from os import mkfifo, remove
from os.path import exists, join
from secrets import token_urlsafe
from collections import namedtuple
from abc import ABC, abstractmethod

from .pipe_reader_thread import PipeReaderThread
from .pipe_writer_thread import PipeWriterThread


class PipeHandler:
    def __init__(self, *pipe_paths):
        self._pipe_paths = pipe_paths

    def recreate(self):
        self.remove()
        for pipe_path in self._pipe_paths:
            mkfifo(pipe_path)

    def remove(self):
        for pipe_path in self._pipe_paths:
            if exists(pipe_path):
                remove(pipe_path)


class PipeIOServer(ABC):
    def __init__(self, in_pipe=None, out_pipe=None):
        self.in_pipe, self.out_pipe = in_pipe, out_pipe
        self._create_pipes()

        io_threads_dict = {
            'reader': PipeReaderThread(self.in_pipe, self._handle_message),
            'writer': PipeWriterThread(self.out_pipe)
        }
        IOThreadsTuple = namedtuple('IOThreadsTuple', sorted(io_threads_dict.keys()))
        self._io_threads = IOThreadsTuple(**io_threads_dict)

    def _create_pipes(self):
        if not self.in_pipe or not self.out_pipe:
            pipe_id = token_urlsafe(6)
            self.in_pipe = join('/tmp', f'in_pipe_{pipe_id}')
            self.out_pipe = join('/tmp', f'out_pipe_{pipe_id}')
        PipeHandler(self.in_pipe, self.out_pipe).recreate()

    @abstractmethod
    def _handle_message(self, message):
        raise NotImplementedError()

    def send(self, message):
        self._io_threads.writer.write(message)

    def run(self):
        for thread in self._io_threads:
            thread.start()

    def stop(self):
        for thread in self._io_threads:
            thread.stop()
        PipeHandler(self.in_pipe, self.out_pipe).remove()