"""
This magical module will rewrite all public methods in the public interface
of the library so they can run the loop on their own if it's not already
running. This rewrite may not be desirable if the end user always uses the
methods they way they should be ran, but it's incredibly useful for quick
scripts and the runtime overhead is relatively low.

Some really common methods which are hardly used offer this ability by
default, such as ``.start()`` and ``.run_until_disconnected()`` (since
you may want to start, and then run until disconnected while using async
event handlers).
"""
import asyncio
import functools
import inspect

from async_generator import isasyncgenfunction

from .client.telegramclient import TelegramClient
from .tl.custom import Draft, Dialog, MessageButton, Forward, Message
from .tl.custom.chatgetter import ChatGetter
from .tl.custom.sendergetter import SenderGetter


def _syncify_coro(t, method_name):
    method = getattr(t, method_name)

    @functools.wraps(method)
    def syncified(*args, **kwargs):
        coro = method(*args, **kwargs)
        return (
            coro if asyncio.get_event_loop().is_running()
            else asyncio.get_event_loop().run_until_complete(coro)
        )

    setattr(t, method_name, syncified)


class _SyncGen:
    def __init__(self, loop, gen):
        self.loop = loop
        self.gen = gen

    def __iter__(self):
        return self

    def __next__(self):
        try:
            return self.loop.run_until_complete(self.gen.__anext__())
        except StopAsyncIteration:
            raise StopIteration from None


def _syncify_gen(t, method_name):
    method = getattr(t, method_name)

    @functools.wraps(method)
    def syncified(*args, **kwargs):
        coro = method(*args, **kwargs)
        return (
            coro if asyncio.get_event_loop().is_running()
            else _SyncGen(asyncio.get_event_loop(), coro)
        )

    setattr(t, method_name, syncified)


def syncify(*types):
    """
    Converts all the methods in the given types (class definitions)
    into synchronous, which return either the coroutine or the result
    based on whether ``asyncio's`` event loop is running.
    """
    for t in types:
        for method_name in dir(t):
            if not method_name.startswith('_') or method_name == '__call__':
                if inspect.iscoroutinefunction(getattr(t, method_name)):
                    _syncify_coro(t, method_name)
                elif isasyncgenfunction(getattr(t, method_name)):
                    _syncify_gen(t, method_name)


syncify(TelegramClient, Draft, Dialog, MessageButton,
        ChatGetter, SenderGetter, Forward, Message)