thread=thread))['posts']
		super(LainchanParser, self).__init__(board, thread, posts, skip_posts)

	@property
	def imageboard(self) -> str:
		return "lainchan.org"
	
	@property
	def op(self) -> Optional[str]:
		op = ""
		if 'sub' in self._op_post:
			op = f"{self._op_post['sub']}\n"
		if 'com' in self._op_post:
			op += self._op_post['com']
		return op if not op == "" else None

	def _parse_post(self, post) -> List[FileInfo]:
		if not 'tim' in post: return None

		dlfname = f"{post['tim']}{post['ext']}"

		if "filename" in post:
			if match(r"^image\.\w+$", post['filename']) is None:
				filename = dlfname
			else:
				filename = f"{post['filename']}{post['ext']}"

		files = []
		files.append(FileInfo(filename, post['fsize'],
			self.__url_file_link.format(board=self.board, filename=dlfname),
			post['md5'], 'md5'))

		if "extra_files" in post:
			for f in post["extra_files"]:
				dlfname = f"{f['tim']}{f['ext']}"
				if "filename" in post:
					if match(r"^image\.\w+$", post['filename']) is None:
						filename = dlfname
					else:
						filename = f"{post['filename']}{post['ext']}"
				dlurl = self.__url_file_link.format(board=self.board, \
					filename=dlfname)
				files.append(FileInfo(filename, f['fsize'], \
					dlurl, f['md5'], 'md5'))
		return files